PROCEEDINGS
OF THE
Iowa Academy of Science
wuu
i
FOR 1916
VOLUME XXIII
Thirtieth Annual Session, Held in Des Moines,
April 28 and 29, 1916
Published by
THB STATE OF IOWA
DBS MOINES
HARVARD UNIVERSITY.
LIBRARY
OF THE
MUSEUM OF COMPARATIVE ZOOLOGY.
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JAN 29 19!?
PROCEEDINGS
OF THE
Iowa Academy of Science
FOR 1916
VOLUME XXIII
Thirtieth Annual Session, Held in Des Moines,
April 28 and 29, 1916
Published by
THE STATE OF IOWA
DES MOINES
IOWA ACADEMY OF SCIENCE
Officers of the Academy
1915-16.
President — H. M. Kelly, Mount Vernon.
First Vice-President — G. W. Stewart, Iowa City.
Second Mice-President — Charles R. Keyes, Des Moines.
Secretary — James H. Lees, Des Moines.
Treasurer — A. O. Thomas, Iowa City.
executive committee.
Ex-officio — H. M. Kelly, G. W. Stewart, Charles R. Keyes, James H.
Lees, A. O. Thomas.
Elective — E. J. Cable, B. H. Bailey, L. B. Spinney.
1916-17.
President — Professor G. W. Stewart, State University.
First Vice-President — Professor L. S. Ross, Drake University.
Second Vice-President — Miss Alison E. Aitchison, State
Teachers College.
Secretary — James H. Lees, Iowa Geological Survey.
Treasurer— Professor A. O. Thomas, State University.
EXECUTIVE COMMITTEE.
Ex-officio — G. W. Stewart, L. S. Ross, Miss Aitchison, James H. Lees,
A. O. Thomas.
Elective — S. W. Beyer, Iowa State College; E. A. Jenner, Simpson
College; D. W. Morehouse, Drake University.
Members of the Iowa Academy of Science
LIFE fellows
Beyer, S. W Ames Pellett, Frank C Atlantic
Clarke, J. Fred Fairfield Ricker, Maurice Des Moines
Conard, Henry S Grinnell Ross> l. s Des Moines
Erwin, A. T Ames SeasH0re. C. E Iowa City
FiTZPATRicK, T. J Shimek, B Iowa City
Summers, H. E Ames
Sylvester, R. H Iowa City
, Sta. A, Lincoln, Nebr.
Greene, Wesley Des Moines
Houser, G. L Iowa City
Kay, George F Iowa City Thomas, A. 0 Iowa City
Kuntz, Albert, St. Louis Univ., Tilton, J. L Indianola
St. Louis, Mo. Williams, Miss Mabel C
Lees, Jas. H Des Moines Iowa CIty
Norton, W. H Mt. Vernon Wylie, R. B Iowa City
IOWA ACADEMY OF SCIENCE
Aitchison, Miss A. E.. Cedar Falls
Albert, Henry. . Iowa City
Almy, F. F Grinnell
Anderson, J. P Sitka, Alaska
Aret, M. F Cedar Falls
Balley, B. H Cedar Rapids
Baker, H. P Syracuse, N. Y.
Baker, J. A Indianola
Baker, R. P Iowa City
Bakke, A. L Ames
Bates. C. 0 Cedar Rapids
Begeman, Louis Cedar Falls
Bond, P. A Cedar Falls
Brown, F. C Iowa City
Buchanan, R. E Ames
Burnett, L. C Ames
Cable, E. J Cedar Falls
Chaney. Geo. A Ames
Condit, Ira S Cedar Falls
Cratty, R. I Armstrong
Dodge, H. L Iowa City
Dox, A. W Ames
Eward, J. M Ames
Farr, C. H... State College. Texas
Fay, Oliver J Des Moines
Finch, Grant E Dillon Mont.
Getchell, R. W Cedar Falls
Guthrie, Jos. E Ames
Hadden, David E Alta
Hance, James H Iowa City
Hayden, Ada Ames
Hendrixson. W. S Grinnell
Hersey, S. F Cedar Falls
Hixson, A. W Iowa City
Jenner, E. A Indianola
Kelly, H. M Mt. Vernon
Keyes, Chas. R Des Moines
King, Miss Charlotte M. ...Ames
Kinney, C. N Des Moines
Knight, Nicholas Mt. Vernon
Knupp, N. D. ..Santa Monica, Cal.
Kunerth, Wji Ames
Learn, C. D Stillwater, Okla.
Leighton, M. M Cedar Falls
Macbrlde, Thos. H Iowa City
McClintock. J. T Iowa City
Martin, Jno. N Ames
Melhus, I. E Ames
Miller, A. A Davenport
Morehouse, D. W Des Moines
Mueller, H. A St. Charles
Norris, H. W Grinnell
Nutting, C. C Iowa City
Orr, Ellison Waukon
Pammel. L. H Ames
Pearce, J. N Iowa City
Pearson, R. A Ames
Peck, Morton E Salem, Ore.
Pew, W. H Ames
Rockwood, E. W Iowa City
Sanders, W. E Des Moines
Sieg, L. P Iowa City
Smith, A. G Iowa City
Spinney, L. B Ames
Stange, C. H Ames
Stanley, Forrester C.Oskaloosa
Stanton, E. W Ames
Stephens, T. C Sioux City
Stevenson, W. H Ames
Stewart, G. W Iowa City
Stookey, S. W Cedar Rapids
Stromsten, F. A Iowa City
Trowbridge, A. C Iowa City
Van Hyning, T. . .Gainesville, Fla.
Van Tuyl, F. M Urbana, 111.
Walters, G. W Cedar Falls
Webster, R. L Ames
Wentworth, E. N
Manhattan, Kas.
Wickham, H. F Iowa City
Wilson, Guy West. .Carmel, Ind.
Woodward, S. M Iowa City
associates
Belanski, C. H Nora Springs
Bennett, Walter W Grinnell
Berninghausen, Fred Eldora
Berninghausen, F. W
New Hartford
Berry, George H.... Cedar Rapids
Bonney, A. F Buck Grove
Boot, David H Iowa City
Boyd, Mark F Iowa City
Brook, Rev. A. H Boone
IOWA ACADEMY OF SCIENCE
Brown, Percy E Ames
Brumfiel, D. M Iowa City
Butterfield, E. J. ..Dallas Center
Carter, Charles Fairfield
Case, Rev. Chatjncey
Ellsworth Station, Ohio
C.wanagh, Lucy M Iowa City
Coffin, Chas. L Oskaloosa
Conklin, R. E Des Moines
Corson, Geo. E Cedar Falls
Cotten, Ruth H Iowa City
Curran, Dr. E Cedar Rapids
Davis, James M. . . . Dallas Center
Davis, W. H Cedar Falls
Dersiiem, Elmer Iowa City
Dieterich, E. O
Minneapolis, Minn.
Diehl, Wm Ames
Dill. Homer R Iowa City
Dodd, L. E Iowa City
Dole, J. Wilbur Fairfield
Doolittle. J. W Iowa City
Doty, H. S Ames
Durrell, L. W Ames
Eastman, Eric E Ames
Eckerson, Ray Humeston
Edmundson, Sophia . . Des Moines
Ellis, S. F Des Moines
Ellyson, C. W Alta
Emery, Geo. V Ames
Ewing, H. E Ames
Fakkenbebg, Rev. H. G
Davenport
Fees, L. V Billings, Mont.
Foft, S. F Waukee
Fordyce, Emma J. ..Cedar Rapids
Fraser, Chas. M.. .Manaimo, B. C.
Frazier, Sabina S Oskaloosa
Frazier, Zoe R Oskaloosa
French, R. A Des Moines
Fulcher, J. E Des Moines
Gabrielson, I. N
Washington, D. C.
Gaessler, Wm. G Ames
Gates, Fanny C Grinnell
Giddings, L. A
Salt Lake City, Utah
Glomset, Daniel J. . . Des Moines
Goodell, F. E Iowa City
Gose, Bert Indianola
Goss, C. A Des Moines
Gould, Harry H Iowa City
Grissel, Earl Iowa City
Hagan, Wayne Clinton
Hastings, Jessie P Iowa City
Hayer, Walter E... Garden Grove
Hayward, W. J Sioux City
Helmick, Paul S Iowa City
Heuse, E. O Champaign, 111.
Higbee, F. G Iowa City
Higley, Ruth Grinnell
Hinman. J. J., Jr Iowa City
Hoersch, Victor A Iowa City
Horsfall, Jno. L Dubuque
Howell, Jesse V Tulsa, Okla.
Hughes, U. B Iowa City
Jacques, H. E Mt. Pleasant
Jeffs, Royal E Norman, Okla.
Jewell, Susan G Tabor
Job, Thesle T Iowa City
Johnson, F. W Chicago, 111.
Kenoyer, L. A.. . .Allahabad. India
King, Inez Naomi. Langdon, N. D.
Knock, Carl J Iowa City
Lamb. A. R Ames
Larson, G. A Des Moines
Lawrence, F. A
Morse Bluff, Neb.
Lazell, Fred J Cedar Rapids
Lloyd- Jones, Orren Ames
MacDonald, G. B Ames
McKenzie, R. Monroe Fairfield
McNally, P. T Iowa City
Merrill, D. E.. State College,
New Mexico
Moon, Helen Iowa City
Morbeck, Geo. C Ames
Muilenburg, G. A Rolla, Mo.
Mull, Lewis B Ottumwa
Nollen. Sarah M Des Moines
Oleson, 0. M Ft. Dodge
Oncley, L Fayette
Overholt, Sigel Millersburg
Overn, O. B Decorah
Paige. F. W Ft. Dodge
Palmer. E. L Cedar Falls
Plagge, H. J Ames
Pomeroy, J. C Ames
Quigley. T. H Fargo, N. D.
Read, O. B Cedar Falls
6 IOWA ACADEMY OF SCIENCE
Reed, C. F Lamoni Stewart, Katherine L.Davenport
Reilly, Jno. F Iowa City Stiles, Harold Ames
Ressler, I. L Ames Stoner, Dayton Iowa City
Reynolds, 0. E Iowa Falls Taylor, Beryl Cedar Rapids
Riggs, L. K Toledo Tenney, Glenn I Des Moines
Roberts, T St. Charles Thone, Frank E. A. .La Jolla, Cal.
Robinson, C. L Iowa City Tisdale, Wilbur E Iowa City
Rogers, W. E Iowa City Treganza, J. A Britt
Rusk, W. J Grinnell Truax, T. R Ames
Sabgent, Louise Grinnell Tuttle, Mrs. F. May Osage
Schatz, A. H Merrill Utz, Carl R Estherville
Schultz, Orville Postville Watson, E. E Fairfield
Shimek. Ella. . . .Hamilton, Mont. Webster, C. L Charles City
Shane, Adolph Des Moines Weigle, O. M Fulton, Mo.
Siiipton, W. D Iowa City Weld, L. D Cedar Rapids
Smith, Geo. L Shenandoah Werner, Herbert L Ames
Smith, Orrin H Mt. Vernon Whitney, Thos. H Atlantic
Somes, M. P St. Paul, Minn. Wifvat, Samuel Des Moines
Spencer, Clementina S Williams. A. J.... Norman, Okla.
Cedar Rapids Wolden, B. 0 Wallingford
Starin, L. M Ames Yothers, J. F Toledo
corresponding fellows.
Andrews, L. W 6643 Stewart Ave., Chicago, 111.
Arthur, J. C Furdue University, Lafayette, Ind.
Bain, H. F London, England
Ball, C. R Department of Agriculture, Washington, D. C.
Ball, E. D State Entomologist, Madison, Wis.
Barbour, E. H State University, Lincoln, Neb.
Bartsch, Paul Smithsonian Institution, Washington, D. C.
Bruner, H. L Irvington, Ind.
Carver, G. W : Tuskegee, Ala.
Cook, A. N University of South Dakota, Vermillion, S. Dak.
Drew, Gllman C Orono, Maine
Eckles, C. W University of Missouri, Columbia, Mo.
Fink, Bruce Oxford, Ohio
Franlin, W. S Lehigh University, South Bethlehem, Fa.
Frye, T. C State University, Seattle, Wash.
Gillette, C. P Agricultural College, Fort Collins, Colo.
Gossard, H. A Wooster, Ohio
Halsted, B. D New Brunswick, N. J.
Hansen, N. E Agricultural College, Brookings, S. D.
Haworth, Erasmus State University, Lawrence, Kan.
Hitchcock, A. S Department of Agriculture, Washington, D. C.
Hume, N. H Glen St. Mary, Fla.
Leonard, A. G Grand Forks, N. Dak.
Leverett, Frank 1724 University Ave., Ann Arbor, Mich.
Miller, B. L Lehigh University, South Bethlehem, Pa.
Newell, Wilmon State Plant Board, Gainesville, Fla.
Osborn, Herbert State University, Columbus, Ohio
Price, H. C Evergreen Farm, Newark, Ohio
Reed, Chas. C Weather Bureau, New York City
Savage, T. E Urbana, 111.
Sirrine, Emma Dysart, Iowa
Sirrine, F. A 79 Sound Ave., Riverhead, New York
Todd, J. E Lawrence Kan.
Trelease, William University of Illinois, Urbana, 111.
Udden, J. A University of Texas, Austin, Texas
IOWA ACADEMY OF SCIENCE
Titles of Papers Received
The number following a title indicates the page of the Proceedings
on which it may be found.
PAGE
Pure Sodium Chloride Nicholas Knight 25
Barium in Tobacco Nicholas Knight 26
Some Rock Analyses Nicholas Knight 29
An Improved Method of Determining Solubility
W. S. Hendrixson 31
Acid Potassium and Sodium Fhthalates as Standards in Acidi-
metry and Alkalimetry, II W. S. Hendrixson
The Behavior of Solutions at the Critical Temperature, a Pre-
liminary Report Perry A. Bond 35
Some Auxoamylases E. W. Rockwood 37
A Comparison of Barbituric Acid, Thiobarbituric Acid and
Malonylguanidine as Quantitative Precipitants for Fur-
fural A. W. Dox and G. P. Plaisance 41
An Accurate Aeration Method for Determining Alcohol in
Fermentation Mixtures A. W. Dox and A. R. Lame
Relative Influence of Bacteria and Enzymes on Silage Fer-
mentation, Preliminary Report A. R. Lamb
Estimation of Calcium in Ash of Forage Plants and Animal
Carcasses S. B. Kuzirian
Electromotive Forces and Electrode Potentials in Pure and
Mixed Solvents, II F. S. Mortimore and J. N. Pearce. 51
The Pleasant Ridge Group of Effigy Mounds Ellison Orr
An Old Roman Coin in South Dakota David H. Boot 73
Geological Conditions Regarding Oil and Gas in Southeastern
Iowa George F. Kay
The SuperKansan Gumbo of Southern Iowa George F. Kay
Progress Report on Studies of the Iowan Drift by the Iowa
Geological Survey and the United States Geological Survey
George F. Kay 75
Contributions to the Geology of Southwestern Iowa
George L. Smith 77
Records of Oscillations in Lake Level, and Records of Lake
Temperature and Meteorology Secured at the Macbride
Lakeside Laboratory, Lake Okoboji, Iowa, July, 1915
John L. Tilton 91
Controlling Fault Systems in Iowa Charles Keyes 103
Terranal Affinities of Original Chouteau Limestone
Charles Keyes 113
Coast Range Cirques of the Skeena Basin Charles Keyes 119
Progress Report ©f Geological Work in the Driftless Area
A. C. Trowbridge
The History of Devil's Lake, Wisconsin A. C. Trowbridge
8 IOWA ACADEMY OF SCIENCE
PAGE
An Outlier of the Clinton Formation in Dubuque County....
J. V. Howell 121
A Correlation of Peneplains in the Driftless Area
Urban B. Hughes 125
New Exposures Showing Superimposition of Kansan Drift on
Sub-Aftonian Drift in eastern Iowa M. M. Leighton 133
A Note on Fulgurites from Sparta. Wisconsin. .W. D. Shipton 141
A New Stratigraphic Horizon in the Cambrian System of
Wisconsin W. D. Shipton 142
The Loess of Crowley's Ridge, Arkansas B. Shimek 147
Bibliography of the Loess E. J. Cable . . . .159
The Lithogenesis of the Sediments F. M. Van Tuyl 163
The Western Interior Geosyncline and Its Bearing on the
Origin and Distribution of the Coal Measures
F. M. Van Tuyl 166
Pleistocene Exposures on Capitol. Hill James H. Lees ... .167
Some Xew Xiagaran Corals from Monticello, Iowa
A. 0. Thomas
A Highly Alate Specimen of Atrypa reticularis (Linne)
A. 0. Thomas 173
Certain Conclusions in Regard to Audition G. W. Stewart
The Effect of Temperature upon the Elasticity of Tungsten..
H. L. Dodge
On the Variation of the Reflecting Power of Isolated Crystals
of Selenium and of Tellurium with the Azimuth of the
Incident Folarized Light L. P. Sieg . . . .179
A Physical Representation of the Summation of Certain Types
of Series L. P. Sieg 1S7
The Tungsten X-Ray Spectrum Elmer Dershem .... 191
A Curve of Moisture Condensation on Glass Wool. .L. E. Dodd 195
The Stroboscopie Effect by Direct Reflection of Light from
Vibrating Membranes L. E. Dodd 199
A Xew Tonoscope L. E. Dodd 204
An Electrical Apparatus for Securing and Maintaining Con-
stant High Temperatures W. E. Tisdale 209
A Study of Some of the Torsional Elastic Properties of
Phosphor-Bronze Wires A. J. Oehler .... 213
A new Method of Identification of Polarized Light Reflected
from Small Opaque Crystals LeRoy D. Weld 235
Why Hot-Water Pipes in Household Plumbing Burst More
Frequently than Cold Water Pipes
F. C. Brown and Waldemar Xoll 237
A Bibliography of the Literature Bearing on the Light Sensi-
tiveness of Selenium F. C. Brown 241
A Sheep's Brain Without a Corpus Callosum; a Demonstra-
tion H. A. Scullen 265
Recent Theories of Heredity in Relation to the Theory of
Xatural Selection C. C. Xutting
IOWA ACADEMY OF SCIENCE
Trophospongium of Crayfish Nerve Cell L. S. Ross
"Axone Hillock" of Crayfish Nerve Cell L. S. Ross
A Malignant Tumor of a Chicken Liver, a Demonstration..
L. S. Ross
The White Admiral or Banded Purple Butterfly in Iowa. . . .
B. 0. Wolden 269
An Hermaphrodite Crayfish Ivan L. Ressler
Life History and Habits of the Gold Banded Paper Maker,
Polistes metricus Say Frank C. Fellett ... 275
Successful Mink Farming in Iowa B. H. Bail-
Notes on the Little Spotted Skunk B. H. Bail- ;
Notes on Two Strawberry Slugs R. L. Webster
A Method of Preparing Studies of Trichinetla spiralis Owen..
Dayton Stoner and Thesle T. Job 299
Distributional Notes on Some Iowa Pentatomoidea
Dayton Stoner
The Growth of Legumes and Legume Bacteria in Acid ana
Alkaline Media R. C. Salter 309
How a Tree Grows Fred Berninghausen 315
A Section of Upper Sonoran Flora in Northern Oregon
Morton E. Peck 317
A Key to the Seeds and Fruits of Some Common Weeds....
E. Laurence Falmer .... 335
Handy Device for Staining Slides E. Laurence Palmer 395
A Forest Census in Lyon County, Iowa David H. Boot 397
The Preservation of Fleshy Fungi for Laboratory Use
Guy West Wilson
Scleroderma vulgare and its allies Guy West Wilson 411
Notes on Some Pileate Hydnaceae from Iowa. .Guy West Wilson 415
Pioneer Plants on a New Levee, II Frank Thone ...
Notes on the Flora of Sitka, Alaska J. P. Anderson ..
Notes on a Cultivated Elodea R. B. Wylie
Insect Pollination of Timber Line Plants in Colorado
L. A. Kenoyer ....
Insect Pollination of Frasera stenoscpala L. A. Kenoyer...
The Sand Flora of Eastern Iowa B. Shimek
Some Observations on the Weeds of Calif ornia.L. H. Pammel..
Some Notes on California Forest Flora L. H. Pammel. .
A Record of Fungus Diseases ■
L. H. Pammel and Charlotte M. King
Notes on the Pollination of Some Plants Robert L. Post
Notes on Anatomy of the Leaves of Some of the Conifers
North America L. W. Durre".
Late Blight Epidemics in Iowa as Correlated with Climatic
Conditions A. T. Er-Ain . .
The Control of the Oat Smut by Formalin Treatment. J. A. Krall . . '
The White Waterlily of Iowa Henry S. Conard . .
10 IOWA ACADEMY OF SCIENCE
Proceedings of the Thirtieth Annual Session, Held
in Des Moines, April 28 and 29, 1916.
The Academy held its meetings in Memorial Hall, Drake Uni-
versity, corner University Avenue and 26th Street, Des Moines.
The first session convened at 1 :30 p. m., Friday, April 28th, with
President Kelly in the chair. Following the general program the
Academy divided into sections for the reading of papers.
Doctor Louis Kahlenberg, of the University of Wisconsin, gave
the annual address, at 8 :00 p. m., Friday, in the University Audi-
torium. His subject was "Some Results from the Experimental
Study of Osmosis."
The Iowa Section and the Ames Section of the American
Chemical Society held their sessions at 9 :00 a. m., Saturday.
Members of the Mathematical Association of America met at
4 :30 p. m., Friday, to organize an Iowa Section.
REPORT OF THE SECRETARY.
Fellows and Associates of the Iowa Academy of Science:
A study of the lists of the Academy membership during re-
cent years shows that while there has been no marked increase in
numbers the Academy has held its own, and that in spite of the
numerous removals which occur every year. The Treasurer and
the Secretary have carried on a follow-up campaign among those
who have been tardy in keeping up their membership. A num-
ber of members have sent in during the year names proposed for
membership. This is a welcome sign of activity and is a prac-
tice which should be followed still more energetically. It is not
enough to maintain our membership at the same level. "We
should endeavor to raise it each year by continual work among
those who are interested in scientific studies.
The recent volume of the Proceedings is the largest yet is-
sued, and certainly has not been excelled in the quality of its
contents. The action of the last Legislature in removing the
REPORT OF THE SECRETARY
page restriction has made this increase possible without casting
an added burden on the treasury of the Academy. The pages
are set one-half inch narrower than in previous volumes, a con-
dition which leaves wider margins and improves the appearance
of the book. I believe that this improvement more than offsets
the few additional pages made necessary. I believe that you will
agree with me that in physical qualities as well as in intellectual
content our Proceedings are among the best of similar publi-
cations.
May I not urge upon you, in the spirit of greatest friendliness,
the desirability, even the necessity of not only maintaining the
high quality of the papers which are presented before the Acad-
emy, but of constantly raising our standards. For our personal
satisfaction we must needs submit our work to the most rigid
tests of accuracy of fact and purity of statement. For the honor
of science and the reputation of our association we wish our work
to broaden knowledge and advance truth upon its main lines of
forward movement and as well upon those secondary lines of
detail which are needed to complete the warp and woof of intel-
lectual achievement. It should not be forgotten that all so-called
"applied science" is simply "pure science" fitted to human need
and made to minister to human betterment. There can be no
higher aim in research than that of helping humanity rise to
higher planes of physical well being, of mental attainment and
of moral power. To ask you to continue to share in this effort is
my privilege.
Two amendments to the Constitution have been submitted to
the voting fellows of the Academy by the Executive Committee.
These amendments suggest changes which the experience of the
Academy has shown to be desirable and the Committee asks for
your favorable consideration of these measures.
Very respectfully,
James H. Lees,
Secretary.
12 IOWA ACADEMY OP SCIENCE
REPORT OF THE TREASURER, 1915-1916.
RECEIPTS.
Cash on hand, May 1, 1915 ,....$ 7.65
Dues from members • • • • 181.00
Initiation fees, fellows 12.00
Initiation fees, associates 34.00
Transfer fees, associates to fellows 8.00
From sale of proceedings 3.24
Total $.245.89
DISBURSEMENTS.
Honorarium and expenses of speaker, 29th meeting. . . .$ 44.99
Supplies for the secretary 6.23
American Lithographing Co., 400 programs and 1,000
membership proposal blanks 14.30
Honorarium to secretary 25.00
To Miss Newman, wrapping and tying volume xxi 10.00
State binder, binding 200 copies Vol. xxi, and separates. 62.00
State binder, binding and separates Vol. xxii, on account 15.00
State printer, for excess pages Vol. xxi 50.00
Refund to bank on account of dishonored check 1.00
Supplies and postage for treasurer 11.75
Total $240.27
Balance on hand . 5.62
A. O. Thomas,
Treasurer.
The Secretary submitted the following names for election in
behalf of the membership committee :
The persons named were declared elected.
Transferred from Associate to Fellow — Forrester C. Stanley,
Oskaloosa.
Elected as Fellows — I. E. Melhus, Ames; James H. Hance,
Iowa City.
Elected as Associates — C. Herbert Belauski, Nora Springs;
George E. Corson, Ames; James M. Davis, Dallas Center; Elmer
Dershem, Iowa City, S. U. I. ; L. W. Durrell, Ames, I. S. C. ; Rev.
MEMBERS IN ATTENDANCE
Ray Eekerson, Humeston; Miss Sophia J. Edmondson, 921 31st,
Des Moines; Wm. G. Gaessler, Ames, I. S. C. ; Dr. Daniel G. Glora-
set, Des Moines; C. Bert Gose, Indianola ; C. A. Goss, Drake Uni-
versity, Des Moines; Earl G. Grissel, Iowa City (home Cedar
Rapids) ; John L. Horsfall, Iowa City, S. U. I.; U. B. Hughes,
Iowa City, S. U. I.; H. E. Jaques, Mt. Pleasant; A. R. Lamb,
Ames, I. S. C. ; Fred Metcalf, Dallas Center, High School (home
Webster City) ; J. C. Porneroy, Ames, Station A, I. S. C. ; I. L.
Ressler, Ames, I. S. C. ; Walter E. Rogers, Iowa City, S. U. I.;
Adolph Shane, 3300 4th St., Des Moines; Miss Clemantina
Spencer; Iowa City, S. U. I. ; L. M. Starin, Ames, I. S. C. ; Her-
bert R. Werner, Ames, I. S. C.
LIST OF MEMBERS AND VISITORS IN ATTENDANCE.
John L. Tilton, Indianola; C. L. Coffin, Oskaloosa; F. C. Stan-
ley, Oskaloosa; G. W. Stewart, Iowa City; Harry M. Kelly,
Mount Vernon ; L. S. Ross, Drake University, Des Moines ; C. N.
Kinney, Drake University, Des Moines; James H. Hance, State
University, Iowa City; Urban B. Hughes, State University. Iowa
City; Frank F. Almy, Grinnell College, Grinnell; Guy West
Wilson, S. LT. I., Iowa City; L. Begeman, Cedar Falls; M. F.
Arey, Cedar Falls; John F. Reilly, Iowa City; E. A. Jenner,
Indianola; C. Bert Gose, Indianola; Charles Carter, Fairfield;
Geo. F. Kay, Iowa City; P. A. Bond, Cedar Falls; Orin H.
Smith, Mt. Vernon; B. H. Bailey, Cedar Rapids; Arthur G.
Smith, Iowa City; Samuel J. A. Wifvat, Des Moines; E. J.
Cable, Cedar Falls; A. L. Bakke, Ames; James H. Lees, Des
Moines ; D. W. Morehouse, Drake University, Des Moines ; F. 0.
Norton, Drake University, Des Moines; Dayton Stoner, Iowa
City; H. A. Scullen, Ames; J. E. Guthrie, Ames; H. L. Dunlap,
Iowa City; J. N. Pearce, Iowa City; A. W. Hixson, Iowa City;
H. R. Wemer, Ames; R. L. Webster, Ames; L. H. Pammel,
Ames; L. B. Spinney, Ames; 0. B. Read, Cedar Falls; S. F.
Hersey, Cedar Falls; J. C. Pomeroy, Ames; J. A. Baker, In-
dianola; J. E. Fulcher, Des Moines College, Des Moines; L. Kah-
lenberg, Madison, Wis.; H. E. Jaques, Mt. Pleasant; Geo. E.
Thompson, Ames, Iowa ; George V. Emery, Ames ; H. G. Ander-
son, Ames; L. E. Dodd, Iowa City, S. U. I.; Elmer Dershem, S.
U. I., Iowa City; L. P. Sieg, S. U. I., Iowa City; W. B. C'oover,
Ames; S. W. Beyer, Ames; C. R. Keyes, Des Moines; C. C. Nut-
ting, Iowa City; F. C. Brown, Iowa City; II. L. Dodge, Iowa
14 IOWA ACADEMY OF SCIENCE
City ; J. M. Davis, Dallas Center ; F. G. Gates, Grinnell ; Nicholas
Knight, Mt. Vernon; R. C. Conklin, Des Moines; A. R. Lamb,
Ames; G. 0. Oberhelman, Grinnell; S. B. Kuzirian, Ames; ~W.
G. Gaessler, Ames; Mr. and Mrs. L. A. Kenoyer, Ames; Elma
Hanson, Des Moines; W. S. Hendrixson, Grinnell; W. J. Kars-
lake, Iowa City; G. W. Roark, Jr., Ames; E. W. Rockwood, Iowa
City; A. W. Dox, Ames; Sophia J. Edmondson, Des Moines.
At the business session on Saturday morning the following
amendments to the Constitution were considered and adopted
unanimously :
Section 3 was amended by making it read as follows : The
membership of the Academy shall consist of life fellows, fellows,
associates, corresponding fellows and honorary fellows. The fel-
lows and associates must be elected from residents of the state of
Iowa, the fellows being those that are actually engaged in scien-
tific work. A fellow moving to another state becomes thereby a
corresponding fellow. Honorary fellows shall be elected from
the productive scholars in science residing outside the state of
Iowa. All elections to membership shall be made at the annual
meeting. The assent of three-fourths of the fellows present is
required for the election of fellows and associates. An honorary
fellow must be nominated by ten fellows of the Academy. This
Domination, together with a record of the achievements in science
of the nominee, must be given the Secretary and by him sent
to each fellow previous to the annual meeting at which the elec-
tion occurs. A unanimous vote of the fellows present is neces-
sary for the election of an honorary fellow.
Section 4 and its adopted amendments were amended by mak-
ing Section 4 read as follows : An entrance fee of $3.00 shall be
required of each fellow and an entrance fee of $1.00 from each
associate, and an annual fee of $1.00, due at each annual meeting
after his election, shall be required of each fellow, associate and
corresponding fellow. A person may become a life fell&w on the
payment of $15.00 after his election as a fellow, the transfer to
be made by the Treasurer. The said life membership fee shall
be invested and only the interest of the same shall be used for
current expenses of the Academy. Fellows, associates and cor-
responding fellows in arrears for two years and failing to respond
to notification from the Treasurer shall be dropped from the
Academy roll.
Iowa Academy Science
Plate I
G. E. Patrick
G. E. PATRICK 17
IN MEMORIAM.
G. E. PATRICK.
L. H. PAMMEL.
Professor G. E. Patrick was born in Hopedale, Massachusetts,
October 22d, 1851, and died in Washington, D. C., on the 22d
of March, 1916. At the time of his death he was in charge of the
dairy laboratory of the Bureau of Chemistry of the U. S. De-
partment of Agriculture. He graduated from Cornell Univer-
sity, receiving the degree of B. S. in 1873 and M. S. in 1874. He
was instructor in Chemistry, Cornell University, 1873 ; assistant
professor and professor of Chemistry, University of Kansas,
1874-1883; Chemist, Iowa Agricultural Experiment Station,
1889-1895, and professor of Agricultural Chemistry, Iowa State
College, 1890-1895; since 1896 he was Assistant Chemist, U. S.
Department of Agriculture ; since 1901, chief of dairy laboratory
of the same bureau. He was also, I believe, a member of the
Delta Upsilon fraternity. He married Hattie E. Lewis of Law-
rence, Kansas, in 1879, and she died in 1909.
Professor Patrick resigned from the Ames position because of
some disagreement with the Board of Trustees. Soon afterwards
he accepted a position with the Bureau of Chemistry of the U.
S. Department of Agriculture in Washington, where he did
splendid work. The disagreement at Ames he thought at the
time was due to personal antagonism of Secretary James "Wilson.
However, when Professor James Wilson was made Secretary of
Agriculture he found Professor Patrick in the Bureau of Chem-
istry where he. was befriended in many ways by his supposed
enemy. Professor Patrick told me many times in later years of
his high regard for the Ex-Secretary and his family.
Professor Patrick published many chemical papers dealing
with Dairy Chemistry. He was certainly active as shown by the
number of papers either published by himself or associated with
others, as the following numbers of the bulletins of the Iowa Ag-
ricultural Experiment Station show : Bulletin Iowa Agricultural
Experiment Station 1 : 11-15 ; 3 : 82-91 ; 4 : 99-103 ; 5 : 143-160
9 r 355; 9: 356-369; 10: 448-480; 11: 481-489; 12: 519-529; 12
530-534; 13: 5-30; 14: 123-151; 14: 152-165; 15: 199-233; 15
2
18 IOWA ACADEMY OF SCIENCE
274-283 ; 16 : 354-355 ; 17 : 389-392 ; 17 : 393-418 ; 18 : 478-487 ; 20 :
690-705; 21: 788-791; 23: 925-939; 24: 969-984. He also con-
tributed a few articles to the Proceedings of the Iowa Academy
of Science : 11 : 73-75 ; 2 : 58-66. During the early days of the
Iowa Geological Survey he was the chemist. The coal analyses
were published in Iowa Geological Survey 3: 504-599. Other
analytic work done by him is reported in volumes 4 and 5.
Professor Patrick was original and forceful and most indus-
trious. Personally he was a most congenial companion. He was
loyal to his friends, but most outspoken to those who differed
from him. "When he had his mind made up on a certain subject
it was difficult to convince him of his errors. He would argue
the point for hours. In recent years his views on many subjects
were greatly modified. In my conversation with him in recent
years I found him to be most considerate for the opinion of
others. He has left a host of warm, personal friends.
HARRIETTE KELLOGG.
L. H. PAMMEL.
The subject of this sketch was born in Grinnell, Iowa, August
23, 1860, and died in Marshalltown, Iowa, from pneumonia fol-
lowing an operation, on January 6, 1916. She received her early
training in the Grinnell schools, and after completing a classical
course in Grinnell College in 1880, she pursued graduate work
in her alma mater and at the University of Chicago, receiving
from her alma mater the A. M. degree. After her graduation
from Grinnell College she taught in the public schools of various
cities in Iowa and in Glenco, Minnesota, where she taught Latin
and literature in Stevens Seminary. She came to Iowa State
College as curator of the herbarium and in charge of the botani-
cal library in 1903. I have known of few persons who discharged
their duties more faithfully than Miss Kellogg. So far as I can
learn she did not publish much before coming to Ames. Her
previous training was a preparation for the work later accom-
plished by her. I find that she contributed to the proceedings
of the Iowa Academy in the following volumes. 19: 113-128;
22: 60-75. She assisted in the preparation of the Lacey Mem-
orial volume published by the Iowa Park and Forestry Associa-
tion. She also prepared the bibliography in the writer's Manual
of Poisonous Plants and the "Weed Flora of Iowa and "Weeds of
Iowa Academy Science
Plate II
Harriette Kellogg
HARRIETTE KELLOGG
the Farm and Garden. At the time of her death she was engaged
on the history and bibliography of the Botanical Department of
Iowa State College. I should like to call attention, especially, to
the indices prepared by her of the Manual of Poisonous Plants,
the Weed Flora of Iowa and the Lacey Memorial Volume, which
show rare ability in the grasping of a subject. The preparation
of these involved an enormous amount of labor and fine con-
structive ability.
It was a pleasure to have been associated with Miss Kellogg
for thirteen years at Ames and in all of these years she was al-
ways of the same cheery disposition. She never shirked in her
duty. Her work was always well done. Miss Kellogg had a win-
ning personality and always had something good to say about
others. She left a host of sorrowing friends in the community
where she spent the closing years of her life.
Miss Kellogg will be missed not only in the meetings of the
Iowa Academy but most of all by those who were privileged to
be intimately acquainted with her in her daily work.
Papers Presented
at the Thirtieth Meeting of the
Academy
PURE SODIUM CHLORIDE 25
PURE SODIUM CHLORIDE.
NICHOLAS KNIGHT.
It is often convenient and necessary to have on hand a supply
of pure sodium chloride for the preparation of standard solutions.
It is quite easy to obtain the substance with a "C. P." label, but
it does not always follow that the article is as pure as the label
may indicate.
It seems to be a difficult matter to obtain common salt that is
entirely free from potassium chloride. We have prepared sodium
chloride by different methods. We have tested these and also the
various samples we had on hand in the laboratory stock room,
and have usually found a small quantity of potassium chloride
present.
1. We prepared a saturated solution of ordinary common
salt, into which we passed hydrogen chloride, made by heating
pure concentrated hydrochloric acid. We filtered off the salt
crystals using a pump and after drying we obtained 0.42 per
cent of potassium chloride.
2. We dissolved 100 grams of ordinary common salt in 300cc
water and filtered into an evaporating dish. This was heated to
boiling, and milk of lime added in small excess. The precipitate
was filtered off, and the excess of calcium and barium precipitated
with sodium carbonate. It was again filtered and the excess of
sodium carbonate was changed to sodium chloride with pure
dilute hydrochloric acid. After drying we found in the specimen
0.32 per cent of potassium chloride.
3. We made a solution of caustic soda by dissolving metallic
sodium in distilled water, and we neutralized this with pure hy-
drochloric acid. The analysis of the dried salt showed 0.27 per
cent of potassium chloride. The sodium must have contained a
small quantity of metallic potassium.
4. The foregoing experiment was repeated using the purest
caustic soda in the laboratory that had not been purified by
alcohol. The resulting sodium chloride showed 0.48 per cent po-
tassium chloride.
26 IOWA ACADEMY OP SCIENCE
We next examined three specimens of salt, each of which was
supposed to be chemically pure. The following results in potas-
sium chloride were obtained :
1. 0.57 per cent potassium chloride.
2. 0.45 per cent potassium chloride.
3. 0.49 per cent potassium chloride.
In each of the seven samples of salt examined, the presence of
the potassium could be distinctly seen with the flame test, using
a piece of blue glass.
The method we employed in separating the sodium and potas-
sium chlorides is the following : We dissolved about a half gram
of the salt in a little water and added perhaps twenty drops of a
ten per cent solution of platinic chloride. Then we added a few
drops of water and moved the mass back and forth till it flowed
freely. There is some difficulty of manipulation here, as too little
water would not dissolve all the Na, Pt Cl6, and too much would
dissolve some K2 Pt Cl6. We filtered and washed first, five or six
times with one volume of water and a half volume of alcohol, then
about six times with a mixture of alcohol and ether. After dry-
ing the precipitate, it was placed over a weighed platinum cruci-
ble and washed into the crucible with boiling water. It was
evaporated to dryness on the water and dried in a thermostat at
105 degrees.
Our thanks are due Clifford Lahman and Lester Rusk for as-
sistance in the analytical work.
BARIUM IN TOBACCO AND OTHER PLANTS.
NICHOLAS KNIGHT.
Scheele in 1788 first observed that barium is found in plants,
as he obtained it from beech trees. Forchammer in 1855, detected
its presence in the ashes of beech, oak and birch trees. In the
same year, Eckhard and Boedeker confirmed its existence in beech
and found it also in the sandstone near*Goettingen.
In 1874, Knap of Leipzig, while investigating the mud carried
down by the Nile river found that barium was present. The fol-
lowing year, Dwarzak confirmed the presence of barium in the
Nile mud, and found it in the leaves, ear and stalk of wheat
grown in the Nile valley.
BARIUM IN TOBACCO 27
A number of investigations have been made in the United
States by the Bureau of Plant Industry and the Bureau of Soils,
for the detection of barium. The work in this country has been
done to ascertain, if possible, if the poisonous properties of the
Loco weed which causes the Loco disease in cattle, is due to the
presence of barium in the plant.
J. S. McHargue, Journal of the American Chemical Society,
June, 1913, describes his work that shows the presence of barium
in tobacco and in various others plants.
Many are doubtless more or less familiar with the wide distri-
bution of barium in soils. The old igneous rocks have disinte-
grated into simpler compounds which finally have become avail-
able as food for the growing plant. It is still a question
whether barium should be considered a plant food at all, although
it is found more or less in the vegetable kingdom, but not in all
the species that have been investigated.
We have examined the leaves and stems of a number of speci-
mens of tobacco, grown in Sumatra, Cuba, and in various parts
of the United States. We desire to express our thanks to Mr. J.
M. Goldstein, of Oneida, New York, for kindly supplying most
of the specimens.
Our method was essentially that outlined by McHargue in the
paper referred to. We selected twenty-five grams of the leaves
which were just sufficiently moist to prevent crumbling. These
were cut into small bits and placed under a hood as the odors are
very disagreeable. The combustion is made with one Tirrell
burner in about two hours. Too great heat is not desirable as it
fuses the ash and renders it more difficult to handle. The ash
is weighed and while in the platinum dish, it is dampened with
distilled water, 15cc. of hydrochloric acid is added, and it is
heated twenty minutes on the water bath to complete the reaction.
There are two conditions in which the barium seems to exist in the
ash — a part soluble in hydrochloric acid, and an insoluble portion
which is barium sulphate. The precipitate containing the barium
sulphate with the ashes of the filter paper is placed in a platinum
crucible to which are added a few drops of dilute sulphuric acid
and lOcc. of hydrofluoric acid. It is digested slowly for several
hours over a free flame. This decomposes the silicates, and the
residue is evaporated to dryness. Next a sodium carbonate fusion
is made with about four grams to decompose the barium sulphate.
28
IOWA ACADEMY OF SCIENCE
The residue is changed to barium chloride with hydrochloric acid
and added to the first hydrochloric acid filtrate. These are heated
to boiling and the barium precipitated in the usual way with a
few drops of sulphuric acid. We treated the stems in the same
way.
As the ash is chiefly carbonates, we found difficulty in getting
a constant weight, as the C02 would be driven off by the heat.
The per cent of the ash represents the mean of two or more deter-
minations.
Kind of Tobacco
Per cent
of Ash
Per cent of
BaS04 in
the Plant
Havanna Tobacco from Cuba —
Leaf
Stem
20.85
25.68
21.98
21.62
20.11
19.38
21.48
24.28
20.81
24.73
21.62
24.49
.0608
.0760
Broad leaf grown in Pennsylvania —
Stem
.0648
.0780
*Havana seed grown in Connecticut
Leaf
Stem
.0600
.0720
Pennsylvania Tobacco grown in Pennsyl
vania —
Leaf
Stem
.0980
.1280
Sumatra Tobacco —
Leaf
Stem
.0308
0408
Wisconsin Tobacco grown in Wisconsin —
Stem
.0192
.280
Tobacco from farm of Leon Bequillard,
Mexico, N. Y. —
Leaf
Stem
.0132
.0504
*Grown under canvas tents.
Kind of leaf
Per cent of
BaS04
Dogwood leaf
.0224
Cottonwood leaf
Cherry leaf
.0052
.0392
Black locust
.0324
Mulberry leaf
.0696
Elm leaf
.0356
.0152
Wild olive
.0048
Plum
.0372
Box elder
.0360
Hard maple
.0368
Walnut
.0752
Pear
.0196
SOME ROCK ANALYSES 29
The leaves were taken from trees on the Cornell College
campus, or from the village of Mount Vernon. They were gath-
ered in the autumn and so were mature leaves. An analysis of a
sample of soil from the campus showed .1312 per cent of barium
sulphate.
We desire to express our hearty thanks to Harold L. Maxwell
and Lester W. Rusk for making the analyses of this paper.
SOME ROCK ANALYSES.
NICHOLAS KNIGHT.
I. A specimen from the Plains of Abraham.
The rock was picked up on the Plains of Abraham, above Que-
bec, but came from a quarry in the neighborhood. The analysis
was made by Mr. 0. E. LaRue, and shows the rock to be a sand-
stone with a considerable admixture of Calcium and Manganese
Carbonates. The result is as follows :
Per cent
Si02 54.54
Fe203 5.37
A1203 6.64
CaC03 , . . 15.12
MnC03 18.33
100.00
The specific gravity is 2.69.
II. A specimen from the Alps.
The rock was obtained from the Alps near Lucerne, Switzer-
land, and is used there as a building and road material. The
analysis by C. M. Peddycoart shows it is an impure limestone.
Per cent
Si02 11.81
Fe203 4.21
A1203 1.15
CaC03 70.23
MgC03 8.17
H20 4.26
99.83
30 IOWA ACADEMY OF SCIENCE
III. Limestone from the Madeira Islands.
The Madeira Islands lie northwest of Africa and about three
hundred and sixty miles from the coast. The group belongs to
Portugal. The soil is very fertile, and the tropical and sub-
tropical vegetation is very luxuriant. The specimen is a lime-
stone, as the analysis by Henry F. Carlton shows.
Per cent
Si02 1.17
FeA 0.61
CaCOs 94.11
MgCO, 4.21
100.10
This specimen represents the paving material used at Funchal,
the chief city of the Islands. Automobiles are now invading the
locality but the former rapid transit was the toboggan used in
the streets for descending the hills and mountains, and the primi-
tive ox cart. The paving from this rock wears to a smooth, hard
metallic-like surface which facilitates the traffic.
IV. Igneous rock from Madeira.
This is a brownish appearing rock which easily disintegrates
and crumbles to a fine powder. It seems to be the origin of the
fertile soil of the islands. The analysis was made by Miss Nela
Smart.
Per cent
SiO„ 43.96
Fe.O, 15.02
A1A 12.44
CaCO, 15.49 .
MgCO, 9.05
TiO, 2.02
Na,0 0.68
K20 0.15
H.O 1.05
99.86
This group of islands is of volcanic origin.
Department op Chemistry,
Cornell College.
METHOD OF DETERMINING SOLUBILITY
31
AN IMPROVED METHOD OF DETERMINING
SOLUBILITY.
W. S. HENDRIXSON.
In the continuation of work on acid sodium and acid potassium
phthalates as standards in acidimetry and alkalimetry1, it seemed
desirable to study among other properties, the solubility of these
salts.
It seems to be generally recognized that none of the methods
for determining solubility is wholly satisfactory. Among the
major difficulties are these: The somewhat complicated machin-
ery necessary to agitate the liquid in the thermostat, and the
solvent, and the difficulty of securing a specimen of the clear
solution for analysis, without change of temperature. fSince this
laboratory-, like most others, is supplied with a practically un-
FlG. 1.
limited amount of compressed air, the attempt has been made to
use it for the agitation of solvent and bath. To avoid the second
difficulty a special form of pipet has been used, which could be
wholly submerged during the time of agitation so as to be at the
^roc. Icnva Acad. Sci., Vol. XXII, p. 217.
32
IOWA ACADEMY OF SCIENCE
same temperature as the solution. The results have been so satis-
factory that a statement describing the method apart from the
main subject of investigation seems to be justified.
The arrangement of the whole apparatus is shown in figure 1.
About ten gallons of water are contained in a tank of sheet iron
covered with layers of asbestos, felt and canvas. The regulator is
the ordinary form of Ostwald, designed for heating with gas.
The vessel for the solution is a large test-tube and it contains
a pipet holding about 20cc. as shown in figure 2, A. A large
rubber stopper was cut through to one of the holes, the shank
was inserted into the hole and the cut was closed with rubber
cement. A second pipet for higher temperatures where the solu-
i
f— J5C«— •]
B
Fig. 2.
tion became more concentrated, is shown in figure 2, B. The
meter shown in figure 1 is a test gas meter reading to .001 cubic
foot.
At first the thought was to stir both the bath and the solvent
with the same stream of air, but this introduced undesirable
complications and two streams were used. Ordinary air from
the reservoir was passed into the bath at the bottom and near
the middle at the rate of about three cubic feet per hour, which
was found ample as shown by two standard thermometers whose
bulbs were placed in different parts of the bath for comparison.
METHOD OF DETERMINING SOLUBILITY
The air for the solution was first passed into a large bottle
having a layer of strong potash solution, then through four
bottles of the same sort of solution of concentration 1 to 2. It
then passed through the meter and through four gas washing
bottles with water which were wholly immersed in the bath.
The purpose of these last bottles was to saturate the air with
water vapor at the temperature of the bath. The use of air for
stirring in such cases is not new2, but so far as could be ascer-
tained there has been no attempt to compensate for the unavoid-
able loss of solvent by evaporation. The air then passed
through the pipet and into the solution. The bottles, tube for
the solution, the pipet and all connections, save only the tip of
the capillary exit tube from the solution vessel, were wholly
immersed.
Before undertaking actual determinations of solubility the
degree of compensation for evaporation was tested by many ex-
periments extending over periods from one to five hours, at tem-
peratures from 25° to 65°, the rate of the air current being
about 1.5 cubic foot per hour. This rate is sufficient for the
agitation of the solution. The tube containing the water and
pipet was weighed at the beginning and end of each experiment.
In some experiments there was a small loss, in others a slight
gain in weight, the difference never amounting to more than .035
gram per cubic foot of air. Since it was shown that the gain or
loss was closely proportional to the volume of air, and, there-
fore, to the time, it is evident that it could not exert any ap-
preciable influence on the results in such work. A few blank
tests have been made at 80°. At this temperature there was
an apparent loss of about 0.2 gram of solvent per cubic foot of
air. This loss is probably due to secondary causes that it may
not be possible to eliminate at such a high aqueous tension. Even
if confirmed by later experiment it seems hardly probable that
it could cause a degree of supersaturation that could materially
affect the results. However, there are other considerations that
make it seem probable that this method is best suited for mod-
erate temperatures, and that at or near the boiling point of the
solvent some one of the special methods for such temperatures
may more conveniently be used.
In carrying out an actual determination the substance under
investigation was dissolved in about 60cc. of water in sufficient
2Pawlewski, Berichte d Deutsch Chem. Gessel., p. 1040.
3
34 IOWA ACADEMY OF SCIENCE
amount to give an abundant crystallization on cooling to the
desired temperature of the experiment. The calibrated pipet
was so inserted as to leave its tip above the surface of the solu-
tion. The whole was then placed in the bath and when solution
and bath were near the same temperature the air was started
through the pipet which was then lowered into the solution. At
the end of a two-hour period the pipet was raised slightly, its
stop-cock was turned and the hose conducting the air was re-
moved. In a few moments the solution became perfectly clear,
and the pipet was filled with it to the stop-cock by suction. The
pipet was removed, washed, dried and weighed. The solution
was run into the titration flask, and the pipet was washed into
the same with warm water. The whole was then titrated. From
the weights and known volume of the pipet, the concentration
per gram and per cc. and also the density of the solution could
be readily calculated.
No filtering device for the pipet was necessary, nor any drip
cap, since the solution could not run out till the stop-cock was
opened. With other substances which settle slowly or not at all
it would be necessary to use a filtering device of gauze or other
material as in other methods. In such case it would probably
be better to pass the air into the solution through an extra tube
and not through the pipet.
After pipetting out at the end of the first experiment the test-
tube and remaining solution were left in the bath. After empty-
ing the pipet and drying it, it was reinserted and a second ex-
periment was carried out extending over an additional period
of two hours, or four hours in all. The duplicate experiments
give almost perfectly concordant results. These and other data
en the acid phthalates are reserved for another communication.
Chemical Laboratory,
Grinnell College.
BEHAVIOR OF SOLUTIONS 35
THE BEHAVIOR OF SOLUTIONS AT THE CRITICAL
TEMPERATURES— A PRELIMINARY REPORT.
PERRY A. BOND.
The writer has felt that at or about the critical temperature
of solutions, there might be found phenomena which would
throw light on the mechanism of the formation of solution. The
question of whether the solvent is chemically combined with the
solute, whether in all or only in special cases, is the final object
of the research.
Thus far the work, carried on in liquid sulphur dioxide, has
given only hints of what may be expected, but enough has been
accomplished to show that interesting results may appear.
In addition to the question of the solubility of a solid in the
gaseous phase which is now being studied, it is expected that the
electrical conductivity of the solutions as they approach the criti-
cal temperature will be investigated. The great problem in a
practical way lies in the fact that the pressures under which
all the experiments must be made lie close to 80 atmospheres,
and in glass tubes which are essential for the work as outlined,
the risk of explosion and consequent loss of calibrated instru-
ments is very great.
A more extensive report will be made in next year's Pro-
ceedings.
Department op Chemistry,
State Teachers College.
SOME AUXOAMYLASES 37
SOME AUXOAMYLASES.
(ABSTRACT.)
ELBERT W. ROCKWOOD.
The amylases, or starch splitting enzymes, are aided, or have
their activity increased, by certain nitrogenous compounds par-
ticularly those which contain the NH2 group. These amylolytic
stimulating substances I have called auxoamylases. All amino
compounds are not auxo substances, however. The experiments
described here have been made to ascertain what compounds do
activate the amylases and the conditions which affect their
action.
Method. — Boiled starch solution was digested at 38° with dilute
enzyme solutions under toluene, portions being removed at in-
tervals for testing. The degree of hydrolysis was determined
by heating the digested solution on a steam bath with an excess
of Fehling's solution, filtering off the cuprous oxide formed, dis-
solving this washed precipitate in nitric acid, boiling off the
nitrous acid, neutralizing the excess of acid, making acid with
acetic acid and precipitating the copper as CuCl with KI. The
iodine thus liberated was determined by titration with tenth-
normal Na,S203 solution. The quantity of reducing sugar
formed by digestion of the starch is, consequently, proportional
to the Na,S203 used. Since the hydrogen ion has a marked effect
on amylases, when the amino compounds had an acid reaction
they were carefully neutralized before the digestion.
The following classification of the nitrogen compounds was
found :
AUXOAMYLASES.
Glycine, NH2CH2C02H.
Tyrosine, HOC6H1CH2CH(NH2)CO,H.
Hippuric acid, QH.CONHCH.CO.H.
Anthranilie acid, NH2C6H4C02H.
Asparagin, NH2COCH2CH(NH2)C02H.
INACTIVE NH2 COMPOUNDS.
Sulphanilic acid, NH2C6H4S03H.
Acid amids like,
Urea, (NH,>)=CO.
Acetamid, CH3CONH2.
Propionamid, CHaCH2CONH2.
38 IOWA ACADEMY OF SCIENCE
Table 1 gives some of the details of sucli a digestion showing
that asparagin acts as an auxoamylase but acetamid does not.
TABLE NO. 1.
ACETAMID AND ASPARAGIN.
Each contained 5 cc. toluene and 180 cc. 1 per cent starch.
A. 10 cc. water and 10 cc. of 3 per cent saliva.
B. 0.5 grin, acetamid in 10 cc. water and 10 cc. saliva.
C. 0.5 grm. asparagin, (neutralized) in 10 cc. of water and 10 cc. of
3 per cent saliva.
Degree of digestion shown by cc. of Na.SAi used:
Digested one hour. Digested two hours.
A= 4.45 cc. Na2S2Oa A= 8.6 cc. Na2SA
B= 4.18 cc. " B= 8.9 cc.
C= 5.90 cc. " C=10.1 cc.
Digested four hours. Digested six hours
A=15.1 cc. Na^SA A=17.9 cc. Na.SA
B=14.85 cc. " B=17.0 cc.
C=18.35 cc. " C=19.1 cc.
Digested 24 hours.
A=25.0 cc. Na2SA
B=24.5 cc.
C=27.8 cc.
In the succeeding tables the details are omitted but the figures,
as before, represent the amounts of sugar formed from the
starch.
TABLE NO. 2.
ACTION OP GLYCINE.
200 cc. of starch-saliva solution used.
Glycine used 0.5 hour 1.5 hours 4.0 hours 5.5 hours
None 3.95 9.70 16.1 18.75
0.1 grm 6.00 11.25 17.2 20.40
0.3 grm 9.00 12.80 18.7 21.20
0.5 grm 8.20 16.50 22.2 23.25
TABLE No. 3.
TYROSINE.
Tyrosine used 40 min. 1.75 hrs. 4 hrs. 6.25 hrs. 24 hrs.
None 1.25 5.35 9.65 11.15 18.55
0.05 grm 2.85 6.20 11.30 13.72 22.25
0.1 grm 3.35 6.55 12.10 13.65 24.00
The volume of the digestion solution was 200 cc.
The amylase was ptyalin.
SOME AUXOAMYLASES
TABLE NO. 4.
HIPPURIC ACID (neutralized).
Digested hours No hippuric acid 1.2 grm. hippuric acid
in 200 cc. solution
1 4.5 9.3
2 9.2 14.8
4 14.05 18.35
24 18.8 20.2
TABLE NO. 5.
ANTHRANILIC ACID (neutralized).
200 cc. of starch-saliva solution used.
Anthranilic acid used 1 hour 3 hours 5 hours 25 hours
None 5.5 12.2 15.1 23.9
0.1 grm 7.1 14.3 17.1 25.8
0.3 grm '. 8.3 15.6 18.5 25.9
0.5 grm 8.8 16.4 18.7 25.1
TABLE NO. 6.
ACTION OP GLYCINE ON PANCREATIC AMYLASE.
1 cc. of pancreas solution.
Glycine 30 min. 1 hr. 40 min. 2 hr. 20 min.
None 14.6 23.9 24.8
0.5 grm 21.1 27.4 30.9
5 cc. of pancreas solution.
None 28.7 29.1
0.5 grm 32.2 35.9
TABLE NO. 7.
ACTION OF UREA ON PTYALIN.
200 cc. starch-saliva solution.
Digested hours No urea 0.5 grm. urea
2 1.8 2.1
4 3.5. 3.6
6 4.0 4.0
24 9.1 9.1
TABLE NO. 8.
SULPHANILIC ACID (neutralized).
Digested No sulphanilic 1.3 grm.Na Sulphanilate
hours acid in 200 cc. of solution
0.5 7.4 7.5
1.5 14.3 14.6
4.0 18.9 19.8
6.0 20.8 21.0
The work is being continued. Its importance is seen from
the fact that amino acids are produced by digestive proteolysis
and that they must act in the intestine as hormones to the amy-
lolytic enzymes.
PRECIPITANTS FOR FURFURAL 41
A COMPARISON OF BARBITURIC ACID, THIOBARBI-
TURIC ACID AND MALONYLGUANIDINE AS QUANTI-
TATIVE PRECIPITANTS FOR FURFURAL.
ARTHUR W. DOX AND G. P. PLAISANCE.
All of the methods for the quantitative determination of
pentoses and pentosans in agricultural products are based upon
the conversion of pentose into furfural by distillation with a
mineral acid, preferably hydrochloric, and subsequent estima-
tion of furfural in the distillate by means of a suitable reagent.
Giinther, Chalmot and Tollens1 titrated the furfural with phen-
ylhydrazine, using aniline acetate paper as an indicator.
Stone2 made use of the same reaction, but used Fehling's solu-
tion to determine the excess of phenylhydrazine. Later, Flint
and Tollens3 showed that this titration method was not accurate,
on account of the levulinic acid resulting from the decomposition
of hexoses, as well as the instability of the standard phenylhy-
drazine acetate reagent used. Jolles4 titrated the furfural with
potassium bisulphite and iodine. In the absence of other re-
ducing substances, the furfural could be determined directly
with Fehling's solution. Giinther and Tollens5 precipitated the
furfural as hydrofurfuralimide by means of ammonia, while
Chalmot and Tollens6 used phenylhydrazine and weighed the
resulting hydrazone. In both cases the condensation product
was somewhat soluble.
Councilor7 was the first to use phloroglucinol for the quanti-
tative determination of furfural. This method was later studied
and perfected by Tollens and his co-workers. The phloroglu-
cinol method, although known to be faulty in several respects,
is the one in general use today, having been adopted as provi-
sional by the Association of Official Agricultural Chemists.8 It
is strictly empirical, since the nature of the reaction and the
constitution of the condensation product have not been deter-
mined. Krober9 compiled a table in which the weight of fur-
furalphloroglucide obtained is interpreted in terms of furfural,
xylose, arabinose or pentose. This table is purely empirical,
being based on trial distillations and precipitations of the fur-
fural or the particular pentose employed, and not upon the
42 IOWA ACADEMY OF SCIENCE
molecular weight of the condensation product. Furthermore,
this method calls for solubility corrections. Krober assumes that
two molecules of water are split out in the reaction between
furfural and phloroglucinal. Goodwin and Tollens10 claim that
only one molecule of water is liberated at ordinary temperature,
but if the reaction is carried out at a temperature of 80° three
molecules are liberated. A slight variation in the conditions
may, therefore, affect the result considerably. Krober noted the
fact also that when the phloroglucide is allowed to stand in the
air for a time, it takes up moisture which cannot be expelled by
subsequent drying. From this brief survey of the literature,
it is obvious that the phloroglucinol method in common use is
not altogether satisfactory.
Other reagents also have been tried with varying success.
Kerp and Unger11 used semioxamizine as a precipitant for fur-
fural, but obtained results that were too low. Conrad and Rein-
bach12 found that furfural and barbituric acid condensed in the
presence of dilute hydrochloric acid. Subsequently, Unger and
Jager13 applied this reaction to the quantitative determination
of furfural. They found that six to eight times as much barbi-
turic acid as the theory required was needed to give the cal-
culated value for furfural. The condensation product had the
advantage of being only very slightly soluble in hydrochloric
acid (1.22 mgm. per 100 cc). They claim that barbituric acid
does not precipitate the furfural derivatives of hexose origin and
that these merely tend to color the solution yellow. The reaction
is a very simple one, consisting in the condensation of one mole-
cule of furfural and one molecule of barbituric acid, through the
aldehyde group of the former and the methylene group of the
latter, with the splitting out of one molecule of water. The pro-
duct was found to contain 13.75 per cent nitrogen, which is
in close agreement with the calculated value of 13.63 per cent.
When prepared from the furfural distillate from natural sources,
the product was found to contain 13.96 per cent nitrogen.
Fromherz1* used barbituric acid as a precipitant for methyl-
furfural, and found the condensation product to be not appre-
ciably soluble. Fallada, Stein and Ravinka15 found that barbi-
turic acid and phloroglucinol gave very nearly the same results
when pure xylose and arabinose were distilled and precipitated.
On the other hand, when sucrose was added to the pentose, the
PREC1PITANTS FOR FURFURAL 43
results were very much higher when phloroglucinol was used as
a precipitant than when barbituric acid was employed, the latter
giving normal values. This substantiates the statements of other
workers who found that hydroxymethylfurfural was not precip-
itated by barbituric acid.
The barbituric acid method possesses, therefore, certain ad-
vantages over the phloroglucinol method, in that the reaction is
more specific and a definite condensation product is formed. The
precipitate, however, is sufficiently soluble to render a solubility
correction necessary. Then again, a large excess of the reagent
appears to be necessary, indicating that possibly an occlusion of
the precipitant leads to a compensation of errors.
The possibility of obtaining better results by using some de-
rivative of barbituric acid will be discussed in the experimental
part of this paper.
EXPERIMENTAL.
Barbituric acid ordinarily is prepared by the condensation of
area with the sodium salt of malonic ester. The corresponding
thio derivative was prepared by Michael10 17 and by Gabriel
and Colmann18 by condensing thiourea with sodium malonic
ester, and the imino derivative was prepared by Michael17 and
by Traube19 from guanidine and malonic ester. These two de-
rivatives are analogus in many respects to barbituric acid. It
remained to be determined whether they would react in a simi-
lar manner with furfural, and possibly give a more complete
precipitation.
The barbituric acid used in this work was a Kahlbaum prepara-
tion, which we purified further by recrystallization from water.
Analysis showed it to contain 21.80 per cent nitrogen; theory
21.87 per cent.
Our first preparation of thiobarbituric acid was made accord-
ing to the method of Gabriel and Colmann. Two and three-
tenths gms. of sodium was dissolved in 50 cc. absolute alcohol,
and 16 gms. malonic ester added, then 7.6 gms. dry thiourea,
previously dissolved in absolute alcohol. The mixture was
heated on a water bath under a reflux condenser for ten hours.
The white pasty mass which resulted was then treated with
80 cc. water and 7.6 cc. hydrochloric acid and gently warmed
until it had dissolved. Upon standing, thiobarbituric acid crystal-
44 IOWA ACADEMY OF SCIENCE
lized out. The yield was about 30 per cent of the theory. In
preparing a further quantity of thiobarbituric acid we found
that a much better yield was obtained when less solvent was
used and the mixture heated for 15 hours in a sealed tube at
105°, with twice the theoretical amount of sodium, as recom-
mended by Fischer and Dilthey20 in their preparation of methyl-
ethyl and dimethylthiobarbituric acid. The product, after
acidifying with hydrochloric acid, was a slightly yellowish crys-
talline powder containing 19.61 per cent nitrogen, whereas the
theory calls for 19.45 per cent. The yield in this case was 45
per cent of the theory.
Malonylguanidine was made according to Traube from free
guanidine and malonic ester. The condensation took place read-
ily and gave an excellent yield. The product was used directly
without further purification. It contained 32.07 per cent nitro-
gen; theory, 33.06 per cent.
Parallel determinations were now conducted, using barbituric
acid, thiobarbituric acid and malonylguanidine as precipitants
for furfural. For this work a stock solution of pure, freshly
distilled furfural of exactly 1 per cent strength was prepared,
and a 5 cc. aliquot taken for each determination. The furfural
was diluted with 12 per cent hydrochloric acid and solutions
of the different precipitants in 12 per cent hydrochloric acid
added, the total volume of the reaction mixture being 400 cc.
The conditions were, therefore, similar to those obtaining in
pentosan determinations. Unless otherwise indicated, a slight
excess of the precipitant was employed, the reaction carried
out at room temperature, and the precipitate allowed to stand
over night before filtering on Gooch crucibles and drying to
constant weight at 100°. The analytical results are set forth
in the following tables :
PREC1PITANTS FOR FURFURAL
45
TABLE I.
BARBITURIC ACID.
Furfural
Wt;. of
Furfural
Error
Mgms.
Furfural
Taken
Precipitate
Calculated
Recovered
Gms.
Gms.
Gms.
Per Cent
.0583
.1180
.0550
— 3.3
94.3
.0583
.1180
.0550
— 3.3
94.3
.0583
.1171
.0546
— 3.7
93.6
.0583
.1174
.0547
— 3.6
93.8
.0583
.0976
.0455*
—12.8
78.0
.0583
.1194
.0556**
— 2.7
95.4
.0583
.1238
.0580***
— 0.3
99.5
*Precipitated with a little more than the theoretical amount o£ bar-
bituric acid.
**Precipitated with 4 times the theoretical amount of barbituric acid.
***Precipitated with 16 times the theoretical amount of barbituric
acid.
From the above table it is at once apparent that the results
with barbituric acid are uniformly low. The last three deter-
minations show the effect of increasing amounts of the precipi-
tant. With barbituric acid and furfural in molecular propor-
tions of sixteen to one, the result is nearly quantitative. This
observation is in accord wTith statement of Unger and Jager that
eight times the theoretical amount of barbituric acid is necessary
for complete recovery of the furfural.
TABLE II.
THIOBARBITURIC ACID.
Furfural
Wt\ of
Furfural
Error
Mgms.
Furfural
Taken
Precipitate
Calculated
Recovered
Gms.
Gms.
Gms.
Per Cent
.0583
.1351
.0584
+ 0.1
100.2
.0583
.1360
.0588
+ 0.5
100.8
.0583
.1372
.0593
+ 1.0
101.7
.0583
.1367
.0591
+ 0.8
101.4
.0583
.1361
.0588
+ 0.5
100.8
.0583
.1368
.0591
+ 0.8
101.4
.0583
.1271
.0550*
— 3.3
94.3
.0583
.1294
.0559*
— 2.4
95.9
♦Precipitated at 60°.
With thiobarbituric acid, as shown in the above table, the pre-
cipitation is quantitative without using a large excess of the
reagent. The results tend even to run just a trifle over the
46
IOWA ACADEMY OP SCIENCE
theory. The last two determinations above show that the reaction
should not be allowed to occur at a high temperature since this
leads to results that are too low.
TABLE III.
MALONYLGUANIDINE.
furfural
Taken
Gms.
Wt. of
Precipitate
Gms.
Furfural,
Calculated
Gms.
Error
Mgms.
Furfural
Recovered
Per Cent
.0583
.0583
.0649
.0640
.0305
.0300
—27.8
—28.3
52.3
51.5
The condensation of furfural with malonylguanidine is not
quantitative. The yield in the two determinations quoted above
was only a little more than half the theory, hence under these
conditions malonylguanidine is not applicable for the quantita-
tive determination of furfural.
Having shown that thiobarbituric acid in moderate excess gives
quantitative results under the conditions of the above exjoeri-
ments, whereas barbituric acid under the same conditions gives
less than 95 per cent of the theoretical yield, it remains to com-
pare these two reagents as regards their sensitiveness to smaller
amounts of furfural. In the determinations recorded in table
IV, four times the theoretical amount of barbituric acid was
used.
TABLE IV.
BARBITURIC ACID.
Furfural
Wtj. of
Furfural
Error
Mgms.
Furfural
Taken
Precipitate
Calculated
Recovered
Gms.
Gms.
Gms.
Per Cent
.0117
none
none
no ppt.
none
.0117
.0061
.0028
— 8.9
26.5
.0233
.0225
.0105
—12.8
45.6
.0233
.0334
.0156
— 7.7
67.0
.0350
.0475
.0221
—12.9
63.1
.0350
.0640
.0298
— 5.2
85.1
It is obvious therefore, that the barbituric acid method is in-
applicable to the determination of small quantities of furfural.
In table V, varying amounts of furfural are treated with vary-
ing amounts of thiobarbituric acid.
PRECIPITANT S FOR FURFURAL
TABLE V.
THIOBARBITURIC ACID.
47
furfural
Taken
Gms.
THIOBARBI-
TURIC Acid
Taken
Gms.
Wt. of
Precipitate
Gms.
Furfural
Calculated
Gms.
Error
Moms.
Furfural
Recovered
Per Cent
.0592
.18
.1369
.0592
0.0'
100.0
.0592
.18
.1398
.0603
+1.1
101.8
.0592
.18
.1370 1
.0592
0.0
100.0
.0592
.18
.1400
.0605
+ 1.3
102.3
.0592
.12
.1390
.0601
+0.9
101.6
.0592
.12
.1400
.0605
+1.3
102.3
.0592
.20
.1372
.0593
+0.1
100.2
.0360
.11
.0835
.0361
+ 0.1
100.3
.0360
.11
.0852
.0369
+0.9
102.5
.0244
.08
.0568
.0247
+ 0.3
.101.2
.0244
.08
.0560
.0243
—0.1
99.6
.0244
.06
.0556
.0240
—0.4
98.3
.0244
.16
.0573
.0248
+0.4
101.6
.0119
.04
.0277
.0120
+0.1
100.8
.0119
.04
.0275
.0119
0.0
100.0
.0119
.03
.0261
.0113
—0.6
95.0
.0119
.08
.0278
.0120
+0.1
100.8
Here again, the results are just a trifle in excess of the theory.
Even so small an amount of furfural as 12 mgms. gave practi-
cally a quantitative yield, and variations in the amount of pre-
cipitant were of very little influence.
Analysis of the condensation products showed the percentage
of nitrogen to be in close agreement with the values calculated
from the formulas.
TABLE VI.
ANALYSIS OF CONDENSATION PRODUCTS.
Nitrogen
Sulphur
Found I Calcu"
] LATED
Found
Calcu-
lated
Furfuralmalonylthiourea
Furfuralmalonylguanidine ...
13.60
12.44
15.61
13.65
12.61
16.01
14.93
14.41
The furfuralmalonylurea is a bright lemon yellow, somewhat
granular precipitate which settles readily. Furfuralmalonyl-
thiourea is also a brilliant lemon yellow precipitate but very
floceulent and voluminous. No difficulty was experienced in
filtering and washing it, although the filtration was somewhat
48 IOWA ACADEMY OF SCIENCE
slow. It was practically insoluble in cold dilute mineral acids
and only slightly soluble in hot acids. It was practically insoluble
in alcohol, ether, petroleum ether, methyl alcohol, acetic acid,
benzene, carbon disulphide and turpentine. In ammonia, pyridine
and caustic alkalies it dissolves with ease, giving at first a green-
ish blue solution which gradually loses its color. From the
alkaline solution it can be recovered by neutralizing with acid.
The filtrates from both the furfuralmalonylurea and the furfural-
malonylthiourea had a very slight tinge of yellow. Furfural-
malonylguanidine, on the other hand, is a very dark green, floc-
culent precipitate, appreciably soluble in hydrochloric acid. The
filtrate is an intense greenish brown.
It was early noted that unless the thiobarbituric acid was care-
fully purified, the precipitation of furfural was not complete,
only 90 or 95 per cent of the latter being recovered, and the fil-
trate possessed a red color or sometimes a green color. In one
set of determinations the difficulty was traced with reasonable
certainty to the presence of cyanacetic ester in the malonic ester
from which the thiobarbituric acid was made. In preparing
malonic ester from chloracetic acid in the usual way, some
cyanacetic ester is apt to remain unless precautions are taken to
carry the saponification to completion. This is difficult to sepa-
rate from the malonic ester because the boiling points of the two
substances lie only a few degrees apart. The cyanacetic ester in
all probability reacts with the thiourea, forming a dicyanacetyl-
thiourea. On fractional crystallization of one of the impure
preparations of thiobarbituric acid, white needle-shaped crystals
were obtained, which on analysis yielded 26.66 per cent nitrogen ;
calculated for dicyandiacetylthiourea, 26.65 per cent nitrogen.
These crystals when dissolved in 12 per cent hydrochloric acid
gave an intensely green precipitate with furfural, just as did the
thiobarbituric acid before purification. For the preparation of
thiobarbituric acid it is, therefore, recommended that the malonic
ester be subjected to a repetition of the simultaneous saponifica-
tion and esterification before condensation with thiourea, and that
the thiobarbituric acid be purified by one or two crystallizations
of its sodium salt.
DISCUSSION.
Our experiments, quoted above, show that thiobarbituric acid
condenses readily with furfural in the presence of 12 per cent
hydrochloric acid. The reaction is quantitative, giving a volum-
PRECIPITANTS FOR FURFURAL
inous precipitate which can be filtered, dried and weighed. As
a precipitant for furfural, thiobarbituric acid is superior to
phloroglucinol, in that no correction for solubility of the product
is necessary. It is also preferable to barbituric acid for the
reason that the reaction is quantitative with as small amounts of
furfural as 12 mgms. and a large excess of the precipitant is not
necessary, thus avoiding possible errors due to inclusion. Un-
like the phloroglucinol product, the resulting furfuralmalonyl-
thiourea is a definite substance resulting from the condensation
of one molecule of furfural with one molecule of thiobarbituric
acid by the elimination of one molecule of water, and a definite
chemical formula can be assigned to it. It has a further ad-
vantage in that the percentages of nitrogen and sulphur, which
agree with those calculated from the formula, can be determined
by analysis and used as a positive means of identification of the
product to distinguish it from, or detect the presence of, similar
products which might result in case homologues of furfural were
present. For example, if a mixture of furfural and methylfur-
fural were precipitated, the determinations of nitrogen and sul-
phur on the product should enable us to compute the relative
amounts of these two aldehydes, and therefore the relative
amounts of pentosans and methylpentosans in the original sample.
At present the only means of estimating separately the furfural
and methylfurfural present in a mixture such as is frequently
met with in analysis, is the supposed differential solubility of their
phloroglucides in alcohol, and this admittedly is unreliable.
It is suggested that thiobarbituric acid, which is not difficult
to prepare in a pure state, may be found useful in the analysis
of agricultural products, in place of phloroglucinol or barbituric
acid, for the determination of pentoses and pentosans.
LITERATURE CITED.
(1) Giinther, Chalmot & Tollens, Ber. 24, 3577 (1891).
(2) Stone, Ber. 24 3019 (1891).
(3) Flint and Tollens, Ber. 25, 2912 (1892).
(4) Jolles, Ber. 39, 96 (1906).
(5) Giinther & Tollens, Ber. 23, 1751 (1890).
(6) Chalmot & Tollens, Ber. 24, 694 (1891).
(7) Councilor, Chem. Ztg. 17, 1743.
(8) Bureau of Chem. Bull. 107, p. 54 (1905).
(9) Krober, J. Landw. 48, 357.
(10) Goodwin & Tollens, Ber. 37, 315 (1904).
4
50 IOWA ACADEMY OF SCIENCE
(11) Kerp & Unger, Ber. 30, 590 (1897).
(12) Conrad & Reinbach, Ber. 34, 1339 (1901).
(13) Unger & Jager, Ber. 35, 4440 (1902); 36, 1222, (1903).
(14) Fromherz, Z. physiol. Chem. 50, 241 (1910).
(15) Fallada, Stein & Ravinka, Oesterr. ung. Z. Zuckerind 43, 425.
(16) Michael, J. prakt. Chem. 35, 456 (1887).
(17) Michael, J. prakt. Chem. 49, 37 (1894).
(18) Gabriel & Colmann, Ber. 37, 3657 (1904).
(19) Traube, Ber. 26, 2553 (1893).
(20) Fischer & Dilthey, Ann. 335, 350 (1904).
Chemical Section,
Iowa Agricultural Experiment Station.
ELECTROMOTIVE FORCES IN PYRIDINE 51
ELECTROMOTIVE FORCES AND ELECTRODE POTEN-
TIALS IN PYRIDINE AND ITS BINARY MIXTURES
WITH WATER, METHYL ALCOHOL AND
ETHYL ALCOHOL.
F. S. MORTIMER AND J. N. PEARCE.
HISTORICAL.
The systematic study of the electromotive forces in non-aqueous
solvents was begun by Jones,1 By using cells of the type:
Ag-AgNO,aq -AgN03non-aq-Ag
with the same concentration of the salt in each solvent, he hoped
to be able to calculate the degree of dissociation in the non-
aqueous solutions. It soon became apparent, however, that the
solution pressure of a metal varies from solvent to solvent. Sub-
stituting the values found by Vollmer2 for the degree of dissocia-
tion of silver nitrate in ethyl alcohol, he calculated the ratio of
the solution pressure of silver in alcohol and in water to be be-
tween 0.021 and 0.024. In all of these measurements the alcoholic
solutions are positive with respect to the water solutions.
Kahlenberg3 measured the electrode potential of ten different
metals in 0.10 N solutions of their salts in about thirty solvents.
The electrodes dipped into the solutions which were contained
in open vessels, connection between the cells being made by strips
of filter paper. The diffusion potential was neglected and ap-
parently no definite temperature was maintained. From his re-
sults, which he stated were only qualitative in nature, he con-
cluded that the solution pressure varies not only with the different
solvents and their mixtures, but also with the nature of the dis-
solved substances. He also tested and found that Faraday's
laws hold for non-aqueous solutions.
Wilson4 measured the electromotive forces of concentration
cells in alcoholic solutions of silver nitrate at both 0° and 25°.
While the values of the electromotive forces calculated from con-
ductivity data deviated somewhat from those experimentally
determined, he concluded that the Nernst equation will be found
to hold as well as in non-aqueous solutions.
JZeit. physik. Chem., 14. 346, 1894.
dissertation, Halle, 1892.
3Jour. Physical Chem., 3, 379, 1899.
'Am. Chem. Jour., 35, 78, 1906.
52 IOWA ACADEMY OF SCIENCE
Neustadt and Abegg5 investigated the electrode potentials and
electromotive forces of a number of cells containing solutions of
the salts of silver, lead, copper, mercury, cadmium, and zinc.
The solvents used were water, methyl alcohol, ethyl alcohol, ace-
tone, and pyridine. In all cases the half cell, Ag-AgN03 — , con-
stituted one-half of the cell. Since the potential differences in
methyl alcohol, ethyl alcohol and acetone are approximately equal
to those in water, they concluded that the solution pressures of
any one of the metals in these four solvents are approximately
equal. The considerably lower values obtained for solutions in
pyridine are attributed to extremely low ionic concentration.
They also consider that, possibly, silver nitrate is ionized in pyri-
dine solution according to the equation:
Ag2(N03)2±^Ag2 N03 + N03
Experiments were made using a number of solution chains as
liquid junctions in an attempt to eliminate the diffusion potential.
Getman6 and Getman and Gibbons7 measured the potentials of
cadmium and zinc in alcoholic solutions of their salts. In each
case the normal calomel electrode constituted the other half of
the cell. For both metals it was found that the electrode
potentials become more negative as the concentration of the salt
increases. Since the effect of concentration is just the reverse
of what is found for aqueous solutions, they concluded that the
applicability of the Nernst equation is very improbable.
Bell and Field8 measured the electromotive forces of concen-
tration cells in water and in ethyl alcoholic solutions of silver
nitrate. Rearranging the Nernst equation to the form:
IT = 2v . RT. log 10=K
log10j^ u+v nf
c2
they calculated the values of K. The values thus obtained varied
between 0.0560 and 0.0623. Assuming the value 0.0623, they
calculated the transport number of the anion of silver nitrate in
water to be 0.523. Since, however, the value of K varies so
widely, they concluded that the transport number must change
with the concentration of the salt.
6Zeit. physik. Chem., 69, 486, 1909.
•Am. Chem. Jour., 46, 117, 1911.
'Ibid., 36, 1630, 1914.
"Jour. Am. Chem. Soc, 35, 715, 1913.
ELECTROMOTIVE FORCES IN PYRIDINE
Getman and Gibbons9 measured the electrode potentials, trans-
port numbers and conductivities in solutions of silver nitrate in
methyl alcohol, ethyl alcohol, acetone, and aniline. They con-
cluded that certain abnormalities in non-aqueous solutions may
be attributed to the formation of complex solute-solvent com-
pounds which dissociate more or less gradually with the dilution.
The first systematic study of electrode potentials and electro-
motive forces in mixed solvents was reported by Pearee and
Farr.10 They determined the electromotive forces of concentra-
tion cells and the electrode potentials of silver against its ions
in water, methyl alcohol and ethyl alcohol and in their binary
mixtures at both 0° and 25°. From the close agreement between
the observed and calculated values of the electromotive forces it
was shown that the Nernst equation can be applied not only to
solutions in non-aqueous solvents, but also to solutions in binary
mixtures of these solvents. The electrode potentials are rela-
tively greatest in methyl alcohol and least in aqueous solutions,
the corresponding values in ethyl alcohol occupying an inter-
mediate position. Further, the values of the electrode potentials
are highest in the most concentrated solutions. In all cases they
decrease rapidly with dilution at first and then subsequently the
decrease proceeds almost linearly with further dilution.
The electrode potentials in the binary mixtures of the alcohols
obey the law of mixtures. In the binary mixtures of water and
the two alcohols, the electrode potentials increase slowly at first
with addition of alcohol from the value in pure water up to mix-
tures containing about seventy-five per cent of the alcohol and
then more rapidly with further increase in the proportion of the
alcohol.
The temperature coefficients of the electrode potentials are
positive for solutions in both alcohols and their binary mixtures.
Those in ethyl alcohol and the aqueous mixtures containing sev-
enty-five per cent and fifty per cent ethyl alcohol, increase with
dilution throughout, while those in methyl alcoholic solutions
pass through a minimum value. The temperature coefficients in
the water and the seventy-five per cent aqueous mixtures are
negative throughout, becoming more negative with increasing
dilution. The influence of the water as manifested by the tem-
perature coefficients of the electrode potentials is displaced to-
ward higher dilutions as the proportion of the alcohol in the
mixture is increased.
"Ibid. 36, 1630, 1914.
10Jour. Physical Chem., IS, 729, 19H.
54 IOWA ACADEMY OF SCIENCE
They also determined the solution pressure of silver in each of
the three solvents, as well as the heats of ionization for the pure
solvents and their fifty per cent binary mixtures.
In the hope that still further light may be thrown upon the
influence of solvent upon the electrochemistry of solutions, a
fourth solvent, pyridine, has been added to the series. To those
who are familiar with pyridine and its properties, little need be
said. Unlike the three liydroxy-compounds of the previous work,
its molecule has the ring structure with one nitrogen atom in
the ring. For many salts it is an excellent solvent and the
solution of these salts in pyridine is accompanied by a very con-
siderable evolution of heat. Silver nitrate, like many of these
salts, separates from its solution in pyridine with pyridine of
crystallization ; its power to form solvates of high complexity is,
therefore, obvious. Of the four solvents named, pyridine has
the smallest dielectric constant, yet with many salts it gives solu-
tions possessing fairly good electrical conductivity.
In the present work the electromotive forces of concentration
cells and the electrode potentials of silver against solutions of its
ions have been redetermined for solutions of the metal in water
and the two alcohols at 0° and 25°. Further, similar data have
been obtained for solutions of silver nitrate in pure pyridine
and for its binary mixtures with water, methyl alcohol and ethyl
alcohol, respectively.
MATERIALS AND SOLUTIONS.
Water — The water used was prepared according to the method
of Jones and Mackay11. Repeated measurements showed it to
have a specific conductivity of approximately 2.0xl0-6 mhos.
Ethyl Alcohol — Ordinary 95 per cent alcohol was allowed to
stand over fresh quicklime for two or three weeks. It was then
decanted and distilled. The distillate was allowed to stand over
anhydrous copper sulphate for one week and then redistilled.
This distillate was refluxed with metallic calcium for ten hours
and again distilled. Finally, it was refluxed for two hours with
silver nitrate to remove aldehydes and other reducing agents.
The distillate from this treatment was collected and preserved
in dry glass-stoppered bottles, being protected from the air dur-
ing distillation by phosphorus pentoxide tubes. In each distilla-
"Ara. Chem. Jour., 19, S3, 1897.
ELECTROMOTIVE FORCES IX PYRIDINE 55
tion a fractionating column was used and only that middle por-
tion which passed over between 77.9° and 78° (uncorr.) was
used.
Methyl Alcohol. — Kahlbaunrs best grade of alcohol was fur-
ther purified in the same manner as the ethyl alcohol, except that
the treatment with quicklime was omitted. Only that distillate
passing over between 64.9° and 65.1° (uncorr.) was used.
Pyridine. — The best grade of pyridine obtainable was allowed
to stand over fused potassium hydroxide for two weeks. It was
then decanted and distilled. That portion passing over between
115.3° and 115.4° was collected and preserved in dry glass-stop-
pered bottles, protected during distillation by a train of phos-
phorus pentoxide and calcium chloride tubes. Because of its
great absorptive power for water, extraordinary care was used
in handling the pyridine.
Silver Nitrate. — Baker's ''Analyzed'"' silver nitrate was re-
crystallized by the rapid cooling of a hot saturated solution of
the salt in conductivity water. The crystals were filtered on a
Buchner funnel, washed with ice-cold conductivity water, sucked
dry, and then heated for several hours in a toluol bath at 109°.
The salt when thoroughly dry was kept in dark bottles further
protected by dark cloths,
Potassium Chloride. — Baker's "Analyzed" potassium chloride
was further purified by precipitating a saturated solution by
hydrogen chloride gas. The precipiate was filtered on a Biich-
ner funnel, washed with conductivity water, heated to dryness
in an air bath at 110° and the crystals preserved in a desiccator
over phosphorus pentoxide. The salt was always strongly heated
before using.
Mercury. — The mercury was repeatedly washed with dilute
nitric acid and the acid removed by repeated washing with con-
ductivity water. It was then distilled under reduced pressure
in a current of air.
Calomel. — Kahlbaum's best grade of mercurous chloride was
repeatedly washed with a 0.10 N potassium chloride solution
after which it was preserved under a fresh sample of the same
solution in dark bottles.
Solutions. — All solutions were prepared by direct weighing,
or by the suitable dilution of freshly prepared solutions. They
56 IOWA ACADEMY OF SCIENCE
were made up to volume at 25° and, to avoid the possibility of
any decomposition occurring in the solutions, all electrometric
measurements were made on the same day.
Mixtures. — The solvent mixtures were made up on a percent-
age basis by weight, the weights of the separate components be-
ing accurate to 0.1 gram per liter.
APPARATUS.
The apparatus used in this work was the same as that used
by Farr.12 The constant temperature baths consisted of large
deep metal boxes inclosed within larger wooden boxes, the space
between being filled with insulating material. The 0°-bath was
obtained by clean finely crushed ice moistened with distilled
water. The water in the 25°-bath was kept in rapid circulation
by a mechanical stirrer. It was electrically heated and main-
tained at 25°+ .01 by an electrically controlled temperature regu-
lator.
Seven half-cells and two calomel electrodes were used in this
investigation. Each half-cell was fitted with a stop-cock in the
connecting tube. These were always kept closed except when
measurements were being made. Loose plugs of filter paper in-
serted in the ends of the connecting tubes practically eliminated
any possible diffusion potential even when the stop-cocks were
momentarily opened for potential readings. The middle vessel
was so arranged that the connecting tubes of all the cells could
be inserted through tight-fitting rubber stoppers. With this
arrangement the solutions were not unduly exposed to the air
and the measurements could be made on any combination by
simply changing the wire leads and opening the stop-cocks in
the connecting tubes. A normal aqueous solution of ammonium
nitrate was used in the middle vessel. It was assumed that
this solution eliminates the diffusion potential.13
The calomel electrodes were prepared in the following manner.
In the bottom of the electrode vessel was placed a large globule
of pure mercury. This was next covered by a calomel paste pre-
pared by intimately mixing calomel and mercury moistened with
0.1 N solution of potassium chloride. Over this was placed a solu-
tion of the 0.1 N potassium chloride which had been shaken with
12Loc. cit.
13Ostwald-Luther : Messungen, 3d Ed., p. 448.
ELECTROMOTIVE FORCES IN PYRIDINE 57
calomel and allowed to stand in contact with it until saturated.
The single potential of the calomel electrode was calculated from
the value given by Kichards,14 the values taken being -j-0.5986
volts at 0° and -f-0.6186 volts at 25°. These electrodes were re-
newed alternately every two weeks and were found to be repro-
ducible to within two-tenths of a millivolt.
The electromotive forces were measured by means of a Wolff
potentiometer in connection with a Leeds-Northrup, "Type IT,"
wall galvanometer. In aqueous solutions it was easily sensitive
to .01 millivolt, but the high resistance in non-aqueous solutions
made it almost impossible to detect differences of less than 0.1
millivolt, A Cadmium-Weston cell which had been recently
standardized against a similar element certified by the Bureau
of Standards was used as the standard of reference. It had an
electromotive force of 1.01745 volts of 25°. While its tempera-
ture coefficient is practically negligible, it was kept at this tem-
perature by insulating it in a beaker immersed in the 25°-bath.
The silver electrodes were prepared according to the method
described by Farr.15 Short pieces of pure silver wire were
fused into the ends of glass tubes. To the ends sealed into the
glass were soldered copper wires, each the length of the glass
tube. The tubes were then filled to within an inch of the top
with hard paraffine which prevented the mercury with which
the contact was made with the wire leads, from amalgamating
the silver. Before being used the electrodes were plated by
connecting them in series in a solution of potassium-silver
cyanide. After a current of ten milliamperes had been passed
for three hours, they were removed, rinsed with distilled water
and allowed to stand for forty-eight hours in contact with a
button of pure silver under a pure- aqueous solution of silver
nitrate. Ten or twelve electrodes were thus prepared. The
choice of the electrodes was made in the following manner. They
were all grouped in a single cell containing a 0.1 N solution of
silver nitrate which was in turn connected with a calomel elec-
trode through an intermediate solution of ammonium nitrate.
Only those electrodes were chosen which gave an electromotive
force varying not more than 0.1 millivolt from 0.3886 volts.
It was observed early in the work that the electrode potential
of a freshly prepared half-cell changes on standing. This
"Zeit. physik. Chem., 24, 29, 1S97.
15Loc. cit.
58 IOWA ACADEMY OF SCIENCE
change, for any given electrode, is most rapid at first, the rate
of change then gradually decreasing to zero at equilibrium. In
order to eliminate any errors from this source, the whole battery
of half-cells with their respective electrodes and solutions was
set up and allowed to stand for at least one and one-half hours
at constant temperature. That this time sufficed for the attain-
ment of equilibrium betwen electrode and solution may be seen
from the following table :
30 60 75
90
105 min.
Electrode potential. . .
. .6559 .6571 .6577
THEORETICAL.
.6578
.6578 volts
There are four sources of electromotive force in any cell : the
thermo-electric potential at the junction of the wire leads with
the electrodes, the diffusion potential at the junction of the two
solutions, and the electrode potentials at the surfaces of contact
between the electrodes and their respective solutions. The first
is entirely eliminated by compensation, and it is assumed that the
diffusion potential has been made negligible by the interposi-
tion of the 0.1 N solution of ammonium nitrate. There is left
for consideration, therefore, only the two electrode potentials.
According to the equation of Nernst, based on the osmotic
theory of the cell, the electrode potentials of a metal in contact
with two solutions of its ions are given by the expressions :
/Ft1 RT , P j rri RT , P ,.x
II 3 = • In — and II t = . In — • (1)
nf p2 nf p!
where R represents the gas-constant, (1.985 calores), T the ab-
solute temperature, n the valence of the cation, and f the faraday
(96540 coulombs), P represents the solution pressure of the
metal, and px and p2 the osmotic pressures of the cation in the
two solutions, the pressure being measured in atmospheres.
Assuming the absence of a diffusion potential, the electromo-
tive force of a concentration cell is therefore given by the ex-
pression :
Tf Ti t? RT i P RT i P / ^ \
II =n 2 — ii ]= __ . in — — — - -. In — > — (pi>p8).
nf p2 nf pt
This by rearrangement becomes,
TT = ^. In 2jl (2)
nf p2
X
lC,
\
2C2 '
In
*i
Ci
ELECTROMOTIVE FORCES IX PYRIDINE 59
Since the osmotic pressures of the ions are proportional to their
concentrations and since for normal electrolytes the concentra-
tions are in tnrn proportional to the equivalent conductivities of
the solutions, then
Pi <* t'Q'i
P2 oc2C2
Substituting in (2), we have
if = '&£• 1
nf \ 3c2
where c, a and x represent the concentration, the degree of dis-
sociation and the equivalent conductance of the electrolyte, re-
spectively.
The temperature coefficients of the electrode potentials were
calculated by means of the relation,
dTf _ TT86— Tf 0 U)
dT TTo '25 ' K }
The relation between the electrical and chemical energies in
a cell is given by the well-known Helmholtz equation,
r Q TdTT'
f dT
By rearranging and multiplying by .2387 in order to convert
joules into calories
Q=f(Tf-T|^)- .2387 , (5)
where Q is the heat of ionization.
By rearranging (1), the solution pressure of a metal is given
by the expression,
. „ 7f nf
RT + P *
By substituting for the osmotic pressure p its value calculated
from the gas laws, i. e.,
P = 22.4 • - • c -^,
there is obtained for the solution pressure of the metal, the
relation
lnP^ + In (22.4 • « ■ c ■ ^ ). (6)
60
IOWA ACADEMY OF SCIENCE
RESULTS.
The results obtained are given in the following tables and
curves :
TABLE I.
Electrode Potentials in Water-Pyridine /Series at 25°.
N
100 Water
VOLTS
75 W-25 P
VOLTS
50 W-50 P
VOLTS
25 W-75 P
VOLTS
100
Pyridine
VOLTS
1.0
1.0513
1.0430
1.0097
.9944
.9774
.9578
.9403
.7513
.7026
.6578
.6371
.6178
.6023
.5928
.7002
.6496
.6070
.5878
.5714
.5504
.5328
.6112
.50
.10
.05
.025
.01
.005
.7603
.7075
.6820
.6650
.6426
.6343
.5866
.5470
.5367
.5255
.5055
.4853
TABLE II.
Electrode Potentials in Water-Pyridine Series at 0°.
N
100 Water
volts
75 W-25 P
volts
50 W-50 P
VOLTS
25 W-75 P
VOLTS
100
Pyridine
VOLTS
1.0
1.0456
1.0411
.7282
.6842
.6836
.6361
.5810
.50
.7382
.5678
.10
1.0095
.7034
.6324
.5946
.5296
.05
.9913
.6739
.6258
.5758
.5216
.025
.9820
.6571
.6085
.5630
.5081
.01
.9625
.6405
.5973
.5421
.4926
.005
.9471
.6334
.5866
5309
.4740
Mean Temperature Coefficients of Electrode Potentials.
.000045 +.000430
+.000762 +.O0O771i +.001293
ELECTROMOTIVE FORCES IN PYRIDINE 61
TABLE III.
Concentration Cells in Wateb-Pybidine at 25°.
Nx-Ns
100 Water 75 W-25 P
50 W-50 P
25 W-75 P
100
Pyridine
1. —.1
.042
.057
.074
.093
.111
.015
.032
.052
.069
.017
.037
.054
.019
.037
.017
.094
.114
.134
.149
.159
.021
.039
.055
.065
.020
.035
.045
.015
.024
.010
.093
.112
.129
J 50
169
.019
.039
.056
.077
.016
.037
.055
.021
.038
.021
065
.05
074
.025
086
.01
104
.005
.126
.1 —.05
.025
.01
.005
.05 —.025
.01
.005
.025— .01
.005
.01 —.005
.025
.042
.065
.074
.017
.039
.049
.022
.031
.008
.010
.021 -
.039
.062
.011
.030
.052
.019
.041
.022
TABLE IV.
Concentration Cells in Water-Pyridine at 0°
Nx-Nj
100 Water
75 W-25 P
50 W-50 P
25 W-75 P
100
Pyridine
1. —.1
.036
.096
089
.051
.05
.054
.090
.107
.059
.025
.064
.119
.120
.073
.01
.083
.131
.142
.088
.005
.098
.018
.142
.003
.153
.018
.101}
.1 —.05
.030
.008
.025
.027
.046
.025
.031
.021
.01
.047
.063
.034
.052
.037
. .005
.062
.072
.046
.064
.051
.05 —.025
.009
.017
.027
.013
.013
.01
.029
.033
.036
.035
.029
.005
.044
.041
.048
.045
.047
.025— .01
.019
.016
.009
.021
.016
.005
.035
.024
.021
.033
.033
.01 —.005
.015
.007
.012
.011
.018
62
IOWA ACADEMY OF SCIENCE
TABLE V.
Electrode Potentials in Ethyl Alcohol-Pyridine Series at 25°
N
100 Ethyl
volts
75 E-25 P
VOLTS
50 E-50 P
VOLTS
25 E-75 P
VOLTS
100
Pyridine
VOLTS
.5
.7986
.7348
.7084
.7007
.6821
.6684
.6872
.6391
.6222
.6148
.5906
.5667
.6380
.5921
.5790
.5655
.5363
.5204
.5866
.1
.05
.025
.01
.005
1.0826
1,0686
1.0592
1.0391
1.0277
.5470
.5367
.5255
.5066
.4853
TABLE VI.
Electrode Potentials in Ethyl Alcohol-Pyridine Series at 0*.
N
100 Ethyl
volts
75 E-25 P
VOLTS
50 E-50 P
VOLTS
25 E-75 P
VOLTS
100
Pyridine
volts
.5
.7698
.6621
.6190
.5678
.1
1.0696
.7144
.6195
.5741
.5295
.05
1.0571
.6866
.6036
.5603
.5216
.025
1.0466
.6739
.5952
.5473
.5081
.01
1.0251
.6583
.5726
5108
.4920
.005
1.0131
.6397
.5512
.5083
.4746
Mean Temperature Coefficients of Electrode Potentials.
+.000506
+.001457
+.001280
+.001295
+.001293
TABLE VII.
Concentration Cells in Ethyl Alcohol and Pyridine at 25°
NyN2
100 Ethyl
75 E-25 P
50 E-50 P
25 E-75 P
100
Pyridine
0.5 —.1
.064
.048
.046
.039
.050
.05
.090
.065
.059
.025
.099
.116
.130
.026
.073
.097
.121
.017
.073
102
117
.013
.061
.01
080
.005
.101
0.1 —.05
.014
.010
.025
.024
.034
.024
.027
.021
.01
.043
.052
.049
.056
.039
.005
.055
.066
.072
.071
.062
.05 —.025
.010
.008
.007
.013
.011
.01
.029
.026
.032
.043
.030
.005
.041
.040
.055
.058
.0*2
.025— .01
.031
.018
.024
.029
.019
.005
.032
.032
.048
.044
.0<U
.015— .005
.012
.014
.024
.016
.022
ELECTROMOTIVE FORCES IX PYRIDINE
63
TABLE VIII.
Concentration Cells in Ethyl Alcohol and Pyridine at 0°
Nx-N2
0.5 —0.1
.05
.025
.01
.005
0.1 — .05
.025
.01
.005
.05 — .025
.01
.005
.025— .01
.005
.01 — .005
100 Ethyl
75 E-25 P 50 E-50 P 25 E-75 P
100
Pyridine
.013
.023
.044
.056
.010
.032
.044
.020
.034
.012
.055
.087
.096
.112
.130
.031
.040
.056
.074
.009
.025
.043
.016
.034
.018
.042
.058
.067
.089
.111
.016
.024
.047
.069
.008
.031
.053
.022
.044
.022
.045
059
.072
.109
.111
.014
.027
.063
.066
.013
.049
052
.036
039
.003
.038
.046
.060
.075
.093
.008
.021
.037
.055
.013
.029
.047
.016
.033
.018
TABLE IX.
Electrode Potentials in Methyl Alcohol-Pyridine Series at 25°.
X
100 Methyl 75 M-25 P 50 M-50 P 25 M-75 P
volts volts volts volts
100
Pyridine
volts
.5
.1
.05
.025
.01
.005
1.0975
1.0799
1.0707
1.0507
1.0286
.8105
.7306
.7145
.6959
.6766
.6612
.7177
.6541
.6369
.6201
.6000
.5834
.6386
.5911
.5690
.5520
.5426
.5280
.5866
.5470
.5367
.5255
.5066
.4853
TABLE X.
Electrode Potentials in Methyl Alcohol-Pyridine at -0°.
X
100 Methyl 75 M-25 P
volts volts
50 M-50 P
VOLTS
25 M-75 P
VOLTS
100
Pyridine
VOLTS
.5
.1
.05
.025
.01
.005
1.0916
1.0706
1.0611
1.0330
1.0167
.7811
.7126
.6970
.6814
.6628
.6493
.6934
.6233
.6184
.6017
.5851
.5614
.6175
.5658
.5522
.5369
.5243
5120
.5678
.5296
.5216
.5081
.4926
.4746
Mean Temperature Coefficients of Electrode Potentials.
+.000368 +.00098 j +.0014191 +.001352| +.001293
64 IOWA ACADEMY OF SCIENCE
TABLE XI.
Concentration Cells in Methyl Alcohol and Pyridine at 25°.
Nx-N,
100
Methyl
75 M-25 P
50 M-50 P
25M-75P
100
Pyridine
.5 —.1
.080
.064
.047
.039
.05
.096
.115
.134
.149
.016
.081
.098
.117
.134
.017
.069
.087
.096
111
.021
.050
.025
.061
.01
.080
.005
.101
.1 —.05
.018
.010
.025
.027
.035
.035
.039
.021
.01
.047
.054
.054
.049
.039
.005
.069
.069
.072
.063
.062
.05 —.025
.010
.018
.017
.017
.011
.01
.030
.038
.037
.027
.030
.005
.052
.053
.054
.041
.052
.025— .01
.020
.019
.020
.009
.019
.005
.042
.035
.037
.024
.041
.01 .005
.022
.015
.017
.014
.022
TABLE XII.
Concentration Cells in Methyl Alcohol and Pyridine at 0°.
NrN2
100
Methyl
75 M-25 P
50 M-50 P
25 M-75 P
100
Pyridine
.5 —.1
.068
.084
.099
.118
.132
.016
.070
.075
.092
.107
.131
.005
.052
.065
.081
093
.106
.013
.038
.05
.046
.025
.060
.01
.075
.005
.093
.1 —.05
.021
.008
025
.031
.031
.021
.028
.021
.01
.059
.050
.038
.041
.037
.005
.075
.063
.062
.054
.054
.05 —.025
.010
.015
.016
.015
.013
.01
.037
.034
.033
.028
.029
.005
.053
- .047
.058
.040
.047
.025— .01
.028
.019
.016
.012
.016
.005
.044
.032
.041
.015
.033
.01 —.005
.017
.014
.025
.012
.018
ELECTROMOTIVE FORCES IN PYRIDINE
65
TABLE XIII.
Concentration Cells in Pure Pyridine.
Nx-Na
Observed 0°
Calculated
Observed 25°
Calculated
1.0 -0.1
+.051
—.021
+.065
—.015
.05
+.059
.—005
+.074
+.0001
.01
+.088
+.032
+.101
+.037
.5 —0.1
+.038
+.031
+.039
+.033
.05
+.046
+.046
+.050
+.049
.01
+.075
+.084
+.080
+.086
.1 —.05
+.008
+.015
+.010
+.015
.01
+.037
+.053
+.039
+.052
.05— .01
+.029
+.037
+.030
+.037
TABLE XIV.
Heats of Ionization.
Solvent
Electrode
Potential
Mean of
the Temp.
Coeff.
Heat of
Ioniza-
tion
Dielec-
tric
Con-
stant
100 water ___ _ _ ___
1.0097
.7075
.6578
.6070
.5470
1.0826
.7348
.6391
.5921
1.0975
.7306
.6541
.5911
—.000069
+.000430
+.000762
+.000691
+.001293
+.000506
+.001457
+.001280
+.001354
+.000415
+.000989
+.001420
+.001356
23728
13352
9925
9243
3726
21472
6927
5938
4346
22440
10045
5321
4310
80.5
75 W— 25 P
56.9
50 W— 50 P
41.1
25 W— 75 P
31.5
100 Pyridine
11.2
100 Ethyl ._
75 E— 25 P .
50 E— 50 P
25 E— 75 P _-.
100 Methyl
32.8
75 M— 25 P
24.5
50 M— 50 P
18.2
25 M— 75 P
TABLE XV.
Solution Pressures in the Pure Solvents.
Solvent
Solution
Pressure
Water
Ethyl Alcohol _
Methyl Alcohol
Pyridine
2.46 x 10- '
2.02 x 10- *
3.55 x 10-1
1.77 x 10- *
66 IOWA ACADEMY OF SCIENCE
DISCUSSION.
The observed electromotive forces of all the possible concen-
tration cells of the type:
Ag— AgN02,cl— 1.0 N NH4N03— AgN03,c,> — Ag
may be found in Tables III, IV, VII, VIII, XI and XII. The
observed values are small, as we should expect. While they
are incumbered, doubtless, with slight errors, they are approxi-
mately of the right order of magnitude. In all cases the posi-
tive electrode was found in the more concentrated solution.
Conductivity data are not available for the solutions in the binary
mixtures containing pyridine as one of the components. It is
therefore impossible to give the calculated values in the mixed
solvents. In the pure solvents, water, methyl alcohol, and ethyl
alcohol, the values obtained agree closely with those obtained by
Fan*,16 thus confirming his statement that the Nernst equation
does hold for concentration cells in these solvents.
During the present year the equivalent conductances of solu-
tions of silver nitrate in pure pyridine have been carefully deter-
mined by Mr. H. L. Dunlap of this laboratory. Repeated deter-
minations give the following values for the equivalent conduct-
ance at infinite dilution :
x°° at 0°=51, Xo° at 25°=71.
In attempting to calculate the electromotive forces of concen-
tration cells in pyridine from Mr. Dunlap 's conductivity data,
it was found that the calculated values deviate considerably from
those observed. They are peculiar in the following respects:
When the normal solution constitutes one-half of the concentra-
tion cell they are smaller than the observed values, but if the
concentrations in each of the half-cells are less than .5 N they
are larger. Furthermore, it will be observed that with the more
concentrated solutions the calculated electromotive forces show
reversal of sign.
The deviations between the observed and calculated values
for the electromotive forces of concentration cells in pure pyri-
dine must be attributed to one or both of two causes, — either the
solution pressure of the metal varies with the concentration of
the dissolved silver nitrate, or, owing to polymerization and sub-
sequent ionization, the equivalent conductivity is not a true
lcLoc. cit.
Iowa Academy Science
Plate IIA
k*r<
2S°
ryridi/u.
(f
Ethyl AUvhc
I-
Py r id i />(
Methyl AUoha
(- Pyndi/iz
Percent of Py r/d i ne
Curves showing the influence of pyridine upon the electrode potentials of silver against
solutions of silver ions in water, methyl alcohol, ethyl alcohol and pyridine, and
in the binary solvents containing pyridine as one component. The upper curve in
each plot represents the most concentrated solution.
68 IOWA ACADEMY OF SCIENCE
measure of the concentration of the silver ions. The latter alter-
native is in accord with the observation of Neustadt and Abegg17
that in the electrolysis of pyridine solutions of silver nitrate both
the silver ion and the nitrate radicle migrate to the cathode,
probably as a complex ion.
"Walden and Centnerszwer18 have found that the molecular
weight of silver nitrate in dilute pyridine solutions is normal,
while in the more concentrated solutions it is greater than nor-
mal, thus indicating association. Since simple silver ions must
be present, if an electromotive force is to exist, it is probable that
silver nitrate may ionize both as simple and as complex
ions. If the ionization of the complex molecule is just
sufficient to form as many particles as there would be if the
substance existed as a simple molecule, then the molecular
weight should appear to be normal. This is probably the case
in the more dilute solutions of silver nitrate in pyridine.
It is evident from Tables I, II, V, VI, IX, X and from Plate
II A that the electrode potentials of silver are much higher for
solutions in water, methyl alcohol and ethyl alcohol than for
equivalent concentrations in pyridine. On comparing the equiv-
alent concentrations, it will be observed that for all binary mix-
tures of pyridine with water and with the two alcohols the elec-
trode potential increases with the decrease in the proportion of
pyridine in the mixture. This increase is very gradual until
seventy-five per cent of the pyridine has been replaced by the
second solvent. For the water-pyridine mixtures the initial in-
crease is apparently a linear function of the per cent of water
present. "With further decrease in the proportion of pyridine
there is a rapid increase in the value of the electrode potential to
its value in the second solvent. The curves for the water-
pyridine series show a strong resemblance to the curve found
by Hartley, Thomas and Appleby19 for the surface tensions of
the same system. Whether or not any relation exists between
surface tension and electrode potential is a question still un-
answered.
For all solvents, simple and mixed, the electrode potentials
increase as the concentration of the salt increases. From the
curves, Plate II B, it will be observed that, starting with the most
17Loc. cit.
lsZeit. phvsik. Chem., 55, 321, 190fi.
"Trans. Chem.. Soc, 93, 549, 1908.
Iowa Academy Science
Plate IIB
Wa. t i
2 f
ryridine
£7 hyl AUoJit
I- Pyrtdn
IS
as*
Methyl Akoti
/(JO/ltthyl
$1 - Pyrj'di'ni
1 AUUy/
m f/A;/
J. It 2t 1C /to 210 to 20 10
D i /u/ ton
Curves showing the relation between the electrode potentials and the concentration of
the silver nitrate in the pure and binary solvents.
70 IOWA ACADEMY OF SCIENCE
concentrated solution, the electrode potential drops very rapid-
ly with the first dilutions, and then decreases almost linearly in
the more dilute regions. It will also be observed from the vol-
ume-electrode potential curves for any set of binary mixtures
and hence for all of the pure solvents as well, that the curves
obtained are practically parallel to each other. If they were
exactly parallel, it would follow, as was stated by Farr,20 that,
"if the electromotive force at the junction of the two solutions
has been entirely eliminated, and since the electromotive force
of a concentration cell at a given temperature is proportional
to the logarithm of the ratio of the ionic concentrations in the
two solutions, it follows that the ratio between the ionic concen-
trations for equivalent concentrations of the salt in the separate
solvents is constant and independent of the dilution."
The mean temperature coefficient of the electrode potentials
in each solvent has been calculated for both the pure solvents
and their mixtures and tabulated at the bottom of the tables for
the electrode potentials. All of the temperature coefficients are
positive except those in the more dilute solutions in the pure
water. In all solutions containing pyridine the temperature
coefficients are extremely large. In the water-pyridine series
they increase continually from the value in pure water to the
value in pure pyridine as the per cent of pyridine is increased.
In the ethyl alcohol-pyridine solutions they increase rapidly with
the first addition of pyridine, then decrease to practically the
value in pure pyridine after fifty per cent of the alcohol is re-
placed by the pyridine. In the methyl alcohol-pyridine series the
temperature coefficients increase rapidly to a maximum value
in the fifty per cent mixture, then decrease slowly to the value
in pure pyridine as the proportion of alcohol is diminished.
The same relations obtain for binary mixtures of pyridine and
ethyl alcohol, except that the maximum occurs in the presence
of a smaller proportion of pyridine.
The heats of ionization are given in Table XIV. They were
calculated by substituting the mean temperature coefficients
and the electrode potentials for the 0.1 N solutions in equa-
tion (5). The heat of ionization in pyridine is very low. In
any series of solvent mixtures, the heats of ionization decrease
the most rapidly upon the first addition of pyridine to the
second solvent, and then more slowly as the per cent of pyri-
»Loc. cit.
ELECTROMOTIVE FORCES IN PYRIDINE 71
dine is increased. The heats of ionization decrease with in-
crease of pyridine relatively more rapidly in each of the alco-
holic-pyridine mixtures than in the water-pyridine mixtures.
In the last column of Table XIV are given a few dielectric
constants21. It will be observed that in this respect also, the
first addition of pyridine to the other solvent produces rela-
tively the greatest change. Are then, the electrode potentials
and heats of ionization functions of the dielectric constants?
The solution pressure of silver in contact with pyridine so-
lutions of silver nitrate is found to be much higher than when
in contact with aqueous or alcoholic solutions, These calcu-
lations were made by substituting in (6) the electrode poten-
tials obtained for the 0.1 N solutions in each of the pure solv-
ents, and the values of = calculated from the following values
of the equivalent conductivities: Water, \0=99.4622 and Xco
= 128.5423. Methyl alcohol, \0=38.57522 and x°°=98.0. Ethyl
alcohol \0=13.21522 and *°°=35.623. Pyridine, \0=27.58522
and x °°=71.22
The solution pressures in water and the alcohols are in good
agreement with those calculated by Farr. The values calculated
for water also are very close to the values 2.3xl0-17, given by
Neumann24. Assuming from conductivity data that silver ni-
trate is one-fourth as highly ionized in pyridine as it is in aqueous
solutions, Kahlenberg calculated the solution pressure of silver
in pyridine to be 3.4xl0-10, a value very close to the one herein
reported.
SUMMARY.
The electromotive forces of concentration cells containing so-
lutions of silver nitrate in the pure solvents: water, methyl alco-
hol, ethyl alcohol, pyridine, and in the binary mixtures of pyridine
with each of the other solvents have been determined at 0C and
25°. It has been shown that the Nernst equation cannot be ap-
plied to solutions of silver nitrate in pyridine, possibly lie-
cause of a change in the solution pressure of the metal with the
concentration of the salt or because of the association and sub-
sequent complex ionization of silver nitrate in pyridine solutions.
The equivalent conductance is not a measure of the concentra-
tion of the silver ions.
"Determined by Mr. Richard Beeson.
22This laboratory.
^Kohlrausch, Sitzungsber, Berl. Akad., 26, 570, 1902.
"Zeit. physik. Chem.. 14, 193, 1894.
72 IOWA ACADEMY OF SCIENCE
The electrode potentials have been determined for the same
solvents at both temperatures. They are much higher in water,
methyl alcohol and ethyl alcohol than in pyridine. In all sol-
vents they are highest in the most concentrated solution, de-
creasing rapidly with the first dilutions and then almost linearly
with further dilution. The electrode potentials in the binary
mixture of pyridine with each of the other solvents decrease
very rapidly with the first addition of pyridine. With further
increase in the per cent of pyridine the values decrease gradu-
ally to that in pure pyridine. For the water pyridine series, be-
ginning with twenty-five per cent pyridine, the decrease in the
value of the electrode potential is linear with the per cent of
pyridine.
The average temperature coefficients of electrode potentials
have been calculated for each of the pure solvents and their
binary mixtures. All are found to be positive except those in
the dilute solutions in pure water. In water-pyridine mixtures
the temperature coefficients increase continuously to the value
in pyridine. In both alcoholic mixtures with pyridine they go
through maximum values.
The heats of ionization of silver in the pure solvents and their
binary mixtures are found to be much higher in water, methyl
alcohol and ethyl alcohol than in pyridine. As the per cent of
pyridine is increased in its mixtures with each of the other sol-
vents, the heat of ionization decreases at first very rapidly and
then more slowly to its value in pure pyridine.
The solution pressure of silver nitrate has been calculated
for each of the pure solvents. It is much higher in pyridine
than in either of the two alcohols or water.
Physical Chemistry Laboratory,
The State University op Iowa.
AN OLD ROMAN COIN IN DAKOTA
73
AN OLD ROMAN COIN IX DAKOTA.
DAVID H. BOOT.
Iu 1910 the writer was at work in Lincoln county, South Da-
kota, and had his attention called one morning to a curious piece
of metal that had just been dug up by one of his neighbors. The
find was apparently an old coin, but no one in that region
could identify it. It was sent to the Smithsonian Institution and
there identified as a coin of Septimius Severus, Emperor of
Rome, A. D. 193 to 211. Some account of this Roman Em-
peror will be of interest in this connection. He was the only
negro that ever ruled the world. In 193 he was commander
of the Roman army on the Danube, engaged in holding off
the armies of the barbarians. He was an Ethiopian who had
risen from the ranks by his great energy and force of char-
acter. The Emperor Pertinax having been murdered in Rome,
Fig. 3 — Coin of Septimius Severus found in South Dakota.
the praetorian guard auctioned off the empire to the highest
bidder and it was sold to Didius Julianus for a price equivalent
to $12,000,000 of our money. At this time there were I
armies in the field protecting the empire, one on the Euphrates,
74 IOWA ACADEMY OF SCIENCE
one on the Rhine and one on the Danube. When the soldiers
heard of the disgraceful transaction at home they rose in re-
volt and at once set out for the capital. Septimius Severus
had the shortest distance to go and reached Rome first. The
praetorians did not even attempt to defend their emperor who
was put to death along with forty senators, and the army pro-
claimed Severus emperor. He knew that as soon as the excite-
ment of the moment had passed, the people would not tolerate
a negro ruler so he very wisely committed the management of
affairs at the capital to the prefect of the new praetorian guard
and returned to the frontier where he spent a long and pros-
perous reign, only returning two or three times and then for a
few days only. He finally died in Britain at York.
The cuts (figure 3) show front and back views of the coin
found in Dakota. Conjecture is useless as to hew it came there,
for the first white man to cross Dakota is supposed to have been
the French explorer Venendre, but the coin was more than
1400 years old when Venendre was born. French Jesuit priests
later worked among the Indians of Dakota, but it would be diffi-
cult to arrive at any reasonable hypothesis involving their con-
nection with it.
Department op Botany,
State University.
THE IOWAN DRIFT PROBLEM 75
A NOTE REGARDING THE PRESENT STATUS OF THE
IOWAN DRIFT PROBLEM.
GEORGE F. KAY.
Among the many persons who, by their publications, have,
made known to the world the Pleistocene history of Iowa, no
one has had a greater part than Doctor Calvin, who spent his
life endeavoring to interpret the geological phenomena of the
state. For many years, but chiefly from about 1895 until his
death in 1911, important papers were written by him in tV
reports of the Iowa Geological Survey, of which he was Director,
and in other channels of publication. None of these publica-
tions are of greater interest than those which describe the char-
acteristics, relationships, and age of the lowan drift. It was
he who, after he had done detailed work on the Pleistocene of
the northeastern and north-central parts of Iowa, became con-
vinced that in this part of the state the evidence indicated that
the ice had invaded the region not twice only, as had been held
by earlier workers in this field, but three times. It was he who
gave to the uppermost of these drift sheets the name "lowan,"
and presented arguments in favor of recognizing the lowan as
a distinct epoch in the Pleistocene.
For a number of years the conclusions of Doctor Calvin were
accepted, but a few years before his death in 1911 some Pleisto-
cene geologists, particularly Mr. Frank Leverett of the United
States Geological Survey, raised the question whether or not
there was sufficient evidence to justify the recognition of the
lowan as a drift sheet separate from the Kansan. In defense
of his interpretations Doctor Calvin prepared a paper entitled
'"The lowan Drift," which he read at the Pittsburgh meeting of
the Geological Society of America, in December, 1910, and which
was published after his death in the Journal of Geology, vol-
ume XIX, No. 7, October-November, 1911.
Since the death of Doctor Calvin, a co-operative study of the
lowan problem has been made, especially during the field sea-
sons of 1914 and 1915, by Dr. W. C. Alden, Chief of the Pleis-
tocene Section of the United States Geological Survey, and Dr.
76 IOWA ACADEMY OF SCIENCE
M. M. Leighton of the Iowa Geological Survey. Their investi-
gations have confirmed the contention of Doctor Calvin that
in northeastern and north-central Iowa there is an Iowan drift.
In September, 1915, after the completion of the field work of
Alden and Leighton, a conference was held in the Iowan area,
in which conference Dr. W. C. Alden, Mr. Frank Leverett, Dr.
R. D. Salisbury, and the writer participated. After a critical
study and discussion of the main lines of evidence in the field,
agreement was reached by all that there is a post-Kansan drift
to which the name "Iowran" was given by Calvin.
A report of the investigation of Doctor Alden and Doctor
Leighton is now being prepared for publication by the Iowa
Geological Survey.
Much of the evidence in connection with the Iowan is very
elusive, and the fact that Doctor Calvin, who was regarded
for many years not as a Pleistocene geologist but as a paleontol-
ogist, correctly interpreted the evidence indicates his keen pow-
ers of observation and his ability to discriminate evidence which
one geologist has said "defies the experts."
Department of Geology,
State University.
GEOLOGY OF SOUTHWESTERN IOWA 77
CONTRIBUTIONS TO THE GEOLOGY OF SOUTH-
WESTERN IOWA.
GEO. L. SMITH.
During the last year work on the geology of southwestern
Iowa has been continued. The different outcrops in the vicinity
of Stennett in Montgomery county have been visited, and im-
portant information obtained of the stratigraphy and paleon-
ology of the Stennett limestones and the Braddyville and Platte
shales. In Fremont county the exposures at Hamburg, McKis-
sicks Grove, Mill creek, as well as those from Opossum creek
north to Thurman have again been examined, in hopes to defi-
nitely locate the break that takes place in the strata between
Thurman and the Wilson section.
The unusual and excessive rainfall of the last summer made
the field work disagreeable by the abundance of mud and high
water. Erosion was many times greater than in any previous
year. In several places overwash and slumping completely cov-
ered outcropping strata, while in other places the creek beds
were swept bare and clean by high water, affording details of
sections not before observed. Erosion has been especially active
in the head of ravines in the loess of the Missouri river bluffs.
At MeKissicks Grove this has exposed about thirty feet of strata
bigher than those already known.
In tracing the different limestone ledges southward, there is
found a marked change in the lithology of the horizon ; the up-
per limestone at Nebraska City and Hamburg grades into sand-
stone in the state of Missouri, within twenty miles of the Iowa
state line. Even at MeKissicks Grove this limestone becomes
very arenaceous, and at the most southern outcrop it might be
termed a calcareous sandstone. The limestone bottom rock of
the Nodaway coal at Carbon in places is five feet thick, south
ward at New Market it thins to eight inches, at Clarinda it is
only a disconnected layer of nodules, and at Coin it is absent.
One of the thin limestone ledges less than two feet thick at the
Wilson section increases in thickness to twelve feet in less than
a mile to the north. This shows the necessity of caution in cor-
78 IOWA ACADEMY OF SCIENCE
relations, and that all the associated strata must be taken into
consideration in the identification of any horizon. Nearly all
the available limestone on Tarkio creek is exhausted ; no quarry-
ing has been done lately, and in recent years no outcrop where
a satisfactory section could be obtained was known. At Snow
Hill, one mile north of Coin, recent erosion has exposed the fol-
lowing section. It is given as it is the only good outcrop at
present on Tarkio creek.
SECTION ON TARKIO CREEK ONE MILE NORTH OP COIN.
FEET.
9. Shale, yellow passing down into blue 9
8. Limestone, gray weathered yellow, Fusulina.... 1
7. Shale, gray, calcareous 3
6. Limestone, blue, weathered brown 2
5. Sandstone, brown, friable 1
4. Shale, gray, weathered 6
3. Limestone, gray 1
2. Shale, red 3
1. Shale, gray, weathered 2
Total 28
The upper eight inches of number six usually parts from the
rest of the ledge, and in some localities this parting becomes a
shale two feet thick.
About two hundred yards east of this outcrop near the Chi-
cago, Burlington and Quincy railroad a core drill hole gives
the following record of the City Bluffs shale. The drilling com-
mences immediately beneath the Tarkio limestones exposed in out-
crop at the old mill site.
SECTION OF CORE DRILLING ON RAILROAD NORTHEAST OF
COIN.
FEET INCHES
21. Light shale 16 8
20. Gray shale 11 4
19. Gray limestone, impure, shaly 9 G
18. Gray shale 32 2
17. Limestone, impure, shaly 6
16. Calcareous shale 2
15. Light shale 3 8
14. Black shale 2
13. Coal, Elmo 6
GEOLOGY OF SOUTHWESTERN IOWA
FEET INCHES
12. Light shale 3
11. Black shale 2 8
10. Gray limestone, impure, shaly 3 4
9. Gray shale 8
8. Limestone, impure, shaly 2
7. Green shale 16 9
6. Gray shale 37 3
5. Gray limestone 1 2
4. Gray shale 44 3
3. Caprock limestone 4 10
2. Black shale 4
1. Coal, Nodaway 1 6
Total 212 7
Records obtained of two core drill holes and two coal mine
shafts within one mile of Coin show no constant horizon that can
be correlated above the Nodaway coal in the City Bluffs shale.
Eecent grading at Hamburg on the street north of the school
house has exposed an excellent section. The bluff at this place
reaches a height of about one hundred and fifty feet above the
river flood lands, with the slope of the west face reaching nearly
45 degrees. The east slope is somewhat less. The crest is wide
enough only for a narrow footpath. The surface of the shale
bed rock closely follows the contour of the bluff, and at the con-
tact of the shale and loess composing the upper part of the bluff,
does not show any traces of weathering previous to the deposition
of the loess.
The Iowa Geological Survey has published several sections of
the strata in this bluff, only one of which is correct, that of J. A.
Udden, in Vol. XIII, Iowa Geological Survey. At the time of
the visit of Dr. Calvin and the writer the limestone and lower
sandstone layers were concealed by debris and were not seen.
SECTION AT HAMBURG BLUFF.
FEET INCHES
6. Sandstone, yellow, coarse grained, the
grains composed of subangular frag-
ments of quartz 3
5. Shale, blue, weathered gray, contains
concretions of pyrite 15
4. Limestone, dark gray, arenaceous, cut
by vertical joints, brecciated, occasion-
ally contains spheroidal lumps of dark
80 IOWA ACADEMY OF SCIENCE
FEET INCHES
color. Some of the lumps consist of
an external shell with an included
structureless nucleus 9
3. Shale, blue, arenaceous 5
2. Sandstone, blue, indurated, micaceous,
and ripple marked 2
I. Shale, arenaceous 1
Total 24
The limestone near the reservoir at the foot of the bluff was the
foundation wall of a building that had been removed.
During the past summer slumping has covered some of the
lower strata at McKissisks Grove ; however, active erosion at the
head of ravines has revealed details of strata not before observed.
The outcrops at this locality are seen successively by following
an unnamed creek to the forks, then the east branch about one-
fourth mile ; on the south branch are several excellent exposures
within a distance of one-half mile. All these outcrops are easily
fitted with each other.
COMPOSITE SECTION AT McKISSICKS GROVE.
FEET INCHES
19. Shale, blue 12
18. Shale, gray, weathered 8
17. Limestone, very dark gray, arenaceous,
many spheroidal lumps, in places
brecciated 1
16. Limestone, blue, very arenaceous, might
be termed a calcareous sandstone. ... 1
15. Shale, arenaceous, micaceous 3
14. Sandstone, blue, weathering yellow fc
13. Shale, arenaceous, micaceous 2 6
12. Sandstone, blue, weathering yellow 1
II. Shale, gray 9
10. Limestone, dark gray, fossiliferous, in
two layers 3
9. Coal, Nyman 1
8. Shale, yellow and blue 31
7. Limestone, gray, fossiliferous 6
6. Shale, dark gray 3 6
5. Limestone, very dark gray 6
4. Shale, blue weathering to yellow 8
3. Limestone, weathered brown. In two
or three layers. Tarkio 4
2. Shale, gray, weathered 12
1. Limestone, dark gray 1
Total 110
GEOLOGY OF SOUTHWESTERN IOWA
The twenty feet of shale, with the associated limestone bands,
above the Tarkio limestone are highly fossiliferous. Two miles
northeast of McKissicks Grove, about one-half the distance to the
Mill creek outcrop, the Nyman coal has been prospected and
found to have a thickness of one foot. The Mill creek outcrop
can be correlated easily with that of McKissicks Grove. In pass-
ing north and east the upper limestone becomes less arenaceous
and more fossiliferous.
SECTION ON MILL CREEK TWO MILES SOUTH OF RIVERTON.
FEEX
6. Shale, gray, weathered 10
5. Limestone in five layers with shale part-
ings. The upper layer six inches
thick is an indurated and white lime-
stone composed of fragments of shells
and crinoid plates arranged in a hori-
zontal position. The two lower layers
ten and four inches thick are a very
dark gray limestone. They contain
numerous round lumps of calcareous
matter one-fourth inch in diameter. . 3
4. Shale, calcareous, weathered yellow.... 3
3. Shale, blue, arenaceous, contains sev-
eral thin bands of sandstone, not well
exposed 9
2. Sandstone, blue, fine-grained, micaceous,
indurated 2
1. Shale, blue 8
Total 35
On the bluff road north of Opossum creek to Thurman several
outcrops of the same ledge of limestone and sandstone can be
seen.
COMPOSITE SECTION SOUTH OF THURMAN.
FEET INCHES
5. Sandstone, blue, fine texture 6
4. Shale, gray 10
3. Limestone, dark gray, cut by vertical
joints into large , blocks, and con-
taining numerous spheroidal calcar-
eous lumps about one-fourth inch in
diameter 3
82 IOWA ACADEMY OP SCIENCE
FEET INCHES
2. Shale, gray, weathered 2
1. Sandstone, light blue, indurated, of fine
texture, in straight layers below, and
ripple marked above 3
Total . 18 6
Lower strata are found in a coal shaft near one of the out-
crops.
RECORD OP BAYLORS SHAFT SOUTH OP THURMAN.
FEET INCHES
6. Blue limestone 3
5. Sandstone 5
4. Shale 20
3. Limestone 6
2. Coal, Nyman 1 2
1. Shale and sandstone
Total 29 8
What is thought to be the same limestone and sandstone is
seen on the wagon road about one mile north of Thurman. The
Nyman coal outcrops in the banks of Plum creek one-fourth mile
east of the village.
A feature unusual in Iowa geology takes place between the
north outcrop and the Wilson section about one mile distant.
There is a break in the strata upwards of three hundred feet, and
as a result the Forbes limestone and Nyman coal each have the
same elevation above the flood land of the Missouri river. The
sandstone beneath the main limestone at the Wilson section is
not the same as that near Thurman ; the latter is blue, indurated,
ripple marked, and three feet thick, while the former is yellow,
friable, micaceous, and eight feet thick in the old quarry east of
Haynies. The texture and contained spheroidal lumps in the lime-
stone at Thurman, Hamburg, McKissicks Grove, and Mill creek
are the same at each place. As this limestone becomes arenaceous
at these southern localities it loses its fossils, and farther south
in the state of Missouri grades into sandstone and cannot be
recognized.
The possibility that the coal at Baylors shaft is the Elmo coal
has been considered. These two localities have been personally
visited, and compared, but as a result the conclusion arrived at
is decidedly against such correlation.
GEOLOGY OF SOUTHWESTERN IOWA
Whether the break south of the Wilson section is a fault or
an abrupt monocline to the south cannot be definitely decided,
at the present time, owing to the heavy covering of loess in the
bluffs; at any rate there is no considerable dip in strata less
than a mile apart.
Twenty years ago the quarrying industry was in a flourishing
condition at Stennett. Many large quarries were in operation,
affording excellent exposures of the different strata. In recent
years this industry is practically abandoned, and owing to over-
wash and slumping a connected section can not be found. Many
of the old quarries are completely covered, and not a single un-
disturbed ledge is visible.
On Pilot creek, one-fourth mile north of Stennett, at the site
of the abandoned Wayne Stennett quarry, is the best and most
extensive section seen in this vicinity.
SECTION AT THE OLD WAYNE STENNETT QUARRY.
FEET
15. Limestone, gray, two layers 2
14. Shale, black 3
13. Shale, gray, calcareous 5
12. Limestone, gray, one layer 2
11. Shale, gray, calcareous 2
10. Limestone, gray, one layer iy2
9. Shale, buff and gray 3%
8. Limestone, brown, cherty, impure 1
7. Limestone, gray, cherty 2*4
6. Limestone, blue 1
5. Limestone, buff 1
4. Limestone, blue 1
3. Limestone, buff, cherty 2
2. Limestone, blue 3
1. Limestone, gray 4
Total 34i;
,-j
The limestones below the shale member number 9 are the upper
layers of the Forbes limestone. In the bed of the creek are several
additional feet of limestone belonging to this formation. The
upper part of the section is the base portion of the Braddyville
beds.
On the Millner farm, about one hundred rods above the bridges
on the creek, thirty feet of Nishnabotna sandstone rests upon the
black shale number 14. In tho year 1900 Doctor Calvin and the
84 IOWA ACADEMY OF SCIENCE
writer found specimens of Anomphalus rotulus in the shale bed
number 9. The dominant fauna of this horizon is Ambocoelia
planocanvexa, both valves, and Pugnax uta.
One mile north of Stennett on the west side of the river, about
one hundred yards above the old mill site, road grading has ex-
posed twelve feet of Nishnabotna sandstone, the base of which
must reach nearly down to the Platte shales. For a distance of
one-half mile south of the mill site in the bluffs on the west side of
the river, is the location of the old extensive quarries of the past ;
at present they are so obscured by slumping no section can be
obtained.
Directly west of Stennett recent road grading has uncovered
the contact of the Platte and Forbes formations at the foot of the
bluffs.
SECTION ONE-HALF MILE WEST OF STENNETT.
FEET INCHES
7. Limestone, in thin layers badly shat-
tered 5
6. Limestone, gray, cherty 1 6
5. Limestone, shaly 2
4. Shale, gray 1
3. Shale, black, carbonaceous 1 6
2. Shale, gray, calcareous 2
1. Shale, blue 4
Total 17
Several thin bands in the shale number 2 are almost entirely
composed of specimens of Chmietes granulifer and Squamularia
perplexa. The strata dip at the rate of twenty-five feet to the
mile, north of east from the outcrops west of the river to Pilot
creek. A number of the gray limestone layers carry many nodu-
lar masses of black chert, and in places are oolitic in texture.
Of all the limestones in the Carboniferous of southwestern Iowa
the Stennett limestones deserve the name of Fusulina limestone.
In past years when the quarries were in active operation, in
the debris, at the foot of the limestone ledges Fusulina could be
found in millions. There seems to be a varietal or even a specific
difference in the Fusulina at Stennett and those at McKissicks
Grove; the former are large and globular, the latter long and
curved forms.
GEOLOGY OF SOUTHWESTERN IOWA 85
Two miles southwest of Stennett on the Red Oak wagon road
and one-fourth mile from a coal prospect tunnel the following
is seen in outcrop :
FEET
2. Sandstone, yellow, friable 5y2
1. Limestone, gray 3
The sandstone number two is the same as that exposed in
the quarries east of Haynies, and immediately underlies the
blue shale, number one in the section west of Stennett.
COMPOSITE SECTION OF DIFFERENT OUTCROPS IN THE
VICINITY OF STENNETT.
FEET
Limestone, gray, two layers 2
Shale, black 3
Shale, gray, calcareous 5
Limestone, gray, one layer 2
Shale, gray, calcareous 2
Limestone, gray, one layer V/2
Shale, buff and gray 3%
Limestone, variable 17
Shale, gray 1
Shale, black, carbonaceous 1%
Shale, gray, calcareous 2
Shale, blue 4
Sandstone, yellow, friable 5%
Limestone, gray .' 3
The late Doctor Calvin maintained that the strata in south-
western Iowa below the Nyman coal were abyssal sea deposits;
those above this coal mostly marginal, as shown by spheroidal
lumps in the limestones and ripple marked sandstones ; also that
the Nodaway coal was formed in a marine swamp, as the bottom
and roof shales of this coal have an abundant marine fauna. A
careful search has been made for fossils of the Lingula group,
as these are good evidence of shallow water deposits, with the
result that only a few doubtful forms have been discovered. The
upper limestone above the cap rock of the Nyman coal not being
a constant horizon it is thought best to leave it unnamed, as it
can not be identified in the state of Missouri, within a few miles
of the Iowa state line.
86 IOWA ACADEMY OF SCIENCE
Collections of fossils have been made at Stennett, near Thur-
man, Hamburg, McKissicks Grove, and Mill creek, south of
Riverton. The lower twenty feet of shales above the Tarkio lime-
stone and the Nyman coal cap rock at McKissicks Grove are
highly fossiliferous, while the upper arenaceous limestone is
sparingly so. It is thought advisable to list the fauna of the
tipper limestone at Thurman and Mill creek separately.
THURMAN FAUNA.
Foraminifeka — Hustedia mormoni.
Fusulina secalica. Marginifera wabashensis.
Anthozoa — Productus cora.
Lophophylluni profundum. Productus semireticulatus.
Crinoidea — Pugnax uta.
Ceriocrinus hemisphericus. Seminula argentea.
Bryozoa — Spirifer cameratus.
Fenestella perelegans. Pelecypoda —
Fistulipora nodulifera. Allorisma terminale.
Rhombopora lepidodendroides. Aviculopecten occidentalis.
Brachiopoda — Edmondia nebrascensis.
Ambocoelia planoconvexa. Myalina swallovi.
Chonetes geinitzianus. Gastropoda —
Chonetes granulifer. Euphemus carbonarius.
MILL CREEK FAUNA.
FORAMINIFERA — PELECYPODA —
Fusulina secalica. Aviculopecten providencesis.
Brachiopoda — Myalina swallovi.
Chonetes geinitzianus. Gastropoda —
Chonetes granulifer. Bucanopsis marcouanus.
Spirifer cameratus.
It is a surprise that Aviculopecten providencesis should be
found so high in the Carboniferous. The identification can not
be mistaken, for, as stated by Beede, it is easily separated from
the other Carboniferous species by its large size and fasciculation
of the striae.
McKISSICKS GROVE FAUNA.
Lowe Shale Fauna.
Foraminifera — Rhombopora lepidodendroides.
Fusulina secalica. Brachiopoda —
Anthozoa — Ambocoelia planoconvexa.
Lophophyllum profundum. Chonetes geinitzianus.
Crinoidea — Chonetes granulifer.
Ceriocrinus hemisphericus. Dielasma bovidens.
Bryozoa — Enteletes hemiplicata.
Fistulipora nodulifera. Hustedia mormoni.
GEOLOGY OF SOUTHWESTERN IOWA
87
Meekella striatocostata.
Orthothetes crassa.
Productus cora.
Productus costatus.
Productus nebrascensis.
Productus punctatus.
Productus semireticulatus.
Pugnax uta.
Rhipidomella pecosi.
Seminula argentea.
Spirifer cameratus.
Pelecypoda —
Aviculopecten occidentalis.
Aviculopecten whitei.
Edmondia nebrascensis.
Entolium aviculatuin.
Leda bellistriata.
Myalina perattenuata.
Myalina subquadrata.
Myalina swallovi.
Parallelodon tenuistriatus.
Schizodus wheeleri.
Gastbopoda —
Aclisina stevensana.
Bucanopsis marcouana.
Bucanopsis montfortiana.
Euompbalus catilloides.
Eupbemus carbonarius.
Pbanerotrenia grayvillensis.
Nyman Coal Cap Rock Fauna.
FOBAMINIFEBA —
Fusulina secalica.
Bbyozoa —
Rbombopora lepidodendroides.
Brachiopoda —
Ambocoelia planoconvexa.
Cbonetes granulifer.
Enteletes bemiplicata.
Marginifera longispina.
Orthothetes crassa.
Productus costatus.
Productus semireticulatus.
Pugnax uta.
Seminula argentea.
Spirifer cameratus.
Pelecypoda —
Myalina subquadrata.
Gastbopoda —
Euomphalus catilloides.
Phanerotrema grayvillensis.
Trilobita —
Griffithides scitula.
Upper Limestoxe Fauna.
Bryozoa — Pugnax uta.
Rhombopora lepidodendroides. Pelecypoda—
Brachiopoda — Myalina swallovi.
Ambocoelia planoconvexa.
As many of the fossils collected at Stennett were found in the
debris of old quarries it is impossible to discriminate closely
between horizons. Those found in situ in the Braddyville and
Platte formations are listed separately.
The species of Orthothetes differs from Orthothetes crassa
found in the shales associated with the Nodaway coal, as it is
much larger, with the dorsal valve more convex. It is doubtfully
identified as Orthothetes rohusta.
88
IOWA ACADEMY OF SCIENCE
STENNETT FAUNA.
Braddyville Formation.
FORAMINIFERA
Fusulina secalica.
Brachiopoda — ■
Ambocoelia planoconvexa.
Dielasma bovidens.
Hustedia mormoni.
Orthothetes robusta.
Platte Formation.
Productus cora.
Pugnax uta.
Seminula argentea.
Spirifer cameratus.
Gastropoda —
Anomphalus rotulus.
Axthozoa —
Lophophyllum profundum.
Brachiopoda —
Chonetes granulifer.
Marginifera longispina.
Productus cora.
Productus symmetricus.
Seminula argentea.
Squamularia perplexa.
Forbes Formation, Main Ledge, and in Debris.
FORAMINIFERA
Fusulina secalica.
Anthozoa — -
Lophophyllum profundum.
Crinoidea —
Ceriocrinus hemisphericus.
Eupachycrinus tuberculatus.
Hydreionocrinus mucrospinus.
ECHINOIDEA
Archaeocidaris agassizi.
Archaeocidaris dininni.
Archaeocidaris hallanus.
Archaeocidaris triserrata.
Bryozoa—
Fenestella tenax.
Fistulipora nodulifera.
Polypora submarginata.
Marginifera longispina.
Meekella striatocostata.
Productus cora.
Productus costatus.
Productus nebrascensis.
Productus semireticulatus.
Pugnax uta.
Rhipidomella pecosi.
Seminula argentea.
Spirifer cameratus.
Spiriferina kentuckiensis.
Squamularia perplexa.
Pelecypoda —
Allorisma terminale.
Chaenomya minnehaha.
Myalina swallovi.
Schizodus wheeleri.
Rhombopora lepidodendroides. Gastkopoda-
Septopora biserialis.
Brachiopoda —
Ambocoelia planoconvexa.
Chonetes granulifer.
Chonetes verneuilana.
Dielasma bovidens.
Enteletes hemiplicata.
Hustedia mormoni.
The writer in the past has used the nomenclature of Grabau
and Shinier in "North American Index Fossils." However,
certain changes should be made, as some of the specific names
used are synonyms.
Bellerophon percarinatus.
Euomphalus catilloides.
Euphemus carbonarius.
Platyceras parvum.
Soleniscus intercalaris.
Cephalopoda —
Orthoceras knoxense.
GEOLOGY OF SOUTHWESTERN IOWA 89
Chonetes gcinitzianus, Waagen, for Chonetes glabra; Lopho-
phyllum distorta, "Worthen, for LophoplniUnm west; Margini-
fera teabashensis, Norwood and Pratten, for Marginifera muri-
catus; Orthoceras knoxense, McChesney, for Orthoceras rushi nsi
as stated by Meek in "Final Report on Nebraska;" Soleniscus
paludinaeformis is probably equivalent to Soleniscus intt rcalaris,
Meek and Worthen, although this species has a strong fold on
the columella which seems to be absent in Meek's description
and figure. The substitution of Echinocrinus for Archaeocidaris
is a biological misnomer, and the term is not used. There is no
marked change in the brachiopod species in the whole series of
strata ; Productus pertenuis has not been found below the Noda-
way coal or Squamularia perplexa above the Platte shales. The
dominant feature of the Stennett limestone is the numerous spe-
cies of Archaeocidaris. No limestone in southwestern Iowa has
such an abundance of Fusulina. The dominant feature in the
lower limestone fauna on the Nodaway is Spirifer cameratus.
Mr. Hy Clement of MeKissicks Grove conducted the writer
to outcrops a stranger would never discover. Studies of the
Structural and Economic Geology of this part of Iowa are in
progress.
BIBLIOGRAPHY.
Geo. H. Girty, Fauna of the Wewoka Formation: Bull. U. S.
Geol. Survey, No. 544, 1915.
Hinds and Greene, Stratigraphy of the Pennsylvania]! of Mis-
souri : Missouri Geol. Survey, Vol. 13, 1915.
Clias. B. Keyes, Synopsis of American Paleozoic echinoids :
Proc. Iowa Acad. Science, Vol. 2, 1895. Foundation of exact
Geologic Correlation : Proc. Iowa Acad. Science, Vol. 22,
1915.
Samuel Calvin, Geology of Page County: Iowa Geol. Survey,
Vol. 11, 1900.
Pirsson and Schuchert, Text Book of Geology: Intraforma-
tional conglomerates. 1915.
C. D. Walcott, Paleozoic intraformational conglomerates: Geo-
logical Society of America. Bull. Vol. 5, 1893.
LEVELS AND TEMPERATURE OF LAKE OKOBOJI 91
RECORDS OF OSCILLATIONS IN LAKE LEVEL AND
RECORDS OF LAKE TEMPERATURE, AND OF
METEOROLOGY, SECURED AT THE MACBRIDE
LAKESIDE LABORATORY, LAKE OKOBOJI, IOWA.
JULY, 1915.
JOHN L. TILTON.
At the Macbride Lakeside Laboratory, Milford, Iowa, the
writer began a series of observations last summer (1915) for his
own information to ascertain what the fluctuations were in the
level of the lake, and to determine the relative value of the
causes that operated to produce those fluctuations. It soon be-
came evident that the records sought were desired also by teach-
ers in other departments because of the bearing of such data on
life zones and conditions in the lake. Since then the government
has called for all data available on evaporation in Iowa. The
data are therefore here presented that they may be of immedi-
ate use and on file for future reference.
To detect the oscillations in the level of the lake it first be-
came necessary to devise a piece of apparatus for that purpose.
A closed hollow cylinder two inches in diameter was placed as a
float in a larger cylinder three inches in diameter, closed at
the bottom. Through the sides of this outside tube a few nail-
holes were punched to let in the water slowly so that the
float inside of this tube would rise and fall gradually but not
move perceptibly for small waves. This was placed in a vertical
position in the water close to the boathouse where the water
was about four feet deep. It was found that waves five or six
feet from crest to crest and perhaps a foot from trough to
crest would move the float about the twentieth of an inch. When
a steamer made a landing the float would rise and fall about
three-eights of an inch. To an upright rod fastened to the float a
thin strip of brass was attached, on the end of which was a pen
which traced all vertical movements on a cylinder that revolved
once a week by clock work. The revolving cylinder, the pen
and penholder, were parts of a thermograph which was thus
made to serve present purposes.
92
IOWA ACADEMY OF SCIENCE
As might be expected the tidal effect (estimated at .0016 inch)
could not be detected at all in a direct reading device of this
kind; but the conditions involved deserve attention. The dis-
tance from the laboratory to Arnold's Park (west to east) is
Fig. 4 — The recorder of variations in the level of the lake.
two and three-fourths miles. From this line north to the head
of the lake the distance is three and a half miles, approximately
the same as the east and west stretch of water. When the east
and west stretch alone is considered it should be low tide when
the moon rises and high tide when the moon sets, with neutral
effect when the moon is on the meridian. When the north and
south stretch alone is considered it should be high tide when the
moon is on the meridian, with neutral effect when Vhe moon
rises and when it sets. Thus even these minute differences
almost exactly neutralize each other.
Oscillations due to changes in barometric pressure were also
too minute to be detected by direct registration without magnifi
cation. One of several computations made to ascertain the mag-
nitude of such oscillations resulted as follows : On June 30 the
weather map gave a barometric pressure of .00041!/^ pounds
per square inch at West Okoboji (at the. north end of the lake)
in excess of that at the laboratory, which pressure would be
counterbalanced hydrostatically by a rise of .00095 inch in the
level of the lake at the laboratory. This difference in barometric
pressure was one of the most marked differences that occurred
during the period of observation.
LEVELS AND TEMPERATURE OF LAKE OKOBOJI
The inflow at the head of the lake, and the outflow over the
dam were not gauged, but by inspection they were judged fair-
ly to compensate each other.
The main changes in level were due to evaporation, to precipi-
tation and to strong winds. For each continuous period of
evaporation without strong wind there was a steady drop in
the level of the lake of from .1 to .3 inch per day. A similar
effect of evaporation was detected when from the height marked
by the gauge the rise due to precipitation was subtracted. The
records of evaporation and of precipitation were obtained from
a glass battery jar about eight inches in diameter and eight inches
high placed over the lake and about a foot above it.
The rise due to precipitation was very evident, at one time
carrying the pointer above the cylinder. (The rise due to pre-
cipitation may be seen in the records for July 6, 11, 15, 19, 26
and 30. Apparently friction slightly interfered with the free-
dom of motion of the pen the first week.)
The total drainage area of the lakes "West and East Okoboji
estimated from the county map of the Iowa Geological Survey
is fifty-five square miles; the area of the lake itself eight and
four-tenths square miles. One inch of rainfall over the drainage
area would raise the level of the lake 6.55 inches if all of the
precipitation were to reach the lake. Evidently much of the
precipitation would soak into the ground and later be evaporated
without reaching the lake at all. Precipitation is generally
unevenly distributed over the area in thunder storms, and the
immediate effect on the level interfered with by the wind. In
one instance precipitation of 1.2 inches at the point of obser-
vation was actually accompanied by a fall in the level of the
lake at that point.
Rise and fall due to the wind was not so great as was ex-
pected, for the crests of the waves under strong wind pressure
present a deceiving appearance. Apparently the differences in
level due to the wind are quickly relieved by a general com-
pensating movement in the lake. In general a strong wind
from the southwest, west and northwest causes a slight fall
in the level of the surface of the lake at the laboratory, while
a strong northeast, east and southeast wind causes a corre-
sponding rise in the surface at the laboratory. Effects of the
wind in lowering the level of the lake at the laboratory may
94
IOWA ACADEMY OF SCIENCE
be seen in the record for June 29, July 1, 10, 11, 14, 16, 19,
20, 25. Effects of the wind in raising the level of the lake
at the laboratory may be seen in the record for July 9, 12, 16
and 28. The effect of large waves superimposed on the effects
of evaporation, precipitation and wind are to be noticed in the
tracing for June 29, 30, July 7, 12-14, 15 (very pronounced),
19, 20, 21, 22, 24-25, 27-28.
THE TEMPERATURE OF THE LAKE.
Three series of observations of the temperature of the lake
were obtained : one at the end of the pier at the laboratory
Fig.
-Apparatus used to ascertain the temperature of the water at
different depths.
where the water was six and a half feet deep ; one, half way
between the pier and the spit and hook at the entrance to the
bay; and one close to the center of oscillation of the lake, as
Iowa Academy Science
Plate III
Temperature curve for Lake Okoboji, August 5, 1915.
96 IOWA ACADEMY OF SCIENCE
near as possible to the place where the record of depth when
the lake was surveyed was 132 feet. The records of temper-
ature were taken by a minimum thermometer kept in a hori-
zontal position and weighted so as to sink readily.
The following are records of the temperature at the bottom
of the lake near the center of oscillation July 13 :
Depth
Temperature Fahr.
Feet
Degrees
85
59
135
56
124
55
115
59
124
59
115
58 y3
Series
of temperatures obtained August 5, 1915:
Depth
Temperature
Fahr. Depth
Temperature Fahr
Feet.
Degrees.
Feet.
Degrees.
0
68.0
50
66.0
5
67.0
55
64.2
10
67.1
60
62.9
15
67.3
65
60.5
20
67.1
70
61.3
25
67.1
80
61.1
30
67.1
90
60.7
35
67.3
100
60.0
40
67.4
110
56.5
45
66.0
115
59.8
At the end of the pier at the laboratory: at surface, 68.7°;
at the bottom, 67.1° (six and a half feet deep).
Half way between the pier and the hook : at the surface, 68.3° ;
at a depth of 5 feet, 67°; at the bottom, depth 10 feet, 67°.
The daily observations of the temperature of the . water at the
end of the pier are recorded with meteorological data in tables
at the end of this paper.
The observations at the end of the pier give a surface tem-
perature of the water that follows the curve of maximum tem-
peratures of the air. The curve of maximum temperature
varied with the amount of sunshine. The surface temperature
of the water fluctuated between 64° Fahr. and 75° Fahr., often
in the morning toward the latter part of the month being above
the temperature of the air at the time, and also above the tem-
perature of the air during stormy weather. A day of bright
sunshine with little wind produced a rise of a degree or two in
the temperature of the surface water. In the evening the dif-
LEVELS AND TEMPERATURE OF LAKE OKOBOJI 97
ference in temperature between the surface at the end of the
pier and the bottom at the same place (six and a half feet deep)
was sometimes as much as two degrees, at one time after a day
of bright sunshine with little wind amounting to five degrees
(July 12). Even this large difference in temperature was
nearly equalized by circulation during the night. A little wind
was commonly enough to bring in and down the warm surface
Avater of the lake, or to blow out and away the warm surface
water, causing the colder water below the surface to rise. The
morning observations often gave the same temperature at the
surface as at the bottom at the end of the pier, and but three
times (July 5, 14 and 30) giving a greater difference than one
degree. These were days of bright sunshine and little wind.
The data for the temperature curve of the lake were ob-
tained the fifth of August, as late as it was convenient to gather
the data. Unfortunately the entire week preceding that date
was characterized by clouds, strong wind and somewhat of rain-
fall, which condition accounts for the irregularity noticeable
in the curve of temperature. Even in this irregularity the
planes of demarcation of the three zones are pronounced. The
area of the hypolimnion extends from near Terrace Park north-
ward through the central portion of the lake to opposite the
center of Omaha Beach. The thermocline extends over this
area and a little to each side of it from Terrace Park to Omaha
Beach and then extends northward to opposite Pikes Point.
It is to be noted that within the epilimnion (where the water is
forty feet or less in depth) is included the waters of all the
bays of "West Okoboji, all of Lower, Middle and Upper Gar
Lakes, and all of East Okoboji for which data on depth are
recorded. The volume of water of West Okoboji included in
the epilimnion at the time of observation, which was very nearly
the maximum for the year,* is computed as approximately
171,540,503 cubic yards. The volume in the thermocline, twenty-
five feet thick, is approximately 72,709,309 cubic yards, and the
volume in the hypolimnion approximately 38,713,961 cubic
yards. The above figures are based on the soundings made in
1905 by the engineering students of Iowa State College.
*Edward A. Birge and Chancey Juday, "A Limnological Study of the
Finger Lakes of New York," Bulletin of the Bureau of Fisheries, Vol. 32,
1912, Document No. 791, page 546.
98 IOWA ACADEMY OF SCIENCE
THE METEOROLOGICAL DATA.
The month of July, 1915, is reported to have been an unusually
cold and rainy month for that time of the year. The maximum
temperature ranged between 70° and 87° Fahr., and the mini-
mum from 44° to 70.5° Fahr. The relative humidity varied
from 52 per cent to 100 per cent, was often close to 100 per cent
and very often above 90 per cent. The details of the data are in
the tables that follow, and are made use of in the analyses of the
curves.
COMMENTS ON PLATES III AND 111 A.
On June 30 the barometric pressure at the north end o£ the lake
in excess of that at the laboratory was sufficient to cause a rise of
.00095 of an inch in the level of the lake at the laboratory. The
preceding day there was no difference in the barometric pressure
at these two extremes, but there was a gradual fall in the level
of the lake, suggesting the need of a record of precipitation, evap-
oration, intake and outflow. Observations on precipitation and evap-
oration were begun July 5.
July 1 the level of the water fell quickly a quarter of an inch on
change of wind from southeast to northwest.
July 3 the excess of barometric pressure at the laboratory over that
at north end of the lake should have caused a lowering of the water
of .0021 of an inch at the laboratory and have maintained that differ-
ence that day and the next. To make such a variation evident the
apparatus should magnify the movement at least thirty times, and
preferably fifty.
July 5 a light southwest wind during the afternoon, aided some-
what by evaporation, sent the pointer below the bottom of the scale.
July 7 the wind shifted to the nortneast, and the water rose quickly
one and one-half inches (from the bottom of the scale to that height),
which level it maintained approximately for about three days.
July 7 the excess of barometric pressure at Arnold's Park over
that at the laboratory would cause a rise of .015 of an inch.
July 8 the excess of barometric pressure at East Okoboji (north
end of the lake) would cause a rise of .03 of an inch in the level of
the water at the laboratory.
July 12-15. If allowance be made for evaporation the general course
of the line is horizontal during a short period of clear weather with
medium to light winds. There are, however, rythmic curves noticeable
with a maximum variation of about one-fifteenth of an inch on the 12th,
13th and 14th, apparently due to variations in the wind; and also
variations lasting from one to three hours amounting to 1-30 inch for
which no suitable explanation is at hand. The long variations of ap-
Iowa Academy Science
Plate IIIA
Graphs of fluctuations in the level of the lake from June 2S to July 31, 1915.
The heavy line gives the fluctuations and the light line the barometric
pressure; other related data are included.
100 IOWA ACADEMY OF SCIENCE
proximately half an inch are thought due to waves caused as a
steamer made a landing and left, as these lines were made in the
daytime and at hours when the steamer was due.
July 15. There was a strong southeast wind till the rain began to
fall; then the wind shifted and blew hard from the southwest at about
3:30 P. M. The precipitation amounted to one and one-half inches,
but the gauge recorded a rise of only half an inch, the difference
being due apparently to the strong wind.
July 16. The pronounced rhythm is not due to the effects of the
storm because the line is straight from midnight to daybreak and
straight again Friday night. It is possible the rhythm is due to
changing winds of which there is no exact record.
July 17. There was heavy precipitation and changing winds of
which there is no record, excepting as the heavy precipitation raiser!
the pen above the revolving cylinder of the gauge (1 and 5-16 in.)
Apparently there was a fall of 3-32 inch at eleven o'clock A. M., just
before the rain came.
July 19-25. The graph is characterized by a constant and almost
uniform lowering of the level of the lake due to evaporation, equalized
by a somewhat strong northwest wind on the 24th, when the line traced
became almost horizontal. The remainder of the week the wind was
light and the barometric gradient zero.
July 26. The rise was due to precipitation.
July 28. The marked rise of three-tenths of an inch was due to the
wind which then began to blow from the northwest.
July 30. The rise was due to precipitation.
SUMMARY.
Tidal effects were almost zero, barometric effects too small to
be detected without magnification, and intake and outflow about
equal. Wind effects were noticeable, and when strong wind
was not prolonged, were quickly compensated by movement in
the lake. The wind directed the circulation in the lake. The
division of the lake water in epilimnion, thermocline, and hypo-
limnion was pronounced, even after strong winds. Evaporation
amounted to about two-tenths inch per twenty-four hours. Rain-
fall caused an immediate rise in the hydrograph.
METEOROLOGICAL DATA AT LAKE OKOBOJI
101
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FAULT SYSTEMS TN IOWA
103
CONTROLLING FAULT SYSTEMS IN IOWA.
CHARLES KEYES.
With its even plains surface, the infrequency of bed-rock
exposures, and the universal presence of thick till or loess man-
tles, detailed geologic mapping of the prairie states is attended
by many inherent difficulties not met with in more broken
country. In consequence of the existence of these unusual
conditions the consideration of possible noteworthy geotectonic
features in the region is largely neglected. Anything beyond
a few of the most obvious local characters completely fail of
record. Over a very large part of the Mississippi basin the
tectonics are commonly treated as if there were none at all. It
seems to suffice to regard the strata as essentially flat-lying and
as having no pretense to deformation of any kind. In Iowa, for
instance, beyond the general assertion that the foundation rocks
dip gently to the southwest no further note is made of the local
or broader tectonic characters.
Lately, both in our own state and in neighboring states, the
neglected problems in regional tectonics have been attacked
from new and unexpected quarters. Novel data have been ob-
tained. Long known but isolated facts have been reviewed, re-
interpreted, and recorrelated. The trend of most fruitful in-
quiry has been pointed out. In Iowa, especially, results quite
surprising have been reached. Attention already has been di-
rected1 to the Triassic mountain-building which took place with-
in our boundaries. Particular interest also attaches to the re-
cent determination2 of the distinct synclinorial character of the
Iowa coal basin. Now note must be made of another instruc-
tive phase of the regional tectonics and the discovery of what
appears to be two well-defined systems of faulting on a large
scale that has heretofore eluded detection.
The lines of faulting of the two systems trend nearly at right
angles to each other. In the system which prevails in the east-
ern part of the state the direction of fracture is northwesl and
iProc. Iowa Acad. Sci., Vol. XXI, 1914, p. 181.
2Ibid., Vol. XXII, 1915, p. 268.
104 IOWA ACADEMY OF SCIENCE
southeast. The amount of displacement is large. The spacing
is wide. The ruptures are long and somewhat curved. In the
other system, which is confined to the western portion of the
state, the value of the movement figures is not nearly so great
as in the case of the other; yet it is still quite notable. The
space beween successive faults represents a distance of about
twenty-five miles. Both systems of faults appear to have greater
displacement values outside of the state and to vanish within
the boundaries of our commonwealth. The faults extend lat-
erally far into neighboring states. (Plate IV.)
At this time it is not necessary to go exhaustively into des-
criptive details concerning the individual faults, since these
features are in another connection subject of extended discus-
sion. The most conspicuous of the displacements is the Cap-
au-Gres fault. It is the most notable line of recent dislocation
found anywhere in the Mississippi valley. Its salient features
are best displayed on the Mississippi river near the mouth of
the Illinois river. The sandstone headland which marks its
position there has been a. prominent landmark to early voya-
geurs and rivermen for a period of more than two and a half
centuries. The upturned edges of the strata constitute one of
the most extensive and complete geological sections on the con-
tinent. "Within a distance of one short mile along the river
bluff, at Folley station, the entire Paleozoic succession, from
Cambric dolomites to Coal Measures, is exposed. Measurements
indicate a vertical displacement of more than 1,000 feet. So
admirably are the disturbed rocks displayed that a photographic
print of the bluff clearly retains all the structural features.3
The line of the Cap-au-Gres rupture extends from Leon, in
southern Iowa, to Vincennes, Indiana, a distance of 400 miles.
At its eastern extremity the fault passes into a fold, probably of
monoclinal rather than anticlinal character, that gives rise to
the great oil reservoir of eastern Illinois and western Indiana.
The western extension likewise passes into a fold which furnishes
the most favorable conditions in our entire state for tVie occur-
rence of oil and gas. At the southern boundary of Iowa the
line of this fault is conspicuously marked on the surface of the
ground by a long eastward protrusion of the Bethany lime-
stone, the basal terrane of the Missourian series. This tongue
carries the Bethany formation a distance of fifty miles beyond
3See Proc. Iowa Acad. Sci., Vol. V, 1898, p. 5S.
Iowa Academy Science
Plate iv
Major faults in Iowa.
106 IOWA ACADEMY OF SCIENCE
its norma] eastern boundary as usually mapped. As it enters
Iowa the Cap-au-Gres fault has a displacement of 100 feet,
so that here it is still a fracture of considerable moment.
Another notable fault-line, which merits fuller investigation
than has been heretofore accorded it and about which so far
as Iowa is concerned relatively little is yet definitely known,
exists near Dubuque. It has a throw of fifty to seventy-five
feet. One reason for its not being better understood doubtless
is the fact of its position for many miles in the channel of the
Mississippi river. According to the maps of Illinois this fault-
line appears to be really the northwestern extension of the
great La Salle fault, which at the town of La Salle has a dis-
placement of quite 1,000 feet. Illinois geologists claim that the
La Salle fault has a north and south trend ; but the geological
maps of the region clearly indicate otherwise, and many other
recorded facts fully corroborate the testimony of the maps.
Between these two great fault-lines are several rather sharp
folds which may pass elsewhere into faults. None of these
has been examined yet in detail. They may prove to be regu-
larly spaced and thus form a part of a definite fault system.
It is, however, to the remarkable fault system of the western
part of the state that attention is here especially directed. Two
faults in particular merit full notice at this time because of the
fact that their discovery necessitates extensive rectification of
geologic boundaries. There are, also, economic bearings
which are of great local importance. The two most instructive
ruptures of this western system are the ones passing near Red
Oak and near Fort Dodge.
For such a profound fracture, with its maximum displace-
ment of not less than 400 feet, the Red Oak fault makes singu-
larly inconsequential impress upon the local relief expression.
In one direction it appears to extend beyond the city of Des
Moines; in the other to Hebron, Nebraska. — a distance of 300
miles. Its features are best displayed at its crossing of the Mis-
souri river, at Wyoming, a short distance above Nebraska City.
When the disturbance was first noted at this point it was
thought to represent a sharp monoclinal fold; and it was so
interpreted by Professor J. E. Todd.4 Later investigation on
the Iowa side of the river, near Truman, showed that there was
4Proc. Iowa Acad. Sci., Vol. I, 1890, p. 58.
FAULT SYSTEMS IN IOWA 107
practically no tilting of the strata, but that the lower beds on
the north side of a given point abutted higher Layers of the
south side.
The detection of this notable fault-line fully explains why.
during the attempt to map geologically Montgomery county,
the Cretacic formations were so well exposed throughout the
southern half of the county, but were apparently entirely absenl
in the northern part. Planation had entirely removed the higher
Mesozoic beds 011 the north, but had not touched those to the
south, where they were deeply depressed and thus escaped ob-
literation. Another hitherto inexplicable fact, which now ap-
pears to be satisfactorily cleared, is the abrupt change of litho-
logic character which has been long known in the Des Moines
river section a few miles north of the city of Des Moines. For
more than a generation this had been one of the most perplexing
problems in Iowa geology.
The Fort Dodge fault is particularly noteworthy because of
the fact that to it the great Iowa gypsum field directly owes its
preservation; and important chalk deposits exist as outliers
eighty miles east of their normal outcrops. As recently acquired
the details on this dislocation are unusually full and may be
with advantage summed up here. They are all displayed in an
exceptionally clear manner within the limits of the city of Fort
Dodge.
The abrupt termination of the thick gypsum bed at the Cum-
mings quarry, in the south bluff of Soldier creek, in north
Fort Dodge, and its replacement at the same level on the north
side of the narrow valley by the St. Louis limestone and coal
measures calls at once for a more critical examination of the
causes therefor than has been hitherto given to the phenomena.
In this district there is a general rising of the limestone towards
the north; but in the same direction a marked falling of the
gypsum. At the mouth of Soldier creek the gypsum layer co
down to a level below that of the creek bed. It is this fact
mainly that has in the past given rise to the inference that the
gypsum finally rests directly upon the 'limestone, especially
since the latter crops out in the banks of the creek and in the
ravines within a distance of a few hundred yards beyond the
last known gypsum exposure.
About three-fourths of a mile upstream £rom the Cummi
locality, in Soldier valley, near the new brick plant, several es-
108 IOWA ACADEMY OF SCIENCE
pecially instructive exposures are now displayed. The valley
here is quite deep and narrow. There are, on one side of
the creek, the ruins of an old lime-kiln. The St. Louis lime-
stone, which was formerly quarried at this point to supply the
kiln, rises about twenty feet above the bed of the stream. Two
hundred feet to the southeast, in another bend of the creek,
the gypsum plate, overlain by thirty to forty feet of reddish,
sandy shale, outcrops at' water-level. Northwest of the lime-kiln,
about 400 feet, on the opposite side of the Soldier gorge, in the
clay pit of the brick plant, forty feet of coal measures are well
displayed. It seems hardly possible that the gypsum-plate, here
twenty-five feet in thickness, should wedge out abruptly and com-
pletely in so short a distance.
The most illuminating section of all in the entire region is
that at the south end of the long narrow ridge which separates
Soldier valley from that of the Des Moines river. Two excep-
tionally fine artificial exposures supplement the natural out-
croppings of strata. On the one side of the ridge the excavation
for one of the abutments for the country highway viaduct over
the Soldier gorge discloses, in fresh, clean face, over seventy-five
feet of the pink shales which immediately overlie the4 gypsum.
The latter lies in the bed of the creek a short distance away. The
Kohl Brewery section is near by, although now nearly com-
pletely obscured by talus. The two sections, which are easily
matched by the sandstone ledges, together give the following
sequence :
SECTION AT LOWER VIADUCT OVER SOLDIER CREEK.
Feet
8. Till, gray and pebbly 10
7. Shale, light reddish, sandy, banded 35
6. Sandstone, soft, buff, calcareous, massive 5
5. Shale, pink and white, sandy, in alternate layers.. 25
4. Sandstone, massive, buff 2
3. Shale, bluish 2
2. Shale, brown, sandy, with gypsum layers 7
1. Gypsum, massive (exposed) 10
This exposure is the most extensive one of the pink shales
yet disclosed. The thickness of the latter is therefore at least
100 feet.
On the opposite, or north side of the high ridge, is the huge
open clay-pit of the Fort Dodge Brick and Tile Company. The
FAULT SYSTEMS IX IOWA
109
bottom of the excavation is nearly, if not quite, down to the St.
Louis formation; and is about thirty feet above the level of the
water in the Des Moines river near by. Fully seventy feet of
shale are exposed in clean section, which presents the following
sequence of beds:
SECTION AT CLAY-PIT OF FORT DODGE BRICK AND TILE
PLANT.
Feet
9. Till, ashen, with pebble bands 15
8. Shale, blue, yellow and variegated 18
7. Sandstone, gray, massive 2
6. Shale, black and gray, with coal-seams 11
5. Shale, white (fire-clay) 2
4. Shale, light-colored and variegated 15
3. Shale, dark-colored, partly hidden at base 25
2. Sandstone, coarse, conglomeratic, ferruginous 1
1. Limestone, gray 30
In cross-section, the ridge appears as represented below
(figure 6), in which the gypsum-plate is noted to lie about thirty
feet beneath the level of the top of the adjoining St. Louis lime-
Port Dodge
Bride & T'ilejf
Pit £-.
CC'oa.l Measure:
.-.---. "shales
70'
Miocene:
Shales-^
^75'
to tr.
/
"T
1
— ~Z— - 1 o
£! /
i i
- St.
-zz — —zz. A to
1
— - ~-^z—- «L r^-t
1
__J 33' 1
- — r "^^///' 1 v^l
*" .,A Gypsum ^^^^
'&~~[
F
l
•/452-J. — » *~ yl
i ' i ' t ' i '
-Coal Measures Shsi
Fig. 6 — Details of Fort Dodge fault.
stone, and nearly one hundred feet beneath the top of the coal
measures of the clay-pit. In stratigraphic level there is thus a
discrepancy of more than one hundred feet between correspond-
ing parts on the two sides of the ridge.
On the west face of the ridge, in a railway cutting, near a
point where on the same level the pink shales appear to be ab-
ruptly replaced by the dark shales of the coal measures, an in-
consequential faulting of the first mentioned beds is plainly
110 IOWA ACADEMY OF SCIENCE
discernible. This slight fault has a throw of about six feet.
It is suggestive of the possibility of the greater displacement
being of the distributive order instead of being a single simple
break in the stratigraphic continuity.
At the old stone wagon bridge over Soldier creek, one-half
mile above the lower viaduct, and immediately north of the Rock
Island railway station, there is a singular physiographic sug-
gestion of notable faulting. For a distance of several miles be-
fore reaching this bridge the creek flows in a deep, narrow gorge.
At the point where the bridge spans the waterway the latter cuts
sharply into the hard St. Louis limestone, so as to form a small
canyon thirty feet wide and twenty feet in depth. The abut-
ments of the bridge are the two walls of the canyon. Less than
one hundred yards below the bridge the limestone, although
standing thirty feet above the creek bed, abruptly disappears.
The Soldier gorge opens out into a 'broad, flat-bottomed amphi-
theatre a thousand feet wide and half a mile long, the flat form-
ing an area sufficiently ample for utilization by the railroad
for its local yard purposes. The amphitheatre is excavated en-
tirely in the friable sandy shales which overlie the gypsum. No
sign of the St. Lonis limestone is to be seen save the point on the
north side where the creek debouches from its canyon.
On the west side of the Des Moines river, opposite the mouth
of Soldier creek, new and important data of an exact kind are
now available bearing upon the points in question. The exten-
sive excavations of the Fort Dodge Clay Works, the construc-
tion of the Omaha extension of the Chicago Great Western Rail-
way, the drilling of numerous deep wells, and the opening up
to inspection of many other sections, disclose a number of in-
structive facts which supply the long missing links in the solu-
tion of the gypsum puzzle. On this side of the river the gypsum
plate retains the same gentle slope to the northward, as it does
on the east side of the stream.
It is shown by drill-holes and by excavations that the gypsum
bed, fifteen to twenty feet in thickness, lies between seventy-five
and ninety feet beneath the upland prairie surface. This over-
burden is composed chiefly of glacial till. Beneath the gypsum
layer are sixty to eighty feet of shale — the coal measures ; then
the St. Louis limestone. The great thickness of the shale sec-
tion carries the limestone a considerable distance beneath the
Level of the water in the Des Moines river, a mile and a half
FAULT SYSTEMS IN IOWA 111
below the mouth of Lizard creek and half a mile below the
mouth of Soldier creek. Yet at the mouth of the Lizard the
limestone is abruptly encountered seventy Heel a'bove the water
level. It is an early observation of C. A. While and others that
no outcrops of gypsum occur for some little distance below the
mouth of Lizard creek; it is also a matter of early record thai
southward beyond the points just mentioned the gypsum sud-
denly appears in outcrop well up in the bluffs. For these
anomalies there has never been any adequate explanation of-
fered. As appears farther on, these features, together with
others, conclusively point to either abrupt flexing of the strata,
or notable dislocation in the continuity of the layers. Either
suggestion is a wholly unexpected phenomenon in this district.
In a region such as Iowa, where there is seemingly so little or-
ogenic disturbance, neither sharp folding nor extensive faulting
is ever appealed to. However, several extensive breaks in the
Iowa rocks are now known ; and other geotectonic features come
to light which give this phase of the State's geology a new trend.
On the geologic map of Webster county,"' the nearly straight
line which the north margin of the gypsum-bearing field makes
is in itself suggestive of structural rather than erosion al causes.
This aspect of the areal limits was not thought of at the time
the map was drawn. The fact of its location shows how accu-
rately is the delineation notwithstanding the circumstance that
the reason thereof was unknown.
As shown by outcrops and numerous well-sections located near
this line on either side, there is a marked discordance in the
meeting or matching of the various strata.
As already indicated, the amount of displacement at the in-
tersection with the Des Moines river is not less than 100 feet.
This may or may not be the maximum throw ; probably it is not.
Several features point to a greater development of the fault
towards the southwest.
The length of this great rent in the earth's crust is not yet
with accuracy determined. That it extends from Clarion, in
Wright county, to Wall Lake, in Sac county, a distance of eighty
miles, seems certain. That it is traceable beyond these points is
cpiite probable. It is safe to say that this fault is not less than
a hundred miles long.
sIowa Geol. Surv., Vol XII, 1902, p. l'J2.
112 IOWA ACADEMY OF SCIENCE
With the recognition of this fault-line a host of features relat-
ing to the distribution of the formations of the region, hitherto
puzzling or uncertain of determination, are fully explained.
North of Fort Dodge there are evidences of another fault
which passes through Pocahontas and which has a throw of
about eighty feet. The horizontal distance between the two
lines of displacement is approximately twenty-five miles. This
figure suggests the spacing value of the whole system. Plot-
ting upon the map of the state other lines to mark possible
positions of other faults we find abundant indications of the
presence of such features. One of these passing a short distance
south of Ames points to the isolated protrusion of Early Car-
bonic limestones being really produced by differential move-
ment along a line of rupture.
It is a well known fact established through extensive ex-
perience in mining operations that when the interval between
two parallel faults is determined that other faults are to be
expected at like intervals. This circumstance is traceable di-
rectly to the nature of the tortional strains which rock-masses
undergo. Whether or not such a high spacing value as twenty-
five miles is actually possible remains to be determined theore-
tically. The problem is readily susceptible of mathematical dem-
onstration as in the cases of fault systems of much closer pat-
terns as recently noted by G. F. Becker6; and it would be ex-
ceedingly instructive to apply the principles involved to the
Iowa situation.
In any case the general geological mapping of the state re-
quires fundamental rectification.
6Bull. Geol. Soc. America, Vol. IV, 1893, p. 13.
CHOUTEAU LIMESTONE 113
TERRANAL AFFINITIES OF ORIGINAL CHOUTEAU
LIMESTONE.
CHARLES KEYES.
In all the Mississippi valley there is no geologic formation
that is so misunderstood, or so illy considered as regards its
stratigraphic relations, as the massive, buff limestone terrane
immediately underlying the Burlington limestone of Missouri
and Iowa. Originally noticed by Prof. G. C. Swallow,1 in 1855,
as a thick, homogeneous lithologic unit typically developed in
central Missouri along the northern flanks of the Ozark dome,
and extended into other parts of the state as the uppermost
member of a tripartite "Chemung" group, little mention is
later made of it.
When, a generation after Swallow, Prof. H. S. Williams2
revived the title it was with an entirely different meaning; the
term then applying not to a terrane at all but to a fauna carried
by all of the Early Carboniferous rock-section beneath the
Burlington horizon. In this he followed Prof. G. C. Broad-
head3 who had, in 1874, proposed the name Chouteau Group to
take the place of Chemung Group of the previous accounts of the
region. In the earlier reports of the present Geological Survey
of Missouri4 the term, in Swallow's original sense', is repeatedly
recognized. Prof. E. M. Shepard reports5 the. formation in
its typical development to occur in Greene county, in south-
western Missouri. In the north, in Iowa, the Chouteau lime-
stone is not generally recognized by title, yet it is several times
so called in the central part of the state.0
In Illinois, where the Chouteau limestone is not known to
be represented, the terrane is commonly merged with the Kind-
erhook group, as is done by F. B. Meek and A. II. Worthen7.
Through the wide usage of the latter title Swallow's name is
1Missouri Geol. Surv., 1st and 2d Ann. Repts., p. 102, 1855.
2Bull. 80, U. S. G. S., p. 169, 1891.
3Missouri Geol. Surv., Rept. 1873-4. p. 26, 1874.
^Missouri Geol. Surv., Vol. IV, p. 57, 1894.
5Ibid., Vol. XII, 1898.
cIowa Geol. Surv., Vol. XXII. p. 154, 1913.
'Am. Jour. Sci., (2), Vol. XXXII, p. 28S, 1861.
8
114 IOWA ACADEMY OF SCIENCE
gradually lost sight of. Whenever reference is made to the up-
permost member of the succession it is called the Kinderhook
limestone8.
Singularly enough, since Swallow's time, the Chouteau lime-
stone in its original locality has never been carefully studied.
Few persons have taken the opportunity to inspect the type-
sections. The eastward attenuation of the formation, in eastern
Missouri, where it again reaches sky after burial in a broad syn-
cline, has made the terrane appear to be an unimportant mem-
ber of the so-called Kinderhook section.
In recent years a large number of deep-well records enables
the underground extent and thickness of many formations in
Missouri and Iowa to be accurately traced and determined far
from their lines of outcrop. Among the terranes of this class, is
the Chouteau limestone. The data bearing upon its stratigraphic
relations permit it to be clearly delimited from Minnesota to
Arkansas, a distance of more than 600 miles, As a definite litho-
logic unit and a sharply delimited terrane the Chouteau lime-
stone presents some features of more than local interest in gen-
eral geologic correlation.
At the original locality, at Chouteau Springs, central Missouri,
and at neighboring places in Saline, Cooper and Pettis counties,
the interval of 125 feet between the undoubted Devonian Calla-
way limestone and the Early Carboniferous Burlington lime-
stone is occupied by grey limestones. This circumstance leads
Professor Stuart Weller9 to regard the original Chouteau sec-
tion as representing the entire Kinderhook succession of other
parts of the Mississippi valley. Swallow10 from the first recog-
nized the fact that the entire section of his "Chemung" (Kinder-
hook) group, which in other parts of Missouri is a three-fold
division, is in the central portion of the state an unbroken se-
quence of limestone layers. Nevertheless?, he considers11 the lower
twenty feet as the Lithographic (Louisiana) limestone division;
and the middle part as replacing the Vermicular (Hannibal)
shales of elsewhere.
Recent observations showr that Swallow is mistaken only in a
single point. Not finding the Vermicular shales in distinct de-
velopment in Cooper county as elsewhere he assumes them to be
sIowa Geol. Surv., Vol. I, p. 56, 1893.
9Bull. Geol. Sop. America, Vol. XX, p. 321, 1909.
"Missouri Geol. Surv., 1st and 2d Ann. Repts., p. 195, 1855.
"Ibid., p. 103.
CHOUTEAU LIMESTONE
115
replaced by limestone. In other parts of Missouri he clearly con-
siders the Chouteau limestone as the upper member of his
' ' Chumung ' ' group.
GEOLOGIC CROSS-SECTION IN MISSOURI BETWEEN SEDALIA AND HANNIBAL
Fig. 7.
Two geological cross-sections constructed at right angles to
each other and intersecting at Chouteau Springs quickly set to
rights all the conflicting notions of the past fifty years concern-
ing the stratigraphic relations of the Chouteau limestone. One
cross-section extends from Hannibal (near Kinderhook, Illinois)
on the Mississippi river, to Sedalia, in Pettis county, a distance of
one hundred thirty miles (figure 7). The other section, fifty
Fig. 8 — Chouteau terrane at type locality.
miles in length, traverses Saline, Cooper and Morgan counties,
from the town of Marshall to thai of Versailles (figure 8). Both
sections are checked at frequenl intervals by rock exposures and
bv well records.
116 IOWA ACADEMY OF SCIENCE
As recently shown 12 the Early Carboniferous section beneath
the Burlington limestone, in northeast Missouri, embraces more
than the three members originally ascribed to it. Two other
members properly belong to its base. This section presents the
following succession :
Feet
Burlington limestone
Unconformity.
Chouteau limestone •. 30
Hannibal shales 75
Louisiana limestone 50
Saverton (blue) shales 50
Grassy (black) shales 40
Unconformity.
By reference to the principal cross-section (figure 8) it is noted
that the Chouteau limestone, which is a hundred feet thick at
the typical locality, gradually becomes thinner until it vanishes
completely just before the Mississippi river is reached, where the
Burlington limestone lies immediately upon the Hannibal shales.
On the other hand the Hannibal shales, which are seventy-five
feet in vertical measurement at the east end of the section, de-
cline in thickness westward until by the time Cooper county is
reached they disappear by attenuation, and the Chouteau and
(Louisiana members come together. The last mentioned lime-
stone, which is sixty feet thick at the Mississippi river, also be-
comes reduced to the west until in Cooper county it has only
about one-third its original measurement. It appears, therefore,
that Swallow13 was actually correct in assigning the lower twen-
ty feet of the Cooper county "Chemung" (Kinderhook) to the
Lithographic (Louisiana) limestone.
The Saverton shales, Grassy (black) shales, and the Snyder
(Devonian, Lime Creek) shales also chance to thin out towards
the west, so that at the western border of Cooper county the
Carboniferous limestones rest directly upon the Callaway (De-
vonian) limestones. Moreover, the Buffalo (Maquoketan) shales,
which are well developed on the Mississippi river, vanish com-
pletely within a distance of fifty miles of that stream. In central
Missouri there is, then, a rock succession extending from the St.
Peter sandstone to the Coal Measures that is without a single
shale or sandstone layer to relieve the limestone uniformity.
This is the reason why it is so difficult usually to interpret satis-
J2Am. Jour. Sci., (4), Vol. XXXVI, p. 160, 1913.
"Missouri Geol. Surv., 1st and 2d Ann. Repts., p. 103, 1855.
CHOUTEAU LIMESTONE 117
factorily the deep-well records of the region; and why driller's
logs are really more accurate than is commonly claimed for them.
Viewing the Chouteau limestone strictly as a lithologic unit,
delimited with unusual sharpness as it happens, several points
are to be especially emphasized. The eastern attenuated margin
of the formation very nearly coincides with the course of the Mis-
sissippi river from the mouth of the Iowa river to that of the
Missouri river. Nowhere does the terrane appear actually to
touch the banks of the great stream. Chouteau limestone is re-
ported to be represented at several points on the river, as at Lou-
isiana14 and Hannibal, in northeast Missouri, and at Burling-
ton13, Iowa. The thin bed referred to at these places may repre-
sent an earthy phase of the Burlington formation, for in this
region the latter formation actually rests in marked unconform-
ity upon the Hannibal shales.
In Iowa, north of the original locality, the Chouteau limestone
commonly goes under the title of Kinderhook Beds10. The for-
mation becomes thicker, reaching a measurement of one hundred
fifty feet in the central portions of the state. Near the Minnesota
boundary, where the Paleozoics are upturned as one limb of the
now truncated arch which once formed the Siouan mountains,
the thickness is even greater. The formation, after crossing this
great Triassie flexure, probably extends northwestwardly far
into Canada.
Between the Missouri river and the Minnesota state-line, a dis-
tance of more than three hundred miles, the Chouteau limestone
has a thickness of one hundred to one hundred fifty feet. Numer-
ous deep-well records in this belt enable the limestone plate to
be traced for a distance of seventy-five miles from its outcrop-
ping.
The axis of the broad syncline lying between Chouteau Springs
and Hannibal extends southwestward over the present Ozark
dome, which of course did not exist in Early Carboniferous times.
When the Kinderhook rocks again appear in southwest Missouri
the same tripartite character as presented in the north part of
the state seems to hold. At Springfield Swallow's original in-
terpretation17 of the sequence appears to be in the main correct.
With the elimination of the so-called Devonian beds of the same
"Am. Jour. Sci., (3), Vol. XLIV, p. 449, 1892.
15Bull. Geo], Soc. America, Vol. Ill, p. 285, 1892.
"Iowa Geol. Surv., Vol. I, p. 56, 1893.
"Missouri Geol. Surv., 1st and 2d Ann. Repts., p. 103, 1Sj5.
118 IOWA ACADEMY OF SCIENCE
section Prof. E. M. Shepard's recognition18 of the Chouteau,
Hannibal and Louisiana members also seems to be fully sub-
stantiated by recent observations. Still later Prof. Stuart
"Weller,19 from a critical study of the fossils found in the so-
called Northview sandstone (Hannibal), furnishes indubitable
evidence in support of the early interpretations. By showing
the identity of the Northview fauna with that of the beds lying
immediately beneath the Burlington limestone at Burlington,
Iowa, correlation with the Hannibal shale seems complete. At
Burlington the latter are known to cover the interval of fifty
feet between the base of the Burlington limestone and the hori-
zon of the Louisiania limestone.20
The correlation of the original Chouteau limestone with the
recently proposed Fern Glen formation, twenty miles west of
St. Louis, presents many uncertainties. South of the Missouri
river the lowermost Burlington limestones lose their character-
istic lithologic features. They no longer remain crinoidal breccias.
Texturally they strongly resemble the typical Chouteau and Lou-
isiana limestones. The red coloration, so conspicuous northward
at Burlington city, persists. As described in detail by Professor
Weller21 the fauna appears to be identical Avith that of the red
Burlington beds occupying the lower twenty to thirty feet of the
Iowa section. Aside from a few weeks7 collecting in the typical
Lower Burlington strata, by the late Doctor Wachsmuth and my-
self, no crinoids of consequence have been obtained at Burling-
ton in forty years, so that the determination of the zonal distri-
bution of these forms has not been recently possible. The figures
of the Fern Glen fossils seem to represent leading species which
Niles and "Wachsmuth22 long ago listed as characterizing their
Lower Burlington division of the Iowa section. These facts are
admirably brought out by Professor Weller23 in his late discus-
sion of the affinities of the Fern Glen faunas.
lsIbid., Vol. XII, p. 49, 1898.
"Journal of Geology, Vol. JX, p. 130, 1901.
"Am. Jour. Sci.. (4), Vol. XXXVI, p. 161, 1913.
^Geol. Sue. America, Vol. XX, p. 265, 191)0.
-Am. Jour. Sci., (2), Vol. XLII, p. 95, 1866.
^Bull. Geol. Soc. America, Vol. XX. p. 265, 1909.
CIRQUES OF THE SKEENA BASIN 119
COAST RANGE CIRQUES OP THE SKEEXA BASIX.
CHARLES KEYES.
(ABSTRACT.)
In British Columbia the manifold aspects of alpine glaciation
are displayed as they are perhaps nowhere else on the face of the
globe. Northward as they approach the southern tip of Alaska
the lofty Cascade ranges of the United States pass into coast
ranges; and the coast ranges of the south run into the sea, giving
rise to the countless islands which are so characteristic of this
part of the Pacific coast.
At a point a few miles from the Alaskan boundary the Skeena
river, after cutting a deep canyon entirely through the coast
ranges, enters the sea. This river is one of the noble streams of
the continent. On either side the mountains rise abruptly to
elevations of 3,000 to 4,000 feet. The permanent snow-line is
here sufficiently low to render it easily accessible. Cirque
phenomena are developed to a wonderful extent.
Glaciers are in all stages of growth and. decline. On every
hand their work is open to the most detailed scrutiny. Emu
from the railway train many of the different aspects are easily
viewed. For a distance of more than 100 miles the rail journey
lies uninterruptedly in the midst of clearly observable cirque
phenomena. In few places in the world are all the details cor-
roborating the Johnson hypothesis of cirque formation so well
displayed.
CLINTON FORMATION NEAR DUB U QUE 121
AN OUTLIER OF THE SO-OALLED CLINTON FORMA-
TION IN DUBUQUE COUNTY, IOWA.
JESSE V. HOWELL.
During the summer of 1914 a considerable amount of grading
was done at the forks of the road on the west side of Lora Hill,
seven miles west of Dubuque. As a result of this work there
was exposed along the road a band of peculiar reddish clay from
one to two feet in thickness, underlain by the characteristic
gray-green, plastic clay-shales of the Upper Maquoketa forma-
tion. The red clay is much less plastic than the underlying
green shales, but is remarkable chiefly for the fact that it is com-
posed largely of iron oxide and contains great numbers of small,
rounded concretions or oolites. Also imbedded in this deep red
clay are: a. numerous pebbles of smooth, polished chert, b.
rounded fragments of indurated material similar to that of the
clay, and c. rounded fragments of slightly iron stained shale.
The fragments belonging to the second class are crowded with
oolites, but contain no fossils. Weathering has so softened the
material of both oolites and matrix that it is not possible to polish
the fragments for satisfactory microscopic study.
"When examined under the low power of the microscope the
oolites are seen to possess the same concretionary structure which
characterizes similar bodies1 in the "Clinton" formation of Wis-
consin and the true Clinton ore of the eastern states. The in-
dividual layers or coatings separate rather readily, exposing,
usually, a more or less definite nucleus. Many of the oolites on
being dried, show somewhat glazed surfaces, especially after re-
moval of the outer layers.
Particularly in those portions of the clay near the contact with
the unstained green shale, the red clay contains many fossils.
All the forms appear to be of Ordovician age, and it seems prob-
able that they come from the green shale, for a majority of the
specimens are not replaced by iron. Two individuals, appar-
ently sponges, are composed largely of iron oxide, but the struc-
ture has been so destroyed by weathering that their identity is
not certain. Most of the fossils are silicified and all of them
are broken and comminuted.
122 IOWA ACADEMY OF SCIENCE
Qualitative chemical examination of the red clay reveals the
presence of ferrous and ferric iron, carbonates, calcium, silica
and aluminum. The oolites are largely siliceous but contain
also calcium carbonate and iron.
Similar outcrops of the ferriginous material are found on the
east side of Lore Hill at elevations which indicate that the bed
lies in a practically horizontal position and probably is con-
tinuous throughout the hill. In one of these outcrops fragments
of impure, cherty dolomite occur just above the iron band.
On the north side of the hill, twenty-one feet above the iron
band, a small quarry exposes typical Niagaran dolomite contain-
ing the following fossils :l
Halysites catenulatus.
Lyellia (probably americana).
Strepte'asma sp.
Cystoid (plate only).
Plectambonites sp.
Orthis flabellites.
Dalmanella elegantula.
Platystrophia daytonensis.
Leptaena rhomboidalis.
Evidently then the iron band lies at or near the contact of the
Niagaran and Maquoketa. It is possible that most of the twenty-
one feet concealed may belong to the recently described Alexan-
drian Series.2
Fig. 9.
The diagram (figure 9) illustrates the probable conditions at
Lore. Since the undisturbed layers are nowhere exposed it is
not possible to ascertain the actual conditions. The thin band
of ferruginous oolite lies between the soft, plastic shales of the
top of the Maquoketa and the massive dolomite of the lower
Niagaran. Probably the iron band originally was indurated,
and this may yet be the condition at some distance within the
identified by Professor T. E. Savage, of the University of Illinois.
-Savage, T. E., Stratigraphy and Paleontology of the Alexandrian Series:
Bull. 111. Geol. Survey No. 23, 1913.
CLINTON FORMATION NEAR DUBUQUE 123
hill. But as weathering has continued inward from the sides
of the hill the iron ore has softened and slumped with the soft
shales underlying: it. The slumping undoubtedly is aided by the
pressure of the dolomites above. Considerable mingling of the
two layers has taken place, and the division line between shale
and iron band is not always definite.
CORRELATION.
The stratigraphic position of the oolitic band at Lore is practi-
cally identical with that of the so-called Clinton iron ore at May-
ville and other points in eastern Wisconsin, as described by
Chamberlin.3 The Wisconsin ore rests on the eroded surface of
the Cincinnati (Maquoketa) shale, and it too contains fossils
of Maquoketa age which Chamberlin considers to have been mixed
with the ore by the action of the glacial ice. Here also there is
more or less mingling with the underlying clay shale, although
the division in general is definite.
Thwaites4 has described the ''Clinton" ores of eastern Wis-
consin as follows :
-an essentially unaltered sedimentary deposit which oc-
curs in broad lenses in eastern Wisconsin, between the overlying
Niagara dolomite (Silurian) and the underlying Maquoketa
("Cincinnati") shale (Ordovician). The lenses vary greatly
in thickness, one of 55 feet being the thickest known. On
the other hand their extent is so meager that by far the greatest
portion of the beds at the ore horizon show not even a trace of
the "Clinton" ore.
Crane5 speaks of the presence of a layer of red, oolitic iron
ore in the Silurian of Holt county, Missouri, and suggests that
it probably is of Clinton age (op. cit., p. 48) . The member, how-
ever, was studied only in the material from a deep drill hole* and
the description is very incomplete.
Savage and KossG have recently studied the "Clinton" de-
posits of eastern Wisconsin, and have found in the ore numerous
fossils which indicate a closer relationship to the Ordovician than
to the Silurian. They consider the ore to have been deposited in
late Maquoketa time in local basins formed after the withdrawal
of the main Maquoketa sea. The name "Neda Iron Ore" is pro-
posed as a substitute for the apparent misnomer ••(Mint mi Ore."
3Chamberlin, T. C, Geology of Wisconsin, Vol. II, 1S77, p. 331.
4Thwaites, F. T., Bull. U. S. Geol. Survey No. 540, p. 338.
5Crane, G. W., Missouri Bur. Geol. & Mines, 2d Series. Vol. X, pp. 148-149.
«Savage, T. E., and Ross, C. S., Am. Jour. Sci., Vol. XLI, 1916, pp. 18.-193.
124 IOWA ACADEMY OF SCIENCE
SUMMARY.
The marked similarity in lithologic character and stratigraphic
position of the "Neda Iron Ore" and the oolitic material at Lore
Hill seem to be sufficient ground for considering them parts of
the same formation. It must not be assumed, however, that the
sea in which they were deposited was continuous over the entire
area between these widely separated outcrops. It is more prob-
able, as suggested by Savage and Ross, that the deposition of the
oolite took place in shallow, local basins which were at least in-
termittently connected.
It is not likely that the "Clinton" or "Neda" formation in
Iowa will ever become of economic importance, for it appears to
have a very limited areal distribution and but slight thickness.
Further search along the Ordovician-Silurian boundary in north-
eastern Iowa may, however, reveal larger patches than the one
described.
Geology Laboratory,
State University of Iowa.
PENEPLAINS OF DRIFTLESS AREA
125
A ( ORRELATION OF THE PENEPLAINS OF THE DRIFT-
LESS AREA.
URBAN B. HUGHES.
The conclusions reached in this paper in regard to the erosion-
al history of the Drif tless Area are the results of evidence secured
from three sources : (1) Field work during the summer of 1915,
carried on by the writer in the Baraboo district and the Rich-
land Center quadrangle, Wisconsin, has furnished direct evidence
for the northern portion of the area under consideration. (2)
The literature on the subject has been used freely, the Lancaster-
Hershey
Lreraceous Plain
Ternary Plain
Celrin
Mlamakee P/-/J00
JrOHirUje rW,Uiain^
Plain No 1 - /300'
Plam No 2 -1/00
Leonard
Lvner Plain- ia
ei/j/as P lain ■ 1^o'
Trowbndae rW<llia//r±
Pii'n Ma 7 - / 2.00'
Pimjit /!/*.£. - <feo'
t> Niagara PIqi., ,,?,-,t,**
Galena Pla 1 n- tvs> foot
Fig. 10 — A sketch map of the southern half of the Driftless Area, show-
ing where and by whom work has been done on the upland plains and
the general conclusions reached by the various workers.
Mineral Point folio by Grant and Burchard having proven espec-
ially valuable. (3) The details of the Elizabeth and Galena
quadrangles were furnished by Prof. A. C. Trowbridge under
126 IOWA ACADEMY OF SCIENCE
whose direction the work has been carried on and whose advice
was most valuable because of his intimate acquaintance with
numerous localities in the Driftless Area.
FORMER WORK DONE.
For the past twenty years geologists who have worked in the
Driftless Area have noticed the broad stretches of upland sur-
face lying at approximately the same levels and harboring a
civilization quite distinct from that of the deep, gorge-like valleys
below the upland levels. In many cases the upland flats are so
conspicuous as to be known locally as "prairies" on which are
located villages, woodland areas, main roads, and many square
miles of flatfish, rolling country. These striking features have
been described in the reports, barely receiving mention in some,
whereas in other cases they have been treated as fully as avail-
able data permitted. It is not surprising that different men,
working independently, at different times, and in widely sepa-
rated, ,portions of the Driftless Area did not round out their
combined work into the harmonious whole. Accordingly, when
an attempt is made to build the blocks as worked out into a unit,
the wide divergence of conclusions is emphasized. The results
of some of the most important work done and the geographical
location of this work is shown is figure 10. For more detailed
accounts of this work, see the brief bibliography following.
BIBLIOGRAPHY.
Bain, H. F., Zinc and Lead Deposits of Northwestern Illinois: Bull.
U. S. Geol. Survey No. 246, pp. 13-16.
Calvin, Samuel, Geology of Allamakee County: la. Geol. Survey, Vol.
IV, pp. 41-44.
Grant and Burchard, Lancaster-Mineral Point Folio: U. S. Geol. Sur-
vey, pp. 1 and 2.
Hershey, 0. H., The Physiographic Development of the Upper Missis-
sippi Valley: Am. Geologist, Vol. 20, pp. 246-268.
Howell, J. V., The Occurrence and Origin of the Iron Ores of Iron
Hill, near Waukon, Iowa: Iowa Geol. Survey, Vol. XXV, pp. 33-69.
Leonard, A. G., Geology of Clayton County: Iowa Geol. Survey. Vol.
XVI, pp. 220-233.
Salisbury, R. D., Preglacial Gravels on the Quartzite Range near
Baraboo, Wisconsin: Jour. Geology, Vol. Ill, pp. 655-667.
Salisbury, R. D., and Atioood, W. TV, The Geography of the Region
about Devils Lake and the Dalles of the Wisconsin: Bull. No. V,
Wisconsin Geol. and Nat. Hist. Survey, pp. 60-64.
PENEPLAINS OP DRIFTLESS AREA L27
Shipton. W. D.. The Geology of the Sparta Quadrangle, Wisconsin:
Master's Thesis State Univ. of Iowa, unpublished.
Trowbridge, A. C, Some Partly Dissected Plains in Jo Daviess County,
Illinois: Jour. Geology, Vol. XXI, pp. 731-742.
Preliminary Report on Geological Work in Northeastern Iowa : Proc.
Iowa Acad. Sci., Vol. XXI, pp. 205-209.
Physiographic Studies in the Driftless Area (abstract) : Bull. Geol.
Soc. America, Vol. 26, p. 76.
Trowbridge. A. C. and Shaw, E. W., Geology and Geography of the
Galena and Elizabeth Quadrangles: Bull. No. 26, Illinois Geol.
Survey, pp. 136-146.
Williams, A. J.. Physiographic Studies in and around Dubuque, Iowa:
Master's Thesis State Univ. of Iowa, unpublished.
Grant and Burchard describe one undoubted peneplain at
1.320 to 1,000 feet altitude which they call the Lancaster Pene
plain, and mention a probable higher peneplain at about 1,420
feet. In the Galena-Elizabeth quadrangles, Illinois, Trow'oridge
found two peneplains, the Niagara plain at 1,170 to 1,100 feet,
and a lower plain, the Galena plain at 975 to 900 feet. Like-
wise, field work by A. J. Williams and others under the direction
of Professor Trowbridge in northeastern Iowa has established
two peneplains. During the past summer W. D. Shipton found
a peneplain and a probable lower one in the Sparta district of
Wisconsin. Work by the writer in the Richland Center quad-
rangle, Wisconsin, seems to have established plains at two dis-
tinct levels. But all the work has not been so nearly harmonious,
for Salisbury and Atwood have suggested the possibility of four
peneplains in the Baraboo district and Hershey has given the
number as five for the entire Driftless Area.
On account of the wide distribution of the areas studied it has
not until now been possible to study the peneplains continuously
over wide areas. At the present time, however, sufficient data
are in hand to make possible the correlation of an area extend
ing from Baraboo, Wisconsin, to Waukon and Dubuque, Iowa.
and to the southern part of the Elizabeth quadrangle in, Illinois.
STRUCTURE OF THE ROCKS.
The structure of the stratified rocks of the area is simple, with
two exceptions. In general the strata form a gently-dipping
monocline, in which the dip is about fifteen feet per mile in a
southwest direction. But the quartzite formation at Baraboo is
closely and intricately folded, and the Paleozoic strata in the
-
IOWA ACADEMY OF SCIENCE
southern part of the Elizabeth quadrangle have much steeper .
- :han the average for the Driftless Area. The seemingly
simple monoelinal structure is further complicated by numerous
gentle anticlines and shallow synclines. much jointing, and slight
faulting.
THE UPPER PLAIN.
plains, the upper and older one will be discuss
Reference to figure 11 shows that over the whole region
there is much flat land which stands distinctly above the level
-: zats and which forms remnants of a now much
plain. In drawing conclusion- r.ing the origin and corre-
.- of this plain, several points si -red.
1 re monadnocks standing above it, which are ero-
sional remnants of a once still higher surf a - is well illus-
1 in the Baraboo region where Sauk Point at 1.620 feet,
above sea level and the west blur lis Lake at 1,560
stand above the plain whose altitude here is 1,400 feet. The
same relation is found at Waukon. Iowa, where a monadnoek
ses at least ] the uppermost plain. Also Platte
Mounds and Blue Mounds may be considered to be monadnocks
- ling upon the upper plain.
_ At many points throughout the southern portion of the
& Area, patches of water- worn gravel are found on the
r plain. On the west bluff of Devils Lake several fe< -
I ae gravels are found on an old erosional surface and
here eloa - -iated with numerous potholes. These
same gravels are found near Sparta. Wisconsin, at an elevation
of 1 - known at Seneca. "Wisconsin, and at
"Waukon. Iowa; they occur at 1300 feet altitude. This deposit
■ .ether with the remnants of higher land above the
plain points to the previous es of a surface which was in
an imperfect state of peneplaination. -with moderate relief, and
reams had sufficient graeL - I :arry gravel such as is
;d.
- plain is not parallel with the underlying strata but
cuts across the bevelled edges of dipping formations, rising strati-
graphically to the south. - n in figure 11. About Devils
and adjacent districts to the west,, there are conspicuous
levels at 1400 feet, which cut across the hard Baraboo quartzite.
.-. dips at angles of 15' and more. If a line is drawn ''the
:i~5'i — —
;
PENEPLAINS OF DRIFTLESS AREA
uppermost line, figure 11] from this 1400- I to the I
of the mounds in the southern portion of the Elizabeth quad-
rangle in Illinois, remnants of this plain between the
extreme points come to about the level of this line. South of
Baraboo. the first great area of upland is an st si idge,
known as Military Ridge or locally known as Dodgeville Prairie
because it is a gently undulating plain and alin ~
nattish surface averag 3 12 : in altitude, with occasional
swells and knobs reaching higher levels. It is here underlain by
Galena dolomite. Farther south the plain is found on th- I
of numerous mounds and ridges at elevations of 1170. 1152. 1160
■ in the northern part of the Elizabeth quadra: _ 1112.
1115. 1065. 1 • L072 : in the central part, and - - 96±.
27. 1004 and 1000 feet in the southern part of the quadrangle.
In the northern part of the Elizabeth quadrangle the plain is
on about I ~ Xiagaran dolomite whereas in the south-
ern part it is on more than 100 feet of the same formation.
The plain is seen to cut from Huronian quartzite at Baraboo
across the Prairie du Chien. St. Peter. Platteville. Deeorah.
Galena, and Maquoketa formations, to the Xiagaran formation
at the south border of the Driftless Area. It slop- - -
amount of six feet per mile in a direction 16 r wesl
4 The surface of the upper plain does nor conform to i
dip of the strata. The strata dip S. 45c W.j the surface
plain slopes S. 16c W. The si I lip about fifteen feel
each mile ; the plain slopes only sis r each mile.
The surface of the upper plain wherever found is ehar-
acteristically more dissected than the lower and younger plain.
This - - -ially noticeable near Dodgeville. Near Highland.
Wisconsin, the ei - - pronounced and the sharp draws -
to what extent the original plain has been dissected.
It is not necessary to suppose that the plain is controlled
by layers of : sisl itherefoi -
trary the features as found in the field are exactly what would
be expected of a partly dissected peneplain. TVherever ti.
resistant rocks, like the Maquokel - vnied the
surface, they have been more eroded than the mor- - s
mations. whose surfaces are left to form the remnants
plain today.
9
130 IOWA ACADEMY OF SCIENCE
THE LOWER PLAIN.
There are considerable areas of fl.a1 land throughout the region
which lie at distinctly lower levels than the flats referred to the
upper plain (see the lower of the two straight lines in figure 11).
In the Baraboo district west of Devils Lake, the lower plain is
extensively developed at 1200 feet altitude, or 200 feet lower than
the upper plain in the same locality. In the Richland. Center
quadrangle there is a remarkably flat area, in places almost un-
touched by stream work, which is seven miles long and as much
as two and one-half miles wide in places. South of the Wiscon-
sin river the lower plain is well developed at Lancaster where
it has an altitude of 1100 feet, and still farther south it is ideally
represented in the Elizabeth quadrangle at 975 to 900 feet. This
plain has been traced in Iowa by Trowbridge and Williams from
the Minnesota line to Dubuque. In the correlation of these va-
rious patches of the lower plain and in assigning their origin to
peneplaination, the following facts are taken into consideration :
(1) The plain has numerous erosional remnants above it, for
wherever the remnants of the upper plain occur in the forni of
mounds or ridges they rise above the lower plain surface, in
most places as much as 200 feet or even more.
(2) This plain is in no way influenced by the strata of resistant
rock, since it cuts across formations dipping at varying angles,
the slope of the plain being remarkably uniform. In the Bara-
boo district the flat at 1200 feet above sea level cuts across the
Baraboo quartzite formation which has dips of 15° or more. In
the adjacent area to the west at the same elevation, the plain
lies upon Prairie du Chien dolomite. South of the Baraboo dis-
trict, the plain next cuts across the Galena dolomite at Lancaster
at an elevation of 1100 feet, and finally in the Elizabeth quad-
rangle it is found upon five to fifteen feet of soft Maquoketa
shale. In Iowa the plain cuts from the Prairie du Chien forma-
tion at the Minnesota line, across the St. Peter, Platteville,
Decorah, and Galena formations, to the Maquoketa formation at
Dubuque.
Over the area studied this plain dips at the rate of about four
feet per mile in a direction 26° west of south. Thus it is seen
that it dips at an angle smaller than that of the upper plain ;
accordingly the two plains drawT more nearly together as they
are projected to the southwest, Moreover, both plains have
PENEPLAINS OF DRIFTLESS AREA 131
angles of dip which are less than the dip of the underlying strata,
and they rise stratigraphically. For the relation of this plain to
the underlying formations and to the upper plain in Wisconsin
and Illinois, see figure 11.
(3) In spite of minor folds and dips, the plain is uniform.
In the southern part of the Elizabeth quadrangle where the strata
dip southwestward at an exceptionally high angle, the general
level of the plain conforms to the level over the rest of the area,
even though it is here on soft Maquoketa shale.
(4) Wherever found the lower plain is characteristically uni-
form and free from stream dissection except around the borders
of -its remnants. Especially is this noticeable when compared
with the dissected character of the upper plain. This is the to-
pography which a younger plain should have in contrast with
that of an older one.
(5) The correlation made in the present paper departs from
that of Grant and Burchard who consider that there is in the
Lancaster-Mineral Point district an upper plain represented by
the tops of the numerous mounds and that all the lower flat are*as,
including the Dodgeville Prairie, the flat around Lancaster, and
the flat north of Cuba, belong to the lower or Lancaster plain.
That this is in error is shown by a study of the elevations of this
supposed plain. As shown by figure 12, the drop from Mt. Ida,
Fir;. 12 — A profile from Mt. Ida on the Dodgeville Prairie south aero
portion of the Lancaster plain. Grant and Burchard assumed that
two upland surfaces shown here belonged U> the lower or Lancaster
plain. The profile makes it clear that two plains are represented.
a distance of only eight miles, is one hundred feet, or more than
ten feet to the mile. Such a relation would be a severe strain on
the idea of peneplaination. In characteristic topography. ;is
well as in altitude, the Dodgeville Prairie belongs with the upper
rather than with the lower plain.
132 IOWA ACADEMY OF SCIENCE
AGE OF THE PLAINS.
, The question of the age of the two plains is not relevant to the
purpose of this discussion and only brief mention is here made
of the two sets of interpretations which have been advanced. The
earlier workers and some of the later ones consider the upper
plain to be of Cretaceous age and the lower one to be Tertiary.
On the other hand Salisbury has called the upper plain Tertiary,
on the basis of a tentative correlation of the gravels on the plain
with the Lafayette formation of the gulf coast. Work by Trow-
bridge and Williams in Iowa has placed the lower plain tenta-
tively as early Pleistocene in age.
SUMMARY.
(1) There are two and only two upland plains in the region.
(2) Both plains are old peneplains.
(3) Both plains slope in a direction south by southwest and
converge toward the south and southwest.
(4) The dip of the plains is less than that of the underlying
strata and they cut across the bevelled edges of dipping strata,
rising stratigraphically to the south.
(5) The upper plain shows more evidence of stream erosion
than the lower.
(6) The Dodgeville plain belongs to the upper plain and the
Lancaster plain of Grant and Burchard is a part of the lower
plain.
Geological Laboratory,
State University of Iowa.
KANSAX DRIFT ON SUB-AFTOXIAX
1 ,1 ■ i
SUPERIMPOSITION OF K AN SAX DRIFT ON SUB
AFTONIAN DRIFT IN EASTERN IOWA.
MORRIS M. LEIGHTON.
Many new exposures have been made by the Chicago, Mil-
waukee and St. Paul Railway in the reconstruction of their line
across Iowa. Various ones of these have proved to be of especial
interest to Pleistocene geologists, and among them are several
cuts in the northern part of Clinton county, showing superim-
position of the two oldest drifts, the Kansan drift on the Sub-
Aftonian drift. This paper is devoted to a description of these
and their interpretation.
1. A significant exposure is located at the second viaduct one-
half mile east of Delmar Junction. The cut is through a divide
with a rounded summit. 250 to 300 yards long, and has a maxi-
mum depth of sixty feet. By reference to figure 13, A. the
relations of the following materials will be clear:
— a.
c
1
K a rt » an
Till
Af tonun
Sub- Af tonian
T. /(
Fig. 13 A — Diagrammatic sketch of the relations of the materials shown in
the south side of the Chicago, .Milwaukee and St. Paul railway cut, one-
half mile east of Delmar Junction.
Fig. 13 B — Cross-section of the railway cut referred to in A. showing
former track-level, m ; the position of the mineralized stump, c; and the
present track-level, n.
134
IOWA ACADEMY OF SCIENCE
Loess
Kansan
Drift
Aftomax
Soil
Sue-
Aftomax
TlLL
Feet
7. Loess, 1 ft. of soil at top, grading below
into brownish yellow to buff loess, wholly
leached of calcareous material, mantles the
eroded surface of the Kansan drift; thick-
ness at the summit 8-10
6. Ferretto zone at the top of the till, absent
from the slopes, reddish brown, leached,
pebbles show considerable decomposition;
thickness 0-1^
Grades downward into:
5. Till, brownish yellow to yellow, summit
rounded, leached of calcareous matrix and
limestone pebbles in uppermost 7 to 8 ft.,
calcareous below with lime concretions
and limestone pebbles, insoluble drift peb-
bles present throughout, lime concretions
most abundant just below the base of the
leached portion; maximum thickness 25
Grades downward into:
4. Till, blue-gray or slate-colored, containing
two large sand pockets, a and b, which
have the appearance of included bodies,
sand pocket a lies in the transition zone
of (4) and (5), matrix of till calcareous
and limestone and other drift pebbles pres-
ent, fragments of wood in the basal portion,
fills an old depression; thickness 0-28
3. Old black soil, with many small fragments of
wood mineralized with iron pyrite, pebbles
rare, some imperfectly laminated clay, soil-
zone delineates an old depression with
slopes as high as 12°. At c, on an old
track level (Fig. 13, B), is a stump with
roots and rootlets running through the
old soil and underlying clay; the wood is
mineralized like the fragments of wood
throughout the soil zone. Thickness of
soil zone 2^-3
Grades downward into:
2. Till, dark bluish green on damp surface,
light grayish green where dry, leached
of calcareous matrix and limestone pebbles
but other drift pebbles are present; thick-
ness 6±
Grades downward into:
1. Till, yellowish to brownish green, with some
maroon-colored material in the lower part,
leached 2-4 ft., calcareous below; thickness
exposed 0-14
KAXSAX DRIFT OX SUB-AFTONIAN L35
Interprt tation. — This exposure seems to show quite clearly two
distinct tills. The dark bluish green color of the till below the
old soil zone is the color of material which has undergone de-
oxidation from a former oxidized state. Its transition below
into material of yellowish to brownish color, with a greenish
tinge, and the presence of carbonaceous material directly above,
indicates that it was once oxidized but has been subsequently de-
oxidized, probably since the soil material has been deprived of
atmospheric oxygen. The leaching of the lower till to a depth of
about eight feet requires an interval of time, much longer than
post-Wisconsin -time, during which oxidation would likely have
taken place. Directly above the soil zone is till which has never
been leached or oxidized. These relations show quite clearly that
the deposition of the two tills was separated by an interval
worthy of the designation of an interglacial epoch.
The upper till-body is unquestionably Kansan. The topog-
raphy of the surrounding region is not only erosional, like the
Kansan area, but the upper till is weathered similar to the till
of the Kansan area, both from the standpoint of degree and depth
of oxidation and from the standpoint of depth of leaching.
Hence, if the upper till is Kansan, the lower till must be sirb-
Aftonian, and the soil development and leaching and oxidation of
the lower till must be Aftonian in age.
The age of the stump just at the old track-level was carefully
considered, tipon examination of various parts of the stump
and its roots, it was found that the wood is mineralized with iron
pyrite just like fragments of wood which are scattered through-
out the Aftonian soil-zone. This evidence led to the conclusion
that the stump belongs to the Aftonian soil and was uncovered
in the excavation of the cut. This attention has been given to
the stump3 not because it necessarily adds to the weight of evi-
dence for the differentiation of the two till-bodies, but it is the
first stump, having an interglacial position, known to have been
reported.
The position of the loess above the ferretto of the Kansan
drift and as a mantle on the eroded surface of the Kansan drift.
warrants the usual interpretation that a considerable interval
of erosion and weathering intervened between the deposition of
the Kansan drift and that of the loess about the Iowan drift
border.
136
IOWA ACADEMY OF SCIENCE
2. Another important cut is just west of the depot at Del-
mar Junction, on the north side of the tracks. This cut has
a maximum depth of about twenty feet, is one hundred yards
long and its summit is round. The materials exposed are as fol-
lows (figure 14, A) :
Fig. 14 A — Diagram of relations of materials in the north face of the Chi-
cago, Milwaukee and St. Paul railway cut, just west of the depot at
Delmar Junction, Clinton county.
Fig. 14 B — Diagram of the relations of the materials in the north face of the
Chicago, Milwaukee and St. Paul railway cut, six miles east of Delmar
Junction, Clinton county.
Feet
[■ 7. Sandy loess, buff, well stratified, leached,
thin soil zone at the top, conforms to the
rounded summit of the underlying mate-
rials; maximum thickness 10-12
Till, brownish yellow to yellow, calcareous
matrix, limestone pebbles present together
with other drift pebbles up to the base of
the loess where there is a concentration of
pebbles; maximum thickness 8±
Loess
Kan san
Till
6.
Till, blue-black, containing some wood, line
of oxidation above quite sharp, probably
due to organic material, but calcareous
like the above; thickness
1-3
Aftonian
Silts
Sub-
Aftoxiax
Tux
4. Silts, dark brown, laminated, appear to have
much carbonaceous substance, leached;
thickness 1-1%
Grades downward into:
3. Silts, gray, laminated, leached 3
2. Till, brownish yellow to yellow, with maroon
streaks and some lamination, pebbles and
cobbles up to 6 in. in diameter, leached
4% ft. in one place, calcareous and lime-
stone pebbles present elsewhere up to the
base of the gray silts, some decayed
pebbles; thickness, maximum 8±
1. Till, bluish drab, calcareous; thickness.
0-3
KANSAX DRIFT ON SUB-AFTOXIAX
137
Pebble counts from the unleached portions of both tills yielded
the following results :
Kind
Kans \n
Tin.
Per Cen'j
SUB-A] IONIAN
Tu i.
Per Cent
Greenstone and Dolerite.
Limestone
Granite
Chert
Quartzite
Schist
Quartz
Volcanic Porphyry
46
30
8
4
6
4
2
0
42
28
6
8
6
2
2
6
100
100
Interpretation: — In this exposure, which is one-half mile from
the former, the existence of the non-calcareous silts, containing
carbonaceous material, between the calcareous till above and the
leached and calcareous till below, makes it obvious that here
there are also two till-bodies of different age. Inasmuch as this
general region is one of mature erosion, as mentioned in the
former case, the upper till is believed to be Kansan till, the silts
Aftonian, and the lower till sub-Aftonian. The relations of
the loess to the Kansan till in this cut do not clearly show an
interval between their dates of deposition, but in view of the re-
lations in the cut first described and of the mantling nature of
the loess, it is probable that the rate of leaching of the Kansan
till was at least equaled by erosion and consequently no leached
zone remains. The lithology of the two tills, according to the
pebble count, does not show any marked difference.
3. Farther east, about six miles east of Delmar Junction and
one mile northeast of Riggs, a Chicago. Milwaukee and St. Pan!
Railway cut, trending north 30° east, fifty to sixty feel deep,
and two hundred yards long, exposes two bodies of till, sep-
arated by a body of gravel. By referring to figure 14, B, the
relations of the materials, which are described below, will be
clear.
F\ E I
7. Loess, soil-layer at the top 1 ft. thick, brownish
yellow and non-calcareous down to the till, snail
shells only in the calcareous portion; maximum
thickness 30±
6. Ferretto zone of till, reddish brown, ahsent on lower
slopes 0- 1 ' j
138 IOWA ACADEMY OF SCIENCE
5. Till, brownish yellow to yellow, leached 6 feet, cal-
careous and limestone pebbles below, upper
horizon conforms to the contour of the hill and
mantled by the loess, maximum thickness 20
Grades downward into:
4. Till, gray-blue, calcareous, occurs below thickest
part of the oxidized till and in a small de-
pression of the underlying gravel; maximum
thickness 8
3. Sand and gravel body, extends across the cut except
where mantled on the slopes by loess; limestone
and other drift pebbles present, yellowish to
brownish in color, lens and pocket-structure;
thickness 10-12
2. Till, light drab to dark drab at the top, brownish
gray to dark gray below, dense and compact,
limestone pebbles to the top, mostly decayed in
the upper one foot, contains some inclusions of
the underlying silt; thickness 12-14
1. Silt, somewhat sandy, yet compact, dark gray, no
pebbles, fragments of wood or roots of wood 1 to
2 inches in diameter exposed near the bottom,
upper horizon somewhat undulating and in places
shows gouging by an over-riding ice-sheet;
thickness 12±
Interpretation: — There is no zone of leaching and oxidation
within the drift materials which warrants a separation into
two distinct tills. It has been thought, however, in view of
the other exposures, that possibly the gravel-body represents
such an interval as the Aftonian and that the overlying drift is
Kansan in age and the underlying is sub-Aftonian. In this
case, the bottom silt formation would be probably pre-Pleisto-
cene. These determinations, however, must remain somewhat
conjectural.
It is quite clear, however, that the loess formation was depos-
ited on the Kansan drift after the latter had been eroded and
weathered to its present state. This means a relatively long
interval between the deposition of the two as compared writh post-
Wisconsin time.
SUMMARY OF THE CHIEF POINTS.
1. These exposures definitely record the invasion of the sub-
Aftonian ice-sheet into the extreme eastern part of Iowa. Tak-
ing into consideration the other known exposures of sub-Afton-
KANSAN DRIFT ON SUB-APTONIAX 139
ian drift in Iowa and Nebraska, it appears that in a broad way
the sub-Aftonian and Kansan Lee-sheets covered approximately
the same territory from east to west, a territory much more ex-
tensive than was covered by any of the later ice-sheets in the
Keewatin field.
2. Where the sub-Aftonian drift is definitely differentiated
from the Kansan drift, the sub-Aftonian shows a leached zone
considerably deeper than that of the Wisconsin drift. On this
1 asis the length of the Aftonian interval was considerably greater
than post-Wisconsin time. This is in harmony with the evi-
dence of the Aftonian mammalian fossils that the interval was
long and warm, and when both evidences are considered it is to
be inferred that the ice-sheet was melted back- at least to its
present limits.
3. The existence of the two oldest drifts in this locality and
the absence of any evidence that the Maquoketa and Wapsipini-
con river valleys below Monticello and Anamosa, have been oc-
cupied by an ice-sheet, indicate that these superimposed valleys
have been carved since the Kansan ice invaded this region.
4. The Kansan drift w<as weathered and eroded to its pres-
ent state before the loess in this locality was deposited, hence
this weathering records an interval much longer than post- Wis-
consin time. The weathering and erosion of the Kansan drift
does not, therefore, represent its age. The loess itself shows
three to four times the leaching that the Wisconsin drift shows,
and the length of time represented must be added to that shown
by the weathering and erosion of the Kansan drift, in order to
folly appreciate the great age of the Kansan drift.
Department op Geology,
University op Washington,
Seattle, Washington.
FULGURITES FROM WISCONSIN 141
A NOTE OX FULGURITES FROM SPARTA. WISCONSIN
W. D. SHIPTOX.
During the summer of 1915 some fulgurites were found near
Sparta. Wisconsin, in a small sand knoll composed of residual
quartz grains of the Potsdam formation, which is Upper Cam-
brian in age. The sand is fairly clean and of uniform char-
acter and is being reworked continually by the wind since there
is only a scant covering of vegetation.
The fulgurites consist of irregular, thin-walled tubes of fused
siliceous sand grains. The tubes vary in length and diameter.
The smallest are about one-eighth inch long while the largest are
several inches in length. The pieces may be the fragments of
one large tube, the smaller pieces being the branches from the
main stem. The surfaces of the fulgurites are very irregular
and are traversed by deep furrows with minor undulations.
The entire surface is covered with the grains of sand which
came in contact with the fused material. Some of the grains
are white and opaque, due to complete fusion, while others are
brown and have remained unaltered. The interior of the ful-
gurites is smooth, highly glazed glass and the surfaces corres-
pond to the furrowed surfaces of the outer walls in outline.
The deviations of the tubes from a circular form are due prob-
ably to the pressure of the adjacent sand while the fulgurites
were still in a fused condition.
Fulgurites are caused by lightning striking in sand and fus
ing the siliceous sand grains into a tubular form.
142 IOWA ACADEMY OF SCIENCE
A NEW STRATIGRAPHIC HORIZON IN THE CAMBRIAN
SYSTEM OF WISCONSIN.
W. D. SHIPTON.
During the summer of 1915 it was the privilege of the writer
\o work on the geology of the Sparta quadrangle, "Wisconsin.
In connection with that work a new stratigraphic horizon in thd
Cambrian was recognized.
The normal section of the Cambrian in Wisconsin1 is as fol-
lows:
Thickness in Feet
3. Madison sandstone 35- 50
2. Mendota limestone 30- 45
1. Potsdam Proper sandstone 800-1000
111 the Sparta quadrangle, the Mendota member is missing,
2nd a new Cambrian member is recognizable. Because of its
wide distribution and excelllent exposures around Sparta, this
persistent, shaly member has been named by the writer the
Sparta member. Its base lies 290 feet and its surface about 90
feet below the top of the Cambrian: that is, the member is ap-
proximately 200 feet thick and includes the upper 165 feet of
the Dresbach member (Potsdam Proper) and the whole of the
Mendota member in the normal section for the state. In the
Sparta quadrangle the Cambrian is divided into the following
members :
Thickness in Feet
3. Madison sandstone 90
2. Sparta shale 200
1. Dresbach sandstone 820-879
Many exposures of the Sparta beds arc to be found through-
out the region. Two type localities are a quarry two miles
southeast of Sparta in the southwest corner of section 30, town-
ship 17 north, range 3 west, and a quarry one and one-half
miles north of Sparta in the center of section 1, township 17
north, range 4 west. From the latter quarry good exposures
may be seen by visiting' the series of quarries along the upland
to the northeast, The beds are well exposed along the road and
Irving, Roland D., Geology of Wisconsin, Vol. II, p. 4 60.
NEW CAMBRIAN HORIZON IN WISCONSIN 14:'.
ii; a gully one-half mile north of Middle Ridge in the north-
west corner of section 2, township 15 north, range 5 west. An-
other good exposure occurs along the road in Pine Hollow two
and one-half miles southeast of Melvina in the northwestern cor-
ner of section 19, township 15 north, range 3 west.
The beds of the Sparta member consist of argillaceous layers
of sandstone alternating with thin, fissile, arenaceous and cal-
careous layers, all with more than fifty per cent sand. The
arenaceous beds are mostly thin, but a few reach two feet in
thickness; the more limy layers are rarely more than one inch
thick. The layers apparently become more calcareous near the
Madison-Sparta contact. The fissile shales vary in color. Some
of the beds are of green glauconitie color, due to disseminated
grains of glauconite. Other beds which contain minute glis-
tening micalike scales and small black particles grade from a
light graj to a dark gray color. Where the beds are mainly
glauconite a greenish color is imparted to the soil. The layers
are distinctly laminated and break into thin plates. The laminae
in most places are horizontal; in many places a minor cross-
bedding is visible. The rocks tend to split alone- the lamina?,
which are formed apparently of the green grains of glauconite,
the diminutive micalike specks, and the minute dark particles.
Some fragments of calcite are found. The most shaly beds are
nicely ripple-marked, the markings being asymmetrical. A
type locality for the ripple-marked layers is two miles north -
31 of Sparta, along the Big Creek road in the eastern pari ol
section 9, township 17 north, range 4 west.
The Sparta beds are used for quarrying purposes; the mem-
ber is called "Free Rock"-owing to its being quarried so easily,
the term being of strictly local application.
This peculiar phase of the Potsdam, here called the Sparta
diale, appears not to have been given a distinct stratigraphie
horizon previously. Chamberlin2 notes a stratum of shales at-
taining a known thickness of 80 feet somewhat above the middle
of the Potsdam formation. Above the shale is 150 feel of
sandstone which is overlain by 35 feel of shale and Limestone (the
Mendota limestone). In the Sparta region the shale stratum
reaches a total thickness of 200 feel and is overlain by the .Mad-
ison sandstone; the Mendota apparently is missing. This may
2Geology of Wisconsin, Vol. I, pp. 121-122.
144 IOWA ACADEMY OF SCIENCE
be a local modification as noted by Chamberlin.3 The Sparta
beds differ from the Mendota limestone in several respects, as
follows :
1. The maximum thickness of the Mendota at the type lo-
cality at Madison is thirty-five feet4 while the maximum known
thickness is eighty feet.5 The Sparta beds reach a maximum
thickness of two hundred feet.
2. The Mendota member has been recognized as a limestone
or a calcareous horizon6 in the upper part of the Potsdam, and,
as such, should effervesce upon the application of acid. No
such action takes place when the acid is applied to the Sparta
beds, although there are minor concentrations of calcium car-
bonate which would undoubtedly respond to acid. An analy-
sis of the Mendota limestone given by Irving7 bears a close sim-
ilarity to the Prairie du Chien (Lower Magnesian) formation.
This analysis shows a high percentage of lime carbonate. As
stated above, the Sparta member contains more than fifty per
cent sand.
3. The Mendota beds have been considered as a horizon for
trilobites,8 and where typically exposed numerous trilobite re-
mains have been found. Although many exposures of the Spar-
ta beds were examined carefully, no trace of trilobite remains
was found. The presence of certain species of brachiopods be-
longing to the Lingula group9 also characterizes the Mendota
horizon. The fauna of the Sparta beds includes an uncertain
species of Obolella and the impressions of a doubtful Orthis.
Faunally, there is a difference between the Mendota and the
Sparta beds.
The Sparta beds do not seem to be the equivalent of the Saint
Lawrence member since Calvin10 recognized the Saint Lawrence
member as evenly bedded calcareous strata corresponding to the
fifth trilobite bed of Owen and attaining a thickness of thirty-
five feet.
In a recent publication of the Wisconsin Geological and Nat-
ural History Survey,11 the Upper Cambrian is subdivided into
3Geology of Wisconsin, Vol. I, pp. 121-122.
*Bull. XIII, Wis. Geol. and Nat. Hist. Surv., p. 92.
5Geology of Wisconsin, Vol. II, p. 259.
"Bull. VIII, Wis. Geol. and Nat. Hist. Surv., p. 37.
7Geology of Wisconsin, Vol. II, pp. 543-544.
sGeology of Wisconsin, Vol. IT, p. 261.
°Geology of Wisconsin, Vol. II. i>. 261.
10Iowa Geol. Survey, Vol. IV, p. 59.
"Bull. XXXV, Wisconsin Geol. and Nat. Hist. Survey, pp. 30-31.
NEW CAMBRIAN HORIZON IN WISCONSIN 145
six formations by (Jlrich, one of which is the Franconia. H is
possible that the Sparta beds may be the equivalenl of the Fran-
conia formation, but since qo description of the Franconia beds
has been published, it is impossible to make a definite statemenl
to this effect. The topographic position of the Franconia ap
pears to correspond with that of the Sparta member.
Winchell12 recognized the Saint Lawrence and associated
shaly beds as having- a total thickness of 200 feet. These beds
are probably the equivalent of the Sparta member.
Department op Geology,
State University of Iowa.
-Final Rept. of the Geo!, and Nat. Hist. Survey of Minnesota, Vol |[, p.
XXII.
10
LOESS OF CROWLEY'S RIDGE, ARKANSAS 147
THE LOESS OF CROWLEY'S RIDGE. A R KANSAS.
B. SHIMEK.
Crowley's Ridge is a narrow, more or less interrupted ele-
vation which extends from southeastern Missouri to Helena,
Arkansas.1 Its slopes, especially on the eastern side, are fre-
quently quite abrupt (see Plate V, figure 1), and it forms a
striking topographic feature of this part of the Mississippi val-
ley.
It has received some notice from geologists. Owen refers to
it in both the First (1858) and Second (1860) Arkansas Re-
ports; and Call has given the most complete account of its ge-
ology,2 including a chapter by Salisbury; and Chamberlin in-
cluded a discussion of it in his paper on the Interval between the
Glacial Epochs.3
The loess of the southern part of this ridge presents certain
interesting features, and it has received some previous attention,
especially from Call. Some years ago (1907) the writer visited
the southern part of Crowley \s Ridge and made some studies of
the loess, the results of which have not been published because it
was planned to extend the observations along the entire ridge.
As this has not yet been possible, the report on the southern por-
tion of the ridge is here presented.
Two distinct sections of the ridge were studied. The first is a
detached portion about seventeen miles long, which extends from
Helena to Marianna, and is cut off from the main ridge to the
north by the valley of the L'Anguille river. The second is that
part of the ridge extending from the L'Anguille valley to Forrest
City and Madison.
The finest exposures were found in Helena, along the eastern
slope of Crowley's Ridge, particularly that part lying west of
Poplar street, between Louisiana and "Walker streets. Three of
these exposures are figured on Plate V, figure 2; Plate VA,
figure 1, and Plate VB, figure 2.
JIt is mapped in the Arkansas Geological Reports, Vol. II, 1891.
2Geol. Survey of Arkansas, Vol. II, 1891.
bulletin of the Geological Society of America, Vol. I, 1S90, pp. 469-80.
148 IOWA ACADEMY OF SCIENCE
The section shown in Plate V, figure 2, is located north of Elm
street, facing- Poplar street. It shows the following' members :
a — Reddish loess, about 2 feet.
b— Whitish loess, 25 to 30 feet,
c — A chocolate-colored band, in some places appearing like old
soil,
d — A mucky reddish clay,
e — Contains more or less gravel.
The maximum height of the exposure is about seventy-five feet.
The reddish loess follows the contour of the hill on the side of
the exposure beyond (a), which faces to the right, and it is near-
ly uniform in thickness, and contains no fossils. The white loess
here contains only fragments of shells. The member (d) is evi-
dently Call's lower "loess"', but it is not loess.
The lines of demarcation between the several members are not
always sharp, but the several divisions stand out quite distinctly.
The cut figured on Plate VA, figure 1 . is located north of Elm
street, facing Poplar street. It shows the following members:
a — Reddish loess, variable in thickness but sometimes forming
nearly one-third of the section. Stands vertically in the
banks. It is fossiliferous.
b — A transition band between reddish and white loess.
Variable in thickness.
c — White loess, very fossi'iferous, partly obscured by the talus.
The same members occur in the exposures near Forrest City.
Plate VB, figure 2. shows a section southwest of Madison, east of
Forrest City :
a — Reddish loess, about 4 or 5 feet; no fossils.
b— White loess, 2 to 3 feet; with fragments of fossils. The
dark line running through (b) is an oxidized band.
c — A gravelly layer, sharply separated from (b).
The division into an upper reddish and a lower whitish loess
is almost everywhere quite pronounced. The two loesses are in
some places quite sharply separated, but usually there is a nar-
row transition band, ordinarily only a few inches thick.
The upper loess differs from the lower not only in being red-
dish in color, but also in texture and other characters. It is grit-
tier, more inclined to stand vertically in the exposures, and it
sometimes shows a fine lamination which follows the contours of
the hills more or less distinctly. It sometimes contains nodules,
Mid it is often fossiliferous.
LOESS OF CROWLEY'S RIDGE, ARKANSAS 149
The lower loess is whitish, often somewhal putty-like, finer.
and less inclined to scale off from vertical banks. It usually con-
tains some calcareous nodules, sometimes iron streaks and bands,
and often many fossils. It is sometimes yellowish, especially just
below the reddish loess, arid it then often shows whitish lines
evidently formed by rootlets.
Sometimes short bands of broken shells appear in the white
loess, especially where the upper pari of the loess is very fossi-
liferous. Such a hand is illustrated on Plate \T>. figure '2. These
hands are usually a foot or more in length, and are evidently
formed in vertical cavities which have been formed by water
following crevices. Such cavities are often gradually tilled with
material from the upper part of the stratum, and if that pari is
fossiliferous shells are sometimes washed down and deposited in
a layer on the hottom of such a cavity. The subsequent filling of
the cavity completes the imbedding of the shell layer. Such a
cavity is shown at (d) on Plate YB. figure 1. and a shell band
(the one which is figured on the same plate, figure 2) is set off by
markers at (c).
In most of the exposures which were examined there is a more
or les-; distinct brownish band just below the lower loess, and
where this is the case the lower limit of the loess is sharply de-
fined. Sometimes this dark band is wanting, and then it is not
always easy to determine the lower limit of the loess, especially if
the underlying layer is of the same color as the whitish loess, as
sometimes occurs. It is evident that Call regarded this layer
below the white loess as "typical" loess, one of the two forms of
loess which he recognized, though he observes that it is not fossi-
liferous. It is probable that Salisbury regarded this as a lower
loess5, and Chamberlin was also inclined to so regard it6, but
added that "it remains with us an open question whether this
belongs to the glacial series or not."
Its texture, its grading into gravelly deposits, and its lack of
fossils clearly show that it is not loess. The presence of calcare-
ous nodules (on which Call placed some reliance) in both the
white loess and the underlying stratum proves nothing as to iden-
tity or close relationship, for such nodules are formed not only
in loess, but also in drift (especially when modified I, etc. There
4Ibid., p. 171.
•Ibid., p. XV.
cBulietin of the Geological Society of America, Vol. I, 1S90, p. 176.
150 IOWA ACADEMY OP SCIENCE
are two loesses on Crowley's Ridge, but they are not the two
described in former reports. The differences between them in
color and texture are probably due to variations in the source of
dust supply during the period of formation, possibly to shifting
of river courses.
The inclusion of the lower stratum as loess led Call to exag-
gerate the thickness of the loess at Helena. It is much less than
ninety feet in thickness.
The fossils. — Both the true loesses of the ridge contain shells,
frequently in large numbers. Both, or either one, may be fossi-
liferous in the same section, or both may be without fossils. All
the fossils (with the exception of Planorliis (Gyraulus) deflectus,
reported by Call as rare, but which the writer failed to find) are
terrestrial. Even the operculate Pomatiopsis lapidaria, which
Call reported as aquatic, is strictly terrestrial so far as the writer
has ever observed. In this respect, therefore, the fauna of this
loess is typical.
However, it presents certain very interesting variations. The
difference between the fossils of the red and white loesses at
Helena, as shown in the appended table of fossils, is not very
great, but the red loess shows a smaller number of species, and
its fauna taken in the aggregate is rather less typically southern
than that of the white loess. When we compare the fauna of the
Helena loess with that of the Forrest City region, however, we
find a greater difference, and the latter is clearly northerly in its
affinities. It is evident that the valley of the L'Anguille river
formed a barrier which was not passed by several southerly
species.
A comparison of the Helena loess fauna with that of Natchez,
Mississippi7, shows that they are very similar, only three of the
Natchez species (Polygyra inflecta, Vitrea hammonis, and Co-
chlicopa lubrica) being absent at Helena, though found at For-
rest City. Eight of the Helena species are not found at Natchez.
The following list of fossils from Crowley 's Ridge adds sixteen
species to the lists published by Call. The figures indicate the
number of specimens collected. Those marked + were reported
by Call.
7See the following for the Natchez list: American Geologist, Vol. XXX,
1902, p. 290; and Bulletins from the Laboratories of Natural History, State
University of Iowa, Vol. V, 1904, p. 310.
LOESS OF CROWLEY'S RIDGE, ARKANSAS
LOESS FOSSILS FROM CROWLEY'S RIDGE.
151
1 [ELENA
Madison
White
Red I
White
Loess
Loess
Loess
Polvgyra albolabris (Sav) Pils
31
Polygyra thyroides (Say) Pils
+
Polygyra exoleta (Binn.) Pils
+
Polygyra elevata (Say) Pils
35
Polygyra multiliueata (Say) Pus
3
35
1
Polygyra profunda (Say) Pils
98
107
1
Polygyra appressa ( Say) Pils
142
76
Polygyra palliata (Say) Pils
+
+
Polygyra frauditlenta Pils
4
2
1
Polygyra obstricta (Say) Pils
+
Polygyra stenotrenia (Fer. ) Pils
19
199
346
10
Polygyra monodon (Rack.) Pils
2
Polygyra monodon fraterna (Say) Pils.
115
34
Strobilops labyrinthica (Say) Pi's
_i_
62
-f-
51
Bifidaria corticaria (Sav) St
11
Vertigo gouldi (Binn.) Stimp
+
86
+
1
Circinaria concava (Say) Pils
25
31
1
3
5
Vitrea harnmonis (Strom.) Pils
. . »
4
Vitrea indentata (Say) Pils
80
143
101
171
2
Vitrea placentula (Shuttl.) Pils
Vitrea capsella (Gld.) Pils
10
Euconulus fulvus (Drap.) Reinh
52
2
2
Zonitoides arboreus (Say) Pils
40
18
2
Zonitoides minusculus (Binn.) Pils....
84
10
2
Gastrodonta ligera (Say) Pils
25
86
6
Pvramidula alternata (Say) Pils
118
52
+
Pyramidula alternata (vat.)
13
1
1
Pyramidula cronkheitei (Newa. ) Pils..
43
33
13
Helicodiscus parallelus (Say)
200
45
8
Punctum pygmaeum ( Drap. ) Binn
696
Sphyradium edentulum (Drap.) St
20
30
29
2
3
16
4
2
+
Helicina orbiculata tropica (Jan.) Pfr..
9
Pomatiopsis lapidaria (Say) Try
70
1
32
Department of Botany
State University.
152 IOWA ACADEMY OF SCIENCE
EXPLANATION OF PLATES.
Plate V, Fig. 1. — A portion of the east side of Crowley's Ridge at
Helena, Arkansas.
Fig. 2. — Cut on the south side of Porter street, west of 1st street,
Helena,
a — Red loess, 2 feet.
b — White fossiliferous loess, 25 to 30 feet,
c — Dark colored band at base of loess,
d — Red mucky clay,
e — A gravelly stratum.
Plate V A, Fig. 1. — Cut facing Poplar street, north of Elm street,
Helena, Arkansas.
a — Red loess, variable in thickness. Fdfesiliferous.
b — Transition band between the two loesses,
c — White loess, very fossiliferous.
Fig. 2. — Cut southwest of Madison, Arkansas.
a — Red loess. 4-5 feet.
b — White loess, 2-3 feet; with fragments of fossils.
c — A gravelly layer.
Plate V B, Fig. 1. — A cut west of Poplar street, and facing St. Mary's
street, Helena, Arkansas,
a — White loess,
b — Heavier clay,
c — Shell band,
d — Cavity in which shell band may form.
Fig. 2. — A shell band between two markers. Same section as in
fig. 1.
Iowa Academy Science
Plate V
Iowa Academy Science
VA
Iowa Academy Scii nee
Plate VB
BIBLIOGRAPHY OF THE LOESS L59
BIBLIOGRAPHY OF THE LOESS.
E. J. CABLE.
Bain, II. F., Geology of Plymouth County, Iowa: Iowa Geol.
Survey, Vol. 8, 1897, p. 318.
Bain, If. F., Geology of Carroll County. Iowa : Iowa Geol. Sur-
vey, Vol. 9, 1898, p. 51.
Beyer, S. W., Loess: Iowa Geol. Survey, Vol. 7, 1896, p. 197.
Broadhead, G. C, Origin of Loess: Am. Jour. Sci., third series,
Vol. 18, 1879, p. 447.
Call, R. E., Loess in Central Iowa: Am. Naturalist. Vol. 15,
1881, p. 782.
Chamberlin, T. C, and Salisbury, R. D., The Driftless Area of
Upper Mississippi Valley. U. S. G. S. Sixth Ann. Rept., 1885,
p. 199.
Hoyden, F. V., Upland Loess of Missouri; its formation: Am.
Geologist, Vol. 25, 1900, p. 369.
Haydi n, F. J'., An. Report of U. S. G. S. of Territories, 1867, pp.
10, 12, 18, 19.
Hayden, F. V., U. S. G. S. of Wyoming and Contiguous Terri-
'tories, 1870, p. 98.
Hershei/, 0. H. , Loess Formation of the Mississippi River: Sci-
ence, X. S., Vol. 5, 1897, p. 768.
Huntington, F., Chart of The Distribution of Loess: Bull,
Geol. Soc. America, Vol. 25, 1914, p. 575.
Huntington, E., Loess Deposit of Kuen Lr.n Mountain: Bull,
Geol. Soe. America, Vol. 17, p. 351.
Keyes, C. R., Eolian Origin of Loess: Am. Jour. Sci.. Vol. 6,
1898, pp. 299-304.
L< verett, F., Significance of the White (lays of the Ohio region:
Am. Geologist. Vol. 10. 1892. ,>. 18.
Leverett, F., The Illinois Glacial Lohe : Monograph U. S. Geol.
Survey, Vol. 38, 1899, p. 156.
160 IOWA ACADEMY OF SCIENCE
Li r< rrtl, /•'., To the .Manner of Distribution: Am. Geologist, Vol
33, 1904, p. 205.
Li r< rt ft. F., Post-Sangamon or Main Loess and Associated Silts :
Monograph U. S. Geol. Survey, Vol. 53, pp. 74-7-6.
L( verett, F., The Loess: Monograph U. S. Geol. Survey, Vol. 38.
Beneath Wisconsin drift, p. 187-188.
Aeolian origin, pp. 183-184.
Analyses of, pp. 158-164.
Discussion of. p. 32.
List of Fossils, pp. 168-174.
Mode of deposition, 176-184.
Relation to gummy clay. p. 31.
Leonard, A. G., Geology of Dallas County, Iowa: Iowa Geol.
Survey, Vol. 8, 1897, p. 51.
Mdbry, T., The Brown or Yellow Loam of Northern Mississippi,
and its relation to the Northern Drift : Jour, of Geology.
Vol. 6, 1898, p. 273.
McGee, W J, Pleistocene History of Northeastern Iowa : U. S.
G. S. Eleventh Ann. Kept,, Vol. 10, 1892, p. 18.
Norton, W. E., Iowa Geol. Survey, Vol. 9, 1898, pp. 404, 481, 485.
Obrucheff, M., Origin of Loess: Geographic Journal. Vol. 42, p.
403.
Owen, Lu-ella A., Evidences on Deposition: Am. Geologist, Vol.
35, 1905, p. 291.
Pumpelly, Raphael, Loess in Central Asia: Bull. Geol. Soc.
America, Vol. 19, p. 243.
Pumpelly, R., Fresh Water Lake Deposits: Am. Jour. Sci., Vol.
6.
Pumpelly, //., The Loess of the Mississippi Valley and the Eolian
Hypothesis: Am. Jour. Sci., third series. Vol. 18, 1879, pp.
l:;:;-144.
Pumpelly, R., Loess in Central Asia; Formation of: Bull. Geol.
Soc. America, Vol. 17, p. 643.
Sarde'son, F. ^Y., What is the loess: Am. Jour. Sci., 4th ser.,
Vol. 7. 1899, p. 58-60.
BIBLIOGRAPHY OF THE LOESS 161
Salisbury, R. D., Loess of Western Illinois and Southeas
Iowa : Journal of Geology, Vol. 4, p. 244.
Salisbury, B. D., Loess in Wisconsin Drift Formation: Journal
of Geology, Vol. 4, p. 929.
Safford, J. M., Geology of Tennessee, 1869. pp. 114, 433, 434.
Shimek, B., Additional Observations on the Surface Deposit of
Iowa: Proc. Iowa Acad. Sci., Vol. 4. 1896, p. 68.
Shimek, B., The Distribution of Loess Fossils: Jour, of Geology,
Vol. 7, p. 122.
Shimek, B., The Nebraska Loess Man : Bull. Geol. Soc. America,
Vol. 19, p. 243.
Shimek, B., Eolian Loess, Origin: Science, N. S., Vol. 33, 1911.
Shimek, B., Loess of Gildner Mound : Bull. Geol. Soc. America,
Vol. 19, pp. 250-255.
Shimek, B., Loess of Peczel, Hungary. Proc. Iawa Acad. Sci.,
Vol. 22, 1915, p. 285.
Shi nick, B.. The Genesis of Loess, A Problem in Plant Ecology:
Proc. Iowa Acad. Sci., Vol. 15. 1908, p. 57.
SJiimck, B., Living Plants as Geological Factors: Proc. Iowa
Acad. Sci., Vol. 10, 1903, p. 41.
shimek, B., The Loess: Bulletins Natural History State Uni-
versity of Iowa, Vol. 5, pp. 341, 359, 360.
Shimek, B., The Loess of the Missouri River: Proc. Iowa Acad.
Sci., Vol. 14, 1906, p. 237.
Shimek, B., Mississippi Loess at Natchez: Am. Geologist. Vol.
30, 1902, p. 279.
Shimek, B., The Loess of Crowley's Ridge, Arkansas: Proc.
Iowa Acad. Sci., Vol. 23, 1916.
Shimek, B., Aqueous Origin Criticism: Am. Geologist, Vol. 35.
1905, p. 291.
Shimek, B., The Theory of Loess.: Proc. Iowa Acad. Sci., Vol,
3, 1895, p. 82.
Shaw, E. W., Origin of the Loess of Southwestern Indiana : Sci-
ence, N. S., Vol. 41, pp. 104-108.
Todd, J. E., The Degradation of Loess: Proc. Iowa Acad. Sci..
Vol. 5, 1897, p. 46.
n
162 IOWA ACADEMY OF SCIENCE
Todd, J. E., Annual Deposits of the Missouri River during the
Post-Pliocene : Proc. Am. Association for the Advancement
of Sci., Vol. 26, 1877, p. 287.
Todd, J. E., The Moraines of Southeastern South Dakota and
the attendant deposits : Bull. U. S. Geol. Survey No. 158,
1899.
Todd, J. E., Pleistocene Problems in America : Bull. Geol. Soc.
America, Vol. 5, p. 351.
JJdden, J. A., Horizontal Shearing Planes: Jour. Geology, Vol.
10, p. 245.
TJdden, J. A., The Mechanical Analysis of Loess: Bull. Geol.
Soc, America, Vol. 25, 1914, p. 728.
Udden, J. A., Iowa Geol. Survey, Vol. 11, 1900, p. 258.
Wright, G. F., Agency of Water in Deposition : Am. Geologist,
Vol. 33, 1904, p. 205.
Wright, G. F ., The Great Ice Age, p. 359.
Wright, F., Origin and Distribution of Loess in Northern China :
Bull. Geol. Soc. Am., Vol. 13, p. 127.
White, C. A., Iowa Geol. Survey, Vol. 1, 1870, p. 531.
Wilder, F. A., Iowa Geol. Survey, Vol. 10, 1899, p. 81.
Wilcox, O. W., On certain aspects of the Loess of Southern
Iowa : Jour, of Geology, Vol. 12, p. 716.
Winchell, N. H., Aqueous Origin of Loess: Bull. Geol. Soc.
America, Vol. 14, pp. 141-143.
Witter, F. M., Observations on the Loess in and about Muscatine,
Iowa: la. Acad, of Sci. Proc, 1877-89, p. 45.
Department op Geography
State Teachers College.
LITHOGENESIS OF THE SEDIMENTS 163
THE LITHOGENESIS OF THE SEDIMENTS.
FRANCIS M. VAN TUYL.
There are few lines of investigation in geology which promise
more fruitful returns than the lithogenesis of the sediments.
The sedimentary rocks have from the first hen sadly neglected
although the igneous and metamorphic groups have been sys-
tematically and more or less intensively studied both in the held
and in the laboratory. Even the megascopic characters of the
sediments have for the most part been indefinitely and vaguely
described and petrographic examinations have until recently
rarely been made. Descriptive terms have been indiscriminate-
ly used and such important features as mud cracks and many
others equally as significant have in many cases been wholly
overlooked. Moreover, until within the last ten years few seri-
ous attempts were made to determine the conditions of deposi-
tion of the clastic sediments. It is little wonder then that the
application of more refined methods of study to these rocks bids
fair to revolutionize the fields of physical stratigraphy and
paleogeography.
The importance of careful study of recent sedimentary de-
posits of both the continental and marine types as a basis for
interpreting the history of the ancient sediments cannot he too
strongly emphasized, as was pointed out recently by both An-
dree1 and Goldman.- Indeed some of the greatest contributions
to stratigraphy have come through such studies. The im-
portance of Drew's recent investigation on the deposition of
limestone through the agency of bacteria in the modern seas^ as
bearing on the origin of the ancient thick, fine-grained limestones
which in themselves furnish no positive clue as to their mode
of formation must be admitted by all.
Witness also the valuable contributions of Grabau and Bar
rell, who, working independently, have been able not only to
prove beyond a reasonable doubt that many of the thick Pale-
ozoic clastic formations of the Appalachian region which were
formerly believed by all to be either of marine or estuarine origin
Tetermann's Mitteilungen Vol. 59, part 2, 1013, p. 117 IT.
2Am. Jour. Scl., 4th ser., Vol. 39, p. 287.
sCarnegie Inst. Washington, Pub. 182, 1914, pp. 9-45.
164 IOWA ACADEMY OF SCIENCE
really represent great continental delta fans, but also to out-
line the probable climatic conditions which existed at the time
they were formed by comparing them with similar recent and
near recent deposits of known origin.
Studies such as those made by Sherzer4, who found upon
examining recent sand grains formed by various agencies that
each type possessed characteristics to a certain degree of its
own, also promise to be of great value in deciphering the his-
tory of the ancient sediments. For instance there are strong
reasons for suspecting that certain sandstone formations made
up of sand grains possessing all the characteristics of recent
wind blown sand are of eolion origin, or at least consist of
eolion sands reworked by the sea as it transgressed upon the land.
Similarly Walther and Huntington and others by their de-
scriptions of the characteristics of modern desert deposits have
contributed valuable data which already have been applied in
interpreting the history of the sediments of the past. Thus,
wind carved pebbles similar in every way to those described
by Walther and others from the Libyan desert have been
found, according to Grabau5 "in the pre-Cambric Torridon
sandstone of Scotland, the basal Cambric sands of Sweden, the
Rothliegende of Germany, the Buntersandstein of Thuringia
and elsewhere" thereby suggesting strongly the existence of
desert conditions at the time these beds were formed. In like
manner a type of cross -bedding shown by "Walther to be char-
acteristic of the modern sand dunes of the deserts of Egypt, and
observed by Huntington in Persia, Transcaspia and Chinese
Turkestan has been observed by Huntington0 in certain Mesozoic
sandstones of Utah and by Grabau and Sherzer in the Sylvania
sandstone of Silurian age, of Michigan7.
But in spite of the great advancement of physical strati-
graphy within recent years resulting from the field study of
sediments, we may expect even greater advances in the future,
especially as the result of more detailed examination of the sedi-
ments with the aid of the microscope. Here lies a great field
almost untouched, although its possibilities have been shown
by the studies of Sorby, Cayeux, Mackie, G. S. Rogers, Gold-
*Bull. Geol. Soc. America, Vol. 21, 1910, pp. C25-GC2.
Principles of Stratigraphy, p. 54.
"Bull. Geol. Soc. America, Vol. 18, 1907, p. 351.
7Micb. Geol. and Biol. Survey, Pub. 2, Geol. Series 1, 1910, p. CI ff.
LITHOGEXESIS OF THE SEDIMENTS 165
man and others. There can be no doubt that the additional evi-
dence furnished by petrographie study as to the composition
and structure of the ancient sediments will aid greatly m in-
terpreting the conditions of their deposition as well as the nature
of their source. Sorbys showed the possibilities in this line
several years ago, by his petrographie examination of clays
and shales. He found the structure of these to differ greatly, a
fact which argues for their formation under very different con-
ditions. That such characteristics are fairly constant for any
given formation is suggested by the experience of Denckmann
who found that a widely distributed Silurian formation of
Silesia possessed distinct, petrographie peculiarities by means
of which he was able to identify it at those localities wher*» fos-
sils were either rare or entirely wanting9. It seems certain that
to some extent at least, the nature and constitution of the sedi-
ments of any given formation are directly related to the climatic
conditions which existed during deposition as well as to the
source from wThich they were derived. If then we may determine
in. what way climatic changes are registered in the sediments
by converging all lines of evidence we shall be able to decipher
more accurately by means of the microscope the climates of the
past as well as the nature of the ancient lands. Some steps
have already been taken in this direction by Mackie10 who has
suggested that the kinds and degree of freshness of the feldspar
grains in sandstones may be used as a key in determining the
climatic conditions under wThich the sandstones were formed,
and who has demonstrated also that the nature of the parent
rock is indicated by the kinds of minerals present and by the
nature of their inclusions.
It is believed that studies of this type will go a long way
toward solving the problem of the origin of certain little un-
derstood formations such as the red beds and the Coal Measures
in addition to furnishing more accurate data regarding the
geography of the past. When all these things are better known
we shall have the basis also for a much more complete classifica-
tion of the sedimentary rocks than the one which we now pos-
sess.
sQuart. Jour. Geol. Soc. Vol. 64. 190S, pp. 171-233.
"Cited by Andree, Geol. Rund., Vol. 2, l'.Ul, p. 61.
10Trans. Geol. Soc. Edinburgh, Vol. 7, pp. 443-46S.
166 IOWA ACADEMY OF SCIENCE
THE WESTERN INTERIOR GEOSYNCLINE AND ITS
BEARING ON THE ORIGIN AND DISTRIBU-
TION OF THE COAL MEASURES.
FRANCIS M. VAN TUYL.
(ABSTRACT.)
Late studies of the Mississippian formations of southeastern
Iowa for the Iowa Geological Survey have shown that these
formations were tilted to the southwestward and partly trun-
cated in late Mississippian time. There is convincing evidence
that this tilting was related to deformation over a wide area in
southern Iowa, southeastern Nebraska, eastern Kansas and north-
western Missouri which outlined a southwest wardly pitching
geosyncline in which the Coal Measures of the Western In-
terior coal field were deposited. This geosyncline was shallow
in early Pennsylvanian time and probably did not greatly ex-
ceed 700 feet in depth at the close of the Cherokee stage.
At the present time, however, it is approximately 2400 feet
deep at the deepest known point which is at McFarland, Kan-
sas. An important part of the deepening is believed to have
been brought about by subsidence during the post-Cherokee
stages of the Pennsylvanian.
The magnitude and significance of the basin has been dem-
onstrated by the construction of 100 foot contours on the base
of the Coal Measures from data furnished by the reports of the
State Geological Surveys of Iowa, Missouri and Kansas.
The presence of this basin not only explains the great dis-
similarity bet ween the Coal Measures of this field and those
of the Eastern Interior field which were undoubtedly deposited
in a distinct basin, but also explains the belted arrangement of
the outcrops of the Pennsylvanian formations, particularly in
Iowa. Missouri and Kansas, where the younger members are
approximately confined to the center of the basin, progressively
older ones being exposed towards its margins. The present
distribution has resulted from post-Paleozoic erosion of the dip-
ping beds but there are reasons for believing that the Missouri
formations were never as extensive as those of the Des Moines
and that the younger members of the Missouri itself were more
restricted than the older ones.
Department of Geology
University of Illinois
PLEISTOCENE OF CAPITOL HILL 167
THE PLEISTOCENE OF CAPITOL HILL.
JAMES H. LEES.
The Pleistocene exposures on Capitol Hill at Des Moines have
become classic through the studies made by MeGee and Call
which, demonstrated the presence of glacial drift overlying loess.
The results of these studies were published in the American
Journal of Science. Volume 21, 1882, pp. 202-223.
Recent extension of the Capitol grounds has necessitated ex-
tensive grading on the south part of Capitol Hill. This has
revealed the strata to considerable depths and made possible
more complete examination of the Pleistocene deposits than
McGee and Call could make. The grading thus far has been
dnn.' on East Court avenue between 10th and 12th streets
and so includes the localities of McGee 's sections 3 and 1. For
tlie sake of comparison these sections are here reproduced
verbatim.
SECTION 3.
N. side Court Av. bet. E. 10th and E. 11th Sts.— Alt. S80± 3 ft.
1. Light reddish-buff unstratified drift clay containing nu-
merous rounded, subangular and angular pebbles, mainly
erratic, up to six inches in diameter, bits of coal and a
lenticular mass of Carboniferous clay three feet long, and
six inches thick. Seven feet.
2. The same, obscurely and irregularly stratified, inter-
stratified with bands of loess, and sometimes contorted,
containing loess-kindchen, tubelets and fossils (often
fragmentary), in the drift strata in direct association
with pebbles, as well as in the bands of loess. Five feet.
3. Loess, similar to and continuous with that observed in sec-
tions 1 and 2, abounding in loess-kindchen, tubelets and
fossils.
SECTION 4.
S. side Court Av. bet. E. 10th and E. 11th Sts.— Alt. S82± 3 ft.
1. Reddish-yellow sandy clay containing numerous rounded,
subangular and angular pebbles up to twelve inches in
diameter, associated toward the base with loess-kindchen
and fossils. About eight feet.
168 IOWA ACADEMY OF SCIENCE
2. Loess, light buff, somewhat sandy and pebbly above, con-
taining numerous loess-kindchen, tubelets and fossils.
Six feet.
The formations above the loess, as described by McGee, are
not visible at present, as they have been in part concealed, in
part removed, by later building operations. However, on the
south side of Court avenue, between 10th and 11th streets the
following section is revealed and must lie below McGee 's sec-
tion :
1. Loess, yellow with gray spots and streaks and masses,
especially where rootlets have penetrated. Ferruginous
"pipe stems" are quite numerous in the gray portions of
the loess. No fossils were seen in the lower three or
four feet, but above this zone they are quite abundant,
in places to the top of the exposure. No kindchen were
seen in this exposure. The lower foot of the body of
loess grades down from yellow to reddish brown with
gray streaks. In one place a four inch band of finely
jointed reddish clay with starchy structure lies four
inches from the base of the loess. It contains some
small sandstone pebbles and extends along the face lor
a few feet. Apparently the loess is all one body. The
great mass, with the exceptions noted, is uniform from
top to bottom in co'or, texture and general appearance.
Fifteen feet from level of 11th street.
2. Geest, residual from Coal Measures shale; reddish brown,
sticky clay containing small pebbles of sandstone and
shale. Contact with loess above sharp, no gradation.
One foot near 11th street, thicker near 10th street, where
cover is thin.
3. Coal Measures shales, red, purple, blue, green, one to three
feet; succeeded by solid bed of light blue shale, with a
two inch band of black shale six feet below the top.
Exposed fifteen feet to grade at 10th street.
The upper surface of the geest is practically horizontal, while
the ground surface slopes to the west toward the Des Moines
valley bottoms. Hence the loess thickens from a thin veneer
at 10th street to fifteen feet at 11th street. A number of years
ago an excavation above the level of 11th street revealed about
six feet of gray loess with "pipe stems" and concretions.
Still farther back from the present exposure the surface rises
about ten feet and probably the loess here is overlain by drift-
Another section on the south side of Court avenue midway
between 11th and 12th streets is representative of the material
along this part of the cut :
PLEISTOCENE OF CAPITOL HILL 169
1. Till, weathered, brownish. About three feet.
2. Till, buff, pebbly. About five feet, grading into No. 1.
3. Till, gray, pebbly, grading into buff above. Four feet.
4. Till, gray, alternating with sand streaks. Two feet.
5. Loess, gray and buff, banded, abundant shells, lower sur-
face sloping to east. One to two feet.
6. Clay, buff, somewhat sandy in places, abundant pebbles.
for most part rather small, some up to two inches, else-
where six to eight inches in diameter. Pebbles are
fresh limestones, quartzes, greenstones, and granites,
some of which are badly disintegrated. Shells of loess
types afso are abundant in this clay in places, while in
others they are rare or absent. Between this member
and No. 5 are rolled masses of gray loess with concentric
lamination well developed. Two to three feet.
7. Clay, brown, jointed, loess shells abundant, no pebbles,
probably a weathered loess. One and one-half feet.
8. Loess, gray, shells abundant. One foot.
9. Loess, buff, fossiliferous. Three feet.
10. Loess, gray, fossiliferous. One foot.
11. Sand, in lens extending 100 feet along Court avenue; here
two feet thick, at its maximum, fifty feet west, six feet
thick. The sand is fine, yellow with brown streaks, and
presents masses of coarser, reddened material near the
top. It is strongly cross-bedded. The lens dips slightly
toward the northeast, in which direction it thins to about
two feet, but attains a length of over 150 feet.
12. Loess, gray for about one foot, then grading down into
buff. Shells are abundant and of the usual loess types.
At several localities along the line of this section there
are shown masses of dark blue loess which is rather
harder than the buff variety. Fossils are abundant here
also. These masses are enclosed by the buff loess and
some of them are as much as five feet in height and
ten to twelve feet long. This blue loess does not seem
to be distinct from the buff loess in anything except
color and doubtless is occupying its original position.
Exposed in gas main trench ten feet. Shales were not
reached at this locality.
The lower body of loess, No. 12. is continuous with the loess
of the first section given, but it rises about ten feet higher in
the first section, as there apparently it was undisturbed by the
overriding glacier and by glacial waters.
It is evident from its situation that the gray loess is an altera-
tion product from the buff loess. It is found uniformly above
170 IOWA ACADEMY OF SCIENCE
the buff loess, and both above and below the sand lens, where
water percolation is more easy than elsewhere, the loess assumes
the gray color. Loess kindchen and "pipe stems'' are found
in the gray loess, not in the original buff type. Wherever
the loess is more than a very few feet thick it is buff with depth.
It is clear that the gray loess is not to be interpreted as a
distinct deposit and the same may be affirmed of the dark blue
masses found in the yellow loess.
These exposures, together with numerous others between
Des Moines and Keokuk, seem to indicate that the gray loess
so common m the lower Des Moines valley may have been
changed from a buff original, one similar to the loess of the
Missouri valley except for the absence of kindchen in the Des
Moines yellow loess and their abundance in the Missouri valley
deposit.
The pebbly fossiliferous clay, number 6 of the above section,
is to be considered, perhaps, as in part a result of the washing
by waters from the Wisconsin ice of the loess with its contained
fossils, and the mingling of this with clay, sand and gravel
from the till. No doubt it is partly the result also of the erod-
ing, mixing work of the ice itself. In character and general
appearance it is intermediate between till and loess. In places
it is gray, and appears as if composed of mingled gray, un-
oxidized Wisconsin till and gray loess. It is very common and
its general relations are well shown just east of 11th street along
the north face of the cut. Here are exposed in horizontal suc-
cession : drift, pebbly, yellow above and gray below, twenty-
five feet; grading into shell-bearing pebbly gray clay, fifteen
feet; replaced abruptly, but with no line of division, by loess,
grayish above, yellow below, thirty feet; succeeded again by
fossiliferous, yellow pebbly clay, twenty feet exposed. Un-
der all of these lies the sand lens, two to three feet thick, and
under this in turn is gray loess. A few feet of yellow or brown-
ish Wisconsin till forms the surface material along all of this
exposure, which is about twenty feet in height.
To show the extreme variability in materials within short
distances the following section from the intersection of 12th
street and Court avenue is added. This is not over two hun-
dred feet from the second section given. Below the level of
12th street the following succession was shown :
PLEISTOCENE OF CAPITOL HILL 171
1. Fill and altered drift, yellow, in places with a thin line
of calcareous nodules at the base. Two feet.
■1. Drift, yellow, pebbly. Two feet.
3. Silt, brownish, no fcssils. Two feet.
4. Silt, red, no fossils. Two feet.
5. Clay, buff, bearing both pebbles and fossils. Five feet.
Laterally this gives way without a break to alternating
gray and buff loess, with many fossils and a few concre-
tions, which here is four feet thick. Below it is exposed
one foot of dark b'ue fossiliferous loess. At the contact
there were found several iron-coated limestone pebbles
two inches long. Two feet above the base of the buff
loess was found a chert pebble two inches long, and at
several points both the blue and buff loess show layers
and pockets of sand, about six inches thick and several
square feet in area. Pieces of wood are quite common in
loess of both colors.
A few feet from the above section a mass of Carboniferous
shale was shown in the wall. It was twenty feet long by three
feet thick and was underlain by typical gray, pebbly Wiscon-
sin till while above it lay altered till which contained lime con-
cretions.
While the great sand lens described in the second section is
overlain by loess on the south side of the cutting, on the north
side it lies directly beneath modified drift and loess which evi-
dently have been disturbed. It seems probable thai il represents
an immense sand bowlder which was forced into its present posi-
tion by the ice. The contorted character of some of the coarser
parts lends to bear out this theory.
Aside from showing the presence of a young drift on the
loess these exposures reveal unusually well the work of 4 he
glacier at the extreme limit of its advance. The intermingling
of the drift and the loess with its fragile shells, many of which
are still entire; the variation of materials within small inter
vals of space; and the preseni f a greal lens of sand lying
on the body of loess — all these are features which show how-
gentle and yet how irresistible was the action of the ice.
The staged of alteration of the Wisconsin drifl were well
shown in several localities. The second section described is
quite typical. The thinness of the drift in this general region
is to lie expected, but the fact that il changes from unaltered
172 IOWA ACADEMY OF SCIENCE
gray through buff to brownish within ten feet or less shows
how brief, relatively, has been the period during which tins
sheet of till has been exposed to the elements-
It will be noted that there is in the first section no trace of
a drift beneath the loess. All of this had been swept away and
the Coal Measures shales leveled off and a layer of geest formed
before the loess was deposited. The cuts indicate also that the
Wisconsin drift in turn was spread out on a mature topog-
raphy developed on the older surface.
Iowa Geological Survey,
Des Moines.
ALATE SPECIMEN OF ATRYPA RETICl/LARIS 173
A HIGHLY ALATE SPECIMEN OF ATRYPA
RETICULARIS (LINN.)
A. O. THOMAS.
The most abundant fossil in the upper part of the Wapsipini-
eon beds at Independence and elsewhere in east central Iowa is
a fine-ribbed representative of Atrypa reticularis (Linn.).1 This
species is found in every fossiliferous horizon in the Devonian
or! the state. Indeed, it is world wide in its distribution and is
the "longest lived of all known organisms,'"- ranging from early
Silurian through the Devonian into the early Mississippian.3
Generally speaking, however, the species came to an abrupt
end with Devonian time although the genus continued on for
a brief period into the Mississippian.4 In a species ranging so
widely both vertically and geographically many varietal form-
are usually developed. In the Devonian of Iowa nearly every
horizon that may be set off at all sharply by lithological or
faunal differences has its peculiar variety or imitation of A.
reticularis which in some cases perhaps could be well d
nated as good species. Such a variety is the fine-ribbed, rather
robust form from Independence which has "a tendency to be-
come alate at the cardino-lateral angles, and having a form
that is decidedly lenticular, particularly in the young and half
grown individuals.""' In rare cases the curious marginal alations
or fringes are preserved.
Specimens illustrating marginal alations were obtained by the
late Professor Calvin from a quarry in the suburbs of Inde-
pendence many years ago. The quarry which furnished the
best specimens has long since fallen into disuse so that good
examples are now obtained with difficulty.
The alations or winglike expansions are made up of a num-
•ber of thin lamellae which extend from the surface of the valves.
ilowa Geol. Surv.. vol. viii. 1898. p. 229.
2Clarke and Swartz. Maryland Geol. Surv.. Upper Dev., 1913, p.
3Herrick: Bull. Sci. Lab. Denison Univ.. vol. iii. 1SST, p. 98, pi. iii, fig. 11;
vol. iv, 1888. pi. ix. fig. 7.
4For "example. Atrypa infrequens Weller. 111. Geol. Surv.. Monog. T. 191 !.
p. 285, pi, xxxv, figs. 1-5, Glen Park limestone (Kinderbook), Glen Park,
Missouri.
6Calvin; Amer. Geol., vol. 8, 1891, p. 143.
174 IOWA ACADEMY OF SCIENCE
;: rising from what are generally regarded as lines of growth on
the ordinary Atrypa shell. These concentric lines, however, are
rather more than records of halts in the growth of the shell, in
appearance they approach varices where the plications are slight-
ly dilated and elevated as may be seen on shells from which the
lamella? are removed. Each lamella extends outward in such
a way as to make a small angle with that part of the shell proper
which continues beyond the line of their common union. The
successive lamellae lie more or less closely one upon another near
their bases but out toward their margins they are considerably
separated and the spaces between them are filled with the ordi-
nary matrix in which the shells are preserved. There is no
evidence that the lamellae ever coalesced. Their surfaces partake
of the characteristic markings of the shell itself and the plica-
tions or ribs on the lamellar surfaces are continuations of those
en the shell; with growth the plications increase in size, bifur-
cate, and so on, as do those which continue over the shell. The
lamellar surface is wrinkled and uneven in contrast with the
smooth evenly rounded surface of the valves. As seen in sec-
tion the lamella? vary in thickness and the outer and inner
surfaces of each lamella are similarly plicated, that is, each
lamella is a rigid corrugated layer. The plications on one lamella
do not coincide either in size or always in direction of growth
with those on the surfaces of adjacent lamella? immediately
above or below.
The alation is developed in a plane roughly parallel to a plane
passed between the valves; its lateral development along the
posterior margin gives the shell the appearance of having a long
straight hinge-line; anteriorly the lamella? bend to conform to
the sinuosity of the front margins of the valves.
The hardness of the rock in which the Iowa specimens occur
and 1 lie fragility of the lamella? make it difficult to disengage
a complete specimen. The one here figured is so broken along
the margin that the full size is not known. Even fragmentary
preservation is rare; the shells showing alations in the collection
,at hand as well as those seen in the field are usually mature
and old individuals, — more frequently the latter, since "those
[lamella?] upon the umbonal and median surfaces of the valves,
have been worn off during the life, or before the fossilization
of the shell."0
<;Hall and Clarke; Pal.. N. V. vol. viii. pt. ii. p. 168, Albany. 1894.
ALATE SPECIMEN OF ATRYPA RETICULARIS ITT,
This feature on A. reticularis was pointed oul and illustrated
sixty years ago by the Sandberger brothers on a specimen Prom
the Rhenish Devonian of Germany.7 Davidson" described and
illustrated some interesting examples of A. reticularis with
"foliated expansions" from the Wenlock limestone, Silurian, of
England. Whiteaves9 figured a specimen from the Devonian of
Canada. His figure illustrates the lamellae remarkably well.
Its greatest width is 14 millimeters more than that of the speci-
men here illustrated from Independence. Clarke and Swartz10
discuss this feature on specimens of this species from the Devo-
nian of Maryland. Other references could easily be added bul
these will suffice to show that this feature is not limited to the
Atrypas of any given locality. Moreover, it seems to have been
a characteristic of A. reticularis at various times throughout
its history and doubtless was developed to a greater or less ex-
tent on several of its many varieties. What the purpose of
these excrescences could have been we can only -conjecture. Such
seemingly useless and extravagant skeletal matter in many cases
presages racial old age and final extinction but their presence
on members of the species in the Silurian soon after the species
had made its appearance seems to preclude this explanation. It
is quite possible that short lived offshoots of the species, destined
to disappear, developed these encumbrances during their later
stages.
The alate specimen which is the subject of this article has a
maximum width of 10 cm. and a length of 6.5 cm.; the "hinge-
line" is 7.3 cm. long. The lamellae which are preserved are all
outgrowths of the pedicle (ventral) valve, those formerly on the
brachial (dorsal) valve having been almost wholly broken away ;
the width of the alation on the specimen averages three centi-
meters.
Specimens from the same bed, on which the alations are nol
preserved, show the usual expression of the species. The non-
lamellate specimens illustrated in the accompanying plate are
quite similar to those described and illustrated from the same
bed by James Hall in 1858.11
7Die Verstein. cl. Rliein. Schicht. in Nassau, pi. x.wiii. fig. l, Weisb;
1856.
sBritish Sil. Brach., pp. 129-133. pi. xiv, figs. I. 2. I Ion, L867.
°Contr. Can. Pal., vol. I, pt. iv, p. 289, pi. xx.wii. fig. 8; Ottawa. 1892.
"Maryland Geol. Surv., Upper Dev., p. 586, pi. Iv, figs. 6, 10; Baltimore,
1913.
"Hall's Geol. of Iowa, vol. I, pt. ii. p. 515, pi. vi, figs. I. 5.
176 IOWA ACADEMY OF SCIENCE
Occurrence: Calvin's "Spirifer pennatus" beds, uppermost
part of the Wapsipinicon stage (Fayette breccia), Devo-
nian; near Independence, Iowa.
Specimens in the paleontological collections of the University of
Iowa.
Geological Laboratories
State University.
EXPLANATION OF PLATE V C.
Atrypa reticularis (Linnseus).
Figure 1. Pedicle view showing the strong development of the mar-
ginal lamella?. Note the fine ribs on the shell and the wrinkling of
the lamellar surface.
No. 600, x J
Figure 2. Same specimen. Posterior view.
Figures 3, 4. Lateral and pedicle views of a young specimen showing
the fine ribs and the "decidedly lenticular" form mentioned by
Calvin. No. 601, x {-
Figures 5, 6. Lateral and brachial views of a nearly mature example
showing the initiation of greater convexity in the brachial valve.
Note the rather weakly developed varices on this and the preceding.
No. 602, x |
Figures 7, 8. Brachial and lateral views of an old individual. Note
the strong sub-equally spaced varices from which the lamellae have
been broken off.
No. 603, x '
Iowa Academy Science
Plate VC
12
REFLECTING POWER OF CRYSTALS L79
OX THE VARIATION IX THE REFLECTING POWER OF
ISOLATED CRYSTALS OF SELENIUM AND OF
TELLURIUM WITH A VARIATION IN THE
AZIMUTH OF THE INCIDENT PLANE
POLARIZED LIGHT.
L. P. SIEG.
The reflecting power of a surface is defined as the ratio of
the intensity of the light, reflected at perpendicular incidence (
to the intensity of the incident light. There are two ways of
determining the reflecting power of a metallic surface. One is
by a direct, or photometric (dioptric) method. The other is
by an indirect (katoptric) method. In the latter an analysis
is made of the elliptic-ally polarized light coming from the sur-
face in question, upon which plane polarized light is incident.
This analysis yields what are called the optical constants of
the substance. These constants are the index of refraction, the
absorption index, and the reflecting power. Both methods have
been used repeatedly and the concordance of the results gives
us such faith in the indirect method, that, in view of the fact
that the absorption index and index of refraction of the metal
constituting the surface arc much more easily determined by
the second method, we generally employ this indirect method.
Nevertheless it is always desirable when possible to check the
results by some direct experimental attack.
Most of the work done on metallic surfaces has been done,
not only by the indirect method, but also on rather large
polished surfaces of the metals in question. In view of the
fact that metals are essentially crystalline, it becomes at once
en open question as to whether the optical constants determined
from large polished surfaces represent the real facts. For unless
the crystals constituting the metal belong to the cubic system,
one should certainly expect a set of optical constants depend-
ing on the orientation of the crystalline axis. In this view,
then, the constants ordinarily determined can represenl only.
except in the case of metals of the eubic system, certain mean
values of the actual constants.
180 IOWA ACADEMY OF SCIENCE
With this view in mind, some two years ago, the writer set
one of his students, Mr. C. H. Skinner, at work to determine
the optical constants by a katoptric method of an isolated cry-
stal of selenium. Although selenium is not regarded as a
metal, it has, nevertheless, optically speaking, many qualities
of a metal. The crystals are optically very dense and offer
brilliant reflecting surfaces. Skinner succeeded in proving
definitely that there were distinct differences in the optical
constants, depending upon whether the long axis of the hex-
agonal crystal was vertical or horizontal. This work is not
yet published in full, but an abstract has recently appeared1.
Some years ago Drude2 and Midler3 worked on isolated crystals
of antimony sulphide, and proved that from one cleavage plane,
(0 1 0) two distinct sets of optical constants were obtained.
Other work has been done, notably by G. Horn4, on the absorp-
tion of certain crystals, but the writer is not aware that any
work on elemental metallic crystals with the exception of a
determination of the absorption of bismuth and antimony by
the latter author, has been done. The reason for this is not
far to seek, for usually the crystals of metals are microscopic in
size. The difficulty in working with such small surfaces by
the ordinary methods led the writer to suggest this task of
obtaining a special method to another of his students, L. D.
Weld. The latter has succeeded admirably in this problem,
and a preliminary report of the work is presented to the Acad-
emy of Science at this meeting.
Aside from the importance of crystals in yielding us
the true constants of various substances, there is good
reason for believing that the crystalline surface should be bet-
ter adapted for the purpose than any artificially formed pol-
ished surface. If this is correct, then even the cubic crystals
should be re-examined by this method. The one reliable trait
of all crystals seems to be their maintaining of constant angles,
and even if there seem to be striations on some of the surfaces,
it may be that these irregularities would not seriously affect
the optical constants. Then too where it is possible to obtain
a fresh surface by cleavage, one should expect the most relia-
1C. H. Skinner, Phys. Rev. 7, 1916, 285.
2P. Drude, Ann d. Phys., 34, 1888, 489.
3E C. Miiller, N. Yahrb, f. Miner. Beil. Bd., 17. 1903, 187.
4G. Horn, N. Yahrb. f. Miner. Beil. Bd., 12, 1899, 269.
REFLECTING POWER OF CRYSTALS 181
ble results. Drude5 and Miiller0 both found that a fresh surface
of antimony sulphide deteriorated rapidly after coming into
contact with the air.
The writer thought it to be highly desirable to determine
the reflecting power of certain of these crystals by a dired
method. If these results should show definitely a difference in
the reflecting power with difference in azimuth of the incident
plane polarized light, then there would be a larger amount of
reliability to be placed in the results that are being obtained
in this laboratory by the more exact, bul indirect methods.
The plan of the experiments was very simple, but the execu-
tion has been rather difficult. The first arrangement was an
apparatus by which plane polarized light from a monochroma-
tor, varying in wave length throughout the visible spectrum,
could be thrown upon a linear thermopile, and secondly re-
flected upon this thermopile b}^ reflection at nearly normal in-
cidence from the crystalline surface. The ratio of the second
deflection of the connected galvanometer to the first would give
at once the reflecting power. By rotating the crystal in the
plane of its surface through 90°, and repeating the above ex-
periment, one could get the reflecting power from this azimuth.
The results were, however, unsatisfactory because not enough
energy could be obtained from the small crystalline areas to
give reliable deflections of the galvanometer.
A second attempt was made in which a crystal of selenium,
connected in a Wheatstone's bridge, was substituted for the
thermopile. The effect of light on the selenium is to decrease
its resistance, and it was thought in view of the fact that a
selenium receiver is much more sensitive in the visible spectrum
than the thermopile that definite results could be obtained.
However, the crystal employed, although more sensitive than
the thermopile, proved unfortunately to be more erratic and
unsteady in its action. While perseverance would no doubt
have led to a more satisfactory crystal receiver, it was de-
cided for the time being to abandon this plan of attack and
to use a speetrophotometric method. The apparatus was ar
ranged in several different ways which need not be gone into
here, before what proved to be a satisfactory method was found.
The plan is shown in figure 15. Light from a Nernsl glower, G
5P. Drude. loc. cit.
6E. C. Miiller, loc. cit.
-
IOWA ACADEMY OF SCIENCE
ter a nitrogen filled tungsten lamp was employed placed
in a light-tight b< x is i - :I by a lens. L. at the point- V
and H. This division of the ligh" - oomplished by means
mirror M. partly in1 tnng the light. .V. is a Nic -
set - _ Passing thr
ts the lens. Lz and by it would be brought
- " t not i stal ] I at X. This latter
- t ' .: ugh the totally reflecting prism. P and it
-K -
Fig 15.
: the slit of the monoehro-
. SE T ion of the original beam of light
_ - enee through the lens /. .
5 A", and V . the latter with an attached circular scale
and lastly is focused by means of the lens Li upon
- monochromator. These two
5 pass 1 - lment and form on the emergent
»es of 1 at slit., one above the other, and formed
oming along the two separal The wave I -
hich 02 ?hes 1 samination is obtain-
» the g ted ?. The instrument had of course
- two images are viewed through the
5 to & for a wave length at
then to rotate the Nicol, N .
. - are matched in brightness. By proper
re:
adju- : the mirror M.. the light coming by 1
path can always be l
than that by - short so that it is
lueed in intensity i
Having run throng sped - V -
long ax; _ a from
V . the latter is now : Through
t this
azimuth of the pola: light s ares i
sity due to the mono tor as 5 due 1
in the : . E i stal, re setting
are enipL stal is rotated 1
.-
r sets 5 one is in a posil
the reflecting po stal with t
of plane pol _ presenl s not desdg
ttaek on 1 solute reflecting
merely to tain 1 5 to these 1
azimuths t light r to g
one must kn iUumir :
stanee of the s reflecting
rhis done in sent eas sing
- ss and on:; _
. ted from the s _ ss rep-
stanl fleeting ugh t
1 published results1
In the near future t is solui
ug powei I se and of other :-rystals a test
confidence can be pla the reflecting powei
throng l the sped that is as i slighl
maxima, or minima, for tainties tching brighl
; - 3 reg to be ob-
tained thror._ ng and
Hov. the fact <: -
ng power
light si - this s the prime
- reh up to 1 sen1
The first stal 1 was
by sublima: tmos gen.
-
-
IOWA ACADEMY OF SCIENCE
_• sents typical results of these experi-
f using four settings was not adopted at
ts were performed. -
Electing power are genuine, there are
should be It will be n. I
stant throughout the
- - in a way s si ted by d.
se brilliant - - -
5
■ /V
1
X
1
X
X
-~— _x x
,
X
^
x x X
X
x —
5c en l/ - A "
" 1 ■
-
--
>!-? "
^— — — ft
o
0
■ — ■^ *-• v.
Li
55 «3
A •' - M
65
y
- - si is along
Chis is _ 1 with what
t is _ - 3 :hat the
tesl tens s of 1 ^d light are taken as
I " squai : v sin I s;le throng
rned from its sition parallel to the
y. Th - suits _ -n eorro results
- no doubt add to the
■
:elluriuni. formed in
s planned - laboratory to make a careful
stants - ment. but up to the
this work is not was thought how-
prelimi: ; eriments or
in the more extended work.
used was s ieular hexagonal cry-
REFLECTING POWER OF
stal, and was made by sublimation ii.
Mr. Tisdale of this laborator :i in
:i this was done is described in
s _ The suit
7 0 mm. and was one of tl
.zonal crystal. In these last exper; :ion was
for the possibility of a variation of the intensi
light passing through the monoehromator. an-:
tion in the area of the crystal illuminated when it
through a right angle. The corrections were made as folic
r.=the intensity of th orht ~hen th-
- ong the crystal's long
r2=the int^: - 'he reflected light when *
is perpendicular to the crystal
Oj==ihe reduction factor for the intensity due to th
through the monoehromator when the
=the reduction factor when the vector is horizontal.
=the fraction of the crystal illumine'
is vertical.
&,=the fraction illuminated when horizontal.
Then r-A-Tj-. for example,, will be the inter-
xperiment 'square of cosine of the ang tation
for an intensity match' of the light reflecl
when both the vector and the "
The other combinations are readily intei
Let r.a.J)-=m
r.q_b=p
r2aJ)r==rl
Solving these we obtain
£ 1
j.2 = (mp nq) ; a a. = '7.\ \ - ; .= n m
In the following table are listed the values of the squar
the cosine of the angle of rotation of the Nicol, V . for the dif-
ferent wave lengths, and for the four positions stated above.
It will be seen that the ratio of the tw ag powers is,
ss in the ease of selenium, practically a constant throughout
the spectrum, the one with the electric vector along the long
186
IOWA ACADEMY OP SCIENCE
axis being greater than the one at right angles to this in the
ratio of about 1.7 to 1. the values of b1/b2 should come out a
constant, and the variation in the table is merely an indication
of the experimental errors. The ratio a^/a,, would not necessar-
ily be a constant, although it so proves to be within the errors
of the experiment.
TELLURIUM.
Wave
Length
VI
V
Q
n
fl./a.
&>/&*
rjr.
( jiicra)
.66
.48
.53
.36
.25
1.14
.78
1.68
.64
.48
.57
.38
.25
1.13
.74
1.70
.62
.50
.55
.35
.27
1.06
.84
1.71
.60
.50
.57
.38
.25
1.15
.76
1.73
.58
.50
.59
.40
31
1.05
.81
1.55
.56
.55
.59
.36
.30
1.06
.88
1.74
.54
.52
.59
.38
.27
1.11
.79
1.73
.52
.53
.57
.38
.27
1.14
.81
1.72
.50
.55
.57
.38
.28
1.15
.84
1.72
.48
.55
.53
.38
.28
1.19
.88
1.66
Conclusion. — The importance of a study of isolated crystals
has been pointed out and preliminary direct results on the re-
flecting power of a selenium and of a tellurium crystal have
been obtained. These results have supported the original con-
tention, and are, the writer believes, the first direct results pub-
lished for these two elements to show that they have different
reflecting powers. Heretofore these reflecting powers have been
determined from large polished mirrors of these elements, and
of course only one value for each element for each wave length
has been determined. Further work along this line is to be
done in the immediate future.
Physics Laboratory,
State University of Iowa.
SUMMATION OF TYPES OF SERIES 1ST
A PHYSICAL REPRESENTATION OF THE SUMMATION
OF CERTAIN TYPES OF SERIES.
L. P. SIEG.
Most of us are on the lookout for concrete illustrations of
abstract ideas. To be able to visualize a mathematical process
is to many of us a step toward the better understanding of that
process. The following brief discussion, although having no
pretentions to absolute originality, is offered as a physical il-
lustration of the summation of certain simple geometric series.
In the accompanying four diagrams of figure 17 we have
a series of four sketches of combinations of simple machines.
In each case a weightless platform supporting a man of weight
W is suspended from the point a of the weightless, frictionless
lever Fab. The fulcrum of this lever is at F. The point of ap-
plication of the force /' which the man exerts, in the manner
shown by the arrow in each case, is at the point b. The force
/' is transmitted to the point b by the frictionless fixed pulleys
1\ and P2 in diagrams 1 and 3, and by the frictionless fixed
pulley P± in diagrams 2 and i. The mechanical advantage of
the lever is considered to be m, in order to make the problem
general, where m is greater than unity in diagrams 1 and 2,
and less than unity in diagrams 3 and 4.
The problem in each case is to determine the force / that will
place the system in equilibrium. This is of course a very simple
physical problem. However, there are at least two ways of ap-
proaching the solution of the problems, and it is in the results
from these two methods of approach that we find the ideas
involved in this paper.
Consider diagram 1. We can solve this problem algebraically
by equating the weight of the man plus the reaction or the
force /, which he exerts, to the upward force / multiplied by /".
the mechanical advantage of the machine. Fab. This gives us
W + f=inf (1)
or /=/!'/ Cm- — I) (2)
The second manner of attacking the problem is in an ap-
proach by an infinite series. The man can be considered as in
readiness to exert the proper force, and he indulges in the fol-
lowing reasoning. First he knows that if his weighl is IV he
must pull with a force of W/m in order to support himself.
But this force will create an additional thrust mi the platform
1SS
IOWA ACADEMY OF SCIENCE
of W/m, and so he must exert an added force of W/m2 to over-
come this. This added force in turn causes an extra thrust on
the platform of W/m2, and so he must exert an additional pull
r
P
w
b a
Fig. 17.
of \\ m :. Without going further we see that tlie total force
he must exert is represented by the infinite series
f= W/m+ W/m,2 + W/m 3 + W/m' + (3)
By equating equations (2) and (3), and cancelling the W's,
we obtain the following series :
SUMMATION OF TYPES OF SERIES 189
l/m + l/m2 + l/mr+l/m4+ = l/(m—l) (4)
This is the correct summation of the series and the series is
convergent, since we assumed m to be greater than unity. Eence
the two methods of approach are equally good, and both lead to
the correct answer.
It is a matter of some interesl to speculate as to which method
would be used by a man on an actual platform of this kind.
It seems that the algebraic method would certainly not be used.
Either his muscles would gradually exert tension in the manner
represented by equation (3), or else he would approach the
correct force by an oscillatory muscular pull, the oscillations
gradually getting smaller and smaller until the correel force
/ has been reached. This type of series will be found in the
discussion below. Such a problem as this, aside from these psy-
chological aspects, cannot help but be of some value to a teacher
of elementary physics or mathematics in that it gives a tangible
meaning to an infinite series. Of course there are many other
problems that will illustrate this particular point.
Consider now the arrangement shown in diagram 2. The re-
action is now opposite in direction to W, and the algebraic so-
lution is given by
W—f=mf (5)
or f=W/(m+l) (6)
The other method of obtaining f is somewhat similar to the
preceding one. A first pull of W/m is necessary. This pull,
however, decreases the load by W/m, and therefore the tension
in the rope must be slacked by an amount W/m2. This in turn
adds to the thrust on the platform of W/m2, and an additional
pull of W/m3 must be exerted. In short the force is determined
by the following series:
f=W/m—W mi+W/m3—W/mi+ (7)
Equating equations (6), and (7), and cancelling the W's we
obtain
1/m— l/m*+l/m*— l/m4+. . ..=l/(m+l) (8)
As long as m is greater than unity this is a convergent sei
and is correctly summed. Here again then we have the two
methods of attack leading in one case to a simple answer, and
in the other to an infinite converging series, the series being
a correct representation of the algebraic result.
190 IOWA ACADEMY OF SCIENCE
Turning now to the arrangement shown in diagram 3 we ar-
rive, by the two methods of approach to equations identical
with equations (2) and (3), respectively. However, in this case,
m is less than unity, so that equation (2) leads to a negative
value for /, which means that no positive pull will yield equi-
librium, and hence that the physical solution is impossible. The
discussion of the two cases when m equals unity is obvious. The
scries (3) becomes now a divergent series, and cannot be sum-
med. Here then the second method of approach fails to yield
any result, whereas the algebraic method does yield a result
although it has no physical reality. A glance at the divergent,
series (3) shows that the man is forced to exert a greater and
greater pull, which situation would no doubt correspond with
the facts in an actual situation. But the more the man pulls the
more certain he is of falling to the ground.
The most interesting case, howTever, is the last one, repre-
sented in diagram i. Here we arrive by the two methods of
approach at equations (6) and (7), respectively. The alge-
braic solution (6), is perfectly definite and physically possible,
even when m is less than unity. However, the series (7) is di-
vergent, when m is less than unity, and ordinarily considered
it has no sum. A glance at the series will show that the man
first pulls with a certain force, then relaxes the tension by a
greater amount, next pulls with a still greater force, and so on,
pulling and relaxing with forces ever increasing in magnitude.
It is evident that this latter method would not be the actual one.
and it again becomes a matter of interesting speculation as to
with what rhythmical, or other, muscular efforts the man arrives
at the correct force for equilibrium. It is possible that the terms
of the divergent series (7) could be grouped in a certain fashion
to yield a convergent series which would have the correct sum.
It is evident that the second method of analysis of the prob-
lem succeeds in cases shown in diagrams 1 and 2, for all values
of m greater than unity, fails in 3, for m is less than unity,
but fails because the solution is impossible, and fails utterly in
4 for values of m less than unity, although the solution of the
problem is possible and perfectly definite.
Physics Laboratorv,
State University op Iowa.
TUNGSTEN X-RAY SPECTRUM 191
THE TUNGSTEN X-RAY SPECTRUM.
ELMER DERSHEM.
Some work has recently been done in this Laboratory In the
analysis of the molecular arrangement in certain crystals by
means of the reflection of X-rays from these crystals. To carry
out this work it was first necessary to determine the wave
lengths of the characteristic lines of the tungsten X-ray spec-
trum because tungsten is the material of the anticathode of the
Coolidge X-ray tube, the most satisfactory tube for this kind
of work.
The method of obtaining the X-ray spectra was essentially the
same as that used by many other X-ray investigators. A crystal
was mounted inside a lead box in such a way that it would be
slowly and uniformly rotated by means of the rising of a float
in a tank into which water from a constant head source was
allowed to flow. A cleavage face of the crystal was placed in
the vertical axis of rotation and X-rays coming through a nar-
row vertical slit in the lead shield between the crystal and the
tube were reflected from the crystal whenever the angle made
by the crystal planes with the incident rays satisfied the condi-
tion given by the formula nx=2dsin €3 in which n is a whole
number, the order of the spectrum. x is the wave length, d is
the distance between planes parallel to the face in question
and €3 the angle between these planes and the incident rays.
A photographic plate was placed inside the lead box and with
its plane perpendicular to the line joining the crystal and the
source of X-rays. In this position it would receive and register
a vertical line, or image of the slit, whenever the angle of the
crystal was such as to accommodate, according to the above
formula, any wave length existing in the X-ray spectrum of
tungsten. The distance along the plate from the center to the
position of any one of the lines and the distance from the axis
of rotation of the crystal to the plate being known it is easy
to determine the angle of reflection since the ratio of these dis-
tances gives the tangeni of twice this angle.
192
IOWA ACADEMY OF SCIENCE
In experimenting with crystals which absorbed X-rays only
slightly, it was found that the lines on the photographic plate
became wide and overlapped, making it impossible to perceive
any spectral lines whatever, the plate giving the apearance of
a continuous spectrum. A study of the conditions which would
cause this led to the conclusion that the resolving power of a
crystal, or its ability to separate lines of nearly the same wave
length could be increased by making the crystal very thin. A
test was made, using a crystal of rock salt which had been
ground to a thickness of 0.2 mm. The results amply justified
tlie theory as the lines were narrower and sharper and lines
appeared in a region which had previously been considered as
a region of continuous spectra only. A print from this plate
is shown in figure 18.
It is impossible to reproduce the finest lines which appear on
the plate. In taking this photograph the crystal was first ro-
tated through the position which would give the tungsten spec-
trum on one side of the center line and then reversed to give
the spectrum on the other side. In this way the distance be-
tween the two positions of a line is twice the displacement dis-
tance of that line. In this case the crystal was rotated about
ail axis passing through one of its faces and which was 15.553
centimeters from the plate. The distance between the two po-
sitions of the strong line of greatest wave length was 18.248
centimeters. One-half of this, 9.124, when divided by 15.553,
gives the tangent of twice the angle of reflection which is found
to be 30° 24'. The angle of reflection is therefore 15° 12'.
In the following table the values of the X-ray wave lengths
cf tungsten are given. The computations are based on the value
of 2.814xl0-s cm. as given by Bragg for the distance between
planes in a rock salt crystal.
Fig. 18.
TUNGSTEN X-RAY SPECTRUM
193
Glancing Angle
OF REFLEC 1 Kin
Wave Length
15°
17'
1.4S3xlO's cm.
Strong
15°
12'
1.476
13°
21.5'
1.300
Strong
13°
11'
1.284
12°
57.5'
1.262
Strong
12°
46.5'
1.244
11°
35'
1.130
Strong
11°
16'
1.100
10°
52'
1.061
10°
31'
1.027
9°
52'
.964
9°
22.5'
.917
7°
33'
.739
4°
55.5'
.483
Other measurements indicate that these values, assuming the
exactness of the above value of d, are correct to within 0.1 per
cent. It is the belief of the writer that the resolving power of
a crystal may be much further increased and the X-ray spectrum
of the elements made almost, if not quite, as extended as the
light spectrum and by means of this greater resolving power the
finer details of atomic structure become known.
Physical Laboratory,
State University of Iowa.
13
MOISTURE COXDEXSATIOX ON CLASS WOOL 195
A CURVE OF MOISTURE COXDEXSATIOX ON GLASS
WOOL.
L. E. DODD.
Experimental results of Professor F. T. Trouton1 relating to
equilibrium vapor pressure and total mass of water vapor fed
to glass wool that had previously been thoroughly dried, showed
an interesting drop in the curve at about half saturation pres-
sure. The character of the curve appeared to afford grounds
for a theory, proposed by Trouton, which supposed the con-
densation to have taken place in two modes, or states, which he
called the alpha and the beta states. After thorough drying,
employing the three agencies of continued vacuum, phosphorus
pentoxide, and a temperature of about 160°, moisture in the
alpha state was supposed to condense on the dried surface first.
The alpha condensation required relatively only a small amount
of water. With the equilibrium pressure at about half the
saturation value, which followed after but two or three feeds,
and with additional water fed to the glass wool, the equilibrium
pressure dropped, at which time the beta condensation was sup-
posed to have begun, following a condition of supersaturation.
The alpha condensation was interpreted as forming a nucleus
for the beta type. After a few more feeds the curve rose again
toward saturation. Trouton took the view that his results were
theoretically to be expected from the shape of curve given by a
characteristic gas equation, and that the same results could be
expected from surfaces in general that had been in like manner
thoroughly dried. More recent work by Mohr2 and by Gossrau3
has, however, thrown doubt on the supposition that Trouton 's
results are simply a response to the demands of the characteristic
gas equation. These investigators found that the Trouton ef-
fect, i. e., the drop in the pressure-mass curve, was present only
in the case of alkali glasses.
With Trouton 's theory in view, before the work of Mohr and
of Gossrau had become known, and in view also of experimental
Crouton, F. T., Proc. Roy. Soc, Ser. A, 79, July 10, 1907. p. 383.
-Mohr, Erich: "Ueber Adsorption uml [Condensation von Wasserdampf an
blanken Glasflachen," Inaug. Dissert., Halle. 1911.
3Gossrau, Gotthard : "Untersuchungen uber Adsorption von Wasserdampf
an blanken Glasflachen," Inaug. Dissert., Halle, 1913.
196
IOWA ACADEMY OF SCIENCE
results obtained in this laboratory by Stewart and by Brown as
well as by the writer, which indicated the presence of electrical
conduction between metal electrodes in air without actual metallic
contact of the surfaces, it was proposed by Stewart to use
Trouton's experimental method on metallic surfaces instead of
glass. The possibility was entertained that the pressure-mass
curve in the case of a metal would show the Trouton effect so
definitely that the beta condensation, or a similar type of con-
densation, could be held responsible for electrical conduction
across the gap observed to occur at a much larger distance be-
tween electrodes on a very humid day. It was hoped that the
Trouton drop in the case of a metal would be found near satura-
tion.
The first metal tried was copper. It was considered desirable
to experiment simultaneously with glass wool in a separate ap-
paratus of the same kind, in order to learn whether the present
experimental conditions, somewhat modified from those of
Trouton, would give the same character of curve he obtained.
The outstanding modification of Trouton 's apparatus was a very
great refinement in the mode of feeding water into the glass wool
C •*
-4
KJ
!J
Fig. 19.
chamber subsequently to the drying, a refinement suggested by
F. C. Brown. "Without describing in the present report the re-
sults with copper, only the results with glass wool will be con-
sidered.
MOISTURE CONDENSATION ON GLASS WOOL
L91
Figure 19 shows the apparatus. The tube A contains distilled
■water freed from air. B is a chamber between stopcocks to con-
tain a small amount of water from A. C is another chamber
between stopcocks, the "feed chamber." A mercury manometer,
D. is for the purpose of reading pressures inside the apparatus.
E is the bulb containing the glass wool. The tube marked "to
pump and gauge" was sealed off following the drying process
and before any water feeds were let into the apparatus.
The method of feeding was to saturate the feed chamber with
water vapor, and then open this chamber into the apparatus, the
stopcock between it and chamber B having first been closed. In
Trouton's apparatus the feed was made from a capillary cham-
ber (with a similar arrangement of stopcocks) filled with water
in the liquid state. Thus the amount of water let in at any one
feed was much greater than in the modified method, and Trouion
could get only two or three separate feeds into his apparatus
before the phenomenon of pressure drop occurred. Likewise in
the part of the curve immediately following this drop only a
general notion of what was actually taking place could be ob-
tained because of the few readings in this region.
Fig. 20.
Trouton's method of drying was to immerse the wool chamber
in hot oil kept at the desired temperature as Long as the drying
continued. In the present work an electric oven served, without
198 IOWA ACADEMY OF SCIENCE
the use of oil. The drying continued for three days and nights
at a temperature of at least 200°. with a Gaede mercury pump
continually running, and in the presence of phosphorus pen-
toxide.
The data for the curve, figure 20, connecting equilibrium
pressure and total mass of water, were taken over a period of
seven or eight months, and while the curve is not yet complete
to saturation the experiment has been carried far enough to re-
veal several matters of interest, mentioned in the summary. In
this curve the separate feeds are numbered. Following any one
feed more readings than one were of course taken, sometimes a
series of readings extending over considerable time.
SUMMARY OF RESULTS.
1. The curve is of particular interest because of the larger
number of separate feeds before the half saturation region is
reached, showing a refinement much greater than in the Trouton
method.
2. The curve is divided into three distinct parts : A, B, C-D.
3. An examination of the ratio y/x2 for part A of the curve
shows that this part approaches very close to the parabolic form.
4. Part B of the curve may be taken as linear, and when pro-
jected it passes through the origin.
5. Part C-D is a region of more or less instability.
6. In part A of the curve more time was required, in general,
for the pressue to reach the equilibrium value than in the other
region, where the equilibrium pressure ensued in a relatively
short time after a feed.
7. Although the pressure data used in the curve were cor-
rected to a constant temperature of 22° C. there still appears a
marked fluctuation of pressure with the actual temperature pre-
vailing at the time the reading was taken, and generally in the
direction one would expect. This effect not only appears in the
main curve shown, but also in auxiliary curves using series of
readings taken between actual feeds. The effect is to we ex-
plained by the change with temperature of the mass of water
present as vapor, while the pressure correction for temperature
assumed a constant mass of water vapor. There would appear
to be sufficient data for information as to how the mass of water
in the condensed film varies with temperature.
THE STROBOSCOPE EFFECT 199
8. There is no noticeable change in pressure with time, which
shows the absence of air leak into the apparatus, in spite of the
presence of two stopcocks that might be expected to afford some
leak. This result may be laid to a careful regrinding with fine
emery and water before use.
THE STROBOSCOPIC EFFECT BY DIRECT REFLEC-
TION OF LIGHT FROM VIBRATING MIRRORS.
L. E. DODD.
A very simple and convenient method of producing the
stroboscopic effect is to reflect light directly from a vibrating
mirror upon a stroboscopic screen. The mirror may be such
as is afforded by a vibrating membrane which is itself reflecting
or has a suitable mirror attached either directly or indirectly
to it.
Any stroboscopic apparatus is divided into two principal
parts, the stroboscopic screen arrangement with its similar fig-
ures in motion, and some means of obtaining periodic glimpses
of the screen. The latter is commonly provided by some method
of periodic illumination with suitable frequency. The mano-
metric gas flame is the device most commonly used 'to pro-
duce periodic illumination, although a periodic electric spark,
or a discharge tube with tuning fork interruptor of the induc-
tion coil primary, give good results. The important condition
of illumination for producing the stroboscopic effect is that there
shall be in any given small region of the screen the periodic
change in light intensity. (It is not necessary that the light be
at any time entirely reduced to zero intensity.) Given such
a small region on the screen and the similar figures of suit-
able size, the stroboscopic effect will occur in this region if the
latter undergoes a periodic change in the intensity of the light
falling upon it, regardless of how this change is produced.
There are in general two possible ways in which the light in-
tensity in the region of small area can change: (1) by a change
in the intensity of the beam of light as a whole, which falls on
the screen, with the beam itself possessing at any instant a uni-
form intensity over its cross-section, or (2) by a periodic back
and forth lateral displacement of a beam whose intensity does
200 IOWA ACADEMY OP SCIENCE
not vary with time, but is non-uniform over the cross-section of
the beam. The writer has no knowledge that this latter way
has heretofore been employed to produce the stroboscopic effect.
In the case of a vibrating membrane which is itself reflecting
we have of course a mirror that changes periodically from con-
vex to plane to concave and back again, and hence a beam of
light reflected from its surface to a screen will periodically
change its total area of cross-section where it is intercepted
at the screen. Since the total quantity of light in the beam does
not change, the intensity of light in the spot on the screen varies
inversely as the area included in the spot. This would give then
on the screen a periodic illumination of the first general type
mentioned.
Alexander Graham Bell1 used such a reflecting membrane in
his photophone, permitting the beam of light to fall upon a
selenium cell. A telephone receiver in series with the cell re-
produced the tone actuating the membrane. Bell explained the
effect on the light sensitive cell by the changing curvature of
the mirror, as described.
The explanation appears to be the obvious one, simple and
final. It would appear to be justified also in the light of other
experimental results obtained by Professor Bell. He constructed
a hollow convex lens with walls of mica or thin glass, and filled
it with a transparent liquid or gas. The walls of the lens could
be made to vibrate under the action of the voice, and thus the
lens curvature could be periodically changed. A beam of light
passing through the lens and falling upon the selenium cell pro-
duced the same effects in the telephone receiver as the vibrating
mirror.
But, taking the case of the mirror, it must be remembered
that the amplitude of vibration is not large, and hence the cur-
vature changes over only a very narrow range. One would
hardly expect therefore that there could be a change in the in-
tensity of the beam of any consequence, at least for very short
distances between mirror and screen at which the stroboscopic
effect can be produced. With larger distances, as in Professor
Bell's work with the photophone, the effect is of course con-
siderably greater.
1BeIl, A. G. : "De la production et de la reproduction du son par la
lumiere," Annal. de Chimie et de Physique, t. XXI, 1880.
THE STROBOSCOPIC EFFECT 201
Professor Bell's explanation, in view of his results with both
the vibrating mirror and the vibrating lens, of the light effed
on the selenium cell may be taken as at least partial explana-
tion of the phenomenon. However, in both cases of mirror and
lens, as the cross section of the beam alternately contracts and
expands, there must be a lateral displacement increasing in
amount toward the margin of the beam. If the beam is not of
perfectly uniform intensity over its cross section, and it is not
likely to be, at any particular fixed point where the beam falls
there will be changing intensity due not only to its expansion
and contraction, but also to the fact that a little element of
the beam incident at this fixed point is being replaced by an
adjacent element of different intensity, different because of
the non-uniformity of the beam. Because of the relatively small
amplitude of the membrane the lateral displacement of the beam
cannot be very large, especially at short distances, and yet it is
sufficiently large to give the stroboscopic effect even in the case
of spots of 3 or 4 mm. diameter on the stroboscopic screen, and
that at relatively short distances. It cannot be supposed there-
fore that, the lateral displacement is sufficient to cause an ele-
ment of the beam to sweep clear across one of these larger spots.
It would seem that we cannot be at all certain without further
investigation as to just how important a role this effect due to
a non-uniform beam plays in the experimental results of Bell
with a selenium cell. We may, however, be certain that it is
present in both the case of the vibrating mirror and that of the
vibrating lens.
One is justified in suspecting that it does play some part in
Bell's results, in view of the results in stroboscopy obtained by
the author. For the stroboscopic effect has been found to exist
very sharply when the vibrating mirror was made by silvering
one of the small circular microscope cover glasses and attaching
it to a vibrating membrane by means of a bit of cork between
them. Under these circumstances it is not to be expected that
the mirror will change its curvature when the membrane vibrates.
but will move as a whole. Moreover the stroboscopic effect was
produced with a piece of ordinary mirror izlass. attached to the
membrane. This mirror glass was much too thick to admit the
possibility of changing curvature. It appears therefore that the
stroboscopic effect is to be explained, in large part a1 least, by
the periodic lateral displacement of a beam of non-uniform in-
202 IOWA ACADEMY OF SCIENCE
tensity over its cross section. We are thus led to suspect that
this same condition, present in Bell's work, played its part in
the effect on the selenium cell. It is more difficult, however,
to accept such a conclusion in the case of the cell's response,
than in that of the production of the stroboscopic effect. In
the former the total amount of light falling upon the cell must
remain very nearly the same, even though at any particular
point on the cell the intensity changes by the lateral displace-
ment, while in the latter case it is a region of small area that
is chiefly concerned.
In a consideration of the stroboscopic effect the fact must
not be overlooked that the eye is extremely sensitive to small
changes of light intensity, so that the changing area of the
beam on the screen may contribute its effect, which, however,
appears to be at most only a minor effect. The decisive experi-
ment must have achieved a separation of the two mechanical
conditions, that of periodic expansion and contraction of the
beam with the accompanying changes in light intensity due to
this expansion and contraction alone, and secondly, the periodic
lateral displacement of the beam. It is easy to have the second
condition alone present, as has been shown, but it is difficult
to see how one could have changing curvature without lateral
displacement.
"While the idea of reflecting light directly from a vibrating
membrane was arrived at independently by the author it was
later learned that the idea was anticipated by Professor Bell
about 1880, who, however, used the reflected light for a differ-
ent purpose. The production of the stroboscopic effect by this
method appears to be new.
In this method various kinds of diaphragms can be used.
Satisfactory results have been attained with silvered mica
membranes, as well as paper and rubber dam membranes (with
mica mirrors attached to them either directly with paste or with
bits of cork or cardboard between mirror and membrane.)
Paper membranes seem to give as good results as any.
A of figure 21 shows an arrangement of a paper membrane
over the end of a short glass tube, with a lever system and a
small mirror (microscope cover glass) that could periodically
be given an angular displacement by the vibrating membrane
actuated by a sounded tone at the open end of the tube. This
THE STROBOSCOPIC EFFFCT
2i»:',
was one of the preliminary experiments to find a method to
replace that of the manometric flame, for the purpose of stro-
boscopy. A reflected beam falling on a rotating mirror gave
Fig. 21.
clearly defined sine waves of large amplitude. A simple step
from this arrangement was to attach the small mirror directly
to the membrane, and then to use a mica membrane that could
be entirely silvered.
B of figure 21 shows, above, a reflecting membrane made by
stretching paper over the large end of a telephone receiver shell
with the cap off, and to the paper attaching as already indi-
cated a mica mirror. Below is shown a glass tube arrangement
204 IOWA ACADEMY OF SCIENCE
as vibrating chamber, with the right end of the large tube cov-
ered with a silvered mica membrane. The left end of the smaller
tube served for mouthpiece. Leaning against the large tube
in the foreground is seen a circular piece of silvered mica such
as was used for a reflecting membrane.
SUMMARY.
1. A new and simple method has been found for producing
the stroboscopic effect.
2. The method appears to employ a general means of produc-
ing periodic illumination changes at a fixed point which has not
been hitherto used ; viz., the periodic lateral displacement of a
beam of light non-uniform in intensity over its cross section.
3. A question for further investigation is : How large a
contribution to the changing light intensity on the stroboscopic
screen is due to changing curvature of the mirror?
4. An additional experiment suggested by the stroboscopic
effect with the vibrating mirror is a similar experiment with a
vibrating convex lens, similar to that used by Bell with a
selenium cell.
A NEW TONOSCOPE.
L. E. DODD.
While undergoing a series of voice pitch tests some three
years ago in the Psychological Laboratory of the State Univer-
sity of Iowa, the author learned that in his own individual case,
as in some others, there existed, according to the statement of
the investigator, Mr. C. J. Knock, a consistent as well as per-
sistent tendency to miss in a definite direction certain intervals
of the musical scale. The instrument used in these tests was
the Seashore tonoscope,1 an indicator of absolute pitch developed
in some of its later stages at this University. In the particular
results mentioned the amount of the error was not so noticeable
to the ear, as the ear has its limitations, especially when it is
the ear of the one who is himself forming the intervals by
voice, but in an absolute instrument like the tonoscope even
very small errors can be detected. The conclusion formed by
the author from these results was that the musical intervals
concerned had been wrongly learned in childhood.
Seashore, C. E. : Psych. Monographs, University of Iowa Studies In
Psychology, No. VI, June 1914, p. 1.
A NEW TONOSCOPE 205
The sources of a child's information regarding musical in-
tervals are his listening to a piano or other musical instrument,
or his hearing the intervals sounded by almosl anyone who may
be at hand to do this for his benefit. The chief difficulty with
the first method is that the instrument may be and generally
is, to an extent at least, out of tune, and in the second case the
fidelity to pitch of the older person who is sounding the inter-
vals is more or less questionable, depending both upon how good
a musician this person is and also upon his physical condition,
which has a marked effect upon one's fidelity to pitch.
A child's first impression is the important impression. In the
interest of making his first impressions regarding matters of
pitch in singing as nearly absolutely correct as possible an in-
strument like the tonoscope should be made readily available to
the public. In fact it should be an instrument available in
the home itself. Availability includes as small size and weight
as possible together with low cost.
The idea of improving the tonoscope in at least these respects
has continued with the author since the series of tests to which
reference has been made. In February of the present year
(1916) experimental work was undertaken with a view to sim-
plifying the instrument. This resulted in a new method of
producing the stroboscopic effect which is particularly adapted
to the tonoscope because it does away with the manometric
flame and its necessary gas supply. It also permits the illum-
ination to come from one end of the drum rather than directly
in front of it. The new method is presented in a separate paper.
It was also found by stroboscopic tesis that a mechanical
clockwork meter of the phonograph type possesses a marked
constancy of motion, which over an interval of aboul two min-
utes is constant to within one-tenth vibration per second. By
introducing an electric wind to keep the spring automatically
at the same tension very great constancy can be secured and
thus the special synchronous motor for constant speed rendered
unnecessary. Also it was found that the stroboscopic drum
could be greatly reduced in size, and both drum and scale placed
at the distance of most distinct vision from the eyes,
Thus there has resulted an improved tonoscope that has the
desirable qualities of portability and reduced cost of manufac-
ture. It is an instrument easily available to the home and the
206
IOWA ACADEMY OF SCIENCE
public school, as well as to music teachers and musicians every-
where, in private studios or conservatories. Because of its wide
Fig. 22.
availability science will have at hand practically unlimited
amounts of data to be used in drawing scientific conclusions, or
formulating laws.
Source
AStrob o scop/c
Ref/e
Fig. 23 — Lighting Scheme in New Tonoscope.
Its uses are numerous, but none would seem to be more im-
portant than its employment in giving to children correct im-
A NEW TOXOSCOPE 207
pressions as their first impressions regarding matters of pitch.
For a child to be at all musical he must learn the musical scale.
The scale is fundamental although simple and usually quickly
learned by the child, and a little time spent with him with the
tonoscope as an aid will give him these correct impressions.
The stroboscopie drum with its phonograph motor drive used
in the demonstration of the new tonoscope at Des Moines is
shown in figure 22. The lighting scheme for the stroboscopie
method is indicated in figure 23.
Physics Laboratory,
State University.
HIGH TEMPERATURE OVEN 209
AN ELECTRICAL DEVICE FOR SECURING AND MAIN-
TAINING CONSTANT HIGH TEMPERATURES.
W. E. TISDALE.
In a paper read before this Academy last year, a device for
controlling comparatively high temperatures (up to about 600°
C) was explained, together with thfj necessary auxiliary appara-
tus, an ordinary electro-magnet circuit breaker, and the source
of constant potential necessary to operate this magnet. The
oven described in that paper consisted of a properly insulated
porcelain tube 30 cm. long and 5 cm. in diameter. It required
10 amperes to heat it to 450° C. The dimensions of the oven
limited the size of the tubes in which the crystals were to be pro-
duced to not more than 3 cm. in diameter and 15 cm. in length,
and admitted but one at a time. Inasmuch as it requires sev-
eral months to produce crystals of a size such as is necessary
for optical and electrical work, the disadvantage of the oven
may be readily seen.
In the catalogues of the various manufacturers of regulated
electrical ovens, there are no descriptions of ovens that go above
300° C, so that the only method of obtaining one that, would suit
our purposes was to manufacture it ourselves.
Accordingly, the oven shown in figures 24* and 25 was de-
signed. Except for the angle irons used in the corners, and the
necessary bolts, it is made entirely of asbestos board three-
eighths inch thick. The oven is double walled, the interspace on
the sides being filled with loose asbestos, and that on the top
with air. The inside dimensions are 12x12x14 inches, the longer
dimension being the height. In figure 24 an elevation view is
shown. The asbestos board with the double row of holes shown
at the left in the figure is the bottom of the oven space, and be-
longs immediately above the heating coils, which may be seen
in place on the bottom. The top shown tipped up is the top of
the oven space, and between it and the top of the entire ap-
paratus (shown in the front of the oven) is a space of three
inches of air. The thermometer is seen projecting at the left.
and on the inside the controlling device (figure 26) is seen in
14
210
IOWA ACADEMY OF SCIENCE
position hanging on the right wall. In figure 25 a plan view is
shown, with the tops and the hottom of the oven space removed.
At the left is shown the electro-magnet device for breaking the
current through the heating coils. This magnet is operated by a
Fig. 2 4.
current controlled by the device shown in figure 26. This con-
sists of a bar of asbestos board, to which is attached a thin metal
strip. The gap shown between the silver tipped screw and the
silver plug in the metal strip immediately below is 8 mm. This
is the amount of rise of the center of the strip for a change of
temperature from 20° C to 360° C.
The oven requires 8 amperes of current to heat it to 450° C,
making the cost about 10 cents an hour to operate it at standard
electrical rates. The controlling device regulates at 450° C to
HIGH TEMPERATURE OVEN
211
not more than one degree variation above or below this value.
and has so maintained the temperature for the six weeks that it
has been in constant operation. It is possible to maintain con-
stant temperature with this apparatus up to 700° C, or about
Fig. 25.
Fig. 26.
1300° F. The apparatus was made completely in the shop of
the Physics department of the University of Iowa, at a cost for
materials only of about $20.00. It has been entirely satisfactory
in its results, having produced crystals for the researches of
four different men.
Physical Laboratory,
University of Iowa.
PROPERTIES OF PHOSPHOR-BRONZE WIRES
21!
CERTAIN ELASTIC PROPERTIES OF PHOSPHOR
BRONZE WIRES.
A. J. OEHLER.
INTRODUCTION.
The work by Guthe1, Guthe and Sieg2, and Sieg3, on platinum-
indium wires when used as suspensions for torsion pendulums,
showed some remarkable elastic properties of that alloy. The
principal one of these was the variation of the period with the
amplitude of vibration. It was these studies that made it seem
very desirable to test other alloys commonly used for suspen-
sions, by a similar method.
Fig. 2 7.
The wires employed in this research were of a phosphor-
bronze alloy and represented thirteen successive drawings from
an original sample. These ranged in diameter from .508 mm.
to .100 mm. The wires were very kindly supplied by the Ameri-
can Electrical Works of Phillipsdale, Rhode Island.
15, 1908, p. 1 17. Abst. in Phys. B
1K. E. Guthe, Iowa Acad
p. 201, 1908
Sci.,
26,
2K. E. Guthe and L. P. Sieg, Phys.
3L. P. Sieg, Phys. Rev., 31, No. !,
::0, 1910, p. 610.
1910, p. 421.
214
IOWA ACADEMY OF SCIENCE
THE PROBLEM.
The extensive use of phosphor-bronze wires as delicate sus-
pensions, makes it very desirable to know intimately the elastic
nature of this alloy. Some work by Professor Sieg and the
writer in 1914, showed that the periods of the torsional vibra-
tions were not constant but varied widely with different ampli-
tudes.
The problem of this research was the verification of this
clastic peculiarity and to prove that there is no justification for
the use of these wires as delicate suspensions. New problems
suggested themselves at once and some of these have been in-
vestigated to find out, if possible, more of the intimate nature
of the alloy.
r^~
Fig. 28.
A preliminary report of certain of these experiments Mas
given before the Iowa Academy of Science in the spring of
1915*.
APPARATUS.
The apparatus is the same one which was employed and de-
scribed by Sieg5. Figure 27 shows the complete apparatus with
the exception of the arc which was used to illuminate the mir-
ror, and figure 28 shows the timing device.
*Iowa Academy of Science, Vol. 22, 1915, p. 321.
5Loc. cit.
PROPERTIES OF PHOSPHOR-BRONZE WIRES
2 1 5
The length of the wire was usually 30 cms. and the initial
twist in most cases was 10 degrees per cm. length of the
suspension.
To make clear the method of observation, and the nature of
the results, a sample of the data follows :
SAMPLE OF DATA.
(Wire No. 4, d=.145 mm; Load=154 g. ; Approximate period=11.8 sec.)
Tape
Corresponding
Average
Average
Readings
Amplitudes
Time
Amplitude
3—32—19.85
32—31.81
32—43.63
254
3—32—43.62
32—55.50
33—07.29
215
3—36—39.85
36—51.74
37—03.47
176
3—37—03.46
37—15.35
37—27.00
149
3—41—46.30
41—58.14
42—09.84
122
3—42—09.87
42—21.68
42—33.41
The above data were then tabulated in the following form :
Vib.
No.
No. of
vibs.
Ave. time
(from above)
Time betw.
Readings
Period
(sees.)
Amp. Ave.
Amp.
3—32—43.62
254
11
22
3—37—03.46
259.86
11.812
176
215
35
26
3—42—09.87
306.39
11.784
122
149
The first column represents the number of vibrations that
have been executed since the pendulum was set into vibration.
It might here be said that the elastic after effect was very
marked in this alloy and so the zero point had to be re-deter-
mined several times during an experiment. The zero point was
known to shift as far as nine degrees in the direction of the
initial twist. This, of course, would introduce quite an error
in the time readings if the above precautions were not taken.
216
IOWA ACADEMY OF SCIENCE
THE RESULTS.
Introduction and general discussion. The experiments soon
showed that there are three distinct states, from one to another
of which the wires would change. The conditions under which
these changes occur are very complicated but in this paper some
of the conditions will be dealt with. The three period-ampli-
ZtOr
10 is
Fig. 29.
tude curves representing the three typical states are shown in
iigure 29. For convenience and brevity in discussion these will
be numbered. They will be discussed in detail in the latter part
of this paper.
Type I shall be the curve (see figure 29), in which there is a
continual decrease in the period as the amplitude decreases.
This departure from a constant period varies greatly in magni-
tude in the different wires and with the conditions imposed upon
the experiment; as variations in the load and the approximate
period. The same holds true also in the other types of curves.
Wires when following this type of curve will be said to be in
slate I.
PROPERTIES OF PHOSPHOR-BR(\\ZK WIRES
217
Type II is similar to the above mentioned curve in the larger
amplitudes but makes a departure from that type at an ampli-
tude of about four degrees per cm. length of the wire, and from
that time on, the period gradually increases with a decrease in
the amplitude. The curve is marked II (figure 29) and will
represent state II.
Type III is seen to be very different from the other two. In
this curve the period increases continually from the large to the
small amplitudes. "When the wires follow this type of curve
they will be said to be in state III.
From figure 29 which shows three curves of an identical sam-
ple of wire under identical experimental conditions, it is at once
seen that the variation from a constant period is very marked.
The magnitude of the variation is perhaps best shown by going
into these particular curves in detail.
The wire was .100 mm. in diameter (No. 1), and supported
a load of 27 grams. Curve II is drawn from the data of June
6, 1915. All experiments of that time showed the wire to be in
soi\
500
<m
__ ?
/It -•> ,.,
'33 nm
,/Vr ".-.
./< »■ * .-
./ft "II
5' >0
/5
Fig. 30.
state II. The wire was then left hanging under its load through
the summer months without vibration and in a room of prac-
tically constant temperature. On October 6, 1915, or four
months later, the experiments were continued and the pendu-
218
IOWA ACADEMY OF SCIENCE
lum was set into vibration without any preliminary vibrations.
The results of this test are shown in curve III. We see that the
wire had changed from state II to state III in supporting its
load during the summer.
ZLO
2.5.0
o
S 10
Amplitude 0*r
Fig 31.
'A
Prom the coordinates it is readily seen that the maximum
variation from a constant period, between the two curves, is
about 3.85 seconds. Considering this variation with the maxi-
mum period of the two curves, it is found to be in the neighbor-
hood of 16 per cent.
Curve I shows the identical sample of wire when in state I.
It is seen that the variation from a constant period is not so
marked in this type.
This phenomenon is found to be less marked as the diameter
of the suspension becomes larger. In other words the draw-
ing of the wires has a tendency to increase the effect. Figure
30 shows the results of experiments with seven successive
drawings when the wires were in state I. Figure 31 shows the
results of the four smallest of the above seven wires when in
state III. The curves of each figure are reduced essentially,
to a common period at a given amplitude. The diameter of the
wires are given in figure 30. This result is similar to that
found in platinum-iridium wires by Sieg6.
eL. P. Sieg, Phys. Rev., Vol. 35, 1912, p. 347.
PROPERTIES OF PHOSPHOR-BRONZK WIRES
219
"We may here note that the wires most eommonly employed
for suspensions are of a diameter in the neighborhood of the
smallest of these wires.
Variation of Load and Period. The existence of these three
states in the wires and their causes and relations then became
the object of research. If the stairs existed, the wires of this
alloy certainly were not reliable for use in scientific instru-
ments. The question then arose as to whether the two varia-
bles, the period of vibration and the load supported by the
wires, might not be the determining factors of the resulting
state.
It was soon discovered that ordinary experimentation did
not alter the condition of any sample of wire and so the experi-
ments could be repeated many times while the wire remained
in essentially the same state. It was found that unless the
treatments were quite strenuous, the wires always behaved
essentially the same. This was verified by repeating an experi-
ment several times in succession and the curves were always
Wr3^
£3.2.
2.S.0
z.1.1
a-. M.ic
a 7.4
2/1.21
#«.
•&.
*°"-
OPi^^lf""'
37. 3^
2|.o5V
/fc-333
goo 300 *»
Fig. 3 2.
identical. In one case wire No. 3 (d=.133 mm.) was used over
a period of nearly two months and the curves of this time are
all of the same type.
To answer the above questions of a varying period and load.
the following experiments were conducted:
22
IOWA ACADEMY OF SCIENCE
Wire Xo. 3 was first used with four 1 4 widely varying
periods of vibration but with a constant load and length of
wire. The initial twist was the same in every ease. The periods
were varied by changing the moment of inertia of the pen-
dulum.
Figure 32 shows the result of this experiment. It was im-
mediately seen that the period-amplitude curves as well as the
period-vibration number curves were similar in the four tests.
Thus the period of vibration had no effect upon the state of
the wire. Further than this, it was found that if each curve
- multiplied by a certain factor the four curves fell practi-
cally upon a single line (see figure 32). The line has not been
drawn, in order that the actual position of each curve may better
be shown. The factors were simply the ratios of the periods
at a certain amplitude, to any arbitrary number, and in this
case they were 1. 1.3. 1.68 and 2.2. Table I below gives the
original periods, the periods multiplied by the factor and the
corresponding amplitudes.
TABLE I.
(l)
(2)
K=l
K=1.3
T.
Amp.
T.
K.xT.
Amp.
27.348
525
21.051
27.366
491
.574
373
.238
.609
360
.889
252
.414
.838
263
28.108
175
.544
28.007
205
.210
135
.644
.137
159
.292
102
.707
.219
125
.349
76
.755
.282
100
.375
58
.784
.319
79
.396
42.5
.812
.356
64
.832
.382
52
.823
.379
42
.844
.297
35
PROPERTIES OF PHOS
K=3 -
K=- -
T.
K.sT.
Ami
T.
K
16..
-
.
.
52
"■
1
--
■
.
-"
-■ : -
.
"-
'. i
"
.155
1
.-
■
.239
14
-
-
•4
•"
17
■ "
57
- •
-
-
Ml
-
.
Having verified this relatio: set tions
then investigated. In this ease t - stanl
wire and initial amplitude bnt a v a :>n the pendulum.
At first an attempt was made * s slant in the
differ - sts bnt beeaus s s of 1
pendulums, this was found to - ss and in vi~
the previous experim-: fc was not eons
suits of this experiment are sho~~ a 3.
2.7 c
^V-
•'
*
• -
-t? 274
:
r
o
Z
0- 27A
• •
27.0
;
2U
•
i 1
3n -'
-\-
The same wire N s us
and -7:2 grams. - the three eur - f the same g
eral shape a the same ] tag
222
IOWA ACADEMY OF SCIENCE
amplitude. Again the factors were simply the ratios of the per-
iods to an arbitrary number. They were in this case 1, 1.16
and 2.16. Table II below gives the data of figure 33.
(1)
TABLE II.
(2)
K=l
K=1.16
T.
Amp.
T.
K.xT.
Amp.
26.833
483
23.166
26.873
490
27.094
342
.307
27.036
366
.325
255
.465
.219
288
.502
194
.624
.404
225
.618
158
.741
.540
179
.707
138
.826
.638
139
.760
112
.886
.708
109
.803
86
.930
.759
87
.835
66
.959
.792
70
.847
46
.978
.814
58
.859
29
.995
.834
47
.859
22
24.015
.857
38
.007
.848
28
(3)
K=2.16
K.xT.
Amp.
12.461
26.915
428
.633
27.287
296
.744
.527
197
.813
.676
119
.849
.754
82.7
.863
.784
63
.870
.799
48
.885
.832
32
.888
.838
22
.891
.845
14.4
.890
.842
9.2
The variation from a single line here is somewhat more
marked than in the previous table (I.) where there was a con-
stant load. The curve (figure 33) shows, however, that the
varying load has no great effect upon the period-amplitude curve.
The loads were so very wide in range that it seems safe to as-
sume that ordinary variations in the load have no effect upon
the action of the wire other than changing the period of vibra-
tion.
PROPERTIES OF PHOSPHOR-BRONZE WIRES
223
Variation of the length of the win with constant load. — The
lengths of the supporting wires were then varied from 30 cms.
to 8.9 cms. and the period-amplitude curves were plotted both
for variable and constant periods (approximate periods, since
the periods were never constant), at the same amplitudes per
unit length. When the pendulum had the same moment of in-
ertia for each length the periods varied as the square root of
the length of the wire. This was to be expected from the for-
mula for the period of torsional vibrations.
T2 = 8 IT IL
nr*
where I is the moment of inertia of the pendulum. L the length
of the suspension, n the coefficient of simple rigidity, and r the
radius of the suspension wire. The periods must of course be
taken at similar amplitudes. In this experiment everything was
kept constant except the period and the length, therefore we
would expect to find that
\'Z
The four lengths 30, 23. 15 and 8.9 cms. gave the values of K as
2.43, 2.47, 2.45 and 2.45 respectively.
7.31
The period-amplitude curves for the shorter suspensions were
somewhat unsatisfactory. The state remained the same in all
cases as is shown by the general shape of the curves but the ir-
224
IOWA ACADEMY OP SCIENCE
regularities became very marked as the wire was shortened.
These are not to be explained alone by the small error in the tim-
ing of the vibrations since the same tendency was noted also
with the longer periods, where the error was the same as with
/3.4
5~ to
Fig. 35.
10
the longer suspensions. A comparison of figures 34, 35 and 36
will illustrate this point. All the curves are of wire No. 4
under a load of 154 grams. Figure 35 shows the period-ampli-
tude curve for a 30 cm. suspension. The curve for a piece of
Rnvf
Fig. 36
15
20
this wire, 8.9 cm. long, is shown in figure 34. Figure 36 shows
the same piece vibrating with a period approximately the same
as that of figure 35.
It is very probable that the shorter wires display more nearly
the actual conditions in the wire whereas there may be a neutral-
ization of some pecularities in the longer wires.
When the periods were kept constant with the above lengths
the curves were somewhat more satisfactory but still had a
great tendency toward irregularity. This point requires further
investigation.
PROPERTIES OF PHOSPHOR-BRONZE WIRES 225
The most striking point to be discussed in connection with the
data of these suspensions of different lengths, is that the num-
ber of vibrations required for the vibrating systems to fall be-
tween given amplitudes, increases ;is the wire is shortened. "We
can readily see that when the wire is shortesl the displacement
for a certain amplitude per unil length is smallesl in magnitude.
Since the periods were kept practically constanl in these tests
the angular velocity must have been greater in the longer sus-
pensions.
Let us say that the average velocity varies as the angle of dis-
placement and inversely as the period. Since the angle of dis-
placement is arbitrarily taken proportional to the length, we
have,
v=kL/T
where v represents the mean velocity of the vibrating system.
L the length of the wire, T the period and k a constant of the
alloy.
Now assume the friction, both internal and external, to vary
as the mean velocity of all the moving parts.7 Then
cv = KL/T = f
So, if we have variable lengths and periods we may say
that if the friction is to be the same in all cases, the ratio of
the lengths to the corresponding periods should be constant.
(This would hold true no matter what assumptions are made
in regard to the power of the velocity with which the friction
varies.) Or we have
L/T=LVT'
Now let AT' be the number of vibrations between any two am-
plitudes per unit length and let N" be the number for another
length of the same wire between the same given amplitudes.
If N is inversely proportional to the friction,
N'=k/f
and X"=k/f"
or N7N"=f"/F'
but f=KL/T
thus N'L'/T'=N"L"/T"
but since the periods are kept constant T'=T", and
.V /,' N"L"
or N'/N"=L"/L'
7The velocity of course Is a continually varying quantity but the integrated
value of the velocity over a whole period varies from v by only a constant,
which is included in the constant fc.
15
226
IOWA ACADEMY OF SCIENCE
Thus we would expect that the number of vibrations executed
between any two amplitudes should vary inversely as the
length, if the above assumptions are correct.
Two specimens of wire Xo. 4 were employed in this experi-
ment, one showing curves of type II and the other, curves of
type III. The results of the wire in state II will be discussed
first. The lengths used were 30, 23, 15 and 8.9 cms. Figure 37
ICO
200 TOO
Vibration Numkr.
Fig. 3 7.
400
shows the vibration number-amplitude curves for the four
lengths. The number of vibrations between any two common
amplitudes per unit length can be interpolated from the
curves.
It was found that there was essentially a constant ratio be-
tween the vibrations of any two curves, throughout the life of
the vibrations. Table III gives some of the interpolated values
from the four curves. The first column gives the lengths- and
each successive column gives the number of vibrations between
the amplitudes given in the parentheses.
PROPERTIES OF PHOSPHOR-BRONZE WIRES
TABLE III.
N1
Length (10-3)
X2
(10-1.5)
N3
(18-1.5)
X1
(14-1.5)
(18-1)
30 80(1)
23 95(1.19)
15 166(2.08)
8.9 205(2.56)
140(1)
169(1.21)
285(2.03)
330(2.36)
170(1)
201(1.18)
340(2.00)
406i:
157(1)
186(1.18)
318(2.03)
377(2.40)
206H.
249> _
416(2.02)
The ratios are given for each N after the number. The num-
ber of vibrations of the longest wire is arbitrarily taken as
unity in each case, and the ratios for the shorter -wires are fig-
ured on this basis. The mean of the four ratios for each length
are 1. 1.18, 2.03 and 2.13 with mean variations of 0. .01. .03 and
.07 respectively.
The values for X.L are then 30. 27. 30.1 and 21.6.
In the case of the wire in state III the lengths were 30. 22.
15 and 10 cms. The values for the above ratios of numbers of
vibrations in this case were 1. 1.72. 2.36 and 3.15. The values
for X.L are thus 30. 37.8, 35.1 and 31.5. We see that the pro-
duct X.L is roughly constant. It must be remembered that it
was impossible to make the periods exactly equal in the differ-
ent lengths, since the periods would have to be made equal at
equal amplitudes per unit length of the suspensions. This was
practically impossible. It is also evident that if the state of the
wire changes we could hardly expect a constant friction. This
point will be taken up again in the discussion of the loss of
energy in the two states.
It should perhaps be said that the greater per cent of all the
cuiwes were either of type II or III and hence most of the data
are on these curves. State I seems to be more or less unstable
and is easily changed into state II. For these reasons type I
is omitted from the discussion.
Variation of the initial amplitude. In a given sample of
wire, the number of vibrations required for the system to fall
through a given range of degrees, varies, in a general way. in-
versely with the mean amplitude of this range taken. In other
words the fall in amplitude is exponential. This is common to
all damped vibrations.
In the phosphor-bronze wires the initial amplitude deter-
mines how rapid this fall shall be. If the initial amplitude is
228
IOWA ACADEMY OF SCIENCE
large the fall in the range of amplitudes common to the two ex-
periments is more rapid than when the initial amplitude is
small.
Figure 38 shows this for wire No. 4 when in state II. The
initial amplitudes were 1, 4, 7 and 10 degrees per unit length
respectively, for the curves 1, 2, 3 and 4. Theoretically the
curves should be parallel but careful measurements prove that
they are not. There is a progressive change in the slopes of
the period-amplitude curves, the curves tending to become
steeper with the larger initial amplitudes. This is not a new
point but has been observed in other wires by Kelvin8, and by
Sieg9. We have reasons to suspect that the previous history
plays a large part in this effect.
States II mid HI. The reasons for the peculiar conditions
of phosphor-bronze wires now became the object of research.
As stated above, curves II and III were the rule while those of
type! I were the exceptions. The very first tests showed all
"Kelvin, Math, and Phys. papers, p. 22.
9Loc. cit, p. 6.
PROPERTIES OF PHOSPHOR-BRONZE WIRES 229
wires from No. 1 to No. 7, inclusive, to be in state I. After that,
however, this state became exceptional. To illustrate how com-
plicated the changes of stales are, the following paragraphs
are given.
It has already been stated how wire No. 1 changed from state
II into state III during the summer without any treatment.
The wire was then vibrated artificially by means of the ap-
paratus shown in figure 27, for 20 minutes at the rate of about
40 complete vibrations per minute. (During this process the
pendulum was fixed.) The state was now I and the curve
is shown in figure 29 (curve I). After another 30 minutes of
rotation the wire was in state III again. Another hour of vibra-
tion had no appreciable effect.
The wire was then annealed by 1.2 amperes current in a ves-
sel exhausted to about 3 cm. pressure and under a load of 27
grams. The first condition above was simply a precaution to
prevent oxidation. The temperature became so high that the
wire softened and allowed its load to fall about 1 cm. to the
bottom of the annealing tube. A test now showed the wire to
be in state II again. At other times the same process yielded
state III.
The same inconsistencies were found in all the wires. There
was never any doubt as to the state of the wires because of the
magnitude of the effects.
Kates of loss of energy in states II and III. If A1: I . .1 , be
the successive amplitudes of vibration, Ave may say that
The Potential Energy at Ax = j^_*Ax
2
where & = Aj A
or P. E. at Ax KA\
L
and P. E. at A« = KAl
their dirTerence is
and the rate of loss of energy is
P.
E. at Ax
P.
E. at At
A*
L
US
-AD
K U\ -
A%)
The rates of loss of energy were calculated for several of each
type of curves. Two of each of types II and III are shown in
230
IOWA ACADEMY OF SCIENCE
figure 39. There is seen a tendency for type II to have a more
rapid rate of loss than type III. Below an amplitude of 200
degrees (with a 30 cm. suspension), the rates of loss are essen-
700
lor,
Zvo 300 400
Fig. 39.
*>oo
1 ially equal. Table IV shows the calculations for one of each
type of curves. It is seen from these data that the difference
between the successive angles is quite large and the calcula-
tions are thus only approximate. The data should be taken
very accurately and the curves plotted on a large scale so that
the rates of loss of energy may be compared. Time would not
permit a more careful study of this point at this time.
PROPERTIES OF PHOSPHOR-BROXZE WIRES
TABLE IV.
231
Tvpe II.
Amplitude Rate of Loss
Type III.
Amplitude Rate of Loss
413
564.1
450
650.5
255
172.4
300
239.5
177
72.2
215
107.5
128
33.8
155
45.9
96
17.3
116
25.6
74
9.3
91
14.2
57
5.5
70
8.3
44
3.1
52
4.3
34
1.8
38
2.1
25
1.3
25
.93
18
.5
If we now assume that the rates of loss are equal in the two
states, for they seem to be nearly so in the smaller amplitudes,
we may say,
K (Al—Al) = K (A'j—Al)
T'L LT"
where T is the steadily increasing period of type III and T" is
the decreasing period of type II. Then T and T" are the only
variables in the above equation and if the equation is to hold
5t
ICO ISO
Ui t rati' o rvs
Fig. 4 0.
ROD
true, the value of (At2 — A./) must also increase in the Left-hand
side and decrease in the right-hand side of the equation. Other-
wise the equality would be destroyed. Hence for equal falls
232 IOWA ACADEMY OP SCIENCE
in amplitude in the two types the loss of energy is smaller in
the first than in the second, or we would expect to find that the
amplitude-vibration number curves would be different in slope,
since one would be damped more rapidly than the other. To
see whether or not this reasoning was correct several curves
of the two types were compared. In every case the curve of
type III fell slightly above the curve of type II. This is shown
in figure 40. As we should expect, the two curves tend to coin-
cide again in the small amplitudes. This is easily explained by
the fact that the period of type II again increases after the
minimum at 4 degrees per cm. length. Again, as we should ex-
pect, type I continues below type III throughout the life of
vibrations.
Logarithmic decrement. In ordinary damped vibrations the
logarithmic decrement is constant and is expressed by log K,
Where A 1, A2, A.6> A4„, .are the successive amplitudes and bear the
relation,
~~J. V 2 X X "' = Kn_1
A2 Aj A4 An
An
then log A'
Kn-i
log Ai — log An
n-l
Table V below shows how the log K varies in a sample of wire
No. 4. These tables have been compiled for several curves of
each type for several diameters of wires and all are found to be
very irregular with a general tendency for the log K to fall off
in the smaller amplitudes. Thus nothing of value can be learned
from the log K curves of the different states. The log K has
no real meaning in these cases.
TABLE V.
Wire No. 4 in state II. (Length=8.9 cms.)
Mean Amplitude Log K
.30.5
.0056
88
.0046
65
.0032
47
.0040
34
.0033
26
.0039
20
.0036
14
.0025
11
.0036
PROPERTIES OF PHOSPHOR-BRONZE WIRES 233
The effecting of states II and III. The inconsistencies of the
effect of annealing and vibrating the wires were at first dif-
ficult to explain. The conditions were evidently very compli-
cated. In annealing, even when the variables of the process,
the load, the current and the time of annealing were kept con-
stant, there was no regularity in the results. A very high tem-
perature by a large current would cause one state at one time
and another state at another time. The wires were heated to a
dull red glow and still the state could not be predicted. Wires
Nos. 3 and 4 were then annealed by different currents, to de-
termine whether there were not perhaps definite lower tempera-
tures at which definite states would result. The currents were
varied by .1 ampere between the range of .2 ampere up to 1.8
amperes when the wires began to glow. After each annealing,
the previous history of the wire was destroyed by the largest
current the wire would carry. Still there was no regularity of
results.
The slow or sudden cooling of the wires after annealing, gave
no clue. At first the time of annealing seemed to have no ef-
fect upon the resulting state. Long continued vibrating by the
motor usually changed the state but unless the process was long
continued nothing could be predicted. It was, however, noted
that when the time of artificial vibration was very long state
II would usually result. Only one exception to this has been
found and that was a sample of wire No. 3, which was not
changed from state III in 13.5 hours of continued vibration.
The required time to bring about state II was found to be in
the neighborhood of 12 hours for wire No. 4. In general the
recpiired time is shorter for the smaller wires and longer for
the larger wires.
The most recent work has shown that long annealing by a
comparatively large current, with the wire supporting a small
load, gives state III. Wire No. 4 was annealed by 1.0 ampere
while it supported a load of about 25 grams, and in four dif-
ferent trials has always been changed to state III. The same
wire under a load of 154 grams was not changed from state II
by the same current in 38 hours. This point requires some fur-
ther investigation before a definite relation of temperature and
the resulting state of the wire can be stated. In general, we
234 IOWA ACADEMY OF SCIENCE
may say that long annealing with the wire under a small load,
and at a comparatively high temperature, causes state III. On
the other hand long continued vibration causes state II.
SUMMARY AND CONCLUSION.
The. main points of this paper on the elastic properties of
phosphor-bronze wire, are:
1. There are three states in which the wires appear.
2. Drawing of the wires has a tendency to increase the ef-
fect of a varying period with the amplitude.
3. The magnitude of the period of vibration and the load
supported by the wire have no appreciable effect upon the
period-amplitude curves.
4. In a given sample of wire with a constant load and
period, the number of vibrations executed during a fall of a
given number of degrees in amplitude, varies inversely as the
length of the suspension. N*xL=K.
5. The initial amplitude determines to a certain extent the
rate of loss of energy of the pendulum.
6. In the larger amplitudes state II has a more rapid rate
of loss of energy than state III and their rates tend to become
equal in the smaller amplitudes.
7. The amplitude-vibration number curve of state III is
gentler in slope than the one of state II but the two coincide in
the smaller amplitudes.
8. In general, long continued annealing at a comparatively
high temperature brings about state III.
9. Long continued vibration will, in general, bring aboirt
state II.
In conclusion we must say that phosphor-bronze wires are
certainly not fit for use in delicate suspensions. The elastic
peculiarities are too complicated to be corrected for.
While these elastic properties may be typical of this alloy
alone, it is reasonable to suspect that other alloys have their
distinct peculiarities just as platinum-iridium and these wires
were found to have.
I wish to acknowledge my indebtedness to the staff of the
Department of Physics for their interest in the problem, and
especially to Dr. Sieg for suggesting it, and for his encourage-
ment and assistance during the progress of the work.
State University of Iowa.
University of Iowa.
identifying; polarized light
235
A NEW METHOD OF IDENTIFYING POLARIZED LIGHT
REFLECTED FROM SMALL OPAQUE CRYSTALS.
LeROY d. weld.
The method is a modification of one used originally by Voigt
for the identification of elliptically polarized light. The light
under examination passes first through an arrangement of quartz
wedges acting as a Babinet compensator, then through a "rota-
tor'' consisting of another pair of quartz wedges cut perpen-
Fig. 41A. View of Apparatus.
Fig 41B. Typical Spot-Patterns with Selenium (19 and 20), and ComparisMn
Pattern (21).
dicular to the axis, one from right-handed, the other from left-
handed quartz: and finally through a large Nicol prism. The
result is that the field is filled with rows of black spots in regu-
236 IOWA ACADEMY OF SCIENCE
lar arrangement ; and from the loeation of these spots with
reference to the cross-hairs, as photographed, the exact character
of the elliptic vibration can be readily calculated.
In this particular application, the parallel beam of light is
reflected from a small metallic crystal and is very slender, so
that only a small portion of the field is illuminated at once.
In order to produce the spot pattern, the analyzing apparatus
is carried back and forth with a sort of weaving motion, at
right angles to the beam, until the whole field is covered. The
pattern then appears clearly on the plate, and measurements
are easily made upon it. Some excellent plates have been
obtained in this manner from very small crystals of selenium.
See figure 41.
From such plates, it ought to be possible to settle the quastion
whether metallic crystals are doubly refracting. In fact, the
preliminary results would indicate that such is the case with
selenium. The research is still in progress.
Coe College and
State University of Iowa.
WHY HOT WATER PIPES Bl'RST 237
WHY HOT WATER PIPES IN HOUSEHOLD PLUMBING
BURST MORE FREQUENTLY THAN COLD
WATER PIPES.
F. C. BROWN AND WALDEMAR NOLL.
Plumbers often notice that the hot water pipes in a plumbing
system that lead to the bathroom or kitchen bursl more fre-
quently than the pipes carrying cold water. It is said that the
ratio is at least four to one. The "Cold Water" usually freezes
so as to lessen the flow of water in the pipes, or to stop the flow
altogether, but the freezing seidoni bursts the pipes unless the
temperature is very low.
In verifying the plumber's observations the exact conditions
as they exist in the pipes wrere not obtained, but some of the
essential features were approached by substituting ulass test
tubes for the pipes. The freezing conditions were simulated
by filling one set of tubes with tap water, freshly drawn, and
by filling an alternate set of tubes with tap water which had
been boiled and then cooled to the temperature of the water in
the other tubes. The glass tubes were of especial advantage in
that the visible appearance inside the tubes gave valuable in-
formation on what was occurring in the respective cases.
The tests carried out fully substantiated the phenomenon that
hot water pipes burst more frequently than cold water pipes.
On seven different occasions over fifty pairs of tubes were used,
filled alternately with boiled and unboiled water, brought to the
same temperature. They were placed in the open air when the
temperature was below the freezing point. The limes of freezing
varied from a half hour, or even less, to three or four hours.
The tubes were of varying size 1ml most <A' them were one centi-
meter in diameter.
Of fifty pairs of tubes used twenty-two pairs burst, and in
eighteen pairs the boiled broke before the unboiled, and in four
pairs the unboiled broke first.
The observations of the plumbers bein li verified, the next step
was to find an explanation of the phenomenon. One day, when
238 IOWA ACADEMY OF SCIENCE
the tubes had been filled with both kinds of water and left stand-
ing, it was noticed that the tubes holding the unboiled tap water
had their walls covered with air bubbles while the others were
perfectly clear. This observation, along with observations
made on the drop of temperature, gave some very valuable in-
formation toward the explanation of the phenomenon. The
temperature drop was read by filling comparatively large tubes
with boiled and unboiled water at exactly the same temperature.
The temperature was approximately the same until at about
zero or a little lower where the unboiled water began to freeze.
The boiled water, however, continued to cool until from minus
two to minus five degrees centigrade, when it suddenly crystal-
lized into ice, while the temperature again rose to zero.
This difference in freezing probably was due to the fact that
air particles, with their impurities, form nuclei where crystalliza-
tion into ice may set in. In the unboiled water crystallization
begins at zero, but in the boiled it is delayed while the water
cools to several degrees below zero. Then when it does set in,
the water freezes more rigidly into the tube, as the ice forms
just as soon in the center as on the outside, which is not the
case with unboiled water. This rigid freezing causes greater
pressure to be exerted on the walls of the tube, making it harder
for the ice to slide away. Then on further expansion of the ice,
the tube bursts.
On studying the ice of both kinds of water it was noticed that
a white, cloudy core existed in the center. The core was much
smaller in the ice from the boiled water. On breaking these
tubes in two, this center was found to be slushy and honey-
combed, and the whole central portion of the tube filled with
air bubbles. Professor Quincke of the University of Heidelberg
(Proc. Roy. Soc. Canada 3, p. 24, 1909) explained the presence
of the air in the center by the fact that at the boundary line
between the ice and the water in a freezing solution a surface
1 ension exists which forces the air and salts away. It is pre-
cisely the same action that causes the ice of impure pond water
to be purer than the mother liquid.
In studying the drop of temperature we noticed that the
boiled water froze just as solid in the center as on the outside
when freezing started. In the unboiled water, however, the ice
formed on the walls and slowly froze toward the center. Thus
in the very act of freezing a core would form in the center of
WHY HOT WATER PIPES BURST 239
tiie unboiled water which would not appear so easily in the
boiled water. Then the occluded air, as explained above, is forced
into this core of the unboiled water. Thus, when the ice freezes
toward the center, enough of this central mixture of ice and
water is forced away to take up the expansion of the ice. This
was proven experimentally. Eleven pairs of tubes were filled
alternately with boiled and unboiled water and frozen, and the
eleven tubes having the greatest expansion out of the top were
noted. Ten of them contained ice of unboiled water, and one of
boiled water. In the plumbing system, this slushy center, in-
stead of forcing the column of ice away as in the test tubes, is
itself forced toward the terminals of the exposed pipe.
Thus we may say that boiled water freezes nearer to the na-
tural conditions than the unboiled. In other words, the un-
boiled water would freeze just as quickly as the boiled water if
it were air free, or vice versa, the boiled water would freeze
like the unboiled if it contained air. The latter was proven ex-
perimentally. Twelve tubes were taken, six filled with unboiled
water and six filled with boiled water that had been saturated
with air. The tubes burst approximately at the same time, as
was anticipated.
The air in the freezing of the liquid, as we saw before, sep-
arates out and forms little white spots in the ice. This weakens
the ice and makes it more mobile, more easily forced away,
when pressure, due to further expansion, is exercised upon it,
than if it were solid. K. R. Koch (Ann. d. Phys. 41, pp. 709-
727, 1913) found the ice containing air bubbles to have a lower
elasticity than air-free ice. In other words, air weakens the
ice. This weak ice has a lower perpendicular pressure on the
walls of the tubes, and, therefore, the probability of the tubes
bursting is lessened.
The air in the water also acts as a compressible medium, that
is, when the ice expands by freezing, the air is compressed to
make room for the expansion of the ice.
Finally to prove that chemical reaction was negligible, boiled
and unboiled distilled water, which is practically free from
chemical impurities, was set to freeze. Adeney (Phil. Mag. pp.
361, 9, 1905) found that water absorbs air. The boiled water
broke the tubes first, as expected. Then the boiled, distilled
water was saturated with air and set out together with unboiled
water to freeze. The boiled water broke the tubes first.
240 IOWA ACADEMY OF SCIENCE
In summing up the results of the experiments it was con-
cluded that the occluded air effects the difference in bursting.
It does this first, by acting as nuclei for crystallization so that
ordinary water freezes less solidly than boiled water. Second,
by causing the ice to freeze less solidly, especially at the center,
until a very low temperature is reached the pressure along
the center is relieved by the water and slush flowing away.
Third, the air acts as a compressible medium, which relieves
the pressure by an unknown amount.
Department of Physics,
State University.
BIBLIOGRAPHY OF SELENIUM 241
BIBLIOGRAPHY OF LITERATURE .BEARING ON THE
LIGHT-SENSITIVENESS OF SELENIUM.
F. C. BROWN.
1818
Berzelius (Schweigg. Journ., 23, pp. 309-344 and 430-484), Dis-
covery, character, compounds, etc.
1826
Seebeck (Fogg., 6, p. 155), Electrification of vitreous Selenium.
Berzelius (Pogg., 7, p. 242), Purification (Pogg., 8, 21), Atomic
Weight.
1827
Mitscherlich and Nitzseh (Pogg., 9, 627-630), Selenic acid and
salts.
Magnus (Pogg., 14, 328, and 10, p. 491), Solubility in sulphuric
acid.
1828
Fischer (Pogg., 12, 153-155), Solubility in sulphuric acid.
Fischer (Pogg., 16; 121), 1829, Solubility in sulphuric acid.
1830
Magnus (Pogg., 20, 165-166), Separation from compounds.
1831
Rose (Pogg., 21, 431), Sulphur. Selenium and Tellurium.
1839
Knox (Trans. Roy. Irish Acad., 19, 149 (1843) ; or Phil. Mag.,
Ser. 3, 16, 185), Conductivity of Selenium and other ma-
terials.
1840
Regnault (Ann., Ser. 2, Vol. 51), Specific Heat.
Frobel (Pogg., 49, 590-591), Crystal form of metallic Selenium.
1845
Riess (Pogg. Ann., 64, 50), Electrification of Selenium.
16
242 IOWA ACADEMY OF SCIENCE
1847
Sacc (Ann., Ser. 3, 21, 119-126). Atomic weight.
1848
Schaffgotsch (Journ. pr. Chem., 43. 308-309, also Pogg., 90, 66).
Specific gravities.
1849
Erdmann and Marchand (Journ. pr. Chem., 55, 202, 1852),
Atomic weight.
1851
Hittorf (Pogg., 84, 214-220), Melting point of the metallic form,
transformation between the allotropic forms.
Mitscherlich (Berlin Acad., 409-416; or Ann. (3) 46, 301-313),
The red crystalline form of selenium and its properties.
1856
liegnault (Ann., ser. 3, 46, 288-301), Specific heat, general prop-
erties, heat of transition.
1857
Oppenhcim (J. pr. Chem., 71, 279-282), Separation from
tellurium.
Botger (J. pr. Chem., 71, 512), Decomposition of selenide so-
lutions.
1858
Bettendorf and Wiillner (Pogg. Ann., 138, 26), Specific heats
of allotropic modifications.
Mattheissen, (Pogg. Ann., 103, 412), The electromotive force of
elements.
1859
Dumas (Ann. d. Phys., (3) 55, 186-187), Atomic weight.
Deville and Troost (Compt. Rend., 56, 891), Vapor density.
1860
Uelsnimm (Ann. d. Phys., 116, 122), Various compounds.
1863
Deville and Troost (Compt. Rend., 56, 891), Vapor density.
Werther (Journ. pr. Chem., 88, 180-181), Spectrum.
BIBLIOGRAPHY OF SELENIUM 24<
1865
Bbttger (J. pr. Chem., 94, 439-440), Separation by dissolving in
sodium sulphite solution.
Neumann (Fogg., 126, 123, 1865), Specific heat and specific
gravity of metallic form.
Plucker and Hittorf (Phil. Trans., 155, 1-29), Spectrum.
1866
Schneider (Fogg. Ann., 128, 327-334), Solubility in selenious
bromide.
1868
Bettendorf and Wiillner (Pogg., 133, 293), Specific heat.
Quincke (Pogg. Ann., 135, 629), Capillary constant.
1869
Fizeau (Compt, Rend., 68, 129, 1125; Pogg. Ann., 138, 26), Co-
efficient of expansion.
Schultz-Sellack (Berl. Akad., Ber. 745; Pogg., 139, 182),
Diathermacy.
Pathke (Journ. pr. Chem., 108, 235-354, 321-356: Ann.. 152,
181-220), Analogies between selenium and sulphur.
1871
Sirks (Pogg. Ann., 143, 429-439), Refraction and dispersion of
selenium.
(Compt. Rend., 73, 622), Spectrum.
1873
Peterson (Berl. Akad., Ber. 6, 1466), Separation.
SaJet (Ann., (4) 28, 47-49), Spectrum.
Sale (Proc. Roy. Soc, 21, 283-289; Pogg. Ann., 150, 333), Con-
ductivity and light effect.
Smith (Am. Journ. Sc, (3) 5. 301), Conductivity and light
effect.
1874
Quincke (Wied. Ann.. Jubelband, p. 336), The refraction and
absorption coefficient of selenium.
Rammdsburg (Pogg. Ann., 152, 151), The modifications of
selenium. *
244 IOWA ACADEMY OF SCIENCE
Ross (Phil. Mag., 47, 161). The resistance of selenium.
HUger (Ann. d. Chem.. 171. 211). Solubility in sulphuric acid.
187-".
Adams (Proc. Roy. Soc. 23. 535; and Pogg. Ann., 159, 622),
The action of light on selenium.
(Proc. Roy. Soc., 4, 163: and Pogg. Ann., 159, 629), The
action of light on selenium and tellurium.
Bolls (Phot, News, p. 407, 1875), Photometer.
Siemens (Berl. Sitz.-Ber.T p. 280; Pogg. Ann., 156, 334), The
influence of light on conductivity of selenium.
Siemens (Dinglers Polytech. Journ.. 217. 61), Electrical pho-
tometer.
1876
Adams and Day (Proc. Roy. Soc, 23, 539), Action of light on
selenium.
Draper and Moss (Chem. News, 33. 1 and 203), The action of
light on the conductivity of selenium.
Gordon (Jahrs. ber. d. Chem., 121), Action of light on con-
ductivity of selenium.
Siemens (Berl. Akad., Ber., p. 299; and Pogg., 159, 117-141),
The effect of light and heat on the conductivity of selenium.
Moss (Chem. News. 33, 1). Conductivity and light-effect.
Adams (Proc. Roy. Soc. 24, 163-164; Pogg. Ann., 159, 629),
Conductivity and light-effect.
1877
Braun (Wied. Ann. 1, 95), Conductivity, Ohms law and light-
effect.
Foi'ssmann (Wied. Ann., 2. 512-521), The conductivity of se-
lenium.
Sit mens (Wied. Ann., 2, 521, 534), The effect of heat and light
on conductivity.
Eggoroff (Journ. Russ. phys. Chem. Ges., p. 304), Experiments
with the selenium photophone.
BIBLIOGRAPHY OF SELENIUM
1878
Sabine (Phil. Mag., (5 5, 401-415 . Effect of light and heat on
the conductivity.
Sabine (Nature, 17, 1878. 512 . Action of light on selenium.
Selecq (Beibl. z. d. Ann.. 3. 294 i , The telectroscope.
1ST!)
Perosino (Beibl. z. d. Ann.. 3. 656), Telephotography without
•wires.
Carnelhj and ^YiUiams (Chem. News, 39, 286), Boiling point.
1880
Brequet (Ann. d. Chira. Phys., 21. 560), Photophone.
Brequet (Compt. Rend., 91, 595), The photophonie experiments
of Bell and Tainter.
Bell (Proc. Am. Ass. Sc., 115-136: Ann. Chem. Phys.. 31, 399:
Electro-tech. Zeits.. p. 391), Selenium and the photophone.
Bell (Sill. Am. Journ. Sc.. 22. 305 . The production and trans-
mission of tones by light.
Bell (Compt. Rend., 91, 726), The use of the photophone for
investigation of sun spots.
Blondlot (Compt. Rend.. 91. 882). New electrical properties in
selenium.
Ob mh (Nature. 22. 496'. Influence of phosphorescent light on
selenium.
Linde (Photogr. Arehiv.. p. 2051. Phonograph.
Paiva (Typographic de J. da Silva. Porto. 1880), An electrical
telescope using selenium.
Perry and Ay rt on (Nature, 21, 589), Seeing by electricity.
Weinhold (Electrtech. Zeits., p. 423), Photophone.
1S81
Bellati and Eomanese (Beibl. z. d. Ann., 6. 116), The rapidity
of change of conductivity by light.
Bidwell (Phil. Mag.. 11. 302), The action of temperature on the
resistance of selenium.
Bidwell (Chem. News. 43. 105: Nature. 23. 58), Telephotog-
raphie and photophon.
246 IOWA ACADEMY OP SCIENCE
Carpenter L. (Nature, 24, 491), The use of the photophone.
Giltay (Nature, 25. 124), An audible photometer.
Kalischer (Rep. d. Phys., 17, 563), Photophon without bat-
teries.
Mercadier (Compt. Rend.. 92, 1407, 1881), Effect of tempera-
ture on photophonie receivers.
(Compt. Rend., 92, 789), Construction of photophonie re
ceivers. Also p. 705, C. R.
Molera and Cebrian (Engineering, 1881, p. 358), Conical form
of selenium cells.
Moser (Soc. Telegr. Engr., 11, May, 1881), The selenium photo-
phon.
Moser (Phil. Mag., 12, 212), The microphonic action of selenium
cells.
Sirks (Beibl. z. d. Ann., 5, 526), The change of resistance of
selenium.
Spring (Bull, de 'lAcad. des Scienc. de Belg., 2, 88, and Beibl.
5, 854), The coefficient of expansion of selenium.
Thompson, S. P. (Eng., 1881, p. 96; and Phil. Mag., 11, 286),
The use of the conical mirror to illuminate selenium.
Thompson, S. P. (Chem. News, 43, p. 43), The photophone.
Tomlinson (Nature, 23, 457), Photophone.
Fitlal (Moniteur de la photogr., 1881, p. 11), Selenium pho-
tometer.
Borntrager (Ding, pol., J. 242, 55), Preparation of metallic
crystals by sublimation.
1882
Troost (Compt, Rend., 94, 1508), Boiling point,
Kienlen (Bull. Belg. Akad., 37, 440), Method of extraction.
1883
Assche (Compt. Rend.. 97, 830), A means of isolating heat and
light radiations.
Bidivell (Phil. Mag.. 15, 31), Resistance of selenium cells.
Fritts (Sill. Am. Journ., 26, 465; and Lum. Eleetr., 15, 226\
Light sensitive selenium cells.
BIBLIOGRAPHY OF SELENIUM 247
Hesehus (Journ. d. Russ. phys. chem. Ges., 1883).
1884
Hesehus (Rep. d. Phys.. 20, 490), Influence of light on the
conductivity of seleuium. p. 060, The theory of light sen-
sitiveness, p. 631, The relation between the light intensity
and the change of conductivity.
(Journ. d. phys. -chem. Ges., 1884, vol. 15, pp. 123 and 146),
Theory of light effect.
Bid well (Chem. News, 51, 261 and 310). The resistance of se-
lenium and sulphur cells.
Divers and Shimose (Chem. News, 51, 199), Separation of se-
lenium and tellurium.
1885
Bidwell (Phil. Mag. (5) 20, 178), The sensitiveness to light.
(Chem. News. 52, 191), Light sensitiveness due to selenides.
Clark (Chem. News, 51, 261), The action of light on selenium.
Morize (Compt. Rend., 100, 271), A selenium actinometer.
Siemens (Berl. Sitz. Ber., 8, 147), Concerning the E. M. F.
developed by illumination, also C. R. 100, 271.
Fritts (Elect. Rev., Mch. 7, p. 208/1885), E. M. F. by illumina-
tion.
1886
Fdbre (Compt. Rend., 103, 53), The heat of crystallization of
selenium.
Kalischer (Wied. Ann., 31, 101), The production of E. M. F.
by light.
1887
Fabre (Ann. d. phys. u. Chem., (6) 10, 472), Heat of trans-
formation.
Bellati mid Lussana (Beibl. z. d. Ann., 11, 818), The influence
of light on the heat conductivity.
Kalischer (Wied. Ann., 32, 108), Relation of conductivity to
illumination.
Mercadier (Compt. Rend., 105, 801), The selenium radiophonic-
receiver of high resistance.
Muthmann (Bull. Belg. Acad., 20, 990), Soluble selenium.
248 IOWA ACADEMY OF SCIENCE
1888
Kalischer (Wied. Ann., 35, 1888, p. 397), Remarks on the ex-
periments of Uljanin and Righi.
Righi (Beibl. z. d. Ann., 12, 683), The E. M. F. of selenium.
Uljanw (Wied. Ann., 34, 241), E. M. F. of selenium in the
light.
(Wied. Ann., 35, 836), Reply to Kalischer.
1889
Cornu (Compt. Rend., 108, p. 917 and 1211), The refraction
and absorption coefficient of selenium.
Kalischer (Wied. Ann., 37, 528), The E. M. F. of selenium.
Korda (Journ. de phys., 8, 1889, p. 231), Electrical action of
light on selenium.
Righi (Wied. Ann., 36, 464), The E. M. F. of selenium.
1890
Liesegang (Photogr. Archiv., 1890, p. 302), Photophon.
Muthmann (Zeits, f. Kryst., 17, 336), Crystallographic studies
of certain modifications of sulphur and selenium.
1891
Bidwell (Electrician, 26, 213; Phil. Mag., 31, 250), Several
studies with selenium cells.
Liesegang (1 Auflag. Ed. Liesegang), The problem of seeing
at a distance electrically.
Minchin (Electrician, 26, p. 361; Phil. Mag., 31, 207), Experi-
ments with photo-electricity.
Peterson (Zeits. f. Phys. Chem., 8, 601), The allotropic forms
of several elements.
Muthmann (Zeits. phys. chem., 8, 396-397), Isomorphism with
sulphur.
Retgers (Zeits. phys. Chem., 8, 72), Isomorphism of Selenium,
Sulphur and Tellurium.
1892
Mi mli in (Astron. and Astroph., 108, 702), photo-electric cells.
BIBLIOGRAPHY OF SELENIUM 249
' 1898
M inch in (Lum. e'lectr., 48, 543), Photo-electric cells.
1894
Marjorana (Rend. R. Ace. d. Line, 3, 183; and Beibl., 18, 930),
The rapidity of light action in selenium.
1895
Bidwell (Phil. Mag., 40, 233), The electrical properties of se-
lenium.
Minchin (Proe. Roy. Soc, 58, 142), The use of selenium in
photometry.
Bidwell (Mechaniker, 1895, p. 232), Telephotography.
1896
Giltay (Nature, 54, 109), Roentgen Rays and the resistance of
selenium.
Marjorana (Beibl. z. d. Ann., 20, 558), Action of a periodically
interrupted light beam on selenium.
1897
Schmidt (Wied. Ann., 62, 407), Electrical phenomena in se-
lenium and fiourspar.
Tammanu (Wied. Ann., 62, 280), Two melting points.
1898
Agostini (Forts, d. phys., 11, 592), The action of electro-mag-
netic waves on selenium.
Dussaud (Compt. Rend., 128, 1132), Transmission of varying
light intensities by electric wires.
Lekner (Journ. Am. Chem., S, 20, 555), Atomic weight.
1899
Dussaud (Compt. Rend., 128, 171), Transmission of tones by
ultra violet light.
Liesegang (Edition 2, pamphlet on the problem of seeing at a
distance).
Perreau (Compt. Rend., 129, 956), Effect of X rays on the re-
sistance of selenium.
250 IOWA ACADEMY OF SCIENCE
1900
Chin sen and v. Bronk (New phenomena in the field of Physics;
self published, Berlin).
Himstedt (Ann. d. Phys., 4, 531), Some experiments with
Becquerel and X rays.
Smolders (Journ. Phys. Chem., 4, p. 423), The allotropic forms
of selenium.
1901
Block (Compt. Rend., 132, 914), Action of Radium rays on se-
lenium.
Giltaij (Phys. Zeits., 1901, p. 675), Apparatus for the demon-
stration of the light-sensitiveness of selenium.
Giltay (Meehaniker. 1901. p. 243), Apparatus for demonstrat-
ing the photophon.
Massmi (Eclair, e'lectr., 29, p. 68), The effect of electromag-
netic waves on the resistance of selenium.
Ruhmer (Phys. Zeits., 2, p. 325), The talking arc with sele-
nium.
Ruhmer (Phys. Zeits., 2, 498), The photographone.
Ritrhmer (Meehaniker, 9, 468 and 2), Simons photophone.
Ruhmer (Meehaniker. 9, 41), The preparation of light sensi-
tive cells. (9. p. 88), The talking arc and light telephony.
Ruhmer (Meehaniker, 9, 1901, p. 13), Seeing at a distance, etc.
Simon (Phys. Zeits., 2, p. 253), Light telephony with the speak-
ing arc.
1902
Cciblyn (Compt, Rend., 135, 684), Seeing at a distance electri-
cally.
Kom (Miinchen Ber., 37, 39), An experiment with electrical
photography at a distance.
Kom (Electroteeh. Zeits., 23, 454), An apparatus for distance
photography.
Pochettino (Beibl. z. d. Ann.. 27, 854), The influence of low
temperatures on the resistance of selenium and the re-
sistance change by light.
BIBLIOGRAPHY OF SELENIUM 251
Ries, Chr. (Dissertation, Erlangen, 1902), The electrical be-
havior of metallic selenium with light and temperature
changes.
Uuhmer (Elektrotech. Zeits., 23, 859), Light telephony.
Fullmer (Phys. Zeits., 3, 468), The light-sensitiveness and fa-
tigue of selenium cells.
Ruhmer (Phys. Zeits., 3, 532), Cylindrical selenium cells.
Uuhmer (Tech. Eundsch., 1902, 339) (Elek. chem. Zeits., 9, 98),
A new light-sensitive cell.
Uuhmer (Mechaniker. 1902, p. 185), The telautograph.
Uuhmer (Monograph pub. by "Der Mechaniker"), Selenium
and its application, with special reference to wireless tele-
phony.
Uuhmer (Zeits. f. Phys. u. Chem. Unt., 15, 12G), Apparatus for
demonstrating light action in selenium.
Simon Th. and Reich (Phys. Zeits., 3, 278), Musical arcs and
light-telephony.
Wood (Phil. Mag.. [6], Vol. 3, p. 607), The refraction and ab-
sorption coefficients of selenium.
1903
Anzel (Zeits. f. Elektrochem., 9, 695), The change of resistance
by light in other materials than selenium.
Aubel (Compt. Rend., 136, 1189; and Phys. Zeits., 4, 808). The
action of ozone-treated bodies on the conductivity of selen-
ium.
Aubel (Compt. Rend., 136, 929, and Phys. Zeits., 4, 807), The
action of radioactive bodies on the conductivity of selen-
ium.
(i ill (ID (Phys. Zeits., 4, 287), Improved apparatus for demon
strating the light-sensitiveness of selenium.
Griffiths (Compt, Rend., 137, 647), Change of resistance of
selenium under the action of certain substances.
Hammer (Trans. Am. Inst. Electr. Eng., 20, 541). The proper-
ties and uses of selenium.
Eesehus (Journ. d. Russ. phys.-chem. Ges., 35, 661), Relation
of electrical conduction to illumination.
252 IOWA ACADEMY OF SCIENCE
Bopius (Beibl. z. d. Ann.. 28, 723), Dependence of the conduc-
tivity on the degree of illumination.
Kom (Compt. Rend., 138, 1190), Picture Telegraphy.
Marc (Zeits, f. anorg. Chemie, 37, 459), The effect of light and
temperature on selenium.
Nutting (Phys. Zeits., 4, 201), The reflection coefficient of
selenium.
Euhmer (Mechaniker, 11, 265), New Selenium apparatus.
1904
Amaduzzi (Phys. Zeits., 5, 647), Selenium.
Berndt (Mechaniker, 1904, p. 97), Selenium cells on carbon.
Berndt (Phys. Zeits., 5, 121), Some observations on selenium
cells.
Berndt (Phys. Zeits., 5, 289), the action of selenium cells on a
photographic plate.
Berthier (Beibl. z. d. Ann., 28, 876), The photo-electric proper-
ties of selenium.
BUtz (Nachr. d. Gott. "Wiss. Ges., 1904, p. 18).
Chabot (Phys. Zeits., 5, 1904, 103 and 168), New rays or a new
emanation. Also Phys. Zeits., 5, 517 and 584.
Agostini (Phys. Zeits., 5, 121), The electrical properties of
selenium.
Davis (Nature, 70, 506), Is selenium radioactive.
Kom (Phys. Zeits., 5, 113), New sending and receiving ap-
paratus for distance photography.
Kom (Phys. Zeits., 5, 164), Receiving apparatus for distance
photography.
Kom (Monograph printed by S. Hirzel press, Leipzig), Elec-
trical distance photography and similar things.
Nisco (Eclair, e'ectric, 30, 1904), Photometer.
Pfund (Phil. Mag., 7, 26), Studies with selenium cells.
Eeiff (Mechaniker, 1904, p. 75, 86 and 100), Transmission of
pictures and writing by the Korn method.
Buhmer (Elektroteeh. Zeits., 25, 1021), Selenium and its tech-
nical applications.
BIBLIOGRAPHY OF SELENIUM 253
Stephan (Beibl. z. d. Ann., 28. 447). Construction and theory
of distance photography.
1905.
Aichi and Tanakadate (Beibl. z. d. Ann.. 29, 997)', The influence
of temperature on the conductivity of selenium.
Brown (Phys. Rev., 20, 185), The effect of pressure on the re-
sistance of selenium.
Block (Le Radium. 2, pp. 323-328, and 363-370), The electri-
cal conductivity of selenium.
Carpini (Phys. Zeits., 7, 306), The photoelectric effect in se-
lenium.
Chabot (Phys. Zeits., 6, 37 and 619). New rays or a new emana-
tion.
Coste (Compt. Rend., 141. 715). The electrical conductivity of
selenium.
Courvoisier (Astrom. Nachr., 167, 218), The use of selenium
cells for making secondary contacts with pendulum.
Giltay (Mechaniker. 1905, p. 280), New forms of selenium
cells.
Giltay (Elektrotechn. Zeits., 26, 313), Selenium cells in vacuum.
Heschus (Phys. Zeits., 7. 163), The light-sensitiveness of se-
lenium.
Korn (Elektrotechn. Zeits., 26, 1131), Electrical distance pho-
tography.
Euhmer (Mechaniker, 1905, p. 280), Reply to Giltay.
Buhmer (Mechaniker, 1905, p. 252), New selenium cells.
Weidert (Ann. d. Phys., 18, 1905, 811), The effect of illumi-
nation on the thermo-electric power of selenium.
Wulf and Lucas (Phys. Zeits., 6, 838), The use of selenium
cells to determine the time of total eclipse of the sun.
Guilloninot (Arch. Electr. Med. Expt, 13, 243). The action of
N rays on selenium.
Guthe (Monthly Weather Rev.. 34, 223. 1906). Photoelectric
properties of selenium cells.
Raupp (Journ. Gas. Ilium.. 49. 603), Selenium and its appli-
cation to s-as technology.
254 IOWA ACADEMY OP SCIENCE
Korn (Compt, Rend., 143, 892). An apparatus for measuring
the inertia of selenium cells.
Berndt ("Weltall, Berlin, 6, 210), Making and mounting of se-
lenium cells.
1906.
Bronk (Phys. Zeits., 7, 281, and p. 431), Announcement on the
selenium cells.
Coste (Beibl. z. d. Ann. d. Phys., 32, 96), The electrical con-
ductivity of selenium.
Giltaij (Beibl. z. d. Ann. d. Phys., 31, 845), The use of selen-
ium cells in double telephony.
Marc (Zeits. f. Anorg. Chem., 48, 393), The effect of light,
Marc (Ber. d. Deutsch. Chem. Ges., 39, 697), Knowledge about
the allotropic forms of selenium.
Pochettino and Trabacclii. (Beibl. z. d. Ann., 32, 93), The effect
of alternating currents on selenium.
Reingamim (Phys. Zeits.. 7, 430), A new form of selenium
cells.
Ruhmer (Phys. Zeits., 7, 430), Announcement on selenium cells.
Schrott (Phys. Zeits., 8, 42), The effect of heat and light on
the allotropic forms of selenium.
Sicphan (Mechaniker, 14, 159 and 173), Construction of a dis-
tance photography machine.
Torda, (Electrician, 56, 1042), Selenium photometer.
Vogler (Mechaniker, 14, 147), A new arrangement of selenium
cells.
1907.
Bidwell (Nature, 76, 444), Practical telephotography.
Bidwell (Nature, 77, 222), The photoelectric properties of se-
lenium.
Brown (Phys. Rev., 25, 505), The effect of radium rays on
selenium.
Glatzel (Deutsch. Median. Zeit., 18, and Verkehrsteehn. Woche,
1907, 45), Selenium and its use in distance photography.
TIaub (Mechaniker, p. 75), A new selenium photometer.
BIBLIOGRAPHY OF SELENIUM 255
Jaeger (Proc. Amsterdam Akad., 9, 809, 1907; and Zeits. f.
Krist, 44, p. 45), A comparison of light-sensitiveness of
selenium and natural crystals of antimonite.
Korn (Phys. Zeits., 8, 18, 19). A light relay.
Korn (Phys. Zeits., 8, 118), A new method of distance pho-
tography.
Korn (Elektrotech. Zeits., 3)3), Picture transmission between
Miinchen and Berlin.
Korn (Zeits. f. Schwachstrom, p. 463), Review of picture trans-
mission.
Korn (Ed. 2. of monograph on picture transmission, pub-
lished S. Hirzel, Leipsig).
Marc (Zeits. f. Anorg. Chem., 53, 298), the effect of light and
temperature on selenium.
Marc (Monograph on the physical-chemical properties of metal-
lic selenium. Pub. by Leopold Voss, Hamburg) .
MincJtin (Nature, 77 173), The photoelectric properties of se-
lenium.
Moss (Nature, 77, 198), The photoelectric properties of selenium.
Xisco (Zeits. f. Sehwachstrom, 1907, p. 253), Seeing at a dis-
tance by means of electricity.
Niewenglowski (Science au XN Sie'cle, 5, pp. 9-11), The trans-
mission of photographs.
Presser (Electrotechn. Zeits., 1907, p. 560), A selenium photo-
meter.
Pochettino and TrabaccJii (Beibl. z. d. Ann. d. Phys.. 31. 1128),
The electrical properties of selenium.
Reinganum (Phys. Zeits.. 8, p. 293 ami 392), A correction on
electrolytic selenium cells.
Sperling (Dissertation (Goettingen) on selenium cells. Also
Ber. cl. Ober. Ges. fur nat. u. heilkunde, X. S. 2, 7". .
Wiedhaas (Zeits. f. Phys. u. Chem. Unterr., 20, 93), Experi-
ments for demonstrating the light telephone.
Will (Elektrotechn. Anz., 24, 115, 127 ami 141 \, Review of dis-
tance photography.
256 IOWA ACADEMY OF SCIENCE
Stebbins and Brown (Astro. Phys. Journ., 26, pp. 336-340), A
determination of the moon's light with a selenium photo-
meter.
Wertheim-Salomonson (Verh. d. Roentgenes, 3, 96-106), The
action of X rays on selenium.
1908.
Athanasiadias (Ann. d. Phys., (4) 25, 92; and vol. 27, 890),
The relation between illumination and conductivity.
Athanasiadias (Ann. d. Phys., (4) 27, pp. 890-891), The action
of X rays on selenium.
Brown and Stebbins (Phys. Rev., 26, pp. 273-293), Studies on
electrical resistance of selenium.
Grippenberg (Phys. Zeits., 9, 519), The use of selenium vapor
in coating selenium cells.
Korn (Natw. Bauds. Braunschweig., 23, 521), New results with
telautagraph.
Kohl (Zts. f. Phys. Chem. Unterr., 21, 142), Demonstration
apparatus for Korn's distance photography.
Merritt (Phys. Rev., 27, 367), The recovery of selenium from
light.
Minehin (Proc. Roy. Soc, A. 81, pp. 9-21), Seleno-aluminum
bridges.
Minehin (Nature, 77, p. 198 and 222: also Elect. Rev.. 52, 172),
The action of mercury vapor on selenium.
Ries, Chr. (Phys. Zeits., 9, 164), Light sensitiveness of selenium.
Ries (Phys. Zeits., 9, 228). Properties of selenium.
Ries (Phys. Zeits., 9, 569), Influence of moisture on the elec-
trical properties of selenium.
Ries, Chr. (Monograph published by the "Mechaniker"), The
electrical properties of selenium and its applications.
Stebbins (Astro. Phys. Journ., 27, 183), The color sensibility
of different selenium cells.
Zemplin (Potf. Ternt. Kozl., Budapest, 40, 68-70), Action of
light on electrical behavior of selenium.
BIBLIOGRAPHY OF SELENK'.M 257
1909.
Chiavini (Rend. R. Ace. dei. Line, 18, 246), The nature of light
action in selenium.
Pfund (Phys. Rev., 28, 324; and Phys. Zeits., 10, 340), The
electrical and optical properties of selenium.
Korn (Phys. Zeits., 10, 793), The fatigue of selenium cells.
Grippenberg (Phys. Zeits.. 10, 957), The crystallization of se-
lenium plates.
Kruyt (Zeits. f. Anorg. Chem.. 64. 305), Dynamic allotropie
of selenium.
Monten (Doctor's dissertation — Uppsala, 1909; Arkiv. f. Math..
Ast., o. Fysk, vol. 44, pp. 1-6), The influence of pressure
on the electrical conductivity of selenium and silver sul-
phide.
McDowell (Phys. Rev., 29, pp. 1-35), Some electrical proper-
ties of selenium.
Ries (Phys. Zeits.. 10, 54). The use of selenium vapor for pro-
ducing light sensitive cells.
Ries (Phys. Zeits., 10, 534), The electrical properties of se-
lenium and the practical applications.
L' triune r (Monograph puh. by "Mechaniker" press), On wire-
less telephony.
Ruhmer (Catalog of selenium accessories).
Wigan-g (Ann. d. Phys., 29, 1-32), Light action in sulphur.
1910.
Baker (Electr. World. 1910. p. 1079), Use of selenium in pho-
to-telegraphy.
Brown (Electr. Rev.. 57, 1178, Phys. Zeits.. 11, 482), A new light
electric property in selenium.
Brown (Phys. Zeits.. 11. 481), Selenium cells of high sensibility.
Amaduzzi (Rend. Acad. Bologne, 16, Jan. 19. 1910), The cause
of the light-sensitiveness of selenium.
Giltay (Phys. Zeits., 11, p. 419), Selenium cells with high re-
sponse to light.
Grippenberg (Phys. Zeits.. 11. 132-133). Selenium cells of high
response to light.
17
258 IOWA ACADEMY OF SCIENCE
Hammer (Eleetr. Rev., 56, 905), Selenium cells.
McDowell (Phys. Rev., 30, 474-484), Some electrical properties
of selenium.
Luterbacher (Ann. d. Phys.. 33, 1392-1412), The influence of
E. M. F. on the resistance of selenium.
Meier (Ann. d. Phys., 31, 1910, p. 1017), Dispersion and ab-
sorption of light by selenium.
Stebbim (Astro. Phys. Journ.. 32, pp. 125-214), The measure-
ment of the light of the stars with a selenium photometer.
Stebbins (Astro. Phys. Journ., 32, 179-182), The brightness of
Halley's comet by a selenium photometer.
Pelabon (Compt. Rendus, 151, pp. 641-644), Cells of antimony
and antimony selenide.
1911.
Brown (Phys. Rev., 33, 1-26), The nature of light action in
selenium.
Brown (Phys. Rev., 33, 403-419), The recovery of the Giltay
selenium cell and the nature of light action in selenium.
Brown (Transit, 16, 61), The electrical properties of selenium
and their applications.
Crum (The Elect, Rev. and West. Elect., 58, 433), The electri-
cal properties of selenium.
Glatzel (Phys. Zeits., 12, p. 480, 570 and 1169), The fatigue .of
selenium cells.
Crum (Phys. Rev., 33, 538-548). Light negative selenium.
Vochettino (Se. Ab., 14, p. 322), Sensitiveness of selenium prep-
arations.
Ries (Ann. d. Phys., 36, 1055), The cause of the light-sensitive-
ness of selenium. (Phys. Zeits., 12, 480, 522.)
Ries (Phys. Zeits., 12. 529), The effect of voltage on the re-
sistance of selenium.
Ries (Ann. d. Phys., 36, 1055-1065), The potential effect in se-
lenium and antimonite.
Stebbins (Astro. Phys. Journ., *33, 395), The radiation of the
companion of Algol.
BIBLIOGRAPHY OF SELENIUM 259
Htebbins (Astro. Phys. Journ., 34, 105-130), The discovery of
eclipsing variable stars.
1912.
Amaduzzi (Phys. Zeits., 13, 165), The Hallwachs effects in se-
lenium.
Fournier d'Albe (Proc. Roy. Soc., 86, pp. 453-461), The varia-
tion of resistance with voltage.
Fournier d'Albe (Proe. Roy. Soc, 13, 942), Application of se
lenium to seeing, the Optophone.
Brown (Phys. Zeits., 13, 689; and Proc. Iowa Acad. Sci., 1912),
The effect of abrasion on the electrical conductivity of se-
lenium.
Brown (Phys. Rev., 34, 403), The effective depth of penetra-
tion of selenium by light.
Glatzel (Verb. d. D. Phys. Ges., 14, 607-623), Light sensitive-
ness of selenium.
Korn and Glatzel (Hand. d. Phototel. u. Teleautogr.), The light-
sensitiveness of selenium.
Grippenberg (Phys. Zeits.. 13, 161 and 168), Selenium plates.
Kaempf (Phys. Zeits., 13, 689), Saturation currents in selenium.
Olie and Eruyt (Sc. Abs., 15, abs. 903, 1912), Photo-electric
properties of antimonite.
Pfund (Phys. Rev., 34, 371-380; and Phys. Zeits.. 13, 507), The
application of selenium cells to photometry.
Pochettmo (N. Cim., (6) 4, 189-203). The cause <>!' the Light-
sensitiveness of selenium.
Stebbins (Astro. Nachr., 192, 190-194), The Lighl variation of
Ursa Minor.
Zoltan (Phys. Zeits., 13, 1912), The Eallwachs effed in se
lenium.
Grippenberg (Phys. Zeits.. 13, 686), Selenium cells of high
sensibility.
1913.
Fournier d'Albe (The Electrician, 72, 102; and Sc. Am.. 93,
467), The type-reading optophone.
260 IOWA ACADEMY OF SCIENCE
Fournier d'Albe (Phys. Zeits., 14. 1306), The smallest quan-
tity of light that can be proved.
Brown (Phys. Rev., (2) 1, 237), A method of production of
light-negative selenium.
Brown (Proc. Iowa Acad. Sci., 20, 261), The similarity of elec-
trical properties in selenium and crystal contacts.
Brown- (Electr. Rev., 62, 104), The electrical properties of se-
lenium.
Brown and Sieg (Phys. Rev., N. S., 2, 487-493), The sensi-
bility curves for selenium.
Grippenberg (Phys. Zeits., 14, 123 and 124), The refractive in-
dex of crystalline selenium.
GuiUeminot (Compt. Rend., 156, 1155), The action of X rays
on selenium.
Nicholson (Phys. Zeits.. 14, 1213; and Phys. Rev., Jan., 1914),
Electron theory of light-sensitiveness.
PigulewsH (Beibl. z. d. Ann., 37, 72), The action of light on
the conductivity of sulphur.
Ries (Zeits. f. Feinmechanik. 21, 61-62), Noteworthy properties
of selenium cells.
Ries (Zeits. f. Feinmech., 21, 5-7), Influence of potential and
previous illumination on the fatigue of selenium.
Ries (Monograph on selenium and its application. 189 pp.
Beibl., 33, p. 627).
Stebbins (Pop. Astro.. 21, 1-9), The period and variation of Alpha
Orionis.
Brown (Phys. Rev. N. S., 2, p. 153), The action of mercury vapor
on selenium.
Brown and Sieg (Phys. Rev., N. S., 2, p. 487), A second paper
on the wave-length sensibility curves of selenium cells.
1914.
Brown (Phys. Rev.; N. S., 4, 85-98), Isolated crystals of metallic
selenium and some of their physical properties.
Brown and Sieg (Phil. Mag.. (6) 28, 497-508), The seat of light-
action in selenium and some new properties in matter.
BIBLIOGRAPHY OF SELENIUM 261
Brown and Sieg (Phys. Rev., N. S., 4, 48-61), Wave length-
sensibility and their significance.
Sieg and Brown (Proc. Iowa Acad. Sci., 21, 259), The adapta-
tion of selenium to the measurement of energy too small
to be measured by other devices.
Sieg and Brown (Phys. Rev., 4, 507-516), Wave length-sensi-
bility curves for the crystals of selenium.
Dieterich (Phys. Rev., N. S., 4, 467-476), Influence of annealing
on the characteristics of light-sensitive selenium.
Dieterich (Iowa Acad. Sci., 21, 257), Notes on the construction
of selenium bridges.
Foersterling and Fredericks (Ann. d. Phys., 43, 1227), The
optical constants of metallic selenium.
Grantham (Phys. Rev., N. S., 4, 255-266), The time factor in
the evaluation of selenium resistance.
Del Regno (Sc. Abs., 18, 140), The nature of the photo-electric
phenomena shown by selenium.
Grippenberg (Phys. Zeits., 15, 462), The depth of light action
in selenium.
Jaenichen (74 pp. Monograph on illumination measurements by
selenium, pub. by "Mechaniker" Press), Zeits. f. Fein-
mech. Press.
Pelabon (Compt. Rend., 158, 1669 and 1897), Tbermo-electrie
power of selenium alloys.
Stelibins (Astro. Phys. Journ., 39, 459-483), Photometric tests
of spectroscopic binaries.
Schmidt (Ann. d. Phys., 44, 477-496), The aetino- dielectric ef-
fect in sulphur.
Tyndall and White (Phil. Mag., 27, 370; and Phys. Zeits., 15,
154), Properties of selenium blocks.
I ntiu-illrr (Engineering, 98, 611). Photoelectric effect in se-
lenium.
(Compt. Rend., 159. 41 -43V Influence of tellurium mi the
sensitiveness of selenium.
1915
Brown (Phys. Rev., N. S., 5, 74-75 t. Some fundamental photo-
electric relations in selenium.
262 IOWA ACADEMY OF SCIENCE
i
Brown ( Pliys. Rev. X. S., 167-175), Physical properties of se-
lenium.
Sieg and Brown (Phys. Rev., N. S., 5, 65-67), Wave length-
sensibility curves for crystals of selenium.
Brown- (Phys. Rev., N. S., 5, 236), The isolation of crystals of
the second and fifth systems.
Brown (Phys. Rev., N. S., 5, 395-403), The nature of electric
conduction in selenium, based on recovery experiments.
Brown (Phys. Rev., N. S., 5, 404, 411), The nature of the trans-
mitted light action in selenium.
Elliott (Phys. Rev., N. S., 5, 53-64), The light-sensibility of se-
lenium and stibnite.
(in ill cm i not (Sc. Ab., 18, 524), The use of selenium in measur-
ing- the intensity of X rays.
Meissner (Electr. Rev., 66. 288), The applications of selenium —
the selenium dog.
Meissner (Purdue Eng. Rev.. 15, 34), Selectivity in torpedo
control.
Sieg (Phys. Rev., N. S., 6, 213-218), The heat .conductivity of
selenium.
Dodd (Proc. Iowa Acad. Sci., 22, 307), The absence of absorp-
tion or liberation of electrons in passing from conducting
to non-conducting state. Also Phys. Rev., 1916.
Brown- (Proe. Iowa Acad. Sci., 22, 317), The crystal Phonopti-
con to enable the blind to read the printed page.
Dodd (Sc. Am., 93, p. 138, Aug. 14, 1915), The mechanical Eye.
The crystal Phonopticon.
d'Albe (Sc. Am., 93, 467), Same ref. previously. A compara-
tive estimate of the merits of the above.
Stebbins (Astro. Phys. Journ., 42, 143), The eclipsing variable
star delta Orionis.
Voltz (Phys. Zeits., 16. 209 and 308), The application of se-
lenium to the measurement of X ray intensities.
Voltz and Fursteneou (Phys. Zeits., 16, 276), Measurement of
X ray intensities with selenium.
Dieterich, E. O. (Thesis. University of Iowa, 1916).
Dieterich, Kathryn Johnston, (Phys. Rev.)
BIBLIOGRAPHY OF SELENIUM 263
1916.
Editorial (Outlook for Blind, Summer number, 1915), A copy on
I)odd\s article in Scientific Am.. Aug., 1914.
Editorials (World of the Blind, Oct.. Nov.. Dec. and .Ian. num-
bers).
Editorial (Century Magazine, Jan.. 1916), Seeing by bearing.
Editorial (The Outlook. Jan. 12, 1916), A mechanical eye.
Editorial (Popular Mechanics, Nov., 1915, p. (ill. Blind read
by sound. Illustrated.
Editorial (Popular Sc. Monthly and Worlds' Advance, Nov..
1915, p. 570), Seeing with your ears.
Editorial (Illustrated World. Nov.. 1915, p. 374'. Seeing with
ears.
Editorials and short articles in many other magazines and
papers.
Dieterich, Kathryn J. I Phys. Rev., N. S., 7. p. 551), The effect of
temperature on the resistance, the Light sensitiveness of
selenium crystals.
Dieterich, E. 0. (Phys. Rev.. N. S., S, p. 1!)1), The effect of
temperature on the light sensibility curves of different types
of selenium cells.
Flowers, John, B. (Proc. Inst, Elect. Bng., :;.",. pp. is::, 201;
Elect. Experiment. Apr., 1916, Use of selenium in voice
controlled phonographic alphabet.
Flowers, John B. (Sc. Am.. Mch. 25. vol. 114. 1916, p. 323), A
typewriter that copies what it sees.
Department of Physics,
State University op Iowa.
SHEEP'S BRAIN WITHOUT CORPUS CALLOSUM 265
A SHEEP'S BRAIN WITHOUT A CORPUS CALLOSUM.
H. A. SCULLEN.
The brain in question was one from a shipment of dissecting
material purchased from the Western Biological Supply Com-
pany of Omaha, Nebraska.
It will be seen from the illustration that the entire Corpus
callosum and the posterior two-thirds of the Fornix are lack-
ing. Lying between the membranes which form the only
wall between the Diacoele and the Paracoele may be seen a
slender cord of alba nearly round and about one-fourth of a
millimeter in diameter. The connection of this cord seems to
be such that it should be considered Fornix and not Corpus
callosum. The remaining commissures and all other parts of
the brain seem to be normal.
The author has had occasion to examine between two and
three hundred sheep brains in the past four years and to date
no other abnormality has been noted. So far as is known no
other similar abnormality has been reported.
Department of Zoology,
Iowa State College.
BANDED PURPLE BUTTERFLY 269
THE WHITE ADMIRAL OR BANDED PURRLE BUTTER-
FLY IX IOWA.
B. O. WOLDEN.
During the early part of the summer of 1914 a butterfly
was observed around the writer's home, which was identified
at the time as Basilarchia arthemis. As there seems to be no
previous record of this butterfly having been collected in Iowa
a brief note, recording the fact, might not be ou1 of place
and might be of interest to students of the Lepidoptera of [owa.
I did not realize at the time that Iowa is not within the
published range of this species or that its occurrence here
was anything unusual and as I was not collecting butterflies
the specimen was not caught. At first I thought there were
several of these butterflies bu1 perhaps it was only one as
only one was seen at a time. At any rate I saw if several
times and had good opportunity to compare it with Com
stock's figure of the species. Later in the summer I saw
again what I thought perhaps was the same specimen but with
torn and ragged wings and faded color. According to Com
stocks' figures there is no doubt but that it was the form hi mi mi
as it had well defined bands on the hind wings, but Holland
figures the form proserpina also with rather distinct white
bands on the hind wings.
No specimen was observed during the summer of 1915 bu1
then there were few butterflies of any kind, at least till the
latter part of the summer. It is to be hoped thai during the
next season specimens can be found, to verify this record.
Wallingford.
A\ HERMAPHRODITIC CRAYFISH 271
AN HERMAPHRODITIC CRAYFISH OF THE SPECIES
CAMBARUS (FAXONIUS) OBSCURUS BAGEN.
I. L. RESSLER.
Recently, in the course of my work in the laboratory, an
abnormally developed crayfish was brouglH to my attention.
This animal had present both male and female characters.
The length of this apparent hermaphorite is 77mm., some-
what smaller than the average for this group.
There is a great variation in the general appearance as com-
pared to the normal creature. It has the characteristic broad
abdomen of the female. The fifth pereipod alone shows no
variation, containing the genital opening in the coxopodite as
found in the normal male. The third pereipod has no genital
opening. This would seemingly make it a male appendage
were it not for the fact that the clasper is not present on
the ischiopodite. Between the coxopodites of the fourth pair
of pereipods is found the annulus ventralis, common only to
females. The first pleopods are characteristic of the male.
They are, however, somewhat shorter and stouter than the
normal first pleopods, and extend cephalad only as far as the
anterior side of the fifth pereipods. The second pleopods are
essentially male structures, although not so prominent. (See
figure 42, A and B.
The above description shows that the specimen bears, ex-
eternally, markings characteristic of both the male and female.
The internal organs of reproduction are equally interesting.
The sperm duct arises apparently from a pair of very small
ovaries which are situated in a position corresponding to that
of the anterior lobes of the testes. The sperm duct itself is
normal in every respect and opens to the exterior through the
coxopodite of the fifth pereipod. The posterior lobe of the
testes is present, extending as far caudad as the first abdominal
segment, between the lobes of the liver.
There are several cases on record where hermaphroditism
has been described. One of the above species has been de-
272
IOWA ACADEMY OF SCIENCE
scribed as follows: "The specimen (55 mm. long) has the
characters of a female in the shape of the chelae and the ab-
sence of hooks on the pereipods. The male genital opening
is in the coxopodite of the fifth pereipod, and the first pleo-
pod is of the male type, although small. The second pleopods
are of the male type." This specimen was regarded, according
to the sexual orifice and the copulatory organs, as a male
with female characters.
"B'
Fig. 42.
A. Dorsal view of crayfish showing abnormal organs. Note the absence
of the anterior lobes of the testes. A, small ovaries ; B, Sperm duct ; C. Pos-
terior lobe of the testes ; D, opening of the sperm duct in the coxopodite of
the fifth pereipod.
B. "Ventral view of the same. Note the absence of the genital opening
on the third pereipod and the absence of the hook on the ischiopodite of the
.same appendage. A, Annulus ventralis ; B, Male genital opening on coxopodite
of the fifth pereipod ; C-D, First and second pleopods showing structures
characteristic of the male.
AX HERMAPHRODITIC CRAYFISH 273
A specimen of Cambarus rusticus is described as follows:
'"The specimen is externally a female, possessing the female
type of claws, a well developed annul us. female sexual open-
ings, and no hooks on the third pereipods. But the first pleo-
pods are peculiar; they are short and stout; the bases are
identical with those of the male pleopods ; the distal parts,
however, reach only to about the middle of the coxopodilrs
of the fourth pereipods; their tips are soft, blunt and slightly
curved inward, and possess the furrow which divides them
into an inner and an outer part, but these parts are not sepa-
rated at the tips. The second pleopods are of the female type.
The specimen is apparently a normal female only the first
pleopods are transformed in a peculiar way, resembling the
male type generally, but differing from the specific shape."
Zoological Laboratories,
Iowa State College.
»Ortmann : The Crayfishes of the State of Pennsylvania.
18
LIFE HISTORY AND HABITS OF POLISTES METRICUS 2'
LIFE HISTORY AND II AH ITS OF POLISTES METRIi US,
SAY.
FRANK C. PELLETT.
The summer of 1915 was not a favorable season in which to
study life histories of such ins< its - the Gold Banded Paper-
Maker. The weather was too cool and there was so much rain
that results were anything but satisfactory. It is very prob-
able that in a season of normal temperature the time required
in the various stages of development would be somewhat
shorter than was the case in 1915. However, since I have
spent considerable time in observing these insects during the
past summer. I am hopeful that these notes may be of inter-
est. Two years before, a similar observation was begun, only
to be interrupted shortly by the destruction of the nest.
The nest of this wasp is composed of a single comb, or series
cf cells opening downward. Unlike the species of vespa com-
monly known as hornets and yellow jackets, no outer cover-
ing is provided. While the nests are often placed under the
cornice of a house roof, they seem to be more often pi
near the ground under a box, or in an old can or other similar
situation. Discarded beehives and winter cases offer attrac-
tive situations on my grounds and I have foun - "al of
the nests during the past summer.
The first nest was found on June 6th. At that time about
half of the cells were built and a count showed that eleven
contained larvae and fifteen contained eggs. Two or three
partly finished cells were empty. This nest was placed under-
neath the cover of an empty beehive. A : etter situation for
observation could hardly have been found, since it was pos-
sible to take up the cover and hold it in any desired position,
and return it to the former place, without disturbing normal
conditions.
Figure 43, A. shows the nest as it appeared at that time with
the mother polistes resting above. To get the proper per-
spective the pictures should be held- above the head and be
seen from below instead of from above.
276
IOWA ACADEMY OF SCIENCE
At first polistes was much disturbed by my presence and
seemed very nervous and moved above restlessly when I was
uear. However, the nest was visited so frequently and so
many hours spent in observing her movements that she soon
manifested little interest in my movements. As soon as she
Fig. 43. A. Nest as ii appeared \\i ei found. B. Polistes feeding hi i young.
became accustomed to my presence the cover was turned over,
leaving the open end of the cells up to make observation
easier. If the wasp flew away the cover always had to he re-
placed in its former position before she could find the nest
again, although she would continue her normal activities with
her house up-side-down.
The eggs were not placed in the center of the bottom of the
cell where the queen bee deposits her eggs, but were attached
to the sides of the cells a little above the bottom. When the
eggs hatched they remained attached to the cell in the same
position. The mother spent much time in feeding the young,
giving them such attention very frequently on warm days,
and also spent a great deal of time with her own toilet. After
i'Yi'vv feeding she would carefully clean first one leg and
then another and brush every particle of dust off her body and
head.
Soon after the nest was found the weather turned cool and
i' rained. With the temperature at about fifty degrees the
mother settled herself quietly above the comb and made no
move to feed her young or to continue her building. Even
LIFE HISTORY AND HABITS OF POLISTES METRICUS ^77
when visited and The nest turned topsy turvy, she hardly moved
from her resting place. Although it remained cool for two
days, the larva' were no1 fed as far as could be seen. The
weather warmed somewhat on the afternoon of the third day.
but the wasp was not apparently conscious of it. The fourth
day she became very active again, and fed the young almost
constantly. At times she would bring little balls of food
which apparently were caterpillars, which she had. caughl
and kneaded into pulp between her mandibles. At other
times she would seem to feed the very young Larvae when she
apparently had nothing' to give them. Thai she did
them was evidenced by the movements of their lips after she
withdrew from the cell. Apparently the very young larvae
are at times fed with regurgitated food. Usually the bads of
food which she brought home were about the size of num-
ber eight shot. After kneading such a bit carefully, turning
it round and round between her jaws, she would divide it into
two or three parts and give it to the larger larva'. Sometimes
they would suck these bits for several minutes, when the
mother would take them again and eat them herself or
them to other larvae. At other times, the youngsters would
swallow them entirely after sucking them for some time.
One day I caught a mosquito, and rolling it between my
finger and thumb, imitated as best I could, the kneading which
the wasp gave the food. Then placing it on a o-rass stem it
was given to a larva. Tin- little larva opened its mouth much
like a young bird waiting to he fed, took the mosquito and
tried for some time to eat it. A red mite was caught and given,
to another larva in similar manner. The mite being \t-r\
small was swallowed at once, but the other larva was still
wrestling with the mosquito when the mother returned and
took it away. After kneading it for a time, she ale it her-
self. Other mosquitoes were caught and offered in the same
way, but she seized them, bit them viciously and dropped
them at once. She became much agitated and flitted her
wings in a most nervous manner. Such a bit was then fed
to a larva without attracting the attention of the mother un-
til it had tried for some time to dispose of it. Again she
took it and kneaded it for a time and this time fed it to
another larva, which swallowed it. Thus I took lessons in
feeding the young larva-, winch were destined to stand me
in good stead later in the season.
278 IOWA ACADEMY OF SCIENCE
Some days elapsed before I saw the wasp in the act of en-
larging- her nest. I had seen her tear down parts of the cells
when she was agitated and could hear the cutting of the
paper with her sharp mandibles. After kneading the bits of
paper for a moment, she had fed them to larvae which ate
them with apparent enjoyment. I had also seen her give a
touch now and then as though in the act of adding some-
thing and had about decided that she did such work at odd
moments, with but a touch here and there. However, on
the 25th of June after nearly three weeks of watching, I saw
her hard at work. It must be remembered that the weather
was cool and wet and seldom favorable to activity of this
kind.
She gathered her raw material near at hand and it was
easy to follow her from her nest to a weather beaten post a
few feet distant, where she secured her wood. After alight-
ing on the post she would cut away enough of the exposed
wood to make a good mouthful. She would then fly directly
to the nest where she would stand for a moment kneading the
pulp between her jaws and with her forefeet turning it round
and round. She would then spend some time looking over
the comb to find the most favorable place to work. When
she had satisfied herself as to the place to begin, she would
bite the soft pulp against the top of the partly constructed
cell. It seemed very soft and waxy and spread easily. She
pushed her forefeet against the opposite sides of tne thin wall,
backing slowly around the cell and drawing out the new tis-
sue very thinly. Sometimes she would pass entirely around
the cell and sometimes only part way. At times she would
add as much as a sixteenth of an inch to the structure with
a single mouthful and but two or three minutes were neces-
sary to get fresh load of raw material. After each trip she
would rest for a moment and make her toilet. Then she would
peek into a few cells and be off again for another load.
Between times, she made a very elaborate toilet, sometimes
standing on her hind legs and rubbing the other four together.
At other times she would stand on her forelegs and extend
the others behind her. Rarely she stood on her right middle
leg in about her normal condition and stroked herself with the
others as well as rubbing them together. Standing thus on
one leg she presented a striking appearance.
LIFE HISTORY AND HABITS OF POLISTES MBTRICUS 279
Although much time was spent with the wasps nearly every
day, it was a long time before the mot her was observed in
the act of laying. When the weather was nice she laid an
egg nearly every day, as was observed by careful note of
all empty cells. In cool weather she would sometimes miss a
day, or even two or three. She laid on the 11th and 12th of
June, then again on the 14th and 15th. Only one more egg
was laid until the 20th. Apparently the wasp was very sensi-
tive to weather conditions.
Finally by noting the conditions at the various times of
my visits it was determined that the eggs were laid in the
morning between eight and eleven o'clock. Accordingly on
the last day of June, even though I had an engagement in a
distant city, I determined to see the eg(<: laid before leaving.
I took up my watch shortly after eight o'clock and waited
rather impatiently. The mother was rather sluggish and there
was little action to keep up interest for nearly two hours,
before she began preparing for her day's work. She would
remain entirely motionless for many minutes at a time, then
she would look into a few cells, and again become quiet. Pinal
ly about ten-thirty a. m., she flew away and was gone but a
few minutes. On her return she began looking about in search
of an empty cell. Finding one by pushing her head deeply
into it, she doubled herself very shortly, and reversed her
position, placing her abdomen into the same cell. She then
remained very quiet with her head toward the center of the
comb for several minutes. At last she moved out and again
put her head in to see that the newly laid vgg was in its
proper place. Afterward she again became quiet for some
time. Although I came near missing the train as a result of
the long wait, I felt that the time had been well spent, and
thereafter had no further difficulty in observing the egg lay-
ing as frequently as I wished.
A number of eggs were marked to ascertain the period re-
quired for hatching. Most of them hatched in just eighteen
days. When the weather warmed a bit some hatched in six-
teen days. Since the weather was cool and the temperature
so much below normal probably this is longer than the normal
period. A number of those observed spinning their cocoons
spent twenty-three days in the pupal state. A few individuals
required twenty-five days to complete the transformation.
280 IOWA ACADEMY OF SCIENCE
Two years before, some under observation completed this stage
in only fifteen days according to my notes, which indicates
that weather greatly influences the length of the various peri-
ods of development.
"When the larvae had completed their growth, the spinning
of the cocoons was an interesting observation. It was on the
24th of June that the first two completed this performance.
Although the operation was not timed, probably not more
than an hour was required to spin the cocoon. The silk was
very filmy and so fine that a single strand could hardly be
seen with the naked eye. During the spinning the larvae
moved their heads back and forth, round and round, constant-
ly adding to the web. At first it was very thin and the in-
mate of the cell could plainly be seen at work through the thin
network. It gradually thickened, until the spinner wras en-
tirely hidden from view, although the movement continued
for some time after the covering became opaque.
Thinking to see something of the transformation a small
hole was cut in the top of one of the cocoons. The day fol-
lowing the cell was found to have been emptied and a new
egg placed therein. Apparently this change is not for the
eyes of man to see.
As the days passed, the experiment of feeding the larva?
was continued. Mosquitoes being plentiful in the weeds near
at hand, they were caught daily and fed to the larva1. At
times the mother would take them away and eat them her-
self. At other times she would feed them to the youngsters
as already described. More often she would resent the in-
terference with her family affairs and toss the dead mos-
quito contemptuously away. At times wiien she became nerv-
ous or angry she would cut the tops of some of her paper
cells. Snip, snip she would cut away using her mandibles
like a pair of scissors. Although on such occasions she was
watched closely, she was not again seen to feed the paper to
her offspring as in the one instance already described. "When
she was offered small caterpillars in place of the mosquitoes,
she would accept them readily, roll them up into a ball and
knead it vigorously and then feed the larvae.
On warm days polistes was very active. Between her build-
ing and the feeding of the larva? she was busy, indeed. After
» LIFE HISTORY AND HABITS OF POLISTES METRICUS 281
each trip afield, whether for food or wood pulp, she would
tarry for a minute or two to clean herself carefully from any
clinging dust and be off again. As the season advanced the
number of larva? increased and made a corresponding demand
upon their mother for food. By the middle of July several
had spun their cocoons, but more eggs were being laid in the
newly built cells and other eggs were hatching.
On the morning of the 16th of July the nest was visited
as usual. There had been a heavy rain lasting through most
of the night before. The nest was dislodged and had fallen
to the ground and the mother wasp was nowhere to be seen.
The nest was carefully replaced and fastened to the board
with glue and pins. After waiting all day for the return of
the mother it became apparent that she was lost. I could
ill afford to lose the wasp family at this stage of the observa-
tion, for eggs, larva? and pupae were marked to ascertain
the period of development. Near at hand was another similar
nest, but the mother was not a lively individual, and the nest
Avas composed of but a few cells. The nest containing the
motherless family was fastened close beside her own to as-
certain whether she would adopt the unfortunates.
The foster mother did not take kindly to such an arrange-
ment and moved rapidly over the strange comb, flitting her
wings violently, and showing marked evidence of displeas-
ure. Since she had seldom been visited I felt that possibly my
presence was responsible for her agitation, and accordingly
she was left alone until the following morning in order to
give her an opportunity to become accustomed to the unusual
condition. On my return the next day she bad her head in
a cell and backed out with an egg in her mandibles which
sli.' proceeded to eat. An examination showed that she
had disposed of some of the larva in similar manner. Since I
could ill afford to have the observation terminated in such a
cannibalistic manner, the nest was taken to the study to see
what could be done toward raising the youngsters by hand.
I soon realized that I had undertaken a rather novel experi-
ment. There were eggs which would hatch every day or two
for three weeks, young larva1 just hatched and others in
every stage of growth. There were also a considerable num-
ber of sealed cells, but as yet none of the pupa- had emerged.
I began to frequent the cabbage patch in search of small
282
IOWA ACADEMY OF SCIENCE
caterpillars or cut worms. The unfortunate worm when found
would be placed on a board and cut into bits with a sharp
knife. The bits were fed to the larvae with a grass stem. It
was found easily possible to feed the larvae, but the younger
ones did not thrive.
On the 18th of July the first wasp emerged. It was a female
and a perfect image of her missing mother. I now felt my
hopes rise high, for would not the newly matured polistes
mother her unfortunate sisters. The nest was placed on the
porch of the study in order to give her an opportunity to
fly to the fields in search of food, as soon as she was old
Fig 44. A. Larva spinning its cucoon. B. The completed nest.
enough to assume such a responsibility. The same day a sec-
ond female emerged, and I felt that soon I would be relieved
cf my arduous task. It is not easy for a mere man to
mother his own offspring at a tender age, and when it comes
to feeding newly hatched wasps, he is hardly prepared to
do justice to the needs of the infants.
Within a few hours after the emergence of the young wasps,
a caterpillar was cut up for the young larvae as usual. Iii-
stead of feeding it to them directly, it was given to one of
the elder sisters to whom I was looking for expert assistance.
To my great joy she took it and holding it between her
forelegs, kneaded it exactly as I had seen her mother do
LIFE HISTORY AND HABITS OF POLISTES METRICUS 283
many times. After the food had received suitable prepara-
tion she fed one or two of the larva'. This action within a
few hours after her own emergence convinced me thai my
troubles were over. Eowever, I was doomed to disappoint-
ment, fortius proved an unusual case As others matured and
the nest became populous with adull females I was greatly
disappointed to find that they not only would not forage
for the family but only now and then would they take the
trouble to feed the infants when worms were brought to them.
The mature wasps remained but a few days until they dis-
appeared.
By the fifth of August about a dozen had emerged and only
one remained at the nest. A larva which had hatched on the
29th of June died that day. Although I had kept it alive
for twenty days after its mother disappeared it was apparent-
ly no larger than when she herself had lasl d'd it. While my
careful ministration had been sufficient to enable the larger
larvae to complete their growth the food which I was able
to supply did not meet the needs of the younger ones. Either
it was not suitable in quality, was not properly prepared or
else it was not supplied in sufficient quantity or at proper
times. At any rate I did not succeed in rearing any of the
larvae that were less than half grown when the mother dis-
appeared.
About this time I found another nest of the same kind un-
der the eaves of the study and having given up hope of
further success by hand, the nest containing the motherless
family was pinned beside it to see whether there would be
any better success in getting the orphans adopted than in
the previous instance. The weather was still cool and wet.
The summer of 1915 was a record breaker in this respect.
A week later the abandoned nest still remained beside the
other, but the mother of that family had apparently gone
also. Two other nesis were examined at that time only to
find them deserted.
On the same day. August 12th. I found another nest of
polistes which previously had been overlooked. It was larger
and more populous than any of the others. All the others ex-
cept the unfortunate one which had received so much at-
tention had been small ami all the mothers had disappeared
early. Since no males had been seen up to this time 1 was
284 IOWA ACADEMY OF SCIENCE
much pleased to find a family in normal condition. An ex-
amination showed that there were still eggs and young larvae
iu the new nest, beside pupae and seven adult females. I was
so curious about the new discovery that four stings were the
net result of the first day's observation. On September 4,
there was only one egg still unhatched but no males had ap-
peared. It was not until September 10, that the first male
emerged. He was recognized instantly by his lighter color
and bright yellow face. The seven segments of the abdomen
and the absence of a sting established the sex beyond cpies-
tion. For several days about as many males emerged as fe-
males, but soon the males predominated. By the 21st of Sep-
tember more males remained at the nest than females. Since
as many wasps were deserting the nest as were emerging
from the pupal state, there was no permanent increase in the
population.
The last larva died on October 3d. It was nearly grown but
apparently had not increased in size for many days. Appar-
ently it was fed just enough to keep it alive but not enough to
enable it to complete its development. It was about the size of
one that was hatched on August 10th. Although the date of
the hatching of this particular larva had not been noted, indica-
tions were that it was about the same age. If so it lived for
about fifty days without being able to complete its develop-
ment. At that time there were a few sealed cells from which
pupae were still to emerge and one lone female remained at the
nest. The season had been so abnormal that it was impossible
to make satisfactory observations on which to base an estimate
of the normal period required to complete the life cycle. It so
happened that something happened to every larva marked to
ascertain the time of the larval period and it was evident
that the variation was so great on account of variable weather
conditions that the period required by a single one would have
been of little value. While I am hopeful of getting more satis-
factory information concerning the periods of development an-
other season I have no expectation of again attempting to rear
;■ family of wasps by hand.
Office of State Apiarist,
Atlantic, Iowa.
SUCCESSFUL MINK FARMING 28.")
SUCCESSFUL "MI'NK FARMING" IN ICAVA.
B. H. BAILEY.
Through the kindness of Prof. C. C. Nutting, Senator Lam-
bert and his brother, Mr. C. Lambert, of Sabula, Iowa, the writ-
er was afforded an opportunity to visit and study the "mink
farm'' owned by ^Ir. C. Lambert and J. E. Densmore, of Sabula,
Iowa.
The mink has been regarded as one of the most difficult ani-
mals to rear in captivity, owing to its natural temper and
habits, but the present successful effort which was started in
1910 has added not a little to our knowledge of the mink in
captivity and the best methods of handling it.
There are at present in this "minkery" thirty-seven indi-
viduals. These are all in perfect health and under absolute con-
trol of the owners. The individual cages in which they are
kept insure the isolation which is natural to the animals in their
native state, and at the same time afford an opportunity for
close observation of each individual as well as a perfect control
of each in feeding and breeding.
The first litter of six young was born in captivity May 7.
1910. They were the offspring of a female which was secured
by trapping. Only three out of the thirty-seven which now oc-
cupy the cages were trapped. The rest have all been born in
captivity. The advantage of having minks raised in captivity
for breeding purposes rather than those that have been trapped,
lies in the fact that they are more docile, and having known no
other home do not seek In escape. An excellent illustration of
this fact came under the observation of the owners ;it one time.
A board having been loosened in one of the cages, there was
given an opportunity to one of the animals to make its way out.
The mink availed itself of this opportunity In it was not missed
until it was seen coming home. It entered the cage by the same
opening through which it had made its exit, and gave every
evidence of having come back because ii regarded this place as
its natural abode. On another occasion a mink was reported
28 6 IOWA ACADEMY OF SCIENCE
at some distance from the mink farm. The animal had entered
a chicken-house and had killed two chickens when it was dis-
covered by the woman who owned the fowls. She drove the
mink out of the chicken-house, but it ran in again, keeping just
out of her reach. She reported the occurrence to Mr. Lambert
because the mink appeared to be so tame and apparently feared
her so little. This animal later returned to the cage. Mr. Lam-
bert was not aware that there had been any successful efforts
to rear minks in captivity elsewhere in the state of Iowa at the
time of his first experiments. His purpose originally was to
demonstrate in the first place that it is possible to rear these
animals in captivity and in the second place the advance in the
price of furs would, he thought, warrant the raising of these
animals for their pelts, provided they could be wred success-
fully and their fur kept in as good condition as in the wild
state. He is satisfied as to both these points and believes that
there need only be a suitable market to make the business a
profitable one.
Some years ago Mr. Lambert sold as beautiful pelts as he had
ever seen for seventy-five cents each. In 1911, No. 1 extra large
dark minks were bringing $9.00. The price in 1916 has ranged
between five and six dollars.
Among the interesting facts which have been noted with re-
gard to these captive minks are the following :
The usual breeding season in this locality is from the 10th or
12th of March to about the end of the first week in April.
The period of gestation is six weeks and the litters range
from three to seven. The average litter is four or five, and but
one litter is raised in a year. The young are about an inch and
a half to two inches long at birth and it is a number of days be-
fore they open their eyes.
Young male minks can usually be recognized by their size,
as they are slightly larger than the females.
The cry of the little ones is a high pitched whine. In the wild
state, the mink is known to move its young from one locality to
another if it is in the least disturbed. This tendency is notice-
able in the animals in confinement, The only period when the
mink is not a solitary animal seems to be during the time when
the female is caring for the young. By the following spring the
SUCCESSFUL MINK FARMING 287
young animals have attained their adult size and do not seem
to grow aftei* they arc two years old. They may lay on flesh,
becoming heavier, but the bony framework docs not seem to
enlarge. Male minks born during one year will breed the fol-
lowing spring.
Since the animals do not pair, but in their natural haunts are
accustomed to travel about, the males going long distances from
place to place during the breeding season; it has been noted
with interest that one male will serve several females, and it is
the custom usually to use the male not oftener than every other
day.
The cry of the male is a short grunting snuffle. The female
gives a high pitched squealing cry. The offensive odor of the
scent glands, noticed when the hide is being removed from a
dead mink, was not noticeable about the pens, excepl at the
time when a pair were being bred.
It is known that in its natural haunts the mink Avill accom-
modate itself to almost any hole that is dry. In the cages small
boxes about eight inches square and a foot and a half long, hav-
ing a circular opening about four inches in diameter at one end.
and partly filled with grass, afford a suitable substitute for
their natural homes. It is known that minks will sometimes
climb into trees if closely pursued by dogs, and their ability to
run about on various surfaces was noticed in the cages, where
they Avere exceedingly agile and very noisy. They seemed to
enjoy pushing their water pans about, apparently for the pur-
pose of hearing the clatter, and when one approached the front
of the cage, the animals in many instances climbed up on the
quarter inch wire mesh, showing almost the agility of squirrels.
The food supplied to these captive minks is doubtless much
the same as is procured by the wild animals. They enjoy fish.
crayfish, musk rats, and rabbits above other foods, and also eat
mice, wild birds, poultry and beef steak. A mixture of corn
meal mush with a little tallow, has been successfully U-^\ to
minks in captivity, and they also -will eat bread and milk. Tt is
found that salted food if continuously fed is fatal. On one oc-
casion when some salted fish were i'ed. fourteen or fifteen young
died as a result of eating them. The full grown mink will
readily go into the water and capture a fish twelve inches Ion-'
or more, and eventually devour the bones and all. It is a
288 IOWA ACADEMY OF SCIENCE
liabit where there are several fish in a small pool to kill all be-
fore eating any of them. A live rabbit which was introduced
into one of the cages was very quickly killed by a male mink.
It is the custom to feed minks in captivity once a day. Run-
ning water is preferable, but not necessary, and it was noted
that where water has been frozen in the pans the minks gnawed
at the ice and lapped up the particles that were dislodged. The
method of drinking milk is similar to that of the cat.
The mink is a very cleanly animal, and the cages which, be-
cause of the cold weather, had not been cleaned recently, were
wholesome and free from odor.
The chief factor in the success of this mink farm lies in the
care and skill shown by the owners in housing, feeding, and
breeding.
The individual cages are about six feet long by three feet
high, and three feet wide. They are built of pine and wire
mesh, the pine box having part of the top at one end and all of
the contiguous end of one-fourth inch mesh wire. That part of
the top which is of wire swings upward on hinges and affords
easy access to the interior of the cage. Within, on the floor, is
a litter of straw and grass, a pan for water, and the box previ-
ously described, in which the mink makes its nest.
It has been found best not to handle them and the easy meth-
od by which handling is avoided and the supposedly difficult
process of getting an animal from one cage to another simpli-
fied, reveals the careful planning by the owners in the conduct
of this experiment. Along the front of each cage and connect-
ing each cage to every other one in the house is a small wire-
constructed alley about six inches high and wide. At eacft par-
tition between cages, this alley is fitted with a sliding drop
door, much like the stop to a grain spout, The door from the
cage into the alley way is similarly guarded by a drop door
which can readily be operated from the outside of the cage. If
it is desired to clean the cage this door is raised, a little rattling
of the wire induces the mink to enter the run-way, the door is
closed and he is prevented from going back into the cage, and
can not follow the run-way farther than to the limits of the
partitions between the cages, where, as noted before, there are
drop doors to close that particular section. The run-way so
closed forms a box three feet long by six inches wide and high.
SUCCESSFUL MINK FARMING 289
If it is desired to transfer this animal to any other cage, the
alley-way is opened all the way to the cage which it is desired
to have the mink enter, and the door is opened into thai cage.
No other mink can enter the runway at that time and the ani
mal in the run-way can go only to the place intended.
The advantage of this method of control is evidenl in breed-
ing, since exact records are kepi of the date of breeding, and
the pedigree of the animals bred.
The docility of the animals, their evident lack of shyness and
the readiness with which they are induced to go in the direction
desired evidences the careful work of the owners.
The houses, or rather sheds, used at Saluda are cement floored
and built much like ehiekenhouses. There are sky-lights but
Mr. Lambert believes that the more the animals are kepi in the
dark the better will be their fur.
In one of the two houses there were twenty-six cages, and
twenty-four iu the other. A device for running water is being
installed that will doubtless be a convenience to the owners and
a comfort and pleasure to the minks.
Up to the present time at the minkery, no animals have been
killed for the fur since it is desired to increase the stock for
supplying other "minkeries."
The readiness with which such an industry might be devel-
oped, since the entire equipment requires only a part of an
ordinary city lot, and the fact that since in most towns running
water is as accessible as in the country, makes it a suitable in-
dustry for the city as well as the country.
A "minkery" in your back yard or in your neighbor's, would
conduce to more neighborly feelings and sounder sleep of morn-
ings than a hen yard, especially if a couple of lusty roosters axe
included among the inmates.
Former experiments in mink raising have failed on account
of ignorance of the real needs of these animals and of their
habits. They can not be allowed to run together as the nudes
fight fiercely and inbreeding would weaken the stock. The care
afforded each individual mink from the time its parents are se-
lected to the time it reaches maturity, results in producing large
animals with fur that is of a superior quality and that need be
taken only when the fur is prime.
It is a beautiful sight to see these little sleek-bodied active
animals moving about the eage and coming to the wire un-
19
290 IOWA ACADEMY OF SCIENCE
afraid when one approaches the cages, and the contrast is more
marked to one who knows the sly, secretive, vicious character
of these animals in the wild. "When the old time trapper shall
have passed and the last pair of steel jaws shall have rusted
away, we may still wrap ourselves comfortably from the wintry
blasts because of the successful solution of those who have es-
tablished the industry of mink farming.
ADDITIONAL NOTES ON THE LITTLE SPOTTED
SKUNK, 8PIL0GALE INTERRUPT A RAF.
B. H. BAILEY.
In volume XXII of the Proceedings of the Iowa Academy
of Science, it was shown that the Little Spotted Skunk is state-
wide in its distribution. Since writing the last article, I have
received specimens from Muscatine, Iowa, from Mr. J. Green-
blatt; also from Mr. Christian Hoeg, of Decorah, Iowa, who
states that they seem to be quite common in that vicinity; and
also from Sabula, Iowa, at which place Mr. J. C. Day and son
had received during the winter of 1915 and 1916, up to the
17th of March, 1916, twenty-five pelts of "civet cats," trapped
in the immediate vicinity of Sabula. Further effort to discover
whether the Little Spotted Skunk has crossed the Mississippi to
the Illinois side has resulted negatively in the region of Musca-
tine and Davenport, but from Mr. C. H. Swift of Sabula, Iowa,
I learned that he had personally trapped two specimens of the
Little Spotted Skunk on the Illinois side of the Mississippi river,
north of Savannah, "twenty years ago." These two specimens
were caught while trapping for larger skunks. That they have
not become common in that region is evident by the testimony
of several men in Savannah, notably, Mr. George N. Machen,
who has for many years been a close observer of the wild life
in that region. Careful inquiry has further confirmed the state-
ment that "civet cats" are far less abundant in the eastern part
of the state than are the common large skunks, and that they
become relatively more numerous in middle and western Iowa.
The firm of J. C. Day & Son, at Sabula, up to date, had pur-
chased 814 hides of the common skunk, while as before stated,
only twenty-five skins of the "civit cat" or Little Spotted Skunk
had been purchased during the same time.
Department op Zoology.
Coe College, Iowa.
TWO STRAWBERRY SLUGS 291
NOTES ON TWO STRAWBERRY SLUGS.
EMPRIA FRAGARI2E ROHWER.
EMPRIA MACULATA NORTON.
R. L. WEBSTER.
The literature of economic entomology has many references
to slugs that feed on strawberry foliage, discussed for the most
part under the name of Harpiphorus maculatus Norton, but also
as Monostegia ignota Norton. That there were two common
species of these slugs affecting strawberry plants was shown by
the work of P. W. Mally (1889). During the five years 1910-
1914 inclusive, the writer has studied both these species in the
insectary at Ames. The present paper is based on a study of
the literature, as well as from additional notes of the writer.
S. A. Rohwer, of the U. S. National Museum at Washington,
examined all the saw-flies reared, and has recently described
Empria fragariae. The life history notes are from the files of
the entomological section of the Iowa Agricultural Experiment
station at Ames. These insects are discussed in a recent bulle-
tin from the Iowa station but some matter is incorporated here
that is not mentioned in the bulletin.
Dr. C. V. Riley (1867), first mentioned Emphytus maculatus
in the economic literature in the Prairie Farmer. This was fol-
lowed by an account by Walsh and Riley (1869) and later by
Riley (1877). These refer to slugs feeding on strawberry foliage
in May (Missouri). The eggs are said to be deposited in the
stems of the strawberry leaves and a second brood of slugs are
said to appear in July. The slugs are described as having a
yellowish head, with two dark brown spots above, one of these
to the front, as well as two smaller ones at each side.
Dr. Riley (1868) said that slugs had injured strawberry
plants at Rockford, Illinois, and Cedar Bluffs, Iowa. He re-
marked that these slugs were probably a variety of Emphytus
maculatus, since they had but one black spot on each side of
the head. This corresponds to the description of Empria
fragariae, later discussed by F. W. Mally under the name of
Monostegia ignota.
292 IOWA ACADEMY OF SCIENCE
Forbes (1884) gave a general account of Emphytus macu-
latus, adapted from previous accounts by Eiley and others.
Here doubt is expressed concerning a second generation, since,
aside from Riley, none had been seen by other observers.
In the same year Forbes (111. Hort. Soc. Rep.) treated briefly
a strawberry slug under the name of Emphytus maculatus. In
breeding this insect only one generation was found. The eggs
were deposited beneath the epidermis of the leaf. Probably
the insect concerned was Empria fragariae, which places its eggs
in the leaf tissue.
F. M. Webster (1888), recorded the abundance of larva? sup-
posed to be Emphytus maculatus at Richmond, Indiana, in Octo-
ber, 1887. This appeared to indicate a second generation.
F. W. Mally (1889) was the first to point out clearly the
presence of a second species of strawberry slug, differing in
several respects from that discussed by Riley. Specimens sent
by Mally to E. T. Cresson were determined as probably
Monostegia ignota Norton. That the species reared by Mally
is really Empria fragariae will be shown later on.
The main points established by Mally 's work are these: (1)
that two species of slugs are found on strawberry foliage in
Iowa, (2) that these are easily distinguished in the larval stage
and (3) that the eggs of the second species (Empria fragariae)
are placed in the leaves, not in the stems. Later (1890) Mally
showed that only one generation of this insect occurred in cen-
tral Iowa.
F. M. Webster (1894) secured larva? from strawberry plants
at La Porte, Indiana, July 5, 1893. These entered the soil in
an insectary cage, remained there all winter, and adults emerged
the next March. Adults deposited eggs in stems of strawberry
plants and specimens were determined by Dr. L. 0. Howard,
as Harpiphorus maculatus.
Dyar (1896), described seven larval stages of Harpiphorus
maculatus and recorded rearing adults of that species from
larva? with immaculate heads, apparently contradicting Mally 's
observations. From these descriptions, however, it seems prob-
able that Dyar had only the one species, maculata, and may not
have seen specimens of the insect considered by Mally as
Monostegia ignota.
TWO STRAWBERRY SLUGS 293
Iii Michigan R. II. Pettit (1899) recorded larvae that he
called Ilarpiphorus maculatus occurring at Stevensville and else-
where in the state in the late summer of 1898. Larva; about
mature were reported for September 22.
J. M. Stedman (1901) gave a general account, under the
name of Harpiphorus maculatus, of a strawberry slug occurring
in Missouri. An examination of this bulletin, however, shows
that it was not that species which Stedman studied. The life
history and habits agree precisely with those of Empria
f rag aria e, as described by F. AY. Mally and as determined more
recently by the writer. The deposition of eggs in the leaves and
the appearance of adults and larva? in early spring (about
strawberry blossom time) shows that Stedman was writing of
this insect under the wrong name. I have attempted to obtain
reared specimens of the saw-fly from Columbia, but Dr. L.
Haseman writes that he finds none in the collection there.
S. A. Rohwer (1914) described Empria fragariae from speci-
mens reared or collected by the writer in Iowa. That this is
the same insect discussed by F. W. Mally is shown by the facts
(1) that most of the material was collected in the same locality,
about Ames, (2) that the life history is the same; the saw-flies
appear early in spring (before strawberry blossom time) and
the eggs are placed in the leaves. Moreover, the writer found
only one generation, as did Mally with his Monostegia ignota.
Unfortunately, there are no specimens reared by Mally in the
collection at Iowa State College, so that an actual comparison
of specimens is not possible.
GENERATIONS OF EMPRIA FRAGARIAE.
From the literature it is very apparent that Empria fragariae
has only one generation. The work of Forbes (1884) which
apparently refers to this insect, of Mally (1890), and of Sted-
man (1901), all show this. Life history experiments by the
writer more recently show but one generation in central Iowa.
The insect has been carried through to the adult stage each
year during four years, and in no case was there any evidence
of a second generation.
Briefly, the life history of Empria fragariae is as follows: The
adults emerge very early in spring, in April in central Iowa,
deposit their eggs singly in strawberry leaves, and larva1 ap-
294 IOWA ACADEMY OF SCIENCE
pear at the blossoming time of the strawberry. The slugs
mature in about a month, enter the soil, where they remain
until the next spring, pupating shortly before the adults emerge.
GENERATIONS OF EMPRIA MACULATA.
Here the situation is more complicated. In the literature
we have the definite statement by Riley that the insect has two
generations in Missouri, and the statements of F. M. Webster
(1888) and Pettit (1899) that larvae were found in abundance
in the fall in Indiana and Michigan. On the other hand, no
other writers have been able to discover a definite second gen-
eration. In fact, F. M. Webster (1894) determined a single
generation from larva? collected at La Porte, in northern In-
diana.
The writer has bred this saw-fly in the insectary at Ames dur-
ing four years, and each year there was but a single generation.
According to these notes the life history in central Iowa is as
follows: The adults emerge in late April or early May and
deposit their eggs in the stems of strawberry plants. The larvae
hatch in late May and are present during June, mature and
enter the soil about a month after hatching. Larvae spend the
winter in the cocoons, pupating the next spring shortly before
the adults emerge. Adults reared in the insectary have been
identified by S. A. Rohwer as Em/pria maculata Norton.
Eliminating references in the literature that clearly refer
to Empria fragariac, the following generalizations are offered:
(1) Riley claimed two generations for Missouri. This may
be possible, since it has not been proved otherwise.
(2) F. M. Webster determined only one generation from
larvaa from La Porte in northern Indiana, in 1894.
(3) Only one generation is present in central Iowa, accord-
ing to notes hj the writer.
(4) This does not dispose of the statements that this in-
sect has been seen in the fall in southern Indiana (Webster)
and Michigan (Pettit).
(5) There still remains a possibility that there is a third
species of saw-fly, the larvae of which attack strawberry plants
in the fall, but which has not been recognized in the economic
literature as a separate species.*
*Emphytus gillettei MacG. feeds on strawberry foliage in Colorado but
there is only one generation. The eggs are placed in the leaf tissue and
larvae appear in late May and early June.
TWO STRAWBERRY SLUGS
295
The following table shows certain characteristics that dis-
tinguish these two species of strawberry slugs. The time of the
season applies to central Iowa.
Ernpria fragariae
Empria macu'.ata.
Generations
One
One
Adults appear
Early April
Late April
Eggs deposited
In leaves
In stems
Larva? appear
May (blossoms)
June (as fruit ripens)
Larvae begin feeding
On upper epidermis
On lower epidermis
Head width stage I
.51 mm.
.32 mm.
Head markings
None
Dark markings above
and at sides
Entomology Section,
Iowa Agricultural Experiment Station.
BIBLIOGRAPHY.
1861.
1868.
1869.
1877.
1884.
1888.
Norton, Edward, Proe. Bost. Soc. Nat, Hist., vol. 8, p.
157. Emphytus maculatus described.
Riley, C. V ., Trans. 111. State Hort. Soc. for 1867, p. 121.
Mentions slugs injuring strawberry plants at Rock-
ford, Illinois, and Cedar Bluffs, Iowa. Says that these
were probably a variety of Emphytus maculatus, the
larva? having but one black eye spot on each side.
Walsh, B. D., and Riley, C. V., Amer. Entom., vol. 1,
p. 90. General account. Mentions two generations
(Emphytus maculatus).
Riley, C. V., Ninth Mo. Rep., p. 27. General account.
Emphytus maculatus.
Forbes, S. A., Trans. 111. St. Hort. Soc. for 1883, p. 121.
Mentions Emphytus maculatus and says that only one
generation was found. Also found eggs beneath the
epidermis on the under side of the leaves.
Forbes, S. A.. Thirteenth 111. Rep., p. 71. General ac-
count. Emphytus maculatus.
Webster, F. M., Rep. Comm. Agr., 1887, p. 152. Larvae
supposed to be this species (Emphytus maculatus) ob-
served in October near Richmond, Indiana.
29 6 IOWA ACADEMY OF SCIENCE
1889. Mally, F. W., Insect Life, vol. 2, p. 138. Gives an ex-
cellent account of the life history and habits of Em-
pria fragariae, with distinguishing characters separat-
ing- it from Empria maculata (Monostegia ignota).
1890. Matty, F. W., Insect Life, vol. 3, p. 9. Describes the
male of Empria fragariae and gives additional notes.
(Monostegia ignota.)
1894. Webster, F. M., Entom. News, vol. 5, p. 275. Number
of generations of Empria maculata. (HarpipJiorus
maculatus.)
1896. Webster, F. M., Bull. Ohio Agr. Exp. Sta., 68, p. 33.
General account. Only one generation proven.
(HarpipJiorus maculatus.)
Dyar, H. G., Can. Ent., vol. 28, p. 236. Descriptions of
the larval stages of Empria maculata. Says that this
is identical with Monostegia ignota.
1899. Pettit, R. H., Bull. Mich. Agr. Exp. Sta., 175, p. 365.
Larva? said to have been observed in September, 1898,
in Michigan, (HarpipJiorus maculatus.)
1901. Stedman, J. M., Bull. Mo. Agr. Exp. Sta. 54. General
account. The insect treated is called Harpiphorus
maculatus, but the account of the life history and
habits is clearly that of Empria fragariae. .
1914. FoJiwer, S. A., Journ. Econ. Ent., vol. 7, p. 479. Em-
pria fragariae described.
1915. Webster, F. L., Bull. Iowa Agr. Exp. Sta., 162. General
accounts of Empria fragariae and Empria maculata.
Iowa Academy Science
Plate VII
Fie:. 1 — The adult saw-fly.
Fig. 2 — Empria fragariae.
Fig. 3 — Empria fragariae.
Fig. 4 — Empria maculata.
Fig. 5 — Empria maculata.
Fig. 6.
Empria ma< uhita. Enlarged 5 times.
Eggs on a strawberry leaf. Enlarged.
Head of mature larva. Enlarged.
Head of larva from side. Enlarged.
Head of larva from front. Enlarged.
Fig. 6 — Empria fragariae. The adult saw-fly. Enlarged 5 times.
PREPARING TRICHINELLA SPIRALIS 299
A METHOD OF PREPARING STUDIES OF
TEICHINELLA SPIRALIS OWEN.
T. T. JOB AND DAYTON STONER.
This work was first attempted with the idea in mind of
securing an adequate supply of laboratory material of
Trichinella spiralis for classes in invertebrate Zoology at the
State University of Iowa.
It is the too general belief that such studies are difficult to
secure and it is to dispel this idea, in part, that this paper is
offered. In fact the comparative ease with which one may
secure a presentable series showing the development, growth,
migration, encystment, etc., of this worm, affords an unusually
good opportunity for illustrating the interesting phenomenon
of typical parasitic life.
Since it is often rather difficult to secure tricliinized meat
from the local shops, the material for the following studies
was obtained by addressing the Chief of the United States
Bureau of Animal Industry at Washington, D. C. This meat
contained the worms in the encysted stage and in suitable con-
dition for transferring to another host where they might live
and reproduce.
A part of the trichinized pork was fed to four young white
rats which were kept confined in a separate cage. After hav-
ing eaten of this pork the rats were again given their usual
diet.
THE TRICHINELLAE AND HOST.
Host No. 1. — Five days after feeding the encysted Trichinella
the first subject was killed. Various openings were made at
different levels in the stomach and intestine and the digestive
content together with scrapings from the mucosa were examined
under the dissecting microscope in 5 per cent formalin.
Free worms were found only in the intestinal content and
the mucosa of the upper ileum. Sections of this portion of the
intestine were preserved in 10 per cent formalin.
3 00 IOWA ACADEMY OF SCIENCE
Host No. 2. — Nine days after feeding, a second subject was
killed. The procedure was as in No. 1. In addition, an ex-
amination of several blood smears from the superior mesenteric
vein and the heart was made. Only one young Triehinella
was found in the smears and that in the blood from the heart.
The embryos at this stage were developed to such an extent
that they could readily be seen in the body cavity of the female.
Again sections of the upper ileum were preserved in 10 per
cent formalin.
Host No. 3. — Fourteen days after feeding, the third subject
was killed. The method was as above. Blood smears were neg-
ative. The Triehinella? were found a little further down in
the ileum and were much larger than in the nine day stage.
Host No. 4. — The fourth subject was to have been killed
twenty-one days after feeding, but it died of trichinosus on the
night of the twentieth day.
On examination, free intestinal Triehinella? were found in
the middle ileum. The muscles surrounding the abdominal cav-
ity, diaphragm, internal and external oblique, transversalis and
Pvsoas, as well as the extensor muscles of the hind legs showed
Triehinella? in the migratory and resting stages. A considerable
number were found in these muscles but the masseter muscles
showed the various stages even better and more abundantly.
In this stage the entire body of the host was preserved in 10
per cent formalin.
METHOD OF PREPARATION.
The material was handled in watch glasses with pipettes.
First, the preserved material was washed thoroughly with dis-
tilled water. This not only removes the formalin but separates
the Triehinella? from the other material so that the worms may
be collected in a pipette and transferred to the next dish. The
staining and dehydration were carried on in the same dish so
as not to injure or lose the specimens, the different fluids being
added and drawn off with the pipette.
Killing and Fixing. — Ten per cent formalin was used in all
cases to kill and fix the tissues and Triehinella?. Carnoy's so-
lution may be used with equally good results.
Staining. — Delafield's hematoxylin and erythrosin, orange G.
methyl green, borax carmine and iron hematoxylin (Heiden-
PREPARING TRICHINELLA SPIRALIS 301
hain) were all tried. Iron hematoxylin seemed to give the best
results with borax carmine next. Where iron hematoxylin is
used, care must be taken to remove all the surplus mordant or
a precipitate will occur on addition of the hematoxylin thus
vitiating the results. The borax carmine has the advantage
in ease of handling.
Clearing — Experiments with xylol, oil of bergamot, chloro-
form and turpentine showed that all these clearing agents shriv-
eled the specimens. As a matter of fact clearing is not at all
necessary.
Mounting. — Specimens mounted in balsam were shriveled just
as when treated with a clearing agent so glycerine was used as
the mounting medium. The permanent mounts were ringed
with lacquer or thick balsam.
It is, perhaps, needless to suggest that great caution be ob-
served in regard to cleaning cages in which hosts are kept,
means of disposition of their bodies and general cleanliness in
handling specimens.
State University op Iowa.
IOWA PENTATOMOIDEA 303
DISTRIBUTIONAL NOTES ON SOME IOWA
PENTATOMOIDEA.
DAYTON STONER.
During the past two summers the writer has been enabled,
through the co-operation of the Iowa Geological Survey, to visit
various parts of the state for purposes of collecting both mam-
mals and insects. In the course of this collecting, some species
of Pentatomoidea not before recorded from Iowa have been
secured and, in addition, distributional records of a number of
species have been added. Considerable collecting has been done
in the vicinity of Iowa City also and this has resulted in some
new additions to and increased the known distribution of the
state fauna in this group.
As more intensive and extensive collecting is done it is in-
teresting to note the considerable number of Pentatomids found
in the state which are usually thought of as being of more
southerly or westerly distribution. However, sufficient collect-
ing has not yet been done to warrant any extended conclusions
being drawn at this time. Since little work has been done by
the writer in western Iowa, some six or seven species recorded
by Professor Osborn more than a decade ago and mostly from
that region remain to be found in the present study.
The species which follow do not represent the entire num-
ber found within the state but only those are included which
would seem to be of especial interest at this stage of the work.
With the conclusion of this paper sixty species of Pentatomoidea
will have been recorded from Iowa through the efforts of Pro-
fessor Herbert Osborn and the writer.
Family THYREOCORIDAE.
Subfamily Thykeocorixae.
Thyrcocoris lateralis Fair. Least common of the members of
the subfamily.
Specimens at hand from Ames, Iowa City, McGregor, Ana-
mosa and Solon.
304 IOWA ACADEMY OF SCIENCE
Thyreoeoris nitididoides Wolff. Generally distributed over
the state; apparently nowhere common.
Thyreoeoris pulicaria Germar. This most common species of
the family has been taken in almost every locality in which
collecting' has been done.
Thyreoeoris vnicolor P. B. First recorded from the state by
the writer (Ent. News, XXVI, 1915, 354), and among the mem-
bers of this family it ranks next in abundance to T. pulicaria.
Specimens are at hand from Iowa City, Des Moines, Centerville,
Hampton, Glenwood, Storm Lake, Fort Madison and several
other intermediate points.
Subfamily Cydxixae.
('yd nus obliquus Uhler. This species was first found in the
state on May 22, 1915. It was discovered about the roots of
Drop-seed Grass. (Sporobohis cryptandrus (Torr.) Gray) on
a sand area two miles north of Iowa City. This sand area
is perhaps two acres in extent, is not cultivated and supports
a vegetation characteristic of arid conditions. On the above-
mentioned date five live specimens 'of this species were found.
Nine days later another visit was made to the sand area and in
a little over three hours twenty-seven specimens were secured.
On this second visit also a pair of the bugs was found in copula.
These Cydnids have not been found elsewhere in the state.
Geotomus parvidus Signoret. Two specimens of this species,
each bearing an Ames locality label were recently discovered by
the writer in the collection of the Iowa State College. This may
possibly be the species to which Professor Osborn referred in
the Proceedings of the Iowa Academy of Science, Volume V,
page 232, 1897, where he lists "Geotomus sp." from Iowa. No
other Iowa records of this western form are at hand.
fleJiirus cinctus P. B. This species, first recorded from the state
by the writer, (Ent. News, XXVI, 1915, 354), has been found
in but two localities, Iowa City and Grinnell. At Iowa City it
was taken from under dried grass along the edges of boards
lying in a pasture in late .March. March 25, 1916, it was taken
from under leaves and some specimens were buried almost an
inch below the surface of the earth beneath the leaves where
they had been hibernating. The single Grinnell specimen was
taken in July on wild raspberry.
IOWA PEXTATOMOIDEA 305
Family SCUTELLERIDAE.
Subfamily Scutellebinae.
Homaemus aenifrons Say. Less common than the following.
Three specimens from Ames, Hills and Iowa City.
Homaemus bijugis Uhler. Several specimens from Iowa City,
Monticello. AVaukon and Storm Lake. Professor Osborn re-
corded it also from Ames and Little Rock.
Eunjgaster aliernatus Say. Professor Osborn says of this
species (Proc. la. Acad. Sei., Vol. I, part II, 1890-91) "not
common," but no localities are cited. A single specimen has thus
far been collected at Red Oak in July.
Family PENTATOMIDAE.
Subfamily Pextatominae.
Banasa dimidiata Say. Recorded from Ames by Professor
Osborn who says further that it is "not common." One speci-
men, November 13, under fallen leaves.
Dendracoris humeralis Uhler. Two localities only are repre-
sented, Solon and Robinson: August. The Robinson specimens
were taken on hazel.
EuscJiistus i&tericus Linn. Iowa City and Algona. Professor
Osborn in Proceedings of the Iowa Academy of Science, Volume
I, part II, 1890-91, records a single specimen of this species
which he says was "doubtless taken in the state."
Etischistus tristigmus var. pyrrhocerus H-S. This variety of
the typical tristigmus was not recorded by Osborn. All the
specimens agree in having the humeri produced into long, acute
spines and in having the antenna? entirely pale; they also aver-
age somewhat smaller than tristigmus. Specimens from Iowa
City and Solon only; taken in August and November. The
August specimens were taken on wild raspberry and the No-
vember specimens from under dried leaves.
Euschistus variohirius P. B. Abundant. Collected in prac-
tically every locality. Apparently hibernates very successfully
under leaves, sticks, grass, etc., and is often found in the same
localities as Hymenarcys aequalis Say.
Minnies insertus Say. Osborn says of this species "rare."
Our collection of twenty-four specimens does not contain ma-
terial from other localities than Iowa City and in no case have
20
306 IOWA ACADEMY OF SCIENCE
they been secured by sweeping. Almost all the specimens have
been found in autumn (November) under fallen leaves, mostly
elm.
Mormidea lugens Fabr. Iowa City, Monticello, McGregor,
Dubuque, Robinson, Solon, Hills. Nowhere common. Swept from
blue grass in open fields in late June. Also found hibernating
beneath leaves in March.
Murgantia histrionica Halm. First recorded from Iowa by the
writer (Ent. News, XXIV, 1913, 132). Since that time, al-
though special search has been made, other specimens have not
been found.
Neoitiglossa sulcifrons Stal. This southern species was first
(Ent. News, XXVI, 1915, 355) recorded from Chariton where
a single adult specimen was found in July. Last summer this
species was found in some numbers at Burlington, Fort Madi-
son and Glenwood. It has also been found at Red Oak and
Shenandoah, all in the southern part of the state. Nymphs of
the species were taken at Burlington during the latter part of
June and at Glenwood July 14. In all instances it has been
swept from" sparsely growing blue grass.
Peribalus limbolarius Stal. One of the commonest species of
Pentatomid found in the state ; perhaps next in abundance to E.
variolarius.
Prionosoma podopioides Uhler. A western species that has
been taken in June at Fort Madison near the extreme south-
eastern corner of the state. A single specimen has also been
taken at Iowa City from under mullein leaves in October.
Solubea pugnax Fabr. Has been taken at Iowa City, Hills
and Moscow. Swept from sparsely growing weeds on sandy
soil.
Trichopepla atricornis Stal. Two specimens, both from Iowa
City. Professor Osborn recorded it from Little Rock and Ames.
Trichopepla semivittata Say. Apparently not common any-
where. A few specimens from Boone, Red Oak and Fort Madi-
son.
Brochymena arborea Say. Three specimens from Robinson,
including a half-grown nymph; collected August 25 on wild
crab apple. One other specimen from Iowa City.
IOWA PENTATOMOIDFA 307
Subfamily Asopixae.
Apateticus cynicus Say. Iowa City and Robinson. Professor
Osborn says of this species "not abundant."
Podisus maculiventris Say. Quite common in almost every
locality.
Podisus modestus Dallas. Professor Osborn records but a
single specimen from Ames. A few specimens are at hand from
Robinson.
Podisus placidus Uhler. Iowa City and Robinson.
Podisus sereiventris Uhler. Iowa City, Independence and
Robinson.
State University of Iowa.
BEHAVIOR OF LEGUME BACTERIA 309
THE BEHAVIOR OF LEGUME BACTERIA IN ACID
AND ALKALINE MEDIA.
RAYMOND C. SALTER.
Several investigators have noted a very marked difference in
the resistance of various legumes to soil acidity. Vast areas
of cultivated land in the United States show an acid reaction,
and as lime is expensive in some localities it has heen suggested
that much can be saved by the choice of acid tolerant crops.1
Red clover, crimson clover, soy bean, cowpea, hairy vetch, lu-
pine and serradella have been reported as acid tolerant, while
on the other hand, alfalfa, one of our most useful forage crops,
is found to be very sensitive to acid.
This sensitiveness may be due to many factors concerning the
nutrition of the plant. Since leguminous plants obtain nitro-
gen by a symbiotic relation with certain bacteria, it seems prob-
able that the ill effects of the acid may be directly upon the
symbiotic bacteria and only indirectly upon the higher plant.
The influence which the acid constituents of the soil may
exert on plant growth has been studied chiefly with reference
to the growth of higher plants. From the nature of the re-
sults of these investigations, it seemed advisable to extend the
study to the lower plants. Probably one of the most striking
examples of the interdependence of higher plants and bacteria,
is the legumes and legume bacteria. Any agent affecting the
one will have a corresponding effect on the other.
The growth of legume bacteria can be measured directly by
plate counts, and their virulence can be tested by the formation
of nodules on the host plant. This property of the organism
makes it well suited for a study of the effect of acid and alkali
on its development. An increase or decrease which might re-
sult will be noted, especially if the result is compared with that
from a neutral culture.
Experiments were planned to study and compare the effect
of acid and alkali on the bacteria and host plant. Since legumes
are found to vary in resistance, the acid tolerant red clover
iCoville, F. V., Bui. 6, United States Dept. Agr. Bur. Plant [ndust.
310 IOWA ACADEMY OF SCIENCE
plant and the sensitive alfalfa plant were chosen for compari-
son. The effect of reaction on the reproduction of legume bac-
teria was studied in Ashby's mannit solution and in soil.
In Solution. The plan below was followed :
1 and 2 — 1.0 per cent of N/1 sulphuric acid.
3 and 4 — 0.5 per cent of N/1 sulphuric acid.
5 and 6 — Neutral.
7 and 8 — 0.5 per cent N/1 sodium hydroxide.
9 and 10 — 1.0 per cent N/1 sodium hydroxide.
Ten 500 cc. flasks were innoculated with 1 cc. each of a water
suspension of the red clover bacteria. At the end of one and
two weeks plate counts were made to show the number of bac-
teria in each flask. It was found that a neutral or slightly acid
reaction in mannit solution is most favorable for the reproduc-
tion of the red clover organism. A slight amount of alkali in-
hibited growth. No growth was found in the presence of one
per cent normal alkali. The results of repeated counts sup-
ported the preceding statement.
Alfalfa bacteria were studied in the same manner. It was
found that Bacillus radicicola from alfalfa grew best in a slight-
ly alkaline or neutral solution. The optimum reaction for the
growth of the alfalfa organism in mannit solution is some-
where between neutral and 0.5 per cent alkali. Unlike the or-
ganism from red clover this strain of legume bacteria was found
to be very sensitive to acidity. An acid reaction of 0.5 per cent
greatly retards growth. After three weeks no living cells could
be found. A repetition of this experiment gave similar results.
In Soil. Twenty-five samples of sterilized Miami silt loam
soil were placed in large test tubes and arranged as follows :
1 and 2 — 1.0 gram of CaC03 or four tons per acre.
3 and 4 — 0.5 gram of CaC03 or two tons per acre.
5 and 6 — Neutral — untreated.
7 and 8 — 1.0 cc. N/1 sulphuric acid or two tons per acre.
9 and 10 — 2.0 cc. N/1 sulphuric acid or four tons per acre.
After treatment the soil cultures were re-sterilized and when
cool, were innoculated with a pure culture of legume bacteria.
Plate counts were made after one week. The figures of the
BEHAVIOR OF LEGUME BACTERIA 311
counts show that calcium carbonate in all proportions hour
fitted the growth of Bacillus radicicola from alfalfa. The great-
est number occurred in the soil treated with two tons of lime-
stone per acre.
Here again, the red clover bacteria failed to show any gain
in numbers in the presence of a basic substance. Large amounts
of calcium carbonate retarded the growth of legume organisms
from clover. Apparently red clover does best in neutral Miami
silt loam soil.
Effect of Reaction on Growth and Nodule Formation of High-
er Plants. — In order to test the effect of reaction on the plant
and the formation of nodules it was necessary to grow the plants
with a pure culture of Bacillus radicicola. Large test tubes
were used. These contained soft filter paper pulp plus mannit
solution of known reaction. The same range of reaction was
used as in the experiments with solution cultures.
Figure A of Plate VIII shows the results with red clover. The
plants developed best in the presence of 0.5 per cent of normal
acid and even 1.0 per cent of the acid does not seriously injure
growth. The nodules on the roots were carefully counted. The
0.5 per cent of acid also seemed most favorable for nodule for-
mation. But, judging from nodule formation in the presence of
alkali, it would seem that the latter was less injurious to the
bacteria than to the higher plant.
Figure B of Plate VIII shows the same experiment carried
out with alfalfa. An alkaline reaction seems to be favored by
this plant. Not only the best growth, but also the greatest
number of nodules were found in an alkaline medium. The al-
falfa plant and bacteria seem to favor alkali in about the same
concentration that the red clover favors acid.
These experiments were repeated in soft mannit agar and in
sterilized soil. In all cases the results confirmed those cited
above. The filter paper pulp furnished the best medium for
the formation of nodules.
Further experimentation is needed to test the effects of dif-
ferent acids or to represent more closely the conditions which
actually exist in an acid soil.
312 IOWA ACADEMY OF SCIENCE
It is very evident from the experiments performed that al-
falfa bacteria are benefitted by an alkaline reaction while the
clover bacteria do best in a neutral or slightly acid medium.
The difference in behavior of alfalfa and red clover plants in
acid soils is characterized by a corresponding difference in the
behavior of their symbiotic bacteria.
Department op Natural Science,
Iowa State Teachers College.
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HOW A TREE GRCT 3 315
HOW A TREE GROWS
FRED BERXIXGHAUSF-X
Profe?sor Ebermeier of Munich. Germany says: "When the
leaves take carbonic acid from the air they break it up and
force its carbon into new chemical compounds which are then
stored away as new material in the tree. The forest is the most
highly organized portion of the vegetable kingdom.*"
Xo man can really know the forest without feeling the gentle
influence of one of the kindest and strongest parts of nature.
It is the most helpful friend of man.
There is no other natural agent which has done so much for
the human race. Its influence upon streams alone makes farm-
ing possible. It supplies fuel, one of the fh si ssaries :
life, and lumber, the raw material without which railroads and
all the great achievements of material progress would have
either been long delayed or wholly impossible.
The forest is as beautiful as it is useful. A tree is a woody
plant growing up from the ground. It consists of three parts :
First, the roots which take up water from the soil and some
mineral substance which the tree needs in its growth ; second,
the trunk, stem or bole which supports the crown itself with its
network of branches, buds, and leaves, in which all the food
taken up by the tree from the soil and air is worked over and
made ready to assist in the growth of the whole tree. The
crown has more to do with the life of the tree than any other
part. The most important process is the reproduction of the
tree and the digestion of the food, which takes place in the
crown. The material upon which the tree feeds is derived from
the soil and the air. The minute root hairs take up water from
the ground and with it substances which it holds in solution.
These are the earthy contents of the tree which appear in the
form of ashes when any part is burned. The water which con-
tains these materials goes straight from the roots to the leaves,
in which the most important process in the feeding of the tree
lakes place. This process is assimilation or taking up and
breaking up by the leaves of carbonic gas from the air. It goes
on only in the presence of light and heat and through the ac-
tion of chlorophyl. a substance through which the leaves and
the bark get their green color. Plants or trees containing
chlorophyl are the chief means by which the mineral materials
are changed into food so that nearly all plant and animal life
316 IOWA ACADEMY OF SCIENCE
depends upon them. Plant cells which contain chlorophyl break
up the carbonic acid gas with which they come in contact, re-
taining the carbon, one of its elements, and sending back the
oxygen into the air. Under the influence of sunlight they com-
bine the carbon with the' oxygen and hydrogen of the water
from the roots into the new chemical compounds ; in which
nitrogen and the earthy constituents mentioned above, that is
to say the food material which reaches the tree through the
roots and leaves, are first digested in the body and are then
sent to all living parts of the roots, stem and crowrn. Some of
this food is stored away until the proper moment arrives. "Wood
is made up chiefly of carbon, oxygen and hydrogen. When per-
fectly dry about half its weight is carbon and half oxygen and
hydrogen in almost the same proportion as water. It contains
about one part in a hundred by weight of earthy constituents.
The nitrogen and wTater taken up by the roots were originally
in the air before they reached the ground. It is true therefore
that when wood is burned those parts which came from the air
go back into it in the form of gas, while those which came from
the soil remain behind in the form of ashes. Besides giving out
oxygen through the leaves to the air they breathe through the
minute openings in the bark. This breathing goes on day and
night and consequently more carbonic acid gas is taken into
the tree than is given out and the surplus carbon is used in
growing. The addition of new material or the foundation of
growth is deposited in a thin coat over the whole tree between
the wood and the bark. There are two layers of this coat sep-
arated by a third one of tender tissues, and the outer or cam-
bium layer forms new bark. Wood is chiefly made up of very
small tubes or cells of various kinds which have special use in
the life of a tree. Some conduct water from the roots to the
crown, some store away digested food, and others merely
strengthen the structure of the wood and hold it together ; but
in each case some of the cells have thick walls and small open-
ings and others wide openings and thin walls. Consequently at
first the tree makes thin walls itself and wide openings through
which water can rise rapidly to the ends of the branches ; later
on when the demand of water is not so great and there is plenty
of digested food to supply building material the cells formed
are narrow and thick walled. Thus the summer growth in
wood is heavier, stronger, darker in color than spring wood.
Hldora.
A FLORA IN NORTHERN OREGON 317
A SECTION OF TPPEK SONORAN FLORA IX NORTH-
ERN OREGON.
MORTON E. PECK.
From July -4 to July 16, 1915, the writer was stationed at
Umatilla. Oregon, as special field agent of the United States
Biological Survey. A part of the work assigned was the gather-
ing of data in regard to the general character of the vegetation
and the listing of the species identified. Most of the facts here
given were embodied in a somewhat briefer form in the official
report.
Umatilla is a small town on the south bank of the Columbia
river, in Umatilla county. 110 miles from the eastern boundary
of the state, and 205 miles from the Pacific coast. The eleva-
tion above sea level is less than 200 feet, and is therefore cpiite
negligible as a climatic factor, while the Cascade mountains to
the westward cut off most of the moisture from the Pacific.
These conditions render the climate extremely dry and hot dur-
ing the summer; moreover in June. July and August strong
hot winds blow almost daily up the Columbia, greatly intensify-
ing the general aridity. The annual precipitation is about 8.70
inches. Except along the streams, the vegetation, as might be
expected, consists of only such plants as can endure rather se-
vere xerophytic conditions.
The Umatilla river, a considerable stream, empties into the
Columbia near the town. Much of the water is now being tak-
en out by an extensive government irrigation project. Besides
tiie Columbia and Umatilla rivers, there is very little water in
the section studied except several small ponds to be mentioned
presently.
Along the immediate shore of the Columbia there are in
places small muddy pools and bayous, hut for the most part the
ground a few yards back from the margin is quite dry. There
is also a little damp land along the Umatilla, which occasionally
expands into small swampy strip-. In many places along the
hanks of the latter stream there is abundant seepage.
318 IOWA ACADEMY OF SCIENCE
For a distance of one-fourth to more than one-half of a mile
back from the Columbia, the ground rises only from four or
five to fifteen or twenty feet above the water. The soil is here
loose and shifting, largely of water and wind formation. Be-
yond this strip of lowland the country rises rather abruptly
two hundred or three hundred feet higher. This is about the
mean elevation of the territory as far to the southward as our
observations extended. There are higher points here and there
and numerous depressions, but on the whole the country is not
particularly rough.
Two or three miles southeast of the town is the end of a long
lava ridge, extending for some miles to the southwestward. In
many places it appears double, as if it had been upheaved and
split. It rises from one hundred to two hundred feet above the
general level of the country. On the eastern side of this ridge
is a depression containing a chain of apparently perennial pools
or ponds, none covering an area of more than an acre at the
date of our visit. They are fed by small springs, and are all
rather strongly alkaline.
On the west side of the Umatilla there is a considerable strip
of land of about the same elevation as that lying along the Co-
lumbia. This has mostly a gradual rise to the westward.
On the whole, the area covered by these observations pre-
sents no great variety of soil conditions aside from water sup-
ply. The low strip along the Columbia and Umatilla rivers is
very sandy, much of the sand being loose and shifting. It has
doubtless been brought up largely from the sandy margin of
the Columbia by the strong winds that blow almost constantly
up stream. These winds sweep with great force across the angle
formed by the confluence of the two streams on the wrest side of
the Umatilla, and here there are many low shifting dunes.
Along the lava ridge the ground is, of course, strewn with frag-
ments of this material ; otherwise throughout most of the ele-
vated area the soil is made up mainly of water-worn gravel,
fine sand, and volcanic dust. In some places the vegetation in-
dicates the presence of a certain amount of alkali, but this is
not abundant except in the above mentioned depression where
the ponds are located.
Aside from water supply, probably the most important factor
in determining the character of the vegetation in any of the
A FLORA IN NORTHERN OREGON 319
areas we have described is the exposure to winds. Nearly all
the taller plants in the less protected situations are bent very
perceptibly to the eastward, the prevailing winds being from
the west; this is notably true of trees and shrubs that have
been planted in the town.
We will now consider briefly the various associations of
plants that are found in these several situations. These forms
that occur very sparingly in any locality, or are much more
characteristic of one of the other associations are omitted from
tlic list for that locality.
The species occurring along the immediate margin of the Co-
lumbia, or at least within the direct influence of the copious
water supply are as follows :
Marsilia vestita Veronica peregrina
Juncus bufonius Verbena hastata
Salix amygdaloides Iva axillaris
Salix exigua Euthamia occidentalis
Polygonum emersum Coreopsis atkinsoniana
Roripa columbiae Gaillardia aristata
Roripa curvisiliqua Helenium autumnale grandiflorum
Roripa obtusa Artemisia dracunculoides
The Marsilia is extremely abundant. The willows form low
thickets in places, which are nowhere very extensive. Roripa
columbiae is a peculiar species, of very limited distribution, ap-
parently mainly confined to the banks of the Columbia in east-
ern "Washington and Oregon; it is not common here. The
Coreopsis, Gaillardia, Helenium, and Artemisia are especially
plentiful. Several introduced plants, especially the Russian
thistle and Atriplex hastata are common here, but are more char-
acteristic of the next higher association. This list is a very
short one, in spite of the abundance of moisture. This is due
largely to the fact that the land here is nearly all below high
water mark, and the late floods prevent many species from se-
curing a foothold.
Between the moist margin of the river and the more elevated
country, lies the low sandy tract above mentioned. The soil
here is dry but not excessively so, and supports a fairly distinct
iciation of plants, though several of the species are equally
characteristic of the higher section. Here we find :
320 IOWA ACADEMY OF SCIENCE
Oryzopsis hymenoides Elymus condensatus
Sporobolus cryptandrus .Tuncus balticus
Salsola kali tragus Grindelia nana
Atriplex hastata Chrysothamnus viscidiflorus
Lepidium medium Artemisia canadensis
Gaura parviflora Artemisia ludoviciana
Anogra pallida Artemisia tridentata
Verbena bracteosa
The Oryzopsis is remarkably abundant. The Russian thistle
here attains its maximum size. The Chrysothamnus is extreme-
ly abundant and is quite generally distributed, while the sage-
brush, though covering a more limited area, grows in places
very rank. That such species as J uncus balticus and Gaura
parviflora- should appear in the same association as sagebrush
seems a little strange. The anomaly is perhaps owing to the
combination of sandy soil, hot, dry winds, and close proximity
to the river. The plants of this section suffer more, it would
seem, from the direct effects of the wind, than any others of
the region. Species with delicate foliage cannot survive here,
and low forms are likely to be buried by the drifting sand.
The vegetation of the slope leading up to the higher land is
scant and mostly short, this being also much exposed to the
wind. Sagebrush is here almost wanting; there is an abund-
ance of very dwarf Chrysothamnus viscidiflorus, Achillea mille-
folium lauulosa, Amsinckia intermedia,, and Bromus tectorum,
while la rue areas are whitened over with PI an to go purshii.
Where there is an abundance of fine loose sand piled into low
dunes by the wind, there may be found here and there large
patches of Cleome lutea and Psoralea lanceolata scabra, and a
scattered growth of a peculiar dune grass, Elymus flaveseens.
The elevated section, by far the most extensive in area, did
not yield a very long list of species. While the total of indi-
vidual plants is sufficiently large, nearly all of them are so
dwarfed as to form but a scant mantle of vegetation. Over
tracts many acres in extent one may scarcely find a plant of any
sort rising to a height of more than two feet. Another pecu-
liarity of the species of this region is their "mosaic" mode of
growth. One will come abruptly upon a certain form dis-
tributed in immense abundance over a considerable area of
land, but when this is crossed, the species leaves off as abruptly,
and perhaps another takes its place in equal profusion. Usual-
ly no particular reason for this phenomenon can be assigned.
At the time of our visit the spring vegetation of ephemeral an-
A FLORA IN NORTHERN OREGON 321
At the time of our visit the spring vegetation of ephemeral an-
nuals and weak perennials had disappeared. This, however,
must have been very scant, or it would have left more traces.
I was told by residents that early spring flowers were here al-
most wanting. The following belong in this association:
Festuca octoflora Lupinus ornatus
Bromus tectorum Erodium cicutarium
Agropyron subvillosum Linum lewisii
Sitanion sp. Euphorbia glyptosperma
Comandra pallida Piscaria setigera
Rumex venosus Sphaeralcea munroana
Polygonum majus Mentzelia laevicaulis
Eriogonum niveum Mentzelia albicaulis
Eriogonum baileyi Opuntia polyacantha
Salsola kali tragus Epilobium paniculatum
Abronia mellifera Pteryxia terebenthina
Sisymbrium altissimum Gilia inconspicua
Kunzia tridentata Coldenia nuttallii
Piptocalyx circumscissus Chrysothamnus viscidiflorus
Solanum triflorum Chrysothamnus nauseosus
Nicotiana attenuata Erigeron hispidissimus
Plantago purshii Balsamorhiza sagittata
Ptiloria paniculata Achillea millefolium lanulosa
Gaertneria acanthicarpa Artemisia tridentata
This list is remarkable not only for its brevity, but also for
the scant representation or total absence of a number of great
genera that dominate most of the other arid sections of eastern
Oregon. Among these may be mentioned Erigonum, Arabis,
Astragalus, Cogswellia, Grilia, and Erigeron.
The only association that remains to be considered is that of
the damp ground along the Umatilla river. We might at first
thought expect to find here the same species that occur along
the Columbia, but in fact we meet with not only ATery different
forms, but a far greater variety. These are mostly Transition
species which, while having plenty of moisture, are protected by
their situation from the floods and winds to which those growing"
along the Columbia are» exposed. The margins of the Umatilla,
then, may be looked upon as forming a very narrow strip of
Transition territory extending down to the lowest level of the
Upper Sonoran that is to be found anywhere in the state. Many
of the species are poorly represented, as might be expected from
the smallness of the area. Even with these omitted, however, the
31
322
IOWA ACADEMY OF SCIENCE
list is very long in proportion to those of other associations.
It is as follows :
Typha latifolia
Potamogeton lonchitis
Potamogeton pusillus
Alisma plantago-aquatica
Paspalium distichum
Panicum crus-galli
Phleum pratense
Polypogon monspeliensis
Sporobolus asperifolius
Agrostis alba
Agrostis exarata
Deschampsia calycina
Deschampsia elongata
Poa annua
Poa pratensis
Poa compressa
Distichlis spicata
Hordeum murinum
Hordeum jubatum
Elymus condensatus
Cyperus inflexus
Scirpus americanus
Eleocharis palustris
Eleocharis acicularis
Carex praegracilis
Carex athrostachya
Lemna minor
Juncus balticus
Juncus bufonius
Juncus tenuis
Vagnera stellata
Salix sp.
Populus trichocarpa
Alnus rhombifolia
Mentha canadensis
Verbascum thapsus
Pentstemon richardsonii
Veronica peregrina
Veronica americana
Mimulus pilosus
Mimulus langsdorfii
Mimulus floribundus
Verbena hastata
Solanum dulcamare
Solanum nigrum
Urtica holosericeus
Rumex mexicana
Rumex crispus
Polygonum aviculare
Chamopodium botrys
Alsine media
Clematis ligusticifolia
Ranunculus sceleratus
Ranunculus cymbalaria
Ribes aureum
Roripa nasturtium
Rosa pisocarpa
Potentilla rivalis
Crataegus brevispina
Thermopsis montana
Melilotus albus
Trifolium pratense
Trifolium repens
Trifolium hybridum
Trifolium sp.
Medicago lupulina
Hosakia americana
Rhus glabra occidentalis
Rhus toxicodendron
Malva rotundifolia
Hypericum scouleri
Epilobium adenocaulon
Berula erecta
Centaurion exaltatum
Lycopus lucidus
Plantago major
Galium aperine
Symphoricarpos racemosus
Agoseris heterophylla
Taraxacum taraxacum
Iva axillaris
Xanthium speciosum
Solidago serotina
Euthamia occidentalis
Bidens cernua
Gnaphalium palustre
The irrigation of a considerable tract has brought about the
establishment of a number of introduced species, which are
mainly confined to cultivated ground and irrigation ditches.
A FLORA IN NORTHERN OREGON 323
Iii concluding this brief account of the distribution of the
flora in the neighborhood of Umatilla, it may be said that there
are few other sections of moderate elevation in the state where
the vegetation is so poor in species and so scant in quantity.
and that this poverty doubtless is due to the low annual precipi-
tation, high summer temperature, strong winds, and loose, light
character of the soil. Omitting the vegetation of the river
banks and cultivated ground, the flora is pronouncedly Upper
Sonoran. Perhaps no better example of the zone is to be found
in Oregon.
The following is a complete list of the species identified, with
brief notes as to abundance, distribution, etc.
Typha latifolia L. Plentiful along the Umatilla.
Potamogeton lonchites Tuck. Rather common in the Umatilla
and in irrigating ditches.
Potamogeton pusillus L. Extremely abundant' in the Umatilla
and in irrigating ditches. In the latter it grows in such
quantities as to completely choke them up, and must fre-
quently be cleaned out.
Alisma plant ago-aquatic a L. Common in mud along the Uma-
tilla.
Paspalum distichum L. Plentiful in places on the banks of the
Umatilla where there is abundant seepage.
Panicum crus-galli L. Common in damp, especially cultivated
ground.
Panicum barbipulvinatum Nash. Very common along irrigating
ditches.
Oryzopsis hymenoides (R. and S.) Rick. This remarkable grass
is one of the most abundant of the family in this locality.
It grows in large, dense tufts that apparently persist for
many years. It is most plentifully distributed on the dry
sandy strip bordering the immediate banks of the Columbia,
but is also scattered over the high arid section.
Phleum pratense L. Frequent in moist ground.
Polypogon manspeliensis (L.) Desf. Very abundant in wet
places along the Umatilla.
Sporobolus depauperatus (Torr.) Scrib. Common on gravellv
bars along the Columbia. A very depressed and dwarf
form.
324 IOWA ACADEMY OF SCIENCE
Sporobolus crypto nclrus (Torr.) Gray. Common in dry sandy
places near the Columbia and Umatilla.
Sporobolus asperifolius (Nees and Mey.) Thurb. Found in
abundance in a moist, slightly alkaline depression along the
Umatilla.
Agrostis alba L. Common along the Umatilla and in irrigated
ground.
Agrostis exerata Trin. Occasional on the margin of the Uma-
tilla.
Deschampsia calycina Presl. Abundant along the Umatilla.
Deschampsia elongata (Hock.) Munro. Frequent along the Uma-
tilla.
Eragrostis hypnoides (Gam.) B. S. P. Infrequent along the.
Umatilla.
Poa annua L. Common in damp places.
Poa compressa L. Common, with the preceding.
Poa campestris L. Common, with the preceding.
Distichlis spicata (L.) Greene. Found plentifully in severa\
moist, more or less alkaline places.
Festuca octoflora Walt. This is one of the very abundant spe-
cies over the dry elevated sections. It is very short lived
and dwarfed.
Festuca megalura Nutt. Found sparingly in sandy ground near
the Columbia.
Festuca elatior L. Found occasionally near the Umatilla and
along irrigating ditches.
Bromus sp. An apparently native perennial in damp ground ;
scarce.
Bromus tectorum L. The most plentiful grass, distributed in
enormous abundance over almost the entire area studied,
without regard to soil or moisture conditions.
Agropyron smithii mollis (Scrib. and Sm.) Jones. In dry
ground ; scarce.
Agropyron subvillosum (Hook.) Piper. In dry ground: infre-
quent. '
A FLORA IN NORTHERN OREGON 325
Horde um murinum L. Frequent on moist banks of the Uma-
tilla.
Hordeum jubatum L. Frequent along the Umatilla.
Hordeum nodosum L. Scarce, in moist ground near the Uma-
tilla,
Etymus condensatus Presl. Frequent in small patches in moist
places along the Umatilla, but seldom covering more than
a very limited area.
Elymus sp., possibly arenarius. Infrequent, in loose sand.
Etymus flavescens Scribn. and Sm. A curious grass, the downy
yellow spikes very conspicuous ; growing rather scantily on
drifting sand.
Sitanion sp. Frequent in very dry ground. A form remarkable
for its dense, soft pubescence.
Cy perns in flex us Muhl. Common in wet places along the Uma-
tilla.
Cyperus escidentus L. In moist ground; scarce.
Scirpus occidentalis (Wats.) Chase. Scarce, along the Uma-
tilla.
Scirpus amcricanus Pers. Very abundant on wet margins of the
Umatilla.
Hemicarpha micrantha (Vahl.) Britt. One specimen, in wet
ground along the Umatilla.
Eleocharis palustris (L.) E, and S. Very abundant along the
margins of the Umatilla.
Eleocharis obtusa Schult. One specimen, near the Umatilla.
Eleocharis acicularis (G.) R. and S. Common along the Uma-
tilla.
Car ex douglasii Boott. A few plants in slightly moist ground
near the Columbia.
Carer praegracUis Boott, Found plentifully in one place among
cat tails along the Umatilla.
Carex athrostachya Oln. Frequent along the Umatilla.
Lemna minor L. Very common along the Umatilla.
Juncus balticus Willd. Plentiful in slightly moist ground along
the Columbia and less so near the Umatilla.
IOWA ACADEMY OF SCIENCE
is bufonius L. Abundant in damp ground.
J uncus tei o Willd. Common in damp ground.
us torreyi Coy. Scarce, along the Umatilla.
J uncus oxymeris Eng. Scarce, near the Umatilla.
Vagnera stdlata (L.j Morong. Plentiful in one place in a damp
thicket on the bank of the Umatilla.
Asparagus officinalis L. Sparingly escaped along the Umatilla.
Salix amygdaloides Anders. Abundant in places along the Co-
lumbia, reaching a height of ten to twelve feet and forming
close thickets. It also occurs plentifully along the Umatilla.
becoming much larger.
Salix exigua Xutt. Frequent with the preceding along the
lumbia.
Salix sp. An undetermined species past fruiting ; common along
the Umatilla and sometimes forming close thickets.
Populus trichocarpa T. and G. Frequent along the Umatilla, and
probably more so formerly. Some of these trees grow about
a swampy place close to the town and have attained a good
size.
Alnus rhonibifolia Xutt. Rather plentiful along the Umatilla.
douglasii Planch. One or two specimens were found on a
high dry slope above the Umatilla.
TJrtica holosericeus Xutt. Frequent along the Umatilla, the
plants remarkably tall and robust.
indra pallida A. DC. Common and quite generally dis-
tributed in the high arid sections.
ms Pursh. Very plentiful in places, especially in
loose, dry sand.
Eumex mexicanus Meisn. Common in moist ground along the
Umatilla.
nex crispus L. Very common in moist ground.
arioides L. Scarce, in wet places along the Uma-
tilla.
Polygonum aviculare L. Common in moist ground.
Polygonum majus ^Meisn.) Piper. Common and generally dis-
tributed through the arid section.
.: ft] Britt Fi I "
along :mbia and Umatilla.
Polygonum lep^f L . - .
vnum £
L th the 1
J - •: ~ - -
• rt. Over - • - ~ •
ally dry and : is :
lor and
spieuou -
fcs.
_: . .inf.
I -
a few spec-i:
er dry ground.
Hi With the poss
B . this is 1 ,
t of our tercii [t 1
margin of
■ ; s
Atrii --.it a L. Abundant in nearly all ? _
ground, especial
■i- album L. Crnunon in all bul
■ '.. » streams
J.5r<ww i I >ugL ^~<?ry eomm -
sand.
7 : 7 :n abundance in .
lumbia.
ETook. I:: - -
Umatilla.
'f!a.
ly on the margin of alkaline pot -
-.".--'. \' --
Umatilla.
328 IOWA ACADEMY OP SCIENCE
Bat nidi ium aquatile (L.) Wimm. A large flowered form was
found in a pool along the Umatilla.
Ranunculus sceleratus L. Frequent along the Umatilla.
Ranunculus Cymbalaria Pursh. Abundant in wet places.
Roripa nasturtium (L.) Rusby. Common along the Umatilla.
Roripa columbiae Suks. Scarce ; a few specimens found in mud
along the Columbia.
Roripa curvisiliqua (Hook.) Bessey. Frequent in damp ground.
Roripa obtusa (Nutt.) Britt. Infrequent, in mud along the
Columbia.
Sisymbrium altissimum L. Very abundant and generally dis-
tributed, being found nearly everywhere in the desert.
Sisymbrium canesens Nutt. Occasional along the Umatilla.
Bursa bursapastoris (L.) Weber. Common about houses.
Lepidvum medium Greene. Abundant in slightly moist ground.
Cleome lutea Hook. One of the most conspicuous plants of the
region. It grows in great abundance on drifting sand,
attaining a height of five to six feet, with stems an inch in
diameter.
Ribes aureum Pursh. Found in a few places along the Uma-
tilla.
Rosa pisocarpa Gray. Common along the Umatilla.
Potentilla rivalis Nutt. Common in damp places along the
Umatilla.
Potentilla permollis Ryd. One specimen, near the Umatilla.
Kunzia tridentata (Pursh.) Spreng. Common and quite gen-
erally distributed in the desert. It is mostly dwarfed and
depressed.
Crataegus brevispina (Dougl.) Heller. Quite plentiful along
the Umatilla, where in places it forms dense thickets.
Petalostemum ornatum Dougl. Common and generally dis-
tributed in dry ground.
Melilotus al bus Desr. Extremely abundant in moist ground,
especially along irrigating ditches.
Trifolium longipes Nutt. Scarce, in damp places near the Uma-
tilla.
Trifolium pratense L. Frequent in moist ground.
A FLORA IN NORTHERN OREGON 329
Trifolium repcns L. Common in moist ground.
Trifolium hybridum L. Frequent in moist ground.
Trifolium spinulosum Dougl. One specimen, in damp ground
along the Umatilla. Our material seems sufficiently dis-
tinct from Trifolium fimbriatv/m to merit recognition.
Trifolium spinulosum Dougl. Frequent along the Umatilla.
Medicago lupulina L. Frequent in damp ground.
Medicago saliva L. Alfalfa is practically the only crop grown
in the area under consideration. It is common as an es-
cape wherever there is sufficient moisture.
Psoralen laneeolata scabra (Nutt.) Piper. Abundant in dry,
drifting sand.
Glycyrrhiza lepidota Nutt. Common in moderately dry
ground.
Hosackia americana (Nutt.) Piper. Scarce, in slightly moist
ground.
Astragalus succumbens Dougl. Scarce, in dry sandy ground.
GeraniuHi carolineanwm L. Scarce, along the Umatilla.
Erodium cicutarium (L.) L'Her. Very abundant throughout
the dry area.
Linum leivisii Pursh. Scarce, in moderately dry ground.
Euphorbia glyptosperma Eng. The most characteristic desert
annual. Hundreds of acres are reddened over by the pecu-
lar tinge of the foliage.
Piscaria setigera (Hook.) Piper. Sparingly distributed in dry
ground.
Rhus glabra occidentalis Torr. Found plentifully in one place
along the Umatilla.
Rhus toxicodendron L. Occurs sparingly along the Umatilla.
Malva rotundifolia L. Common in cultivated ground.
Sphaeralcea munroana (Dougl.) Spach. Infrequent, on high
dry ground.
Hypericum scouleri Hook. In a few places along the Umatilla.
Mentzelia laevicaulis (Dougl.) T. & G. In a few places on dry
slopes.
l/< nizelia albicaulis Dougl. Common and generally distributed
in the desert.
330 IOWA ACADEMY OF SCIENCE
Opuntia polyacantha Haw. Abundant in arid sections, but of
uneven distribution, being quite wanting over large areas
and in some places the dominant species.
Gaura parviflora Dougl. Common especially in the sandy
strip along the Columbia.
EpiloMum angustifolium L. One small specimen along the
Columbia.
EpiloMum paniculaium Nutt. Infrequent in moderately dry
ground.
Epilobium adenocaulon Haussk. Very common in wet ground.
Oenothera biennis muricata (L.) Lind. Two specimens were
found along the Columbia representing, apparently, two
strikingly different "mutants" of this confused group.
Anogra pallida (Lindl.) Britt. An abundant and character-
istic species of the low sandy strip along the Columbia.
Boisduvalia densiflora (Lindl.) Wats. Found sparingly along
the Umatilla.
Myriophyllum sp. In alkaline pools; scarce.
Daucus pusillus Michx. Scarce, along the Umatilla.
Pteryxia terebinthina (Hook.) C. & R. Frequent in dry sand.
Berula erect a (Huds.) Cov. Frequent in swampy places.
Centaurion exaltatus (Griseb.) Wight. Very common in wet
places.
Asclepias speciosa Torr. Scarce, in damp ground.
Asclepias mexicana Cov. Scarce, in moderately dry ground.
Phlox sp. A single specimen in dry soil.
Gilia inconspicua (Smith) Dougl. Frequent, in moderately
dry soil.
Navarretia intertexta (Benth.) Hook. Scarce, in damp ground
near the Umatilla.
Phacelia sp. Common in moderately dry to very dry ground.
Conanthus parviflorus Greenm. Infrequent, in dry ground.
Coldenia nuttallii Hook. Frequent in dry ground.
Heliotropinm curassavicidum L. Abundant in slightly moist,
usually somewhat alkaline soil.
A FLORA IN NORTHERN OREGON 331
Amsinckia intermedia Fisch. & Mey. Abundant in dry soil.
Piptocalyx circumscissus (Hook. & Am.) Torr. Scarce, in dry
ground.
Marrubium vulgare L. Frequent, in moderately dry ground.
Lycopus lucidus Turcz. Common in wet ground along the
Umatilla.
Mentha canadensis L. Abundant in wet ground.
Verbascum thapsus L. Common in moderately dry ground
near the Umatilla.
Verbascum blattaria L. Scarce, along the Umatilla.
Pentstemon richardsonii Dougl. A remarkable and handsome
species, occurring in considerable quantities on moist basal-
tic outcroppings along the Umatilla.
Ilysnathes dubia (L.) Bern. Scarce, along the Umatilla.
Veronica peregrina L. Common in moist places.
Veronica americana Schwein. Found sparingly along the Uma-
tilla.
Mimulus pilosus (Benth.) Wats. Frequent along the Umatilla.
Mimulus longsdorfii Donn. Very common in wet places.
Mimulus floribundus Dougl. Frequent in wet ground along
the Umatilla.
Verbena bracteosa Michx. Abundant in moderately dry ground,
especially along the Columbia.
Verbena hastata L. Common in slightly damp ground, espe-
cially along the Columbia.
Solatium dulcamare L. Frequent in thickets along the Uma-
tilla.
Solanum nigrum L. Frequent along the Umatilla.
Solanum triflorum Nutt. One of the very abundant and char-
acteristic species of the desert ; very generally distributed.
Nicotiana attenuata Torr. Very common in rather dry ground.
Orobanclie comosa Hook. Found in only one place; parasitic
on the roots of Tva axillaris.
Plantago major L. Infrequent, along the Umatilla.
332 IOWA ACADEMY OF SCIENCE
Plantago purshii Roem. & Schult. Very abundant in the more
arid parts, sometimes imparting a gray appearance to
large areas of ground.
Galium aperine L. In one place along the Umatilla.
Sambwcus glauca, Xutt. In one place along the Umatilla.
Vahriaix lla macrocera (T. & G.) Gray. In one or two places
in slightly moist ground near the Columbia.
Dipsacus sylvestris Mill. "Well established but not common
along the Umatilla.
Cichorium intybus L. In cultivated ground; scarce.
Ptiloria paniculata (Nutt.) Greene. Common in moderately
dry ground.
Symphoricarpos racemosus Michx. In one or two places near
the Umatilla.
Agoseris lieteropliylla (Xutt.) Greene. Scarce, in moist places.
Taraxacum taraxacum (L.) Karst. Frequent, in damp ground.
Lactuca scariola integrator (Gren.) Godr. Very abundant, espe-
cially in rather dry ground along the Columbia.
Lactuca pulchella (Pursh) D. C. Scarce, along the Columbia.
Sonchus asper (L.) Hill. Frequent, in moist ground.
Iva axillaris Pursh. Abundant in slightly moist, often alka-
line ground along the Columbia and Umatilla.
Xanthium speciosum Kearn. Common along the Columbia and
Umatilla.
Xanthium oligacanthus Piper. Scarce, along the Umatilla.
A curious species, seemingly of very limited distribu-
tion.
Gaertneria acanthicarpa (Hook.) Britt. Very plentiful in
moderately dry ground.
Grmdelia nana Nutt. Common along the Columbia.
Chrysopsis cillom (Pursh) Nutt. Along the Columbia; rather
scarce.
Chrysothamnus viscidiflorus (Hook.) Nutt. The most abundant
of the shrubby Composite ; to be regarded as the dominant
desert species. Almost universally present, and only oc-
casionally yielding precedence to any other form.
A FLORA IN NORTHERN OREGON 333
Chrysothamnus nauseosus (Pall.) Britt. Common in the desert
section, but much less so than the preceding, and often
wholly wanting.
Solidago serotina Ait. Common along the Umatilla.
Euthamia occidentalis Nutt. Abundant in damp ground.
Tmvnsendia florifer (Hook.) Gray. Scarce, in dry ground.
Erigeron hispidissirmus (Hook.) Piper. Frequent in dry ground.
Rays always white.
Erigeron poliospermus Gray. Though Umatilla is the type lo-
cality of this species, it seems to be very scarce, only one
specimen being found. Very dry ground.
Erigeron canadensis L. Very common in moist or moderately
dry soil.
Machaeranthera attenuata Howell. Scarce, in dry ground.
Lagophylla ramosissima Nutt. Frequent in moist to moderately
dry ground.
Bidens rulgata Greene. Common along streams and ditches.
Bidens cernua L. Common, with the last.
Coreopsis athinsoniana Dougl. Very common along the Co-
lumbia.
Balsamorliiza sagittata (Pursh.) Nutt. Frequent in very dry,
sterile ground.
Heliantkus annuus L. Frequent in moist ground.
Chaenactis doitglasii (Hook.) H. & A. Infrequent, in dry soil.
Gaillardia aristata Pursh. Very common along the Columbia.
Helenium autunvnale grandiflorum (Nutt.) Gray. Common
along the Columbia.
Achillea millefolium lanulosa (Nutt.) Piper. Abundant
throughout the arid section.
Artemisia dracunculoides Pursh. Abundant along the Colum-
bia and in other moist places.
Artemisia canadensis Michx. Frequent along the Columbia.
Artdnis-ia ludoviciana Nutt. Rather common along the Colum-
bia. A form witli mostlv entire leaves.
334 IOWA ACADEMY OF SCIENCE
Artemisia tridentata Nutt. Sagebrush is abundant but not
evenly distributed, being often nearly absent in large
areas. It is mostly low and dwarfed, reaching its best
development on the low strip along the Columbia, and
elsewhere in depressions where the moisture conditions are
.a little better than common.
'GiMJcplialium palustre Nutt. Common along the Umatilla.
Gnaphalium chilense Spreng. Scarce, in moderately dry places.
Carduus lanceolatiis L. Common in moist ground.
Carduus undulatus Nutt. Found in rather dry ground in only
a few places.
Willamette University,
.Salem, Oregon.
A SEED KEY TO COMMON WEEDS 335
A SEED KEY TO SOME COMMON WEEDS AND PLANTS.
E. L. PALMER.
INTRODUCTION.
The aim of this thesis is three-fold. Primarily, it is written
to furnish a method of determining accurately the names of
various seeds and seedlike fruits with the express purpose of
detecting adulterants in commercial seeds. The key should
also aid in determining plants in the fruiting condition when
the flower parts are too far advanced for identification by the
ordinary method. Further, it should serve as a check to de-
terminations from a study of the flowers.
The terms "weeds" and "seeds" may be variously inter-
preted. A weed has been defined as "a plant out of place" or
better still as a "useless or troublesome plant." Using the
latter interpretation, the author chose those plants which were
listed as troublesome weeds in the publications of various
agricultural experiment stations. A few other wild plants
were added and as special attention was paid to the adulter-
ants of the seeds of Red Clover, White Clover, Alsike Clover,
Alfalfa, Timothy, and Red Top, these seeds were inserted in
the key. The term ' ' seeds ' ' was interpreted in the broad sense
and includes not only true seeds but seedlike fruits such as are
found on Taraxacum officinale Weber (Dandelion), Arctium
minus (Burdock) ; etc. The botanical nomenclature used is
the same as that found in the seventh edition of "Gray's New
Manual of Botany" 1908.
LITERATURE.
Quite a few publications have been made in connection with
seed study. The work of Harz seems to be the most thorough
of these. It deals principally with the anatomy, histology and
chemical properties of various seeds. The bulletin of W. J.
Beal entitled "The Seeds of Michigan Weeds," 1910, gives
accurate descriptions of the more common weeds of Michigan.
Excellent illustrations by Mr. F. H. Hillman serve as a check
336 IOWA ACADEMY OF SCIENCE
to the descriptions. Mr. Hillman also is the author of Farmers'
Bulletin 428, 1911, U. S. D. A., which gives valuable lists of
adulterants of commercial seeds. He also has published num-
erous other bulletins but the author considers the above men-
tioned the most comprehensive. ''The Seeds of the Blue
Grasses," Bulletin 84 of Bureau of Plant Industry, U. S. D. A.,
1905, by Edgar Brown and P. H. Hillman, includes a key to
the seeds of six species of Boa as found in commercial seeds.
Aside from this last mentioned paper, no literature has been
found which concerns itself with a key which will aid in the
systematic determination of different seeds.
METHODS OF STUDY.
The specimens studied were collected for the most part dur-
ing the summer and fall of 1911. These were carefully labelled
with the common and scientific names. An attempt was then
made to describe each seed carefully, using the external char-
acters which were most evident with the use of an ordinary
hand-lens. From these descriptions and with the use of the
specimens constantly for reference, the key was constructed.
Drawings were used in preference to photographs because it
was believed that by them the distinguishing characters could
be brought out to a better advantage. The seeds of the grasses
were described as they appear with the glumes or scales re-
moved, at least where these are easily removed by rubbing
between the thumb and fore-finger. Seeds vary considerably
and where there was any doubt as to which one of two descrip-
tions would serve, the seed was entered under both headings.
In this way the opportunities of misinterpretation were mini-
mized. A given seed may be entered many times, due to its
variations. This might appear to be a bad condition of affairs
and lead one to believe that better distinguishing characters
might have been chosen. A trial of the key in actual testing,
however, should prove to the individual that the arrangement
into distinct groups according to size facilitates the quick
determination of a seed. It should be noted that even in the
most complex instance but twenty steps are required to make
tlic determination.
A SEED KEY TO COMMON WEEDS 337
THE USE OF THE KEY.
To secure satisfactory results, the key should be used with
the drawings as a guide to correct interpretation. To deter-
mine a given seed, first rub it vigorously between the thumb
and fore finger to remove any loose scales or flower parts
which may be adhering. Now determine the length in mili-
meters exclusive of any fragile terminal appendage and turn
to the group which would include a seed of that length. In
this group are two other groups numbered (II). Determine
in which of these the seed belongs and continue in a like man-
manner until the name of the seed is found. If any char-
acter is not plain turn to the picture of a seed described as
having that character.
The writer wishes to thank Prof. W. W. Rowlee, Dr. H. B.
Brown and Mr. H. P. Brown for advice and criticism during
the progress of the work.
Descriptions of Seeds Given in the Key.
Abbreviations: (L)=Length; (W)=Width; (C)=Color;
(S)=Shape; (0)=Occurence as an adulterant.
1. Digitaria sanguined is (L.) Scop. Crab Grass, Finger
Grass. L. 1.8 — 2.2 mm. W. .6 — .8 mm. C, light straw to brown
or dull green. S., broad spindle shaped to blunt especially at
the base; boat shaped; the scar on one side running about one-
half the length of the seed : outer chaff usually present, the
outer scale being as long as the seed and three-ribbed, the
inner about one-half the length of the seed. "Edges of floral
groove smooth" Beal. O., sometimes very troublesome, com-
mon in clover grass and alfalfa seeds. Introduced from
Europe. For drawing see Harz p. 1258, fig. 166, XXIII-XXV.
2. Panicum capillars L. Old Witch Grass. Tickle Grass, L.
1.2 — 1.8 mm. W. .8 — 1.5 mm. C, greenish yellow, glossy, dark
in the middle and lighter at the ends. S., oval to elliptic and
slightly flattened ; glume with five fine longitudinal nerves,
inner glume with two fine longitudinal lines. 0., a common
tumbleweed, common in alfalfa and the grasses ; rather unim-
portant. Native.
3. Echinochloa cruss-galli (L) Beauv. Barn-yard Grass. L.
2.2 — 3.2 mm. W. 1.3 — 2.8 mm. C, shining gray brown to
22
338 IOWA ACADEMY OF SCIENCE
straw colored. S., oval in outline with one side flat and the
other convex; surface smooth. O., common, especially on
waste ground, in gardens, etc. Native.
4. Setaria glauca (L) Beauv. Yellow Fox-tail, Pigeon
Grass. L. 2.5 — 3.4 mm. W. 2. — 2.8 mm. C, dark brown or
straw colored. S., flattened oval, tapering almost equally at
each end : one side flat or sometimes slightly concave, the other
side quite convex. The concave side has coarser ridges, the
flat side being occupied by a sunken area. At one end, a
slight elevation is evident. Surface covered with minute
lateral striations. The extremities are blunt and the seed is
widest at the middle. 0., very common in gardens, bother-
some; commonly found in alfalfa, red clover and many other
kinds of farm seeds. Introduced from Europe.
5. Setaria viridis (L) Beauv. Green Foxtail, Bottle-grass,
Green Pigeon Grass. L. 1.8 — 2.5 mm. W. 1.2 — 2. mm. C, dull
pale green to gray-brown often mottled with black. S., oval,
flattened on one side and concave on the other; surface with
fine longitudinal and transverse striations and a small rounded
projection at the basal end: resembles Setaria glauca but is
smaller and differs in that the flat side lacks the sunken area.
0., common in many farm seeds much the same as Setaria
glauca. Especially common in alfalfa, timothy and red clover
seeds. Introduced from Europe.
6. Phlcum pratense L. Timothy, Herd's Grass, L. 1.2 — 1.8
mm. W. .7 — 1. mm. C, light straw to yellow. S., broad fusi-
form with the base slightly oblique and the surface reticulated
with oblong ridges or shallow pits. 0., common in grass
lands, cultivated. Introduced from Europe.
7. Agrostis alba. L. White Marsh Bent Grass, Red Top,
Herd's Grass, Fiorin. L. .8 — 1.2 mm. W. .4 — .7 mm. S.,
spindle shaped, almost elliptical, broad with one end pointed
and the other rounded ; scar short and rounded and not more
than i/4 the length of the seed: palea two-nerved and lemma
three-nerved, nearly equalling the glumes. 0., common in
grass lands and cultivated. Introduced from Europe. See
Harz, p. 1262, fig. 167, I-IV.
8. Eragrostis megastachya (Koeler) Link. Stink Grass,
Snake Grass. L. .4 — .8 mm. "W. .3 — .5 mm. C. red-yellow
A SEED KEY TO COMMON WEEDS 339
to dark brownish red. S., broadly oval and slightly flattened
with each end slightly pointed; very finely netted with dark
lines. 0., common in waste land. See Beal. Fig. 15. Intro-
duced from Europe.
9. Poa pratcnsis L. June Grass, Spear Grass, Kentucky
Blue Grass. Length of floret 3.0 — 4.4 mm., of the seed 1.1 —
1.5 mm. Width of seed .4 — .8 mm. C, light brown. S., equal-
ly three-sided in cross section with a shallow groove on one
side ; surface finely hairy at the angles ; angles quite distinct ;
quite long and attenuate at the apex. Introduced from
Europe.
9a. Poa compressa L. Canada Blue Grass. This grass very
closel}T resembles Poa pratensis L. and is used as an adulterant
of the same. According to Hillman and Brown, Bull. 84, IT.
S. D. A., Bureau of Plant Industry, it differs principally in that
the intermediate veins of the glumes are distinct in Poa praten-
sis L. and indistinct in Poa compressa L.
10. Glyceria nervata (Willd) Trin. Fowl Meadow Grass,
Beard Grass. L. .6 — 1. mm. W. .4 — .5 mm. C, black with
silvery reticulations. Very broadly elliptic or spindle-shaped
with a short acutely tipped apex ; base with a short blunt tip ;
surface irregularly wrinkled. 0., common in marshy regions;
found in seeds of alsike clover. Introduced from Europe.
11. Bromus secah'nus L. Chess, Cheat. L. 5.8 — 7.2 mm.
W. 2.2 — 2.9 mm. C, dark brown or flesh colored. S., oval,
at least in general outline, very deeply heart-shaped in cross
section or spindle-shaped with a broad very deep groove up
one side: ''floral glume rounded on the back and obscurely
seven nerved; palea with a single row of stiff hairs; club-
shaped rachilla distinguishes it from the cultivated grasses."
Hillman. 0., common in seeds of cereals and large seeded
grasses especially in orchard grass; sometimes found in the
clovers. See Beal, fig. 7. Introduced from Europe.
12. Laportea canadensis (L) Gaud. "Wood Nettle. L. 2.8 —
3.8 mm. W. 2.5 — 3. mm. C, dark brown to black. S., almost
circular but with two short projections on the edge rather
near each other but diverging, pronouncedly flattened. O.,
not a bad weed in crops but common in lowlands. Native.
13. Rumex crispus L. Narrow-leaved or Curled Dock. L.
1.2 — 2.2 mm. W. .7 — 1.4 mm. C, dark brown to reddish
340 IOWA ACADEMY OF SCIENCE
brown. S., triangular in cross section with acute angles;
abruptly obtuse at the base and rather attenuate at the apex
(not as attenuate at the apex as Rumex obtusifolius). 0., the
commonest Rumex in farm seeds, found chiefly in blue grass,
orchard grass and red clover. Introduced from Europe.
14. Rumex obtusifolius. L. Broad leaved or Bitter Dock.
L. 1.8 — 2.4 mm. W. .8 — 1.4 mm. C, light reddish brown
or tan and shining. S., triangular in cross section; rather at-
tenuate at the apex and more contracted at the base ; sides
convex or slightly so ; angles near the base slightly concave,
near the apex convex. 0., sometimes found in farm seeds. In-
troduced from Europe.
15. Rumex Acetosella L. Field or sheep sorrel. L. 1.2 —
1.8 mm. W. .8 — 1.4 mm. C, shining reddish brown. S.,
three-sided in cross section, abruptly tapering to a point at
the apex and rounded at the base; angles rounded and sides
convex. 0., common in red clover, orchard grass and timothy.
Native.
16. Polygonum aviculare L. Knot Grass, Knot-weed. L.
1.8 — 2.4 mm. W. .8 — 1.4 mm. C, dull reddish brown. S.,
unequally three-sided, tapering at the apex to a long acuminate
but at length rounded point; base moderately tapering to a
rounded point; angles rather abrupt and rounded; surface
finely granular in longitudinal striations. 0., of minor im-
portance as a field weed although often found as an adulter-
ant of red clover. Native.
17. Polygonum Persiearia L. Lady's Thumb. L. 2. — 2.8
mm. W. 1.7 — 2. mm. C, shining jet black. S., broadly oval
or round with a short point at the apex and a short pro-
jection at the base; flattened, although the faces are more or
less concave. 0., common in various kinds of farm seeds
especially in red clover. Introduced from Europe.
18. Polygonum rirginianum L. Virginia Knotweed. L.
3.4 — 4.4 mm. W. 1.8 — 2.4 mm. C, shining chestnut brown.
S., chestnut shaped but more attenuate at the base, oval in
general outline ; surface smooth and highly polished. 0.,
common in low and waste grounds. Native.
19. Polygonum Convolvulus L. Wild Buckwheat, Black
Bindweed. L. 2.5—3.5 mm. W. 1.8—2.3 mm. C, dull jet
A SEED KEY TO COMMON WEEDS 341
black. S., triangular in cross section tapering at both ends
to a somewhat attenuate point ; faces somewhat concave. O.,
common in all kinds of farm seeds from all sources, particular-
ly in the seeds of cereals, millet and flax. Introduced from
Europe.
20. Polygonum, scamdens. L. Climbing False Buckwheat.
L. 3.5 — 7.2 mm. W. 3. — 4.8 mm. C, shining jet black. S., tri-
angular in cross section, tapering almost equally at each
end to a point; faces slightly concave; angles slightly rounded.
0., not common. Introduced from Japan.
21. Chenopodium kybridum L. Maple -leaved Goosefoot.
L. 1.2—2.2 mm. W. 1.2—2.2 mm. Thickness .4— .6 mm. C,
shining black or gray. S., almost round with a shallow notch
on one side ; sides equally convex ; a groove on one side lead-
ing from the notch to near the center. 0., not very common,
but often found on waste land. Native.
22. Chenopodium album L. Lamb's Quarters, Pigweed. L.
1. — 1.5 mm. W. .8 — 1.5 mm. C, dull black or shining or
gray. S., circular except for a notch on one side ; one face
nearly flat, the other convex ; the edge rounded. 0., common
in all kinds of farm seeds particularly clover and grass seeds.
Introduced from Europe.
23. Atriplex patula L. Spreading Orache. L. 1.3 — 1.9 mm.
W. 1.4 — 1.7 mm. C, black or dull dark gray speckled with
light gray when the involucre is on ; shining black with the
involucre off. S., nearly circular with a slight notch on one
side ; face nearly flat ; groove on one side running from the
scar towards but not to the center. 0., not common. Intro-
duced from Europe.
24. Amarantlnts retroflexus L. Rough Pigweed. L. .8 — 1.2
mm. W. .6 — .9 mm. C, shining jet black or reddish if im-
mature. S., obovate or broadly oval with a slight notch at
one side of the narrower end ; smooth surface very finely re-
ticulated with fine lines when seen with a low-power micro-
scope. "When seen edgewise the hem-like margin in this
seed is less prominent than in A. graecizans, A. hybridus and
A. blitoides." Beal. 0., common in various kinds of farm
seeds, especially clover and timothy.
25. Anmranthus hybridus h. Slender Pigweed. L. 1. — 1.5
mm. W. .8 — 1.4 mm. C, shining black unless immature and
342 IOWA ACADEMY OF SCIENCE
then reddish, or purplish. S., broadly ovate or nearly circular;
more pointed than A. graecizans; notch on one side of the nar-
rower end; thickest in the middle, curving- convexly to a rather
acute angle. 0., not important ; introduced from Tropical
America.
26. Amaranthus graecizans L. Tumble-weed. L. .6 — 1. mm.
W. .4 — l.mm. Thickness about .3 mm. C, shining jet black.
S., nearly circular, thick at the middle and tapering to a rather
acute angle at the edge ; a notch on one side and fine reticula-
tions on the surface. 0., common in farm seeds, especially
clover. Introduced from Tropical America.
27. Spergula arvensis L. Spurry. Corn Spurry. L. 1.2 — 1.8
mm. W. 1.2 — 1.6 mm. C, black with a narrow yellowish Wing
and a few short yellowish spines. S., broadly lens shaped with a
slight notch on one side, often with two notches close together
at the hilum ; surface with very minute shallow pits. 0., found
in grain fields and light sandy soil. Naturalized from Europe.
28. Arenaria serpyllifolia L. Thyme-leaved Sandwort. L.
.3 — .5 mm. W. .2 — .4 mm. Thickness .2 — .3 mm. C, grayish
black or reddish brown, somewhat lead-colored. S., almost cir-
cular with the exception of a notch at one side ; surface covered
with about seven concentric or eccentric rows of oval-shaped
elevations on each side. 0., common in sand soil and found in
many farm seeds. Introduced from Europe.
29. Stellaria media L. Cyrill. Common Chickweed. L. .8
— 1.2 mm. W. .6 — .9 mm. C, reddish yellow to brown. S.,
disc-shaped, round, almost as thick at the edges as at the center;
surface covered with concentric rows of tubercle-like projec-
tions; a slight notch at one side at the scar. 0., very common
especially in imported and domestic clover seeds. Naturalized
from Europe.
30. Cerastium viscosum L. Mouse-ear Chickweed. L. .6 —
.8 mm. W. .4 — .6 mm. C, reddish yellow-brown with less red
than in Stellaria media. S., somewhat circular or disc-shaped
but quite angled, somewhat wedge-shaped ; surface covered with
concentric rows of tubercle-like projections more pronounced
than in Stellaria media. 0., common in small clover and grass
seeds, "particularly in alsike and timothy from Canada" (Hill-
man). Introduced from Europe.
A SEED KEY TO COMMON WEEDS 343
31. Agrostemma Githago L. Corn Cockle. L. 2.8 — 3.5 mm.
W. 2.5 — 3.3 mm. C, dark brown to black. S., irregularly
round with two broad shallow grooves following the outline of
the cotyledons, quite angular; surface covered with numerous
(about thirty) rows of short rounded elevations. 0., "common
in seeds of cereals, millets, vetches and flax from all sources"
(Hillman). Introduced from Europe.
32. Lychnis alba. Mill. White Campion. L. 1.2—1.8 mm.
W. 1.2 — 1.4 mm. C, dusty yellow with numerous black topped
tubercles. S., short kidney-shaped with about fifteen rows of
tubercles on each side, base of tubercles not notched as in Silene
noctiflora L. 0., rather common along roadsides. Introduced
from the Old World.
33. Silene noctiflora L. Night-flowering Catch-fly. L. 1.2
— 1.8 mm. W. 1. — 1.3 mm. C, gray-brown with a slight red-
dish or pink tinge. S., very short kidney-shaped; flattened
especially on one side ; surface covered with concentric rows of
glandular-like structures. 0., common and often abundant in
seeds of red and alsike clovers. Introduced from Europe.
34. Saponaria officinalis L. Soapwort or Bouncing-Bet. L.
1.8—2.4 mm. W. 1.8—2.4 mm. C, dark bluish black. S.,
short kidney-shaped to circular with a notch on one side; sur-
face covered with concentric rows of tubercle-like projections.
0., sandy land and roadsides; in various farm seeds. Natural-
ized from Europe.
35. PorUtlaca oleracea L. Purslane, Pussley. L. .5 — .8 mm.
W. .3 — .6 mm. C, shining black or sometimes with a purplish
tinge. S., broadly ovate, flattened ; sometimes almost circular
but usally quite pointed near the scar; surface covered with
numerous shallow cavities; one large cavity running from the
scar back along the seed. 0., very common in gardens and in
waste lands. Introduced from the southwest.
36. Ranunculus abortivus. L. Small flowered Crowfoot. L.
.8 — 1.4 mm. W. .6 — 1.2 mm. C, light yellowish brown. S.,
lenticular in cross section, slightly winged around the margin:
a beak at the end short and curved ; surface wrinkled radially
around the margin. 0., not particularly common but very
abundant in certain regions. Introduced from Europe.
37. Ranunculus acris L. Tall Crowfoot or Tall or Bitter
Buttercup. L. 2.5 — 4. mm. W. 2.5 — 3.5 mm. C, dark brown
I l IOWA ACADEMY OF SCIENCE
or yellowish brown, s.. obovate or ovate with a slight curved
beak at the apical end and a narrow wing around the edge;
base set obliquely to the longitudinal axis of the seed: one side
convex, the other nearly flat; thin. (>.. common in lowlands
and fields. Introduced from Europe.
Lepidium rude-rale L. Pepper Wort, Pepper Crass. L.
1.4 — l.S mm. \Y. .6 — 1. mm. C. tan to yellow-brown. S..
obovate, narrowly winged; narrower at the apical end thus
differing from Arabis laevigata; with a groove running down
each side Prom the scar. C. common in clovers and grasses.
[ntroduced from Europe.
39. Capsella Bursa-pastoris. L. Medic. Sheperd's Purse
I. 5 —1.2 mm. W. .2 — .8 mm. C, yellow to reddish brown.
S.j flattened oblong with a longitudinal groove running in a
loop from the base for nearly the whole length of the seed.
0., common in white, alsike and red clovers, also in blue grass,
a pest in alfalfa. Introduced from Europe.
40. Brassica nigra. (L) Koch. Black Mustard. L. 1. — 1.8
mm. AY. 1. — 1.6 mm. ('.. dark reddish brown with a net-
work of lighter lines, s.. only slightly flattened spherical^;
sometimes a trifle angular: surface pitted and covered with a
network of ridges. <).. found in clovers and grass seeds. In-
troduced from Europe.
41. Sisymbrium officinale (L) Scop. Hedge Mustard. L.
.8 — 1.5 mm. W. .3 — .8 mm. ('.. tan or yellowish, greenish
brown. S., quite irregularly oval to oblong, usually more blunt
at the apical end and tapering at the base: a curving line
from the scar down one side follows the outline of the cotyle-
dons, 0., a rather common weed. Introduced from Europe,
42. Barbarea vulgaris. R. Br. Common Wild Mustard. L.
.8 — 1.7 mm. W. .6 — 1.2 mm. C. light brown shining slight-
ly under the microscope. S., flattened oval, irregular and with
a distinct elevation at the sear: surface sparingly covered with
a network o\ fine ridges or pits. Differs from Brassica nigra
in being lighter in color, flatter and in having less pronounced
ridges or pits. 0., common in fields and gardens and in many
seeds. Introduced from Europe.
43. Arabis laevigata Muhl Poir. Rock Cress. L. 1.5 — 1.8
mm. W. .8 — 1. mm. C. tan to yellow-brown. S., flattened
oval to oblong with a small hook at the blunt end; with a
A SEED KEY TO COMMON WEEDS 345
groove extending from the hook back along the sides showing
the location of the cotyledons; winged around the margin;
broadest toward the apical end. ()., not a remarkably bad
weed but rather common. Native.
44. PotentUla monspeliensis var norvegica L. Rydb. Cin-
quefoil, Five Finger. Length .6 — 1. mm. W. .6 — .9 mm. C,
light yellowish brown sometimes slightly shining. S., nearly
round except for a short straight area on one side; sometimes
flattened and Ions-shaped in cross section ; surface covered with
numerous forked ridges or wrinkles. 0., common in alsike
clover and in timothy. Introduced from Eurasia.
45. Agrimania striata Michx. Tall Agrimony. Length of
fruit 5. — 10. mm. including the hooked prickles. W. 4. — 8.
mm. C, reddish brown. S., turbinate or top-shaped with a
crown of hooked prickles; lower part with, about fifteen longi-
tudinal flutings; fruit two-celled and two-seeded; the lower
part slightly hairy. 0.. not a bad weed. Introduced from
Eurasia.
46. Trifolium pratense L. Red Clover. L. 1.5 — 2. mm. W.
1. — 1.4 mm. C, light yellowish to bluish brown. S., some-
what triangular to ovoid; flattened; scar near the center of
one edge: differs from Medicago I a patina in not having the
prominent elevation at the seat-. O. cultivated. See Hillman.
Introduced from Europe.
47. Trifolium repens. L.. White Clover. L., .8 — 1.4 mm.
W., .8 — 1.1 mm. ('.. yellow to brownish red. S., somewhat
shield-shaped; flattened; with a groove extending for a short
distance from the straight or concave end; one end rounded.
0., cultivated. Introduced from Eurasia.
48. Trifolium hyhridum h. Alsike Clover. I... .8 — ■ 1.6 mm.
W., .5 — 1.4 mm. C, dark yellowish green to black. Shape.
almost identical in shape with Trifolium repens differing from
it principally in the color. 0.. cultivated. Introduced from
Europe.
49. Melilotus alba Desr. White Melilot or Sweet Clover.
L.j 2. — 2.4 mm. W., 1.2 — 1.5 mm. (.'.. dull greenish brown
to greenish yellow, usually quite light colored. S.. smooth and
very nearly truly elliptical, with a broad shallow notch near
one end; has a peculiarly sweet odor. 0., found in alfalfa,
and red clove)-. Introduced from Europe.
346 IOWA ACADEMY OF SCIENCE
50. Medicago sativa L. Alfalfa, Lucerne. L., 1.8 — 2.5 mm.
W., 1. — 1.4 mm. C, greenish yellow to brown. S., kidney-
shaped to diamond-shaped with edges less rounded than in
Melilotus alba; slightly thinner and larger than Medicago lupu-
lina and without the prominent elevation near the scar. 0.,
widely cultivated. Introduced from Europe.
51. Medicago lupulina L. Yellow Trefoil, None-such, Black
Medick. L., 1.5 — 2.4 mm. W., .7 — 1. mm. C, yellowish green
or brown. S., flattened oval especially near the scar; with an
elevation near the scar extending beyond the general outline
of the seed. 0., found especially as an adulterant in alfalfa.
Introduced from Europe.
52. Amphicarpa monoica (L.) Ell. Hog Peanut. L., 4.2 —
5.8 mm. W., 3.2 — 4.8 mm. C, purplish black mottled with
gray. S., short flattened oval with the hilum on the edge;
surface smooth. 0., not a bad weed; common in thickets grow-
ing over other weeds. Native.
53. Rhus Toxicodendron L. Poison Ivy. L., 3. — 5.8 mm.
W., 2.8 — 5. mm. C, white or nearly so. S., fruit nearly globu-
lar, seed somewhat kidney-shaped with two flutings on each
side. 0., common in rocky and swamp places, shrubby or
climbing; poisonous. Native.
54. Impatiens biflora Walt. Spotted Touch-me-not. L., 3.8
— 5.8 mm. W., 2. — 3.5 mm. C , usually quite dark reddish
brown. S., oval with a slight beak on one end and four or
sometimes five narrow longitudinal ridges on the sides; some-
what flattened with two ridges on the outer face and one down
each face; surface somewhat wrinkled. 0., common in damp
places and spreading quite rapidly. Native.
55. Abutilon Theoplirasti. Medic. Indian Mallow, Velvet
Leaf. L., 3.2 — 4.4. mm. W., 2.6 — 3.4 mm. C, graying brown.
S., somewhat kidney-shaped to ovoid; resembling Datura but
having a much more pronounced notch; flattened. 0., flat
waste lands and in pastures. Introduced from India.
56. Malva rotmidifolia L. Common Mallow, Cheeses. L.,
1.2 — 2.2 mm. W., 1.2 — 1.8 mm. C, light greenish brown. S.,
nearly circular except for a notch on one side; flattened and
slightly thinner on the side next the notch; seeds borne in
disc -like fruits. Introduced from Europe.
A SEED KEY TO COMMON WEEDS 347
57. Malva moschata L. Musk Mallow. L., 1.8 — 3.2 mm.
W., 1.6 — 3. mm. C, fruit dark gray or brown appearing sil-
very because of numerous hairs, seeds resembling Malva ro-
tundifolia but lighter in color. S., short kidney-shaped or cir-
cular with a notch on one side and a space of apparently differ-
ent texture in the center. 0., common in fields and meadows.
Introduced from Europe.
58. Hypericum, perforatum L. Common Saint John's Wort.
L.. .5 — 1.2 mm. W., .2 — .5 mm. C, dark brown, shining. S.,
abruptly tapering or rounded at the ends; cylindrical; surface
covered with longitudinal rows of minute (about twenty in a
row), indented scales or rectangular markings. 0., very com-
mon and troublesome. Introduced from Europe.
59. Oenothera biennis L. Common Evening Primrose. L.,
1.1 — 2.2 mm. W.. .5 — 1.5 mm. C, brick red. S., very irreg-
ularly 4 — 6 sided, usually sharp angles and flat faces; angles
often winged; surface minutely ridged or wrinkled. 0., quite
common in pastures, common in timothy and found in clover.
Native.
60. Carum Carvi L. Caraway. L., 2.8 — 4.4 mm. W., .7 —
1.4 mm. C., rich yellowish red with six lighter longitudinal
ridges. S., somewhat fusiform with one side slightly concave
and the other broadly convex ; with six longitudinal ridges.
0., not a bad weed, sometimes cultivated. Introduced from
Europe.
61. Daucus Carota L. Wild Carrot. L., 1.5 — 4.8 mm. W.,
.8 — 2. mm. C, light greenish brown with lighter stripes. S.,
flattened hemispherical, oval, with a row of frail edges along
the acute edges and from two to five rows of still more frail
spines running from end to end on the convex surface ; very
variable in size and shape ; in commercial seeds the spines are
often rubbed off. 0., common in red clover and in imported
alfalfa seeds. Introduced from Europe and spreading rapidly.
62. Asclepias syriaca L. Common Milkweed. L., 6. — 8. mm.
including the wing. W.. 3. — 4.2 mm., including the wing.
Thickness, .8 — 1.2 mm. C, light reddish brown. S., ovate,
much flattened ; the base abruptly truncate ; one side slightly
concave and bearing a slight keel in the center extending for
about one-half the length of the seed ; with minute appressed
hairs. 0.. troublesome in pastures.
348 IOWA ACADEMY OF SCIENCE
63. Cuscuta Gronovii "Willd. Gronovius Dodder. L., 1.4 —
1.9 mm. W., 1.2 — 1.8 mm. C, dark brown, granular, dull,
sometimes yellowish. S., almost globular, closely resembling
clover seed but more close and compact ; embryo in a spiral ;
without a noticeable concavity at the scar. 0.. very common
in lowlands. Native.
64. Cuscuta epithymum Murr. Clover Dodder. L., .6 — 1.2
mm. W., .7 — 1. mm. C, variable, usually dusty light brown
to black. S.j irregularly spherical with distinct shallow pits
when seen through a hand microscope ; usually with a fairly
distinct sear at point of attachment; often with two adjacent
flattened areas near the scar. 0.. quite common in clover and
alfalfa.
65. Cuscuta arvensis Beyrich. Field Dodder. L., 1. — 1.8
mm. W., .8 — 1.5 mm. C, quite light pinkish yellow or flesh
colored, rarely dark brown ; with a grayish dusty appearance
under the microscope. S., irregularly spherical; almost in-
variably with two or three adjacent flattened areas on one side
and with the other side rounded regularly. Surface of a gran-
ular appearance. Embryo curled. Surface not prominently
pitted as in C. epithymum Murr. Much lighter in color than
C. Gronovii Willd. 0., found occasionally in red clover. In-
troduced from Europe.
66. Lappula' virginiana (L.) Greene. Stickseed, Beggar's
Lice. L., 3. — 4.4 mm. W., 2. — 2.9 mm. C, dark brown to
black. S., broadly ovate with spines on one side and about
four ridges radiating from an ovate ridge on the other, spines
with bulbous tips. 0., abundant along roadsides and found
as an adulterant of red clover seed. Native.
67. Lithospemtum arvense L. Corn Gromwell, Wheat Thief,
Red Root, Stoneseed. L., 2.5—3.8 mm. W.. 1.8—2.2 mm. C,
light gray-brown with a dark area at the base, dull. S., tur-
binate or somewhat spherical with a long drawn out protuber-
ance at the apical end and a slight keel on the back surface *,
base truncate with two minute tubercles visible to the naked
eye; very hard. 0., found in seed of red clover, alfalfa, ce-
reals, grasses, etc. Naturalized from Europe.
68. Verbena urticae folium L. Nettle-leaved Vervain. L.,
1.5- — 2.2 mm. W.. .5 — .9 mm. ('.. dull dark reddish brown
with a pronounced white spot at one end. S.. oval to oblong,
A SEED KEY TO COMMON WEEDS 349
somewhat four-angled, shorter and broader than Verbi na
hastata. 0.. common along roadsides and found as an adulter-
ant of red clover. Native.
69. Verbena hast at a L. Blue Vervain. L.. 1.7 — 2-4 mm.
W., .4 — .7 mm. C. dull reddish brown. S., oblong to cylin-
drical : one side very convex and with about five narrow longi-
tudinal ridges, the other side made up of two plane faces set
at an angle of about 40 degrees and with a white scar at one
end; shorter and broader than Verbena urticaefolmm. 0., com-
mon in some clovers. Native.
70. Nepeta Cataria L. Catnip. Cat Mint. L.. 1.3 — 1.7 mm.
W., .8 — 1.2 mm. C. and S., dull red with two oval-shaped
white cavities placed end to end near one end of the seed, the cav-
ities being filled with a white cottony substance ; broadly oval
and slightly compressed. 0.. very abundant but not danger-
ously common in clover seeds. Introduced from Europe.
71. Prunella vulgaris L. Self Heal. Heal All. Carpenter
Weed. L.. 2. — 2.6 mm. W., .9 — 1.2 mm. C. shining light or
dark brown. S.. slightly flattened oval tapering at one end
to a small triangular whitish appendage ; with two dark longi-
tudinal lines on each side. 0.. one of the commonest impuri-
ties of clover, alfalfa and grass seeds. Introduced near Wash-
ington from Europe.
72. Leonurus Cardiaca h. Common Motherwort. L.. 2. —
2.5 mm. AY.. .8 — 1.2 mm. C. light or dark brown. S.. one
side rounded, two sides plane with the apex of the seed broader
than the base. 0.. common in waste places. Introduced from
Europe.
73. Datura Stramonium L. Stramonium, Jimson-weed.
Thrrn Apple. L.. 3.-3.8 mm. AY.. 1.7—2.2 mm. C. dark
brown. S.. flattened oval with irregular elevations and pits ;
one edge nearly straight, the rest curved. 0.. found quite com-
r. mly in waste places: poisonous. Introduced from Asia.
71. Verbascum Thapsus L. Common Alullein. L.. .5 — 1.
n m. AY.. .4 — .7 mm. C. usually dark brown, sometimes light.
somewhat cylindrical but of a slightly smaller diameter at
the apical end: surface covered with oval grooves or pits. ""The
p'.:um; surface seems to predominate in Verbascum Blattaria
350 IOWA ACADEMY OF SCIENCE
whrle the grooved surface seems to be more common in Ver-
bascum Thapsus." Beal. 0., very common in meadows and
pastures. Introduced from Europe.
75. Verbascum Blattaria L. Moth Mullein. (See descrip-
tion of Verbascum Thapsus.)
76. Linaria vulgaris Hill. Butter and Eggs, Ramsted, Toad-
flax. L., 1.5 — 2.1 mm., including wing. W., the same. Thick-
ness about .2 — .3 mm. C, dark grayish brown to black. S.,
flat and circular with a broad wing around the margin ; wing
marked with very fine radiating lines ; surface with numerous
rounded elevations. 0., a bad weed in grass lands and pas-
tures. Introduced from Europe.
77. Plantago major L. Common Plantain, Broad-leaved
Plantain. L., 1. — 1.8 mm. W., .5 — 1.2 mm. C, variable shades
of yellow, brown and black. S., very variable, oblong, pyra-
midal, oval or rhomboidal with minute waving markings. 0.,
very common in door yards and found in red clover seeds.
Introduced from Europe.
78. Plantago Bugelii Dene. Rugel's Plantain. L., 1.5 —
2.7 mm. W., .6 — 1. mm. C, dull dark brown to black. S.,
very variable; flattened variously with rather acute angles and
no regular markings, although the surface is finely granular
or roughened. O.., a bad weed, especially in clover and timothy,
also in redtop. Native.
79. Plantago lanceolata L. Rib-grass, Ripple Grass, Eng-
lish Plantain, Narrow-leaved Plantain and Buckhorn. L., 2. —
2.8 mm. W., .8 — 1.2 mm. C, shining amber-brown to black.
S., allantoid in cross section, tapering at the ends; elongate
saucer-shaped with a deep crease running down one side. (See
fig. XV.) 0., very common in grass seed, alfalfa and red
clover. Introduced from Europe.
80. Dipsacus sylvestris Huds. "Wild Teasel. L., 3. — 4.2 mm.
"W, .8 — 1.3 mm. C, dark or light grayish brown and finely hairy.
S., oblong; nearly square in cross section, with three rounded
ridges on each side which unite at the apex; apex slightly hol-
lowed with a tuberele-like projection in the center, base cor-
rugated. 0., common in lowlands and pastures. Naturalized
from Europe.
81. Eupatorium purpureum L. Joe-Pye Weed, Trumpet
"Weed. L., 2.8—3.3 mm. "W., .4— .6 mm. C, dark greenish
A SEED KEY TO COMMON WEEDS 351
brown. S., oblong, four-angled in cross section; contracted at
the base to a sharp point; rather thickly dotted with particles
of resin-like matter. 0., common in lowlands. Native.
82. Eupatorium perfoliatum L. Thorough wort, Boneset. L.,
1.8 — 2.8 mm. W., .2 — .5. C, dark grayish brown with irri-
descent spots. S., oblong, four-angled; contracted at the base
into a rather long drawn out point. 0., common in waste land.
Native. •
83. Erigeron annuus (L.) Pers. Daisy Fleabane, Sweet
Scabious. L., .6 — 1. mm. W., .1 — .4 mm. Color and shape
as in the following species but slightly darker and with the
hairs less evident. 0., quite a bad weed. Introduced from
Europe.
84. Erigeron canadensis L. Horseweed, Butterweed. L.,
.8 — 1.5 mm. W., .2 — .6 mm. C, yellowish white. S., flattened;
somewhat oval and broader at the apical end ; covered with stiff
v.hite hairs. 0., common in alfalfa and along hedge-rows.
Native.
85. Inula Helcnium L. Elecampane. L., 3.8 — 4.8 mm. "W.,
.8 — 1.2 mm. C, light or dark brown. S., linear, four-angled
with about twenty to thirty fine longitudinal lines; base of the
pappus bristles quite persistent. 0., common in rocky pastures
and by roads. Introduced from Europe.
86. Ambrosia trifida L. Giant or C4reat Ragweed. L., 9 —
12 mm. W., 4 — 8 mm. C, dark brown to black. S., thick
spindle-shaped or somewhat turbinate with five to seven very
prominent ribs terminating in points slightly above the middle
of the seed ; beak 2 — 3 mm. long and quite thick at the base.
0.> common in low lands. Native.
87. Ambrosia art emisii folia L. Ragweed, Roman Wormwood,
Hogweed, Bitterweed. L., 2.4 — 4.8 mm. W., 1.1 — 1.5 mm. C,
dark mottled brown. S.. very thick spindle-shaped with from
five to ten lateral ridses terminating in short beaks just above
the middle; terminal beak about 1.5 mm. long. 0., common in
dry meadows and found in alfalfa, red clover and cereals.
Native.
88. Xanthium canadensis Mill. Cocklebur, Clotbur. L.,
Fruit about 18 to 25 mm. long. W., about 10 mm. C, rusty
brown. S., thick spindle-shaped terminating in two stout beaks
352 IOWA ACADEMY OF SCIENCE
and covered with stout hooked spines ; two seeds in each fruit ;
seeds are brown to black and flattened spindle-shaped. 0., com-
mon in waste lands. Native.
89. Xanthium spinosum L. Cocklebur. Like the preceding
species but about one-half the size and with much weaker spines.
90. Heliopsis kelianthoides L. Sweet Ox-eye. L., 4. — 6.4
mm. W., 1.8 — 2.6 mm. C, brown to straw-colored. S.. oblong
wedge-shaped usually very prominently four-angled ; tapering
at the base and abruptly cut off at the apex ; with a very low
collar or elevation at the apex. 0., quite common. Native.
91. Budbeckia hirta L. Black-eyed Susan, Yellow Daisy.
L., 1.5 — 2. mm. W.. .3 — 5 mm. C, dark brown to black. S.,
somewhat four-angled ; tapering from apical end to the base ;
apex concave; with twenty to thirty fine longitudinal lines
composed of numerous small brick-shaped scales placed side by
side. 0., quite widely distributed and found chiefly in tim-
othy seed. Native.
92. Helianthus divaricatus L. "Wild Sunflower. L., 3.8 — •
6.5 mm. W., 1.8 — 2.2 mm. C, brownish black, sometimes gray.
S., obovate and slightly four-angled; pointed at one end. 0.,
common in waste places, thickets, etc., also in alfalfa seeds.
Native.
93. Bidens frondosa L. Beggar's ticks. L., 5 — 15 mm. W.,
2 — 4 mm. C, dull brown blotched with black. S., diamond-
shaped in cross section ; much flattened ; with two or some-
times three slightly diverging awns at the apical end. 0., com-
mon in waste land. Native.
94. Bidens cernua L. Sticktight. L., 3.8—6.4 mm. W., 1.4—3.
mm. C, dark greenish or grayish brown. S., somewhat wedge-
shaped, four sided with a slight groove on each face and four
awns at the apical or broader end. 0., quite common. Intro-
duced from Europe.
95. Galinsoga parviflora Cav. L., 1.2 — 1.6 mm. W., .5 — .7 mm.
C, dark gray or brown with numerous silvery hairs. S.. some-
what pyramid-shaped with four sides; broadest towards the
apex; surface covered with short (.2 mm.) upward pointing
hairs and crowned at the apex with a fairly persistent row of
white chaffy bristles. 0., becoming rapidly abundant about
Ithaca, New York; introduced near the Agricultural College
about 1907. Native of tropical America.
A SEED KEY TO COMMON WEEDS 353
96. Achillea Millefolium L. Yarrow, Milfoil, L., 1.8—2.5 mm.
W., .7 — 1. mm. C, grayish flecked with darker spots. S., flattened
obovoid, sometimes curved : apex abruptly contracted and bear-
ing a tubercle ; surface with numerous very fine longitudinal
striations. 0., rather common in grass seeds. Introduced from
Europe.
97. Anthem is Cotula L. May-weed, Dog Fennel. L., 1.2 — 2.
mm. W., .5 — 1.5 mm. C, light brown or dark straw-colored.
or brown. S., obovoid with about ten ribs composed of tubercle-
like projections ; base tapering into a cone-shaped structure ;
with a small tubercle at the apical end. 0., very common, es-
pecially in timothy, blue-grass and clover seeds. Introduced
from Europe.
98. Anthemis arvensis L. Corn Chamomile. L., 1.4 — 2.5
mm. W., .5 — 1.5 mm. C., light brown or dark straw-colored.
S., somewhat four-angled or rounded in cross section ; apex trun-
cate and concave; base with a rounded knob; with about nine
rounded ridges on the sides. C, quite common in clover seeds.
Introduced from Europe.
99. Chrysanthemum LeucantJiemum L. Ox-eye or White
Daisy, White Weed. L., 1.5—2.4 mm. W., .6 — 1.1 mm. C, dark
background with about ten heavy white ridges giving the whole a
light appearance. S., obovate with ten longitudinal ridges slight-
ly broader at apical end. 0., frequent but not abundant in
clover and small grass seeds. Introduced from Europe.
100. Tussilago Farfara L. Colt's Foot. L., 3.2—4 mm. W., .4
— .6 mm. C, dark gray, appearing silvery because of the covering
of gray hairs. S., narrowly spindle-shaped; more attenuate at
the apex than at the base; with about six rows of long hairs
pointing towards the apical end; circular in cross section. 0.,
not a bad weed but very common in certain places. Introduced
from Europe.
101. Erecht'ites hieracifolia (L.) Raf. Fireweed. L., 2. — 3.1
mm. W., .3 — .5 mm. C, dark brown with lighter markings.
S., spindle-shaped with ten vertical light-colored ridges between
which are minute appressed white hairs ; expanded slightly at
the extreme apex. C, common in certain regions. Native.
102. Senecio vulgaris L. Common Groundsel, Rag-wort,
Squaw-weed. L., 2.4 — 3.6 mm. W., .2 — .5 mm. C, light straw-
colored with vertical rows of white ascending hairs. S., clavate
23
354 IOWA ACADEMY OF SCIENCE
and abruptly truncate at the apex; base long- attenuate; differs
from Tussilago Farfara in being smaller and broader towards
the apex rather than towards the base. 0., quite common in
waste places. Introduced from Europe.
103. Arctium- minus Behr. Burdock. L., 4 — 6 mm. W., 1.8 — 2.8
mm. C, dark brown spotted or mottled with black; with fine
longitudinal dark lines. S., straight or curved; somewhat ob-
long; tapering at the base; with a few narrow longitudinal
ridges. 0., not truly pernicious but common. Introduced from
Europe.
104. Cirsium lanceolatum L. Hill. Common or Bull Thistle.
L., 3. — 4.2 mm. AY.. 1.2 — 2. mm. C, light straw-colored flecked
with blackish markings. S., smooth, slightly flattened, obovate;
apex set at an angle to the longitudinal axis, cup-shaped with in-
curving sides ; base rather abruptly contracted. 0., common in red
clover, alfalfa and grass seeds. Naturalized from Europe.
105. Cirsium ar reuse L. Scop. Canada Thistle. L., 2.2 — 3.4
mm. W., .8 — 1.2 mm. C, rich golden brown. S., obovoid and
slightly flattened, apex truncate and cup-shaped with incurving
edges. 0., found in clover seed. Naturalized from Europe.
106. Centaurea Cyanus L. Blue Bottle, Bachelor's Button.
Corn Flower. L., 3.2 — 4.8 mm. W., 1.8—2.2 mm. 0., shining
white or yellowish gray, sometimes bluish white. S., flattened
cylindrical except that the base is obliquely truncate; apex
abruptly and squarely truncate with a tubercle in the middle ;
pappus bristles quite persistent, 0., common in coarse clover and
grass seeds. Appeared in Ithaca, New York, in 1885 and is grow-
ing more and more abundant each year. Introduced from Europe.
107. Cichorium Intybus L. Common Chicory. Blue Sailors.
L., 2.5 — 3.5 mm. W., .8 — 1.2 mm. C. light yellowish brown,
slightly mottled with black. S., irregularly truncate ; four or five-
angled with two to four faint longitudinal lines on each side ; sur-
mounted by a double row of scales or bristles. 0., found in
clover, alfalfa and grass. Introduced from Europe.
108. Tragopogan porrifolius L. Salsify. L., 10 — 18 mm.
without pappus and 70-80 mm. with pappus. W., 1.8 — 2.3 mm. C,
brownish gray flecked with small whitish scales. S., nearly cylin-
drical but quite spindle-shaped ; tapering and curving at the
A SEED KEY TO COMMON WEEDS 355
apex; ten ribbed, the ribs being composed of diverging scales;
beak slender and from twenty to thirty mm. long. 0., fairly
common. Introduced from Europe.
109. Tragopogon pratensis L. L., 10 — 15 mm. without pap-
pus; 12 — 25 with pappus. W., 1.4 — 2 mm. Color and shape,
almost identical with Tragopogon porrifolius. 0.. common in
rocky fields. Introduced from Europe.
110. Taraxacum officinale Weber. Common Dandelion. L.,
3. — 1.5 mm. without the style. W., .8 — 1.2 mm. C, straw-
colored or dark reddish brown. S., oblanceolate with twelve
to fourteen longitudinal ridges composed of barblike projections
pointed toward the apical end, near which they are clustered ;
beak in two parts, one short and thick and the other two or
three times the length of the achene. 0., very common espe-
cially in grass seeds. Naturalized from Europe.
111. Sanchus oleraceus L. Common Sow Thistle. L.. 2.8 —
3.1 mm. W., 1. — 1.2 mm. C, straw-colored to reddish brown.
S., flattened oval with nine to fourteen fine longitudinal ridges ;
both ends rather abruptly terminated; with transverse wrinkles.
0., rather common in many farm seeds. Introduced from
Europe.
112. Sonchus asper (L.) Hill. Spiny-leaved Sow Thistle. L..
2.2—3.2 mm. W., .8—1.2 mm. C, dull reddish brown. S.,
flattened oval sometimes with a slight wing; sometimes spindle-,
shaped ; with three to five longitudinal ridges on each face. 0.,
rather common. Introduced from Europe.
113. Lactuca scariola L. Prickly Lettuce. L., 3. — 3.8 mm.
W., .7 — 1 mm. C, dull brown and slightly mottled. S., spindle-
shaped, slightly broader towards the apical end, with five to
seven vertical ridges. 0., spreading rapidly and becoming quite
common. Introduced from Europe.
114. Lactuca canadensis L. "Wild Lettuce or Horseweed. L.,
3.3 — 4.8 mm. without the style. W.. 1.5—2.2 mm. C, dusty
black. S., flattened oval with three prominent ridges on each
face ; has the appearance of a winged seed ; beak quite persistent.
0., very common, and often troublesome. Native.
115. Lactuca spkata (Lam.) Hitchc. L.. 3.5 — 5.2 mm. W..
1. — 2.2 mm. C, dark brown. S., flat and irregularly oval with
from ten to sixteen ridges. 0., not particularly common.
Native.
356 IOWA ACADEMY OF SCIENCE
116. Prenanthes alba L. "White Lettuce, Rattlesnake-root.
L., 4. — 6.2 mm. W., .8 — 1.4 mm. C, rich dark brown. S.,
linear oblong, contracted at the base but not at the apex ; some-
what four-angled with seventeen to twenty long striations ; pap-
pus rusty brown. 0., quite common. Native.
117. Hieraciiim aurantiafiim L. Orange Hawkweed, Devil's
Paint-brush. L., 1.8 — 2.4 mm. W., about .3 mm. C, dead
black. S., fluted cylindrical with ten longitudinal ridges which
dilate slightly at the apical end; with very fine hairs about 15
io 20 mm. arranged on the ridges and pointing towards the apical
end. 0., very common in grass seed. Naturalized from Europei.
118. Hieraciiim scabrum. Michx. L., 2. — 2.8 mm. W.,
.2 — .4 mm. Color, dead black. S., fluted cylindrical, expanded
at the extreme apex and more attenuate at the base than
Uieracium aurantiacam; hairs on the ridges also slightly more
numerous. 0., fairly common in pastures. Native.
KEY TO PLATE IX.
Seven-tenths size of original.
I. Sonchus oleraceus L.
II. Cichorium Intybus L.
III. Lactuca spicata (.Lam.) Hitchc.
IV. Arctium minus Bernh.
V. Hieracium scabrum Michx.
VI. Lactuca canadensis L.
VII. Chenopodium hybridum L.
VIII. Cirsium arvense (L.) Scop.
IX. Galinsoga parviflora Cav.
X. Lithospermum arvense L.
XI. Verbena hastata L.
XII. Oenothera biennis L.
Iowa Academy Science
Plate IX
v£a
* 6 *
fH c
\ 1 1
n/VII
KEY TO PLATE X.
Seven-tenths size of original.
XIII. Dipsacus sylvestris Huds.
XIV. Ambrosia trifida L.
XV. Plantago lanceolata L.
XVI. Taraxacum officinale Weber.
XVII. Prenanthes alba L.
XVIII. Tussilago Farfara L.
XIX. Cirsium lanceolatum (L.) Hill.
XX. Nepeta Cataria L.
XXI. Carum Carvi L.
XXII. Asclepias Syriaca L.
XXIII. Bromus secalinus L.
XXIV. Verbascum Thapsus L.
XXV. Prunella vulgaris L.
Iowa Academy Science
a
i;
\
'/
Plate X
xyrji
KEY TO PLATE XI.
Seven-tenths size of original.
XXVI. Anthemis arvensis L.
XXVII. Anthemis Cotula L.
XXVIII. Chrysanthemum Leucanthemum L.
XXIX. Bidens frondosa L.
XXX. Daucus Carota L.
XXXI. Centaurea Cyanus L.
XXXII. Medicago sativa L.
XXXIII. Medicago lupulina L.
XXXIV. Stellaria media (L.) Cyrill.
XXXV. Polygonum Convolvulus L.
XXXVI. Rumex crispus L.
XXXVII. Setaria glauca (L.) Beauv.
XXXVIII. Abutilon Theophrasti Medic.
XXXIX. Barbarea vulgaris R. Br.
XL. Capsella Bursa-pastoris (L.) Medic.
XLI. Amaranthus retroflexus L.
/
Plate XI.
3 64 IOWA ACADEMY OF SCIENCE
KEY TO SEEDS.
I. 10 to 20 mm. long.
1. With more than 1 appendage (figs. XXIX and XIV).
2. Covered with hooked spines.
8. 18 to 25 mm. long XantMum canadensis Hill 88
3. 10 to 13 mm. long XantMum spinosum L. 89
2. With appendages at apical end.
3. With 2 to 4 nearly equal appendages (fig. XXIX)
Bidens frondosa L. 93
3. With more than four unequal appendages or spines at apical
end (fig. XIV) Ambrosia triflda L. 86
I. Without more than 1 long appendage.
2. 10 to 18 mm. long without pappus. Beak 1 to 10 mm. long
Tragopogon porrifolius L. 108
2. Beak short, about 4 mm. long Tragopogon pratensis L. 109
I. 9 to 10 mm. long.
II. At least twice as long as broad.
1. With 2 or 3 long equal terminal appendages (fig. XXIX)
Bidens frondosa L. 93
II. Not twice as long as broad.
1. With numerous (4 to 8) unequal terminal straight appen-
dages (fig. XIV) Ambrosia triflda L. 86
1. With numerous (more than 8) terminal hooked prickles
Agrimonia striata Michx. 45
I. 8 to 9 mm. long.
II. At least twice as long as broad.
1. With 2 or 3 terminal appendages (fig. XXIX)
Bidens frondosa L. 93
II. Not twice as long as broad.
1. With numerous terminal appendages.
2. With 4 to 8 straight appendages (fig. XIV)
Ambrosia triflda L». 86
2. With more than S hooked appendages
Agrimonia striata Michx. 45
1. Without numerous appendages but with a wing
Asclepias syriaca L. 62
1. 7 to 8 mm. long.
II. At least twice as long as broad.
1. With 2 to 4 long terminal appendages, flattish (fig. XXIX)
Bidens frondosa L. 93
1. Without terminal appendages, deeply grooved up one side (fig.
XXIII) Bromxis secalimcs L. 11
II. Not twice as long as broad.
1. Triangular in cross section, shining black (figs. XXXV and
XXXVI) Polygonum scandcns Michx. 20
A SEED KEY TO COMMON WEEDS 365
1. Not triangular in cross section or shining black.
2. With numerous hooked terminal appendages
Agrimonia striata Michx. 45
2. Without terminal appendages but with a wing (fig. XXII)
Asclepias syriaca L. 62
I. 6 to 7 mm. long.
II. Spindle shaped with a deep groove up one side, twice as long
as broad (fig. XXIII) Bromus secaiinus L. 11
II. Not spindle shaped or with but one deep longitudinal groove.
1. Triangular in cross section, shining black
Polygonum scandens Michx. 20
1. Not triangular in cross section.
2. With terminal spines or prickles.
:'.. With not more than 4 awns or prickles.
4. With 4 awns, 4 angles, faces slightly concave
Bidens cernua L. 94
4. With not more than 3 awns, usually 2, faces strongly
1-nerved (fig. XXIX) Bidens frondosa L.
3. With more than 4 terminal prickles usually hooked
Agrimonia striata Michx. 45
2. Without terminal spines or prickles.
"3. Seeds winged (fig. XXII) Asclepias syriaca L. 62
3. Seeds not winged.
4. Uniform rusty brown, not over 1.4 mm. wide (fig.
XVII) Prcnanthes alba L. 116
4. Not uniform, rusty red.
5. Quite pronouncedly 4-faced, angles nearly equal..
Heliopsis helianthoides L. Sweet 90
5. Not pronouncedly 4-faced or equally angled, usually
mottled in color.
6. Usually with 1 or more longitudinal striations
quite angular (fig. IV) . . . .Arctium minus Berh. 103
6. Without longitudinal striations, not angular. . . .
Helianthus divaricatus L. 92
I. 5 to 6 mm. long.
II. At least twice as long as broad.
1. With long terminal awns.
2. With not more than 3, usually 2 straight awns (fig.
XXIX) Bidens frondosa L. 93
2. With 4 awns, 4-angled Bidens cernua L. 94
1. Without long terminal awns.
2. Less than 1 mm. thick, curved with from 10 to 16 longi-
tudinal ridges, dark (fig. Ill)
Lactuca spicata (Lam.) Hitchc. 115
2. More than 1 mm. thick.
3. Uniformly rusty red or gold-brown, less than 1.5 mm.
broad, without a deep groove (fig. XVII)
Prenanthes alba L. 116-
366 IOWA ACADEMY OF SCIENCE
3. Not uniformly rusty red or golden brown, more than 1.5
mm. broad.
4. With a deep groove up one side. . .Bromus seca'.inus L. 11
4. Without a deep groove up one side.
5. Quite pronouncedly 4-faced and uniformly colored
Heliopsis helianthoides L. Sweet. 90
5. Not pronouncedly 4-faced, usually mottled in color.
6. Usually with 1 or more longitudinal striations,
quite angular (fig. IV) .. .Arctium minus Bern. 103
6. Without longitudinal striations, not angular....
Helianthus divaricatus L. 92
II. Not twice as long as broad.
1. Triangular in cross section, shining black
Polygonum scandens Michx. 20
1. Not triangular in cross section.
2. With hooked terminal prickles (Bur)
Agrimonia striata Michx. 45
2. Without hooked terminal appendages.
3. Almost globular white fruit Rhus Toxicodendron L. 53
3. Not globular or white.
4. Short kidney-shaped, flattened, brown, mottled with
purple Amphicarpa monoica (L.) Ell. 52
4. Somewhat fusiform, reddish with 4 or 5 distinct longi-
tudinal ridges Impaticns biflora Walt. 54
I. 4 to 5 mm. long.
II. At least twice as long as broad.
1. Surface shining.
2. Rich chestnut brown, oval Polygonum virginianum L. 18
2. Grayish white, obliquely truncate at base (fig. XXXI)...
Centaurea Cyan us L. 106
1. Surface not shining.
2. With numerous longitudinal notched ridges.
3. Fruit broadest in middle, concavo-convex or plano-con-
vex, oval ridges pronounced and notched entire length
(fig. XXXV) Daucus Carota L. 61
3. Fruit narrow, broadest toward apical end, oblanceolate,
with 12-14 longitudinal ridges pronouncedly notched
near apical end (fig. XVI) Taraxacum officinale Weber 110
2. Without numerous longitudinal notched ridges.
3. Surface smooth, not pronouncedly ridged.
4. Seeds very light-colored, some faintly blotched with
dark (fig. XIX) Cirsium lanccolatum L. Hill. 104
4. Seeds dark, usually mottled.
5. Quite angular, mottled in transverse lines (fig. IV)
Arctium minus Berh. 103
5. Not angular, mottled longitudinally
Hclianthus divaricatus L. 92
A SEED KEY TO COMMON WEEDS 367
3. Surface with longitudinal striations.
4. Fruit very thin but not narrow.
5. Broader towards apex, winged, black with usually
but one longitudinal ridge on each face (fig. VI)
Lactuca canadensis L. 114
5. Broadest toward base or near center, brown, with
two or more longitudinal ridges (fig. Ill)
Lactuca spicata Lam. Hitchc. 115
4. Fruit not thin, nearly as thick as broad.
5. More than 1.5 mm. broad.
6. Quite pronouncedly 4-faced and uniform in color
Heliopsis helianthoides L. Sweet. 90
6. Not pronouncedly 4-faced and usually mottled in color.
7. Usually with 1 or more longitudinal striations,
angular and mottled transversely (fig. IV)
Arctium minus Berh. 103
7. Usually without longitudinal striations, not
angular and if mottled, mottled longitudinally
Helianthus divaricatus L. 92
5. Less than 1.5 mm. broad.
6. Quite pronouncedly curved, tapering at both ends
with about 6 light longitudinal striations (fig.
XXI) •. Carum Carvi L. 60
6. Not pronouncedly curved or tapering at each end.
7. With two deep grooves or three ridges on a
side, comparatively short, quite 4-sided (fig.
XIII) Dipsacus sylvestris Ruds. 80
7. Without deep grooves or with more than 3 ridges
on a side.
8. Distinctly reddish brown, with 17-20 fine lon-
gitudinal striations (fig. XVII)
Prenanthes alba L. 116
8. Not reddish brown, with 20-30 fine longitudi-
nal striations Inula Helenium L. 85
II. Not twice as long as broad.
1. Triangular in cross section, shining black
Polygonum scandens Michx. 20
1. Not triangular in cross section.
2. With numerous terminal appendages or spines
Ambrosia artemisiifoUa L. 86
2. Without numerous terminal appendages.
3. Surface shining.
4. Rich chestnut brown, oval. .Polygonum virginianum L. 18
4. Grayish white, obliquely truncate at base (fig. XXXI)
Centaurea Cyayius L. 106
3. Surface not shining.
4. Fruit globular, white Rhus Toxicodendron L. 53
4. Fruit not globular nor white.
168 IOWA ACADEMY OF SCIENCE
*
5. Very thin, black, winged, with 1-2 fine longitudinal
striations, broadest toward apex (fig. VI)
Lactuca canadensis L. 114
5. Thicker, not winged.
6. Plano-convex or concavo-convex, broadest at mid-
dle, tapering at both ends almost equally (fig.
XXX) Daucus Carota L. 61
6. Not tapering equally at both ends.
7. One side covered with prickles not arranged in
lines, irregular in shape
Lappula virginiana (L.) Greene 66
Without spines.
8. With 4 to 5 longitudinal striations, tapering
more acutely at apex, red
Impatiens biflora Walt. 54
8. Without longitudinal striations, not red.
9. Plump, light brown with purplish blotches,
no prominent notch at hilum
Amphicarpa monoica (L.) Ell. 52
9. Slightly concave on each side with a pro-
nounced notch at hilum, short kidney-
shaped (fig. XXXVIII)
Abutilon Theophrasti Medic. 55
. 3 to 4 mm. long.
II. At least twice as long as broad.
1. With more than one persistent terminal appendage.
2. 1 to 4 awns at apex.
3. Awns y-2 length of achene Bidens cernua L. 94
3. Awn less than y2 length of achene Bidens connata L.
2. With more than 4 terminal appendages.
3. With a double row of chaffy scales at apex (fig. II)
Cichorium IntybuA L. 107
3. With a pappus of capillary hairs at apex.
4. Seed light straw-colored and obliquely truncate at
base, thick set (fig. XXXI) . . .Centaurea Cyanus L. 106
5. Dark brown, very slender and somewhat square in
cross section Inula Helcnium L. 85
3. Terminal appendages short and stiff.
4. Top-shaped with spines arranged in a ring around
the top and with one in the center
Ambrosia artemisiifolia L. 87
4. Somewhat spindle-shaped with 12-14 longitudinal
ridges notched in short spines near apex (fig. XVI)
Taraxacum officinale Weber 110
1. Without more than 1 persistent terminal appendage.
2. Surface shining, rich chestnut brown
Polygonum virginianum L. 18
A SEED KEY TO COMMON WEEDS 369
2. Surface not shining.
3. Surface smooth, not hairy or with longitudinal lines.
4. More than 1.2 mm. wide, not reddish or tan.
5. Light straw-colored (fig. XIX)
Cirsium lanceolatum L. Hill. 104
5. Dark-colored Helianthus divaricatus L. 92
4. Less than 1.2 mm. wide, reddish (fig. VIII)
Cirsium arvense L. Scop. 105
3. SuPface ridged or hairy, not smooth.
4. Less than 1 mm. hroad.
5. Pronouncedly flattened.
6. Very sharp attenuate at apex, dull brown
Lactuca scariola L. 113
6. Not sharply attenuate at apex.
7. Distinctly reddish with fine longitudinal ridges
Sonchus oleraccus L. Ill
7. Brown, with comparatively heavy longitudinal
ridges (fig. XXX) Daucus Carota L. 61
5. Not pronouncedly flattened.
6. Square in cross section.
7. Sharply pointed at base, very slender
Eupatorium purpureum L. 81
7. Not sharply pointed at base or slender
Dipsacus sylvestris Huds. 80
6. Not square in cross section.
7. Very prominently 6- or 7-ridged, curved, usually
greenish, piano- or concavo-convex (fig. XXX)
Daucus Carota L. 61
7. Not prominently 6- or 7-ridged or curved.
8. Light brown, broadest toward apex
Senecio vulgaris L. 102
8. Dark brown, broadest toward middle
Erechtites hieracifolia (L.) Raf. 101
8. Silvery or dark gray, broadest toward base
(fig. XVIII) Tussilago Farfara L. 100
4. More than 1 mm. broad.
5. Surface not pronouncedly ridged.
6. Very light colored, some faintly marked with
dark (fig. XIX) . . . .Cirsium lanceolatum L. Hill 104
6. Not light colored.
7. Quite angular, mottled in transverse lines (fig.
IX) Arctium minus Berh. 103
7. Not angular, mottled longitudinally
Helianthus divaricatus L. 92
5. Surface conspicuously ridged.
6. Distinctly flattened.
7. Black, winged with 1 to 2 ridges on each face
(fig. VI) Lactuca canadensis L. 114
24
370 IOWA ACADEMY OF SCIENCE
7. Dark brown with 10-16 ridges irregularly oval
(fig. Ill) Lactuca spicata (Lam.) Hitchc. 115
6. Not distinctly flattened.
7. Plano-convex or concavo-convex, ridges spiny,
wide (fig. XXX) Daucus Carota L. 61
7. Square in cross section with 2 grooves on each
face (fig. XIII) Dipsacus sylvestris Huds. 80
7. Not square in cross section, very prominently
6- or 7-ridged, ridges not spiny, reddish (fig.
XXI) Carum Carvi L. 60
II. Not twice as long as broad.
1. Triangular in cross section.
2. Black.
3. Shining black, over 3.5 mm Polygonum scanclens L. 20
3. Dull black, less than 3.5 mm. (fig. XXXV)
Polygonum Convolvulus L. 19
2. Not black.
3. Prominently transversely ridged with black or darker
lines Setaria glauca ( L. ) Beauv. 4
3. Surface not transversely striate, shining
Echinochloa Crus-galli L. Beauv. 3
1. Not triangular in cross section.
2. Black or nearly so.
3. Round and markedly shining. . .Polygonum Persicaria L. 17
3. Not round and not markedly shining.
4. Thin and wafer-like, usually winged.
5. Nearly circular without longitudinal striations. . . .
Laportea canadensis (L.) Gaud. 12
5. Oval with 1 to 2 longitudinal striations on each face
(fig. VI) Lactuca canadensis L. 114.
4. Not thin or wafer-like or winged.
5. One side covered with stiff prickles
Lappula virginiana (L.) 66
5. Not as above.
6. Acuminate at one end, not pronouncedly ridged
Helianthus divaricatus L. 92
6. Not acuminate at one end.
7. Surface covered with gray hairs
Malva moschata L. 57
7. Surface not covered with hairs.
8. Nearly as thick as wide, surface with about
30 rows of short rounded projections,
angular Agrostemma Githago L. 31
8. Not nearly as thick as wide, surface with
shallow pits somewhat kidney-shaped
Datura Stramonium L. 73
2. Not black or nearly so.
3. Shining chestnut brown Polygonum virginianum L. 18
3. Not shining chestnut brown.
A SEED KEY TO COMMON WEEDS 371
4. Fruit white and almost globular
Rhus Toxicodendron L. 53
4. Not white or globular.
5. Wafer-like usually with 2 short projections on the
margin, often with a narrow wing.
6. Style bent towards hilum, usually quite dark....
Laportea canadensis (L.) Gaud. 12
6. Style straight or bent away from hilum
Ranunculus acris L. 37
5. Not wafer-like.
6. Shining whitish, noticeably obliquely truncate at
base, pappus quite persistent (fig. XXXI)
Centaurea Cyanus L. 106
6. Not shining white.
7. With longitudinal striations noticeable to eye.
8. With numerous terminal appendages, top-
shaped Ambrosia artemisiifolia L. 87
8. Without numerous terminal appendages.
9. Plano-convex or concavo-convex, striations
prominent and often spiny, greenish
brown (fig. XXX) Baucus Carota L. 61
9. Not as above.
10. Light colored.
11. Plano-convex tapering almost equally
at each end
Echinocliloa Crus-galli L. Beauv. 3
11. Tapering unequally at the ends, not
plano-convex.
12. Surface pitted, short and thick,
hilum dark, apex long alternate,
hard (fig. X)
Lithospermum arvense L. 67
12. Surface not pitted, not short and
thick, apex not long alternate (fig.
XIX) .Cirsium lanceolatum L. Hill 104
10. Dark colored.
11. With four or five marked striations,
not mottled, oval, reddish
Impatiens biflora Walt. 54
11. Usually mottled without marked stria-
tions.
12. Angular and mottled in transverse
lines (fig. IV) . .Arctium minus L. 103
12. Not angular and if mottled, mottled
longitudinally
Helianthus divaricatus L. 92
7. Without noticeable longitudinal striations.
8. Plano-convex, not turbinate or kidney-shaped.
372 IOWA ACADEMY OF SCIENCE
9. With fine transverse striations
Setaria glauca L. Beauv. 4
9. Surface shining without transverse stria-
tions Echinochloa Crus-galli L. Beauv. 3
8. Not plano-convex.
9. Somewhat turbinate, not at all kidney-
shaped, hilum dark, surface light spotted
with dark (fig. X)
Lithospermum arvense L. 67
'9. Not at all turbinate, somewhat kidney-
shaped.
10. Surface shallow-pitted, dark
Datura Stramonium L. 73
10. Surface smooth, not pitted.
11. Usually over 3.2 mm. long, notch at
hilum very deep (fig. XXXVIII)
Abutilon Theophrasti Medic. 55
11. Usually under 3.2 mm. long, notch at
hilum not very deep
Maiva moschata L. 57
I. 2 to 3 mm. long.
II. At least twice as long as broad.
1. Appearing white or nearly so, streaked with dark gray.
2. Flattened Achillea millefolium L. 96
2. Not flattened (fig. XXVIII)
Chrysanthemum Leueanthem urn L. 99
1. Not white or gray.
2. Black or nearly so.
3. Boat-shaped or aUantoid in cross section, shining
(fig. XV) Plantago lanceolata L. 79
3. Not boat-shaped or allantoid in cross section.
4. More than .6 mm. broad.
5. Shaped like a quarter of a cylinder, very regularly
angled, crowned with short gray hairs
Leonurus Cardiaca L. 72
5. Irregularly angled, surface not reticulated, angles
distinct Plantago Rugelii Dene. 78
5. Broad spindle-shaped, blunt at base, flattened on
one side Digitaria sanguinalis (L.) Scop. 1
4. Less than .6 mm. broad.
5. Base drawn out into a long acute point, not jet black.
6. Over 2.8 mm. long, dark green-brown
Eupatorium purpureum L. 81
6. Less than 2.8 mm. long, dark gray-brown
Eupatorium perfoliatum L. 82
5. Base not drawn out into acute base, jet black.
6. Nearly square in cross section, 20 to 30 longi-
tudinal lines Rudbeckia hirta L. 91
A SEED KEY TO COMMON WEEDS 373
6. Not nearly square in cross section with 10 longi-
tudinal ridges Hieracium sp. 117-118
Not black or nearly so.
3. With numerous short terminal appendages and one long
beak, turbinate Ambrosia artemisiifolia L. 86
3. With a double row of short persistent scales at termi-
nal end (tig. II) Cichorium Intybus L. 107
3. Without numerous terminal appendages.
4. Surface markedly shining.
5. Very dark brown, oval, a small whitish appendage
near hihim, tapering at both ends (fig. XXV)
Prunella vulgaris L. 71
5. Light brown or tan, not tapering at both ends, a
cuplike collar at apex (fig. VIII)
Cirsium arvense L. Scop. 105
4. Surface not markedly shining.
5. Surface covered with about 10 longitudinal rows of
tubercle-like projections (fig. XXVII)
Anthemis Cotula L. 97
5. Longitudinal lines if present not composed of tu-
bercle-like projections.
6. Thin and wafer-like, flattened.
7. With a narrow wing, 3 to 5 regular ridges and
broadest near middle
Sonchus asper L. Hill. 112
7. Without a wing, broadest toward apex
Sonchus oleraceus L. Ill
6. Not thin and wafer-like.
7. Plano-convex or concavo-convex.
8. Broad, with longitudinal rows on the surface
usually composed of short bristles, not red-
dish Baucus Carota L. 69
8. Narrow, without many longitudinal rows of
bristles Digitaria sanguinalis (L.) Scop. 1
7. Not plano-convex or concavo-convex.
8. Comparatively short and distinctly triangu-
lar in cross section.
9. Equally 3-sided, angles not rounded
Rumex obtusifolius L. 14
9. Unequally 3-sided, angles slightly rounded
Polygonum avicu:are L. 16
8. Not distinctly triangular in cross section.
9. Light straw-colored, broad at apex, con-
tracted at base, with about 9 longitudi-
nal grooves (fig. XXVI)
Anthem is arvensis L. 97
9. Not light straw-colored or noticeably broad-
er at the apex.
374 IOWA ACADEMY OF SCIENCE
10. .5 mm. or less broad.
11. Light brown, broadest toward the
apex Senecio vulgaris L. 102
11. Dark brown, broadest toward the mid-
dle. .ErecMites Meracifolia (L.) Raf. 101
10. Over .5 mm. broad.
11. With pronounced lateral ridges.
12. With more than 5 prominent ridges,
not square in cross section, dark
surface with lighter ridges (fig.
XXI) ! Carum Carvi L. 61
12. With less than 5 prominent ridges,
somewhat square in cross section,
one face noticeably lighter and a
light scar at hilum (fig. XI)
Verbena hastata L. 69
11. Without prominent lateral ridges...
Cirsium . arvense (L».) Scop. 105
II. Not twice as long as broad.
1. Noticeably triangular or semi-circular in cross section.
2. Semi-circular in cross section.
3. Surface smooth Echinochloa Cras-galli (L.) Beauv. 3
3. Surface not smooth.
4. With lateral striations, usually over 2.5 mm. long (fig.
XXXVII) Setaria glauca (L.) Beauv. 4
4. With lateral and longitudinal striations, usually 2.5
mm. long Setaria viridis (L.) Beauv. 5
2. Not semi-circular in cross section but noticeably triangu-
lar.
3. Dull black, over 2.5 mm. long. .Polygonum Convolvulus L. 19
3. Brown or tan, usually under 2.5 mm. long.
4. Shining, abruptly attenuate at end, angles acute.
5. Sides and angles concave and dipping just back of
apex (fig. XXXVI) Rumex crispus L. 13
5. Sides and angles straight, apex more acuminate..
Rumex obtusifolius L. 14
4. Not shining, angles somewhat rounded, unequally 3-
sided Polygonum avicuJare L. 16
1. Not noticeably triangular in cross section.
2. Thin and wafer-like.
3. White or light gray, obovoid. . . .Achillea millefolium L. 96
3. Not white or light gray.
4. Black or blackish.
5. Shining, almost round Polygonum Persicaria L. 17
5. Not shining.
6. With a broad wing all around periphery
Linaria vulgaris Hill. 76
A SEED KEY TO COMMON WEEDS 375
6. With a narrow wing and two projections, the
style bent towards hilum
Laportea canadensis L. Gaud. 12
4. Not black or blackish.
5. Margin rounded Polygonum Persicaria L. 17
5. Margin acute Ranunculus acris L. 37
2. Not thin and wafer-like.
3. Surface shining.
4. Flattened.
5. Round Chenopodium hybridum L. 21
5. Not round.
6. Black, broadly spindle formed
Polygonum Persicaria L. 17
6. Not black, shield shaped. .. .Trifolium pratense L. 46
4. Not flattened.
5. With a small white appendage at base (fig. XXV)
Prunella vulgaris L. 71
5. Dark disk at base, turbinate. .Lithos per mum arvense 67
3. Surface not shining.
4. Diameter from end to end nearly uniform, somewhat
4-angled.
5. Dark brown and comparatively thick
Verbena urticaefolium L. 68
5. Light brown and comparatively slender
Verbena hastata L. 69
4. Diameter not uniform from end to end.
5. Black or nearly so.
6. Covered with bristling gray hairs (fruit)
Malva moschata L. 57
6. Not covered with gray hairs.
7. More than 2.5 mm. long. .Agrostemma Githago L. 31
7. Less than 2.5 mm. long
Saponaria officinalis L. 34
5. Not black or nearly so.
6. Pointed at least at one end.
7. Plano-convex or concavo-convex with longitudi-
nal striations, oval (fig. XXX)
Daucus Carota L. 61
7. Not plano-convex or concavo-convex.
8. Distinctly red-brown.
9. Coat closely fitting, irregularly or regu-
larly triangular in cross section, reddish
brown (fig. XXX) Daucus Carota L. 61
9. Coat loosely fitting, angles slightly winged
Oenothera biennis L. 59
8. Not red-brown.
9. Broadest at apex, light straw-colored with
about 9 longitudinal lines (fig. XXVI)..
Anthemis arvensis L. 98
376 IOWA ACADEMY OF SCIENCE
9. Broadest toward base, turbinate, base very
dark (fig. X) . . . . Lithospermum arvensc L. 67
6. Not pointed at either end.
7. With longitudinal striations or sharp angles.
8. Dark brick-red Oenothera biennis L. 59
8. Not dark brick-red.
9. Plano-convex or concavo-convex, greenish
brown (fig. XXX) Daucus Carota L. 61
9. Not plano-convex or concavo-convex, light
straw-colored, blunt at the ends (fig.
XXVI) Anthemis arvensis L. 98
7. Without longitudinal striations.
8. Flattened or concave on two sides.
9. Covered with short hairs (fruit)
Malva moschata L. 57
9. Not covered with short hairs.
10. With a narrow wing, almost round, thin
at edges Ranunculus abortivus L. 36
10. Without a narrow wing, thick at one
edge, thinner at the other.
11. No angles, edges rounded, faces con-
cave with outer coat on
Malva moschata L. 57
11. Faces plane with outer coat on, darker
than next preceding. .Malva rotundifolia L. 56
8. Not flattened or concave, faces slightly convex.
9. With a short distinct elevation near scar
reaching beyond the normal outline of the
seed (fig. XXXIII) . . .Medicago lupulina L. 51
9. Without. a short distinct elevation at scar
extending beyond normal outline of seed.
10. Kidney shaped or angular usually with
deep concavity near scar (fig. XXXII)
Medicago sativa L. 50
10. Almost uniformly oval.
11. Usually over 2 mm. long, notch near
one end Melilotus alba Desr. 49
11. Usually under 2 mm. long, notch near
the center of one side
Trifolium pratense L. 46
I. 1 to 2 mm. long.
II. At least twice as long as broad.
1. Black or nearly so.
2. Rounded alike at both ends, bisymmetric when cut trans-
versely; surface appearing granular but composed of
rectangular markings Hypericum perforatum L. 58
2. Not rounded at both ends or bisymmetric when cut trans-
versely.
3. Quite pronouncedly square in cross section.
A SEED KEY TO COMMON WEEDS 377
4. Angles acute, base contracted to a sharp point
Eupatorium perfoliatum L. 82
4. Angles slightly rounded, apex slightly rounded, base
not contracted to a sharp point. .Rudbeckia hirta L. 91
4. Angles rounded, seed like a four sided pyramid with
short white hairs, not over 1.6 mm. long (fig. IX)
Galinsoga parviflora Cav. 95
3. Not pronouncedly square in cross section.
4. Fluted cylindrical in shape, usually over 1.8 mm.
long Hieracium sp. 117-118
5. Quite attenuate at base. .Hieracium scabrum Michx. 118
5. Abruptly contracted at base
Hieracium aurantiacum L. 117
4. Not fluted cylindrical in shape.
5. Over 1.1 mm. long.
6. Pyramid or cone-shaped with numerous short
white hairs, pappus of chaffy bristles when
present (fig. IX) Galinsoga parviflora Cav. 95
6. Irregularly angled, surface not covered with hairs,
no pappus, not reticulate, granular
Plantago Rugelii Dene 78
5. Under 1.1 mm. long. .Glyceria nervata (Willd.) Trin. 10
1. Not black or nearly so.
2. Nearly triangular in cross section.
3. With more than 3 prominent longitudinal striations
(fig. XXX) Daucus Carota L. 61
3. With but 3 prominent longitudinal striations.
4. Rich dark reddish, comparatively short.
5. Surface shining, angles distinct, sides nearly equal
Rumex obtusifolius L. 14
5. Surface dull, angles sometimes rounded, especially
toward base Polygonum aviculare L. 16
4. Light brown, comparatively long, a shallow groove on
one side, angles often hairy Poa pratensis L. 9
2. Not triangular in cross section.
3. Appearing white or light gray.
4. Thin and wafer-like, white with darker markings. .
Achillea Millefolium L. 96
4. Background dark with 10 heavy white longitudinal
ridges, not wafer-like (fig. XXVIII)
Chrysanthemum Lcucanthemum L. 99
3. Not appearing white or light gray.
4. Thin, wafer-like, cream-colored.
5. With a slight margin around the edge, translucent,
"usually under .9 mm. long" B., sometimes slightly
over 1 mm Erigeron annuus (L.) Pers. 83
5. Without noticeable margin with noticeable hairs,
"usually over .9 mm. long." Beal
Erigeron canadensis L. 84
378 IOWA ACADEMY OP SCIENCE
4. Not thin, wafer-like and cream-colored.
5. Angular or angles distinct.
6. Very light straw-colored with about 9 rounded
longitudinal ridges (fig. XXVIII)
Anthemis arvensis L. 98
6. Not light straw-colored.
7. Distinctly square in cross section, very dark
brown to black.
8. Angles acute, base drawn into an attenuate
point almost uniform in diameter except at
base, pappus capillary, over 1.8 mm. long. .
Eupatorium perfoliatum L. 82
8. Angles not acute, pappus of chaffy bristles,
surface hairy, not uniform in diameter, te-
trahedonal, under 1.8 mm. long (fig. IX)..
Galinsoga parviflora Cav. 95
7. Not distinctly square in cross section.
8. Plano-convex or concavo-convex in cross sec-
tion.
9. With 2 to 5 rows of frail spines on convex
surface, longitudinal ends not attenuate,
lines pronounced (fig. XXX)
Daucus Carota L. 61
9. Without longitudinal rows as above, ends
attenuate Digitaria sanguinale Scop. 1
8. Not plano-convex or concavo-convex with lon-
gitudinal striations.
9. Cone shaped, with numerous gray hairs
and pappus of chaffy bristles (fig. IX)
Galinsoga parviflora Cav. 95
9. Not cone shaped or hairy.
10. With longitudinal ridges or angles.
11. Comparatively thick set, dark, see de-
scription. .. .Verbena urticaefolium L. 68
11. Comparatively slender and light (fig.
XI) Verbena hastata L. 69
10. Without marked longitudinal striations.
11. Surface finely reticulate
Plantago major L. 77
11. Surface granular, not reticulate
Plantago Rugelii Dene. 78
•".. Not angular.
6. Surface shining.
7. Not at all uniform in diameter.
8. Uniform in shape, one end pointed, usually
with a whitish triangular appendage (fig.
XXV) Prunella vulgaris L. 71
S. Not uniform in shape.
A SEED KEY TO COMMON WEEDS 379
9. With a slight groove down each side, va-
riously colored. Sisymbrium officinale Scop. 41
9. Without a groove on each side, surface
finely reticulate Plantago major L. 77
7. Quite uniform in diameter.
8. With a slight groove down each side, va-
riously colored. .Sisymbrium officinale Scop. 41
8. Without a groove on each side.
9. Almost circular in cross section, surface
with rectangular markings
Hypericum perforatum L. 58
9. Not circular in cross section, surface finely
reticulate Plantago major L. 77
6. Surface not shining.
7. Compressed.
8. With a groove on each side.
9. Groove indicated by a loop or double line,
not over 1.3 mm. long (fig. XL)
Capsella Bursa-pastoris L. Medic. 39
9. Groove indicated by a single line.
10. Groove running out on to one end
Sisymbrium officinale L. Scop. 41
10. Groove ending on the face of the seed,
broader Lepidium ruderale L. 38
8. Without a groove on each side.
9. Surface finely reticulate. .P'.antago major L. 77
9. Surface not reticulate.
10. Light straw-colored and spindle-shaped.
11. Scar on one side extending about one-
half length of seed, seed not under 1.6
mm. long. . . .Digitaria sanguinale Scop. 1
11. Scar on one side short, not more than
one-fourth length of seed, seed not
over 1.2 mm. long
Agrostis alba Schrad. 7
10. Not light straw-colored or spindle-
shaped.
11. Not at all kidney-shaped, usually dark
brown to black, Plantago Rugclii Dene. 78
11. Usually kidney-shaped and usually not
dark brown to black.
12. With a short distinct elevation near
scar reaching beyond the normal
outline of the seed (fig. XXXIII)
Meclicago lupulina L. 51
12. Without a short distinct elevation
at scar extending beyond normal
outline of seed.
380 IOWA ACADEMY OF SCIENCE
13. Kidney-shaped or slightly angular,
usually with a deep concavity
near scar (fig. XXXII)
Medicago sativa L. 50
13. Almost uniformly oval.
14. Usually over 2 mm. long, notch
near one end
Melilotus alba Desr. 49
14. Usually under 2 mm. long, notch
near center of one side
Trifolium pratense L. 46
7. Not compressed.
8. With about 10 ribs composed of tubercle-like
projections, broader at apex, dark (fig.
XXVII) Anthemis Cotwla L. 97
8. Without ribs composed of tubercle-like pro-
jections.
9. With about 9 prominent rounded longitudi-
nal ridges, light straw-colored (fig.
XXVIII) Anthemis arvensis L. 98
9. Without 9 prominent rounded ridges.
10. Surface finely marked throughout.
11. Diameter nearly uniform, ends round-
ed with rectangular markings
Hypericum perforatum L. 58
11. Diameter not uniform, reticulated
longitudinally, irregularly shaped...
Plantago major L. 77-
10. Surface not finely marked throughout.
11. Dark brown.
12. Cone- or tetrahedral-shaped, usually
with white hairs, broadest at one
end (fig. IX)
Galinsoga parviflora Cav. 95
12. Irregularly shaped, no hairs, not
broadest at one end
Plantago Rugelii Dene. 78
11. Light straw-colored, spindle-shaped.
12. Scar on one side extending at least
one-third length of seed, seed usu-
ally over 1.7 mm. long
Digitaria sanguinale Scop. 1
12. Scar on one side extending only
one-fourth length of seed, seed
under 1.4 mm. long
Agrostis alba Schrad. 7
II. Not twice as long as broad.
1. Distinctly triangular in cross section.
A SEED KEY TO COMMON WEEDS 381
2. With more than 3 longitudinal ridges, greenish in color
(fig. XXX) Daucus Carota L. Gl
2. With 3 or less longitudinal ridges.
3. Equilateral or very nearly so.
4. Without pointed ends, angles sometimes indistinct,
never over 2 mm. long Rumex Acctosella L. 15
4. With pointed ends, angles very distinct, apical end
sharp pointed, basal end blunt pointed, shining.
5. Rarely under 2 mm. long, less shining than the
following species, apex more acuminate
Rumex obtusifolius L. 14
5. Usually about 2 mm. long, shiny, apex not attenu-
ate, angles dip slightly just back of apex (fig.
XXXVI ) Rumex crispus L. 13
3. Not equilateral.
4. Light straw-colored.
5. Over 1.5 mm. long Setaria viridis K. Braw. 4
5. Less than 1.5 mm. long Agrostis alba L. 7
4. Not light straw-colored.
5. Seed coat loosely fitting, irregularly shaped, brick
red (fig. XII) Oenothera biennis L. 59
5. Seed coat tightly fitting.
6. Surface granular, usually black
Plantago Rugelii Dene. 78
6. Surface finely striate.
7. Usually over 1.8 mm. long with a remnant of
calyx at one end, other end quite acuminate,
striations quite straight
Polygonum aviculare L. 16
7. Usually under 1.8 mm. long, irregularly shaped,
striations wavy, variously colored
Plantago major L. 77
1. Not triangular in cross section.
2. Black or nearly so.
3. Round with a wing.
4. Wing very broad, seed very thin
Linaria vulgaris Hill. 76
4. Wing narrow, seed thick Spergula arvensis L. 27
3. Without a wing.
4. Shining markedly.
5. Slightly pointed at opposite ends, fairly thick edges
rounded Polygonum Persicaria L. 17
5. Not pointed at opposite ends.
6. Calyx persistent, when rubbed off seeds slightly
flattened on both faces.
7. One side flattened more than the other, margin
not always rounded, slight curved groove on
one side Chenopodium allnim L. 22
382 IOWA ACADEMY OF SCIENCE
7. Equally flattened or convex, margin rounded,
no groove but a slight notch present (fig. VII)
Chenopodium hybridum L. 21
6. Calyx not markedly persistent, seeds strongly con-
vex on both faces.
7. Seeds almost perfectly round in outline, rarely
over 1.2 mm. long. . . . Amaranthus graecizans L. 26
7. Seeds not perfectly round in outline, broadly
ovate.
8. Angle at margin very marked, usually larger
than next following species
Amaranthus hybridus L. 25
8. Angle at margin indistinct, usually smaller
(fig. XLI) Amaranthus retroflexus L. 24
4. Not shining, dull.
5. Not at all round, angles quite distinct.
7. Surface with fine reticulations. .Plantago major L. 77
6. Surface granular, not reticulate
Plantago Rugelii Dene. 78
5. Round or nearly so.
6. Surface covered with concentric rows of small
tubercle-like projections giving a granular ap-
pearance, somewhat kidney-shaped
Saponaria officinalis L. 34
6. Surface quite smooth.
7. Broadly notched at one side, not lens-shaped..
Trifolium hybridum L. 48
7. Notch slight, somewhat lens-shape.
8. With calyx present, lines of calyx run trans-
versely entirely across the seed; with calyx
off a "groove runs from the side to the
notch" Atriplex patula L. 23
8. With calyx present, lines of the calyx run
radially; with calyx off, a groove runs from
notch to center of the face of the seed ....
Chenopodium album L. 22
2. Not black or nearly so.
3. Shining surface.
5. Over 1.8 mm. long.
5. Pronouncedly compressed, broad oval or kidney-
shaped.
6. Black Polygonum Persicaria L. 17
6. Not black Trifolium pratense L. 46
5. Not pronouncedly compressed.
6. Usually with a whitish appendage at base, not
flattened on one side (fig. XXV)
Prunella vulgaris L. 71
6. Flattened slightly on one side, without appendage
Setaria viridis L. Beauv. 5
A SEED KEY TO COMMON WEEDS 383
4. Under 1.8 mm. long.
5. Light straw-colored, slightly flattened on one side,
see description Panicum capillare L. 2
5. Not light straw-colored.
6. With a pronounced groove running up one side
and onto the end. . . .Sisymbrium officinale Scop. 41
6. Without a groove.
7. Surface finely reticulate Plantago major L. 77
7. Surface finely pitted Barbarea vulgaris R. Br.
3. Surface dull.
4. Surface covered with pits or tubercle-like projections
easily visible with hand lens.
6. Shallow pitted or granular.
7. Granular, usually flesh-colored, light
Cuscuta arvensis Beyrich 65
7 Distinctly pitted, not flesh-colored.
8. Irregularly flattened; convex at scar with a
slight concavity on either side near scar
(fig. XXXIX) Barbarea vulgaris R. Br. 42
8. Not flattened markedly, scar not as noticeably
convex, duller in color than the next preced-
ing Brassiea nigra L. Koch. 40
6. Deeply pitted in longitudinal rows (fig. XXIV)
. .Verbascum Thapsus 74 or Verbascum Blattaria 7.~>
5. Surface with tubercle-like elevations.
6. Round to short kidney-shape.
7. Distinctly red in color, usually not over 1.2 mm.
in diameter, somewhat angular with about 5
rows of tubercles on each face (fig. XXXIV)
Stellaria media L. Cyril. 29
7. Not usually distinctly red in color, over 1.2 mm.
in diameter.
8. Background of seed brown, rarely reddish, not
angular, short kidney-shaped
Silene noctiflora L. 33
8. Background of seed distinctly black or dark
gray, somewhat more angular and larger
than next preceding Lychnis alba Mill. 32
6. Seeds not at all kidney-shaped, ridges not dis-
tinctly tubercled (fig. XXIV)
Verbascum Thapsus L. 74 or Verbascum Blattaria L. 75
4. Surface not pitted or tubercled.
5. Wafer-like, thin especially at the edges.
6. With longitudinal lines (fig. XXX)
Daucus Carota L. 61
6. Without longitudinal lines.
7. Without projections on the margin, usually
narrowly winged with a groove on each side
Arabis laevigata Muhl. Poir. 43
384 IOWA ACADEMY OF SCIENCE
7. Usually winged and with at least 1 short curved
projection on the margin, without grooves on
the sides Ranunculus abortivus L. 36
5. Not wafer-like or thin at the edges.
6. With pronounced lateral ridges.
7. Distinctly reddish or dark brown in color.
8. Regularly 3-angled, not always equilateral . .
Polygonum aviculare L. 16
8. Not regularly 3-angled.
9. Oval, flattened with 2 marked longitudinal
striations (see description)
Setaria viridis L. Beau v. 5
9. 'Irregularly shaped, angles distinct (fig.
XII) Oenothera biennis L. 59
7. Not distinctly reddish in color.
8. With about 9 distinct rounded longitudinal
ridges, broadest at apex, light straw-colored
usually (fig. XXVI) Anthemis arvensis L. 98
8. Not broadest at apex and with 9 distinct
rounded longitudinal ridges.
9. Irregularly shaped, black when fully ripe.
10. Surface finely reticulate
Plantago major L. 77
10. Surface not reticulate, granular
Plantago Rugelii Dene. 7S
9. Regularly shaped.
10. With more than 2 longitudinal ridges
(fig. XXX) Daucus Carota L. 61
10'. With not more than 2 longitudinal lines.
11. More than 1.5 mm. long
Setaria viridis L. Beauv. 5
11. Less than 1.5 mm. long
Agrostis alba L. 7
6. Without pronounced lateral ridges.
7. With two small oval white scars placed end
to end near one end of the seed (fig. XX) . .
Nepeta Cataria L. 70
7. Without scars as above.
8. Ellipsoidal in cross section and almost cir-
cular in greatest outline, usually with a nar-
row lighter colored wing, angle at edge
distinct Spergula arvensis L. 27
8. Not as above.
9. Markedly angled and irregular in shape.
10. With a distinct groove on the faces of the
seed, quite strongly flattened.
11. Groove extending entire length of seed
Sisymbrium officinale (L.) Scop. 41
A SEED KEY TO COMMON WEEDS 385
11. <Jroove not extending entire length of
seed, quite flattened, pointed at one
end Lepidium ruderale L. 38
10. Without a distinct groove on the faces.
11. Seed coat loosely fitting or wrinkled,
brick red, angles very distinct and
acute (fig. XII) . .Oenothera biennis L. 59
11. Seed coat not noticeably wrinkled,
angles more rounded.
12. Not black when ripe, usually flesh-
colored and granular
Cuscuta arvensis Beyrich 65
12. Black when fully ripe.
13. Surface reticulated
Plantago major L. 77
13. Surface not reticulated
Plantago Rugelii Dene. 78
9. Not markedly angled, quite regular in
shape.
10. Almost round, both faces concave, a
slight notch at one edge, the opposite
edge thicker Malva sp. 56-57
11. Dark reddish brown usually under
2 mm. in diameter
Malva rotundifolia L. 56
11. Light grayish in color, usually over
2 mm. in diameter
Malva moschata L. 57
10. Not round, with both faces concave as
above.
11. With a distinct longitudinal groove
starting at the narrow end of the
seed and extending at least one-half
length of seed.
12. Surface finely dotted or pitted, dis-
tinctly gray-brown, somewhat
shiny; inserted here as a check
(fig. XXXIX)
Barbarea vulgaris R. Br. 42
12. Surface not finely dotted or pitted.
13. Groove extending entire length of
the seed and running on the end,
broader
Sisymbrium officinale Scop. 41
13. Groove not extending entire
* length of seed.
14. Groove double or looped, under
1.2 mm. long (fig. XL)
Capsella Bursa-pastoris A. Medic. 39
25
IOWAACATI'V )F SCIENCE
'.-. >r::~T single ti:-:::l; :r.e
:;:•:- :-:"; liris ler.r:l; ::'
ttened and orer 1.3
mm. kmg 1 ; :iiiun rudt
- r. :t longitudinal groove.
1. Dne end sharply poir"
in appearance, usually with an
a: : : z: ; .- r. y : r. £ = i-ale
13. Us . - Fei 1 . mm. long, pointed
each end P'^'.eum pratens? L -
13. Usually under L2 mm. long,
pointed at one end, scar less
than one-fonrth length of seed
Agrostis alba Schrad. 7
12. Ends not sharp pointed, appearance
z:~ ::~.y LrT«:
B rfaee rery finely pir.ei
1 - Lig I :>red, often with
. adjacent flattened areas. . .
Beyrich 65
1- ■ . - :ri :- as
'.' Erreg olarly flattened, -;me-
Sg. XXXIX
. . . .Baroarea vulgaris R. Br. 42
15 ■ markedly flattened, dn
thai. U :ng. .. .
Brassica nigra L. Koch. 40
- -face not finely
- race granular.
I r notch near the scar,
■ :
Cuzcuta GronovH Willd. 63
la Light red, often with
flatten e ; a res.-, clearly
ma: ar.g".es
. . . ' Beyrich 85
14. Surface not granular, usually
a notch near the -
: " Witl a shorl -;.--..-.--. ;-!;:
::'.: - --■- r "
rnal outline
on the
end, nsually
: " | flg.
■;::::
Mea'icago lupuHna L. 51
- :iz :-:z'. t -
1-: "----
- - - - '
1-
7 -
17. Light
lHtrs-a
~ ;: _? _;. 7 i'. :~-e - ~ i
-
-
...... i _ "
1&. Us - ~~
- "
-
- - ...
..." - -
- . mm
-
II. s
III - - -
7
III ■-•■■- - ses -
1. 3m -
■ -
. - - - -
- XXX.X r
. - - -
3
. -
I
.- - -
IIS
- _ - - -
! N
388 IOWA ACADEMY OF SCIENCE
4. Long oval or irregular in shape with a groove
running the entire length of the seed and onto
the end Sisymbrium officinale Scop. 41
4. With a double or looped groove
Capsella Bursa-pastoris A. Medic. 39
3. Black or with slight brown cast at apex, pointed
at both ends Glyceria nervata Trin. 10
2. Without a groove running more than one-half length of
seed.
3. Thickest in the middle coming to a more or less acute
angle at the edge, notch at scar very shallow.
4. Ovate, angle at edge more rounded
Amaranthus retroflexus L. 24
4. Round, angle at edge distinct, slightly smaller than
next preceding Amaranthus graecizans L. 26
3. Angles at edges rounded, notch at scar quite marked.
4. Green to black Trifolium hybridum L. 48
4. Yellow to light brown Trijolium repens L. 47
II. Not shining.
III. With distinct forked curved wrinkles or ridges, light
colored Potentilla monspelicnsis L. 44
III. Without distinct forked curved wrinkles or ridges.
1. Surface with a longitudinal groove starting at one end,
not pitted.
2. Groove looped or double, not running the entire length
of the seed (fig. XL) . .Capsella Bursa-pastoris A. Medic. 39
2. Groove not double but running entire length of seed ....
Sisymbrium officinale Scop. 41
1. Surface without a longitudinal groove starting at one end.
2. Surface finely pitted qr with numerous tubercle-like
elevations.
3. Surface pitted.
4. Nearly cylindrical, one end smaller than the other,
pits deep (fig. XXIV)
Verbascum Thapsus L. or Blattaria L. 74
4. Not cylindrical.
5. A slight groove at one end, grayish brown (fig.
XXXIX) Barbarea vulgaris R. Br. 42
5. Without a groove at one end.
6. Pits quite distinct under a microscope; with
quite a pronounced concavity at the scar
usually under .9 mm. long
Cuscuta epithymum Murr. 64
6. Pits not markedly distinct; more granular in
appearance; not markedly concave at scar but
with more marked flattened areas than in next
preceding species. .. .Cuscuta arvensis Beyrich 65
3. Surface with concentric or eccentric rows of tubercle-
like projections.
A SEED KEY TO COMMON WEEDS 389
4. Dark gray or black when mature.
5. Dull lead-colored, almost circular, not over .5 mm.
in diameter Arenaria serpyllifolia L. 28
5. Almost shiny black, more ovate in shape, over
.5 mm. in diameter Portulaca oleracea L. 35
4. Distinctly reddish to red-brown in color.
5. Over .8 mm. in diameter with 5-6 curved rows of
minute tubercle-like projections on each face,
dark (fig. XXXIV) Stellaria media L. Cyril. 29
5. Under .8 mm. in diameter with coarser tubercles,
lighter Cerastium viscosum L. 30
2. Surface smooth, not pitted or tubercled.
3. Flat, nearly circular without a noticeable notch but
with a short projection on the margin and a narrow
wing Ranunculus abortivus L. 36
3. Not flat, narrow winged or circular.
4. Dark brown to black, with an oily appearance,
under .8 mm. in length, broadly oval
Eragrostis megastachya Host. S
4. Not dark brown to black, usually over .8 mm. long.
5. Nearly spherical, minutely pitted or with a dis-
tinct granular appearance.
6. Pits quite distinct under a microscope, with a
pronounced concavity at the scar, usually
under .9 mm. long. .Cuscuta epithymum Murr. 64
6. Pits not markedly distinct, more granular in
appearance, not markedly concave at scar but
with more marked flattened areas than the
next preceding species.
Cuscuta arvensis Beyrich 65
5. Not spherical, pitted or with granular appearance.
6. Somewhat shield-shaped with a notch at apical
end, a slight groove on each side of the notch.
7. Green to black Trifolium hybridum L. 48
7. Yellowish to light brown. .Trifolium repens L. 47
6. Not shield-shaped or with grooves.
7. Surface finely hairy, flattened oval, tapering
at the base Erigeron cayiadensis L. 84
7. Somewhat spindle-shaped with a scar at the
broader end extending not over one-fourth
length of the seed Agrostis alba Schrad. 7
390 IOWA ACADEMY OF SCIENCE
BIBLIOGRAPHY.
Beal W. J.. 7 - Is of Michigan Weeds: Bull. 260. Michigan
Agricultural Experiment Station. 1910. East Lansing.
Michigan.
Brown . E.. and Hulman. F. H.. Seed of Red Clover and Its Im-
purities: U. S. Dept. of Agriculture. Farmer's Bull. 260,
Washington. D. C.
Darlington. ~Wm., American Weeds and Useful Plants: 1858.
Orange Judd k Co.. New York.
. L. H.. Weeds and How to Kill Them: U. S. Dept. of
- ieulture. Farmer's Bull. 28, 1895. Washington. D. C.
Dudley, W. B., '. uga Flora. 1886. Andrus & Church.
Ithaca.
er, A., and Pranfl, K.. Die Xaturlichen Planzenfamilien.
L887. Leipzig.
, G T.y Set Tests Made at the Station: Geneva Agricul-
tural Experiment Station. Bull. 333. 1911, Geneva. X. Y.
Gorman, H.. On Adulterants and Weed - s in Kentucky,
38, Orchard Grass. Timothy. Bed Clover
and Alfalfa: Bull. No. 124 of the Kentucky Agricultural
S1
Gray. A.. New Manual of Botany. 1908. American Book Co.,
New York.
Harz, Dr. C. D., Landwirthschaftliche Samenkunde, 1885. Ber-
lin.
Hill/nan. F. H.. Testing Farm Seeds in the Home and Kural
School: U. S. Dept. of Agr., Farmer's Bull. 428, 1911.
Washington. D. C.
Boberts, H. F., and Freeman, G. F .. Commercial Seeds of Brome-
- ss and of English and Kentucky Blue-grasses: Adul-
it»j i Substitutes and their Detection. Kansas Station.
Bull. 111. 1907. Manhattan, Kan.
.A. I).. A Second Ohio Weed Manual: Ohio Station, Bull.
L75, ] ' si Ohio.
Wilcox, E. M., and & . N., Report of Nebraska Seed Lab-
oratory : Bull. 110, Agr. Sta.. 1908. Lincoln. Xeb.
Woods, A. F.; The Wastes of the Farm: The Yearbook of the
3. Dept. of Agriculture. 1908. Washington, 1). C.
A SEED KEY TO COMMON WEEDS J91
INDEX.
Abutilon Theophrasti 55 Buckwheat. Climbing False... 20
Achillea Millefolium 96 Buckwheat. Wild 19
Agrimonia striata 45 Bull Thistle 104
Agrimony, Tall 45 Burdock 103
Agrostemma Githago 31 Butter and Eggs 76
Agrostis alba 7 Buttercup. Bitter 37
Alfalfa 50 Buttercup, Small-flowered .... 36
Alsike 4S Buttercup, Tall 37
Amaranthus graecizans 26 Butterweed S4
Amaranthus hybridus 25 Campion, White 32
Amaranthus retroflexus 24 Canada Blue Grass 9a
Ambrosia artemisiifolia S7 Canada Thistle 105
Ambrosia trifida 86 Capsella Bursa-pastoris 39
Amphicarpa monoica 52 Caraway 60
Anthemis arvensis 95 Carpenter-weed 71
Anthemis Cotula 97 Carrot. Wild 61
Arabis laevigata 43 Carum Carvi 60
Arctium minus 163 Catchfiy. Night-flowering 33
Arenaria serpyllifolia 25 Cat Mint 7 '
Asclepias syriaca 62 Catnip 70
Atriplex patula 23 Centaurea Cyanus
Barbarea vulgaris 42 C-erastium viscosum 30
Barnyard Grass 3 Chicory 107
Batchelors' Button 106 Chamomile. Corn 9S
Beard Grass 10 Cheat 11
Beggar's Lice 66 Cheeses 56
Beggar's Ticks 93 Chenopodium album 22
Bidens cernua 94 Chenopodium hybridum 21
Bidens frondosa 93 Chess 11
Bindweed. Black 19 Chiekweed. Common 29
Bitter Dock 14 Chickweed. Mouse-eared 30
Bitterweed S7 Chrysanthemum Leucanthe-
Black-eyed Susan 91 mum 99
Black Medick 51 Cinquefoil 44
Blue Bottle 106 Cirsium arvense 105
Blue Sailors 107 Cirsium lanceolatum 104
Boneset S2 Cichorium Intybus 107
Bottle-grass 5 Clotbur S>
Bouncing Bet 34 Clover. Alsike 4>
Brassica nigra 40 Clover. Red 46
Broad-leaved Dock 14 Clover. Sweet 49
Bronius secalinus 11 Cockle. Corn 31
Buckhorn 79 Clover. White 47
392 IOWA ACADEMY OF SCIENCE
Cocklebur 88-89 Groundsel 102
Colt's-foot 100 Hawkweed, Orange 117
Corn Chamomile 98 Heal-all 71
Corn Cockle 31 Helianthus divaricatus 92
Corn Flower 106 Heliopsis helianthoides 90
Corn Gromwell 67 Herd's Grass 6
Corn Spurry 27 Hieracium aurantiacum 117
Crab Grass 1 Hieracium scabrum 118
Crowfoot, Small-flowered 36 Hog Peanut 52
Crowfoot, Tall 37 Hogweed 87
Curled Dock 13 Horseweed 84 and 114
Cuscuta arvensis 65 Hypericum perforatum 58
Cuscuta epithymum 64 ilmpatiens biflora 54
Cuscuta Gronovii 63 Indian Mallow 55
Daisy Fleabane 83 Inula Helenium 85
Daisy, White 99 Ivy, Poison 53
Daisy, Yellow 9.11 Jimson-weed 73
Dandelion 110 Joe-Pye Weed 81
Datura Stramonium 73 Kentucky Blue Grass 9
Daucus Carota 61 Knot Grass 16
Digitaria sanguinalis 1 Knot-weed, Common 16
Dipsacus sylvestris 80 Knot-weed, Virginia 18
Devil's Paint-brush 117 Lactuca canadensis 114
Dodder, Clover 64 Lactuca scariola 113
Dodder, Field 65 Lactuca spicata 115
Dodder, Gronovius 63 Lady's Thumb 17
Dog-fennel 97 Lamb's-quarters 22
Echinochloa cruss-galli 3 Lappula virginiana 66
Elecampane 85 Laportea canadensis 12
Eragrostis megastachya 8 Lepidium ruderale 38
Erechtites hieracifolia 101 Leonurus Cardiaca 72
Erigeron annuus 83 Lettuce, Common Wild 114
Erigeron canadensis 84 Lettuce, Prickly 113
Eupatorium perfoliatum 82 Lettuce, White 116
Eupatorium purpureum 81 Linaria vulgaris 76
Evening Primrose 59 Lithospermum arvense 67
Field Sorrel 15 Lucerne 50
Finger Grass 1 Lychnis alba 32
Fireweed 101 Mallow, Common 56
Five-finger 44 Mallow, Indian 55
Fleabane, Daisy 83 Mallow, Musk 57
Fowl Meadow Grass 10 Malva rotundifolia 56
Foxtail, Green 5 Malva moschata 57
Foxtail, Yellow 4 Mayweed 97
Galinsoga parviflora 95 Medicago lupulina 51
Glyceria nervata 10 Medicago sativa 50
Goosefoot, Maple-leaved 21 Medick, Black 51
Gromwell, Corn 67 Melilot, White 49
A SEED KEY TO COMMON WEEDS 393
Melilotus alba 49 Prickly Lettuce 113
Milfoil 96 Primrose, Evening 59
Milkweed 62 Prunella vulgaris 71
Moth Mullein 75 Purslane 35
Motherwort 72 Pussley 35
Mouse-ear 30 Ragweed, Common 87
Mullein, Common 74 Ragweed, Giant 86
Mullein, Moth 75 Ragweed, Great 86
Mustard, Flack 40 Ragwort 102
Mustard, Common Wild 42 Ramsted 76
Mustard, Hedge 41 Ranunculus abortivus 36
Narrow-leaved Dock 13 Ranunculus acris 37
Nepeta Cataria 70 Rattlesnake Root 116
Nettle, Wood 12 Red-root 67
Night-flowering Catchfly 33 Red-top 7
None-such 51 Rhus Toxicodendron 53
Old Witch Grass 2 Rib Grass 79
Orach, Spreading 23 Ripple Grass 79
Ox-eye 99 Rock Grass 43
Ox-eye, Sweet 90 Roman Wormwood 87
Paint-brush 117 Rudbeckia hirta 91
Panicum capillare 2 Rumex Acetosella 15
Pepper Grass 38 Rumex crispus 13
Pepperwort 38 Rumex obtusifolius 14
Phleum pratense 6 Saint John's Wort 58
Pigeon Grass 4 Salsify 108
Pigeon Grass, Green 5 Sandwort, Thyme-leaved 28
Pigweed, Common 22 Saponaria officinalis 34
Pigweed, Rough 24 Scabious, Sweet 83
Pigweed, Slender 25 Self Heal •• 71
Plantago lanceolata 79 Senecio vulgaris 102
Plantago major 77 Setaria glauca 4
Plantago Rugelii 78 Setaria viridis 5
Plantain, Broad-leaved 77 Sheep Sorrel 15
Plantain, Common 77 Shepherd's Purse 39
Plantain, English 79 Silene noctiflora 33
Plantain, Narrow-leaved 79 Sisymbrium officinale 41
Plantain, Ruga's 78 Snake Grass 8
Poa compressa 9a Soapwort 34
Poa pratensis 9 Sonchus asper 112
Poison Ivy 53 Sonchus oleraceus Ill
Polygonum aviculare 16 Sorrel 15
Polygonum Convolvulus 19 Sow Thistle Ill
Polygonum Persicaria 17 Sow Thistle, Spiny-leaved. .. .112
Polygonum scandens 20 Spergula arvensis 27
Polygonum virginianum 18 Spurry 27
Portulacca oleracea 35 Squaw-weed 102
Potentilla monspeliensis 44 Stellaria media 29
Prenanthes alba 116 Stickweed 66
394
IOWA ACADEMY OF SCIENCE
Stick-tight 94
Stink Grass 8
Stoneseed 67
Stramonium 73
Sunflower, Wild 92
Sweet Clover 49
Taraxacum officinale 110
Teasel, Wild 80
Thistle, Bull 104
Thistle, Canada 105
Thistle, Common 104
Thistle, Sow Ill
Thorn-apple 73
Thorough Wort 82
Tickle Grass 2
Timothy 6
Toadflax 76
Touch-me-not, Spotted 54
Tragopogon porrifolius 108
Tragopogon pratensis 109
Trefoil, Yellow 51
Trifolium hybridum 48
Trifolium pratense 46
Trifolium repens 47
Trumpet Weed 81
Tumble Weed 26
Tussilago Farfara 100
Velvet Leaf 55
Verbascum Blattaria 75
Verbascum Thapsus 74
Verbena hastata 69
Verbena urticaefolium 68
Vervain, Blue 69
Vervain, Nettle-leaved 68
Virginia Knot-weed 18
Wheat Thief 67
White Marsh Bent Grass 7
Wild Buckwheat 19
Wild Carrot 61
Wormwood, Roman 87
Xanthium canadensis 88
Xanthium spinosum 89
Yarrow 96
A HANDY DEVICE FOR STAINING SLIDES
395
A HANDY DEVICE FOR STAINING SLIDES.
E. LAURENCE PALMER.
The simple staining apparatus illustrated in the accompany-
ing diagram was devised to take the place of the more expen-
sive staining jars .sold by most of the scientific supply houses.
Besides the cheapness of the outfit, which fits into any tumbler,
there is the added advantage that all of the slides being stained
J U U L
9
cm
-&
L...«
Jcm,
ui Uf •
a
o
yj 1]°^ n an
Fig. 45.
may be removed from the jar at once and may be rinsed while
still in the frame. Fourteen slides may be inserted into the
frame at one time, which is four more than the average stain-
ing jar holds.
396 IOWA ACADEMY OF SCIENCE
The device is made by bending eight strips of zinc 15x200
mm. into the channels (a) (figure 45). These are soldered in
position according to the diagram, to the 20x140 mm. zinc strip
(b) which is then bent into a rectangular form with the chan-
nels on the inside. The strip (c) 1x26 cm. is then soldered to
the ends of the strip (b) forming a handle with which to lift
the frame, and a guard to prevent the slides from falling out at
the bottom.
This piece of apparatus has proved particularly handy in
staining work where most of the slides require the same treat-
ment.
Department of Botany,
State Teachers College.
A FOREST CENSUS IN LYON COUNTY
397
A FOREST CENSUS IN LYON COUNTY, IOWA.
DAVID H. BOOT.
The northwest corner of Iowa has comparatively few native
trees because of the xerophytic conditions which prevail there.
The rainfall of this part of the state is the least in Iowa, at
times going as low as eighteen inches for the year, and in ex-
posed regions, the forest trees have been unable to obtain a
xs: n
xiz nx
I
mi
r 2 3m vm
Fig. 46.
footing. The native trees are nearly all found along the streams
or in protected valleys. A good illustration of this is in Cen-
tennial township in the southwestern corner of Lyon county,
398
IOWA ACADEMY OF SCIENCE
where the Big Sioux river flows in a westerly direction for
several miles at the foot of a series of high bluffs. The north
face of these bluffs is heavily timbered, and is the subject of
this paper.
The particular locality chosen was on the south bank of the
Big Sioux river at a point known as Syverud Bluff, where the
high hills on the south side of the river rise to a height of about
180 feet above the stream. This maximum height is attained
at a distance of about one-fourth of a mile south of the river.
A typical strip of the timbered land extending from the river
south to the bare prairie at the top of the bluff was selected for
the survey. This strip was 145 feet wide. The woodland chosen
was divided into quadrats, and a careful census made of all
trees and shrubs, the size of each being taken, and a special
effort made to locate each one accurately. The charts accom-
panying this report indicate the localities of growth. The list
of trees, vines, and shrubs is as shown in the following table,
and the accompanying graph, figure 46., indicates proportions.
Name of Plant
No. OF
Speci-
mens
I. Acer saccharinum L. (soft maple)
II. Ulmus americana L. (American elm)
III. Salix nigra Marsh (black willow)
IV. Acer negundo L. (box elder)
V. Vitis vulpina L. (wild grape)
VI. Fraxinus pennsylvanica var. lanceolata
(Birk) Sarg. (green ash)
VII. Tilia americana L. (Basswood)
VIII. Ribes Cynosbati L. (goose berry)
IX. Alnus sp. (alder)
X. Prunus virginiana L. (choke cherry)
XI. Rubus idaeus var. aculeatissimus (C. A.
Mey) Regel & Tiling (raspberry)
XII. Symphoricarpos occidentalis- Moench (buck
bush )
XIII. Ostrya virginiana (Mill) K. Koch (Ameri
can hop hornbeam)
XIV. Gymnocladus dioica (L.) Koch (Kentucky
coffee tree)
XV. Quercus macrocarpa Michx. (bur oak) ....
XVI. Crataegus mollis (L. & G.) Scheels (haw-
thorn)
XVII. Celastrus scandens L. (climbing bitter
sweet)
XVIII. Prunus americana Marsh (wild plum) ....
XIX. Juglans nigra L. (black walnut)
XX. Juniperus virginiana L. (red cedar)
Total
40
440
117
9
13
43
•1184
382
8
16
6
33
685
24
190
50
5
148
5
1
3399
Per Cent
1. +
12. +
3. +
•2 +
•3 +
1. +
34. +
11. +
•2 +
•4 +
•1 +
• 9 +
20. +
•7 +
5. +
1- +
•1 +
4. +
•1 +
.02+
100.
Iowa Academy Science
Plate XII
\ »"i
3ZX
TTL
fVjag
•«*
400 IOWA ACADEMY OF SCIENCE
The distribution of these trees and shrubs is very interesting
and calls for the following description :
Extending south from the Big Sioux to the foot of the bluff
is a tract of low river bottom subject to overflow, in width about
350 feet. At the south edge of this flat, the bluff rises abruptly,
reaching its crest 1,250 feet south of the river, at which point
it has an elevation of about 180 feet. All the soft maple trees
(Plate XII, figure I) are located on the river flat, and none of
them appear on any part of the bluff. This is to be accounted
for because the soft maple is a water lover, and finds an abun-
dance of moisture, and good protection from the dry southwest
winds of summer, under the shelter of the bluff. These trees
run to large dimensions, some of them being as much as twenty-
four inches in diameter. The American elms (Plate XII, fig-
ure II), 440 specimens, are divided into four principal groups.
The greater part are to be found in the thick timber on the
upper third of the bluff face. Below this, there is an interval
of several rods succeeded by a considerable interval thickly
timbered with the American elm. Then comes another interval
without elms, after which they are scattered rather freely down
to the foot of the bluff. The fourth group consists of a few
scattered individuals located on the river bottom, close to the
foot of the bluff, and made up of trees probably seeded from
the trees on the bluff face. There is a very conspicuous absence
of these trees from the greater portion of the river bottom,
which is to be accounted for by the river floods, by the sand
and gravel soil, and by the over supply of ground water. The
elm's ability to vary its transpiration and to withstand severe
evaporating tendencies in environment will be brought out in
the records of transpiration and evaporation to appear in an-
other paper.
The black willows (Plate XII, figure III) are one hundred
ten in number, all grouped on the low ground near the river,
with the exception of a few trees about 100 feet from the river
bank. This grouping is readily accounted for by the tree's
fondness for water. These trees occur chiefly in clumps sur-
rounding a center where the parent of the group formerly stood.
There are five box elder trees (Plate XII, figure IV), in the
tract studied, four of which occur on the edge of the river, and
the fifth one some seventy-five feet south of it, but all of them
so located on the river bottom that they are certain of an un-
A FOREST CENSUS IN LYON COUNTY 401
failing supply of water. As is well known, this tree adapts
itself to varied conditions of climate and exposure when forced
to it by artificial planting; but in this study, we consider only
undisturbed trees, and these box elders have been planted by
nature and grow in a very moist situation.
Eleven grape vines (Plate XII, figure V) are found in the
tract, none of them on the river bottom, and none of them on
the upper half of the bluff face. They are widely scattered,
and evidently avivectant, all of them being located at the foot
of trees, up and over which they climb. It is unusual not to
find the wild grape on the river bottom nor in the forest on
the upper part of the bluff face. For the, river bottom this can
only be ascribed to the chance work of the birds, with some
help possibly toward elimination by the river floods. "With the
upper bluff face, the absence is probably in part due to over-
crowding by other vegetation, as well as to the seed-carrying
birds seeking out the lower, more sheltered regions, in the hot
months of autumn when the fruit is ripe.
Forty-three specimens of green ash occur (Plate XII, figure
VI), three only on the river bottom and close to the foot of the
bluff, most of the river bottom being devoid of this species. The
next group of them is at a considerable distance up the hill, and
after another vacant space of several rods we find two other dis-
tinct groups, the one somewhat scattered, the members of the
other near together in a manner to indicate that the several trees
are the descendants of the same ancestor. Still farther up, and
in the drier part of the wood area, we come to two groups, which
also indicate by their manner of growth that each group is from
one ancestor, and finally, almost at the upper tree limit, where
the conditions for tree growth are severe, we find two individuals.
Contrary to expectation, the trees at the bottom where moisture
is abundant and protection good, do not differ in size very
markedly from the trees at the top, where the conditions are
more severe, as the largest of them vary from four to six inches
in diameter, except in the case of two individuals close to the
upper tree limit, which are stunted, and only two inches in
diameter. A considerable part of the upper third of the forested
area is devoid of ash, since it lacks sufficient moisture and is
over-crowded with other vegetation, but lack of moisture cannot
be urged for the lower third of the bluff, or for the river bot-
26
402 IOWA ACADEMY OF SCIENCE
torn, and crowding can play no part in the distribution on the
river bottom, because the forest there is thinly scattered. In
place of over-crowding there, we have the river floods acting
as a destructive agent when they periodically inundate this land.
Nearly twelve hundred bass wood trees (Plate XII, figure
VII) grow in the region studied. None of these are found on
the river bottom. On the bluff face they are scattered quite
regularly from almost the foot of the bluff to within a distance
of two to five rods of the upper tree limit, with the exception
of an area about five rods wide a little below the middle of the
forested tract. A most noticeable thing with the bass wood is
the "family group," as it might be called, in which a consid-
erable number of individuals are clustered about the grave of
the parent from which they sprang. While the bass wood is
able to adapt itself to great variations in growing conditions,
it shows plainly by its development the influence of those con-
ditions, as the largest and tallest trees are found near the foot
*of the bluff, where they are well protected. A large number
of the trees at the upper limit of their growth do not run more
than one or two inches in diameter.
There are three hundred eighty-two gooseberry bushes (Plate
XIII, figure VIII) in the tract. None of them occur on the
river bottom, but they are distributed with a fair degree of
equality from the foot of the bluff almost to the upper limit of
the forest, with the exception of several large spaces a little
below, and also a few a little above, the middle of the forest,
where they are probably crowded out by other vegetation.
In some cases, groups of these bushes indicate by their arrange-
ment that they are from one parent plant.
There are eight elder bushes in this tract (Plate XIII, figure
IX), loeated in two groups not far apart, near the mouth of
a gully at the bottom of the bluff, where they are well pro-
tected, and receive abundant moisture. The arrangement of the
members of these two groups is such as to show that each group
is from a single parent that formerly stood at this spot. We
may attribute their absence from the river flat to the flood
waters of the river, and their absence from the upper parts of
the wooded bluff to insufficient moisture.
There are sixteen choke-cherry trees (Plate XIII, figure X),
one group of which is found on the escarpment at the foot of the
bluff, about ten feet above the river flat. These are in a close
Iowa Academy Science
Plate XIII
:znr
4 04 IOWA ACADEMY OF SCIENCE
group indicating common ancestry. The second group is some-
what scattered near the middle of the west side of the area. None
of these trees occur in the upper half of the forested area, and
none of them occur on the river bottom. They appear to seek
the medium conditions as to moisture and shelter, and the scatter-
ed ones are apparently aviveetant.
There are six raspberry bushes (Plate XIII. figure XI i distri-
buted, three of them in the upper section, and three in the middle,
of the lower part of the wooded bluff face in such a way as to
indicate that they are planted by birds.
Thirty-three buck bushes ( Plate XIII. figure XII) occur, dis-
tributed in three groups, one group, in two parts, near the upper
limit of tree growth, another near the middle of the west side,
the third a short distance above the foot of the bluff. This dis-
tribution may be taken to show ability in this plant to adapt itself
to considerable ranges of humidity and exposure, and. in the
lower groups at least, it is apparently the work of birds. The
bush does not occur at all on the river bottom where the condi-
tions affecting plant life are such as to require the ability to
handle much moisture.
Six hundred eighty-five hop hornbeam trees (Plate XIII. figure
XIII i appear in the tract. Xone of these trees are on the river
bottom, and the greater part of them are grouped in close associa-
tions on the lower half of the bluff face. Some of these groups in-
dicate a distribution from a common center, a parent tree. Vacant
areas among them are to be attributed to over-crowding by other
trees. Some of these trees are found in the upper part of the
forest, and one small group occurs near the upper forest limit,
showing that they are able to adapt themselves when necessary
to considerable variation in conditions. Xone of these trees are
large, as large size would be impossible because of their crowded
manner of growth.
Twenty-four Kentucky coffee bean trees (Plate XIII. figure
XIV. occur on the bluff face not far from its foot. This tree
grows to considerable size and in this place has good protection
and plenty of moisture, but is unable to survive the very wet
conditions of the river flat.
Only one red cedar grows in this piece of timber ('Plate XIV,
figure XX . and it is a small one of only one-half inch diameter,
found in an opening among the bass woods and hop hornbeams,
Iuwa. Acadc
7: .A~ XIV
;■-
XX
'XT'
• . . - ■ •
406 IOWA ACADEMY OF SCIENCE
so abundant about the middle of the bhiff face. Red cedars are
uncommon in this part of the state, this being the only one found
in several years' work along the Big Sioux' river in Lyon county.
The one hundred and ninety bur oak trees (Plate XIV, figure
XV) are arranged in two very significant groups, one of which is
further subdivided in a characteristic manner. One group is
near the top of the bluff, and comprises about seventy individ-
uals. They are almost the extreme outposts of the xerophytic
trees, crowding up close to the bare prairie. The remainder of
the oaks are located chiefly near the middle of the north slope ojf
the bluff, and are in about ten small clusters, plainly indicating
by their grouping a common origin for the separate clusters. It
is probable that a parent tree supplied acorns for each separate
group. The great ability of the bur oak to adapt itself to ex-
treme variations in humidity and water supply does not come out
as strikingly here as in many other localities, for there is a totai
lack of these trees on the river bottom.
There are fifty hawthornes (Plate XIV, figure XVI), all
located near the middle of the forest, none of them going as high
as the extreme top of the hill, nor as low as the lower third of
the hill, and they do not occur on the river bottom. Most of
them are found in half a dozen clusters indicating centers of dis-
tribution, but about ten are scattered as if planted by birds.
Three climbing bitter-sweets (Plate XIV, figure XVII) are
found near together at the midde of the woods. From their
habitat at the foot of trees, they probably have been planted by
birds.
There are about one hundred and fifty wild plum trees (Plate
XIV, figure XVIII), none of them found on the river bottom,
nor on the lower half of the hill, and nearly all within forty
yards of the upper tree limit. They are grouped in thickets
indicating their common origin from parent trees, and the method
of propagation by suckers and fallen fruit. A very few scattered
trees probably have been planted by animals. This tree is one
of the hardier of the forest inhabitants, able to endure the severe
conditions near the upper tree level.
Five black walnut trees (Plate XIV, figure XIX) occur, four
in one group within thirty yards of the upper tree level, and on©
solitary specimen about one-third the way down the hillside.
The group of four appear to have a common origin, the seed of
Iowa Academy Science
Plate XV
A FOREST CENSUS IN LYON COUNTY
409
all of them probably having been planted by the same squirrel.
It is rather remarkable that these trees should be found in this
part of the wood only, and none lower down, especially on the
river bottom.
Figure XXI of Plate XIV shows the entire forest. It will
be noticed that the river bottom is thinly forested, that most of
the trees on it are found close to the river, and that large tracts
are devoid of arboreal vegetation. The face of the bluff is densely
covered from its foot to the upper tree limit, excepting small
openings here and there, usually not more than two or three rods
in diameter. Looking at the chart the forest appears very uni-
form, and it is only when one goes out into the field that the great
difference due to the different species of trees, and to the different
conditions of growth becomes apparent, the lower forest (Plate
XV, figure A) , being very dense and heavy, and the upper forest
lower and less dense, as will be seen in the accompanying photo-
graphs (Plate XV, figures B and C). The effect of environment
in selecting the forest trees of a locality clearly appears in this
tract. Figure 47 is a sketch of the bluff, giving elevations and
^oi>^'.
aX*v& a*"**
Stt^»
SWL^
frCJt^Z -^ « fUt X« A^M. ■&**£
'■ • ■■ IH -. S 4
Fig. 47.
distances. The observations on the herbaceous plants, on evapor-
ation, transpiration, and meteorological conditions made at this
point during three years will appear in another paper.
Department of Botany,
State University.
SCLERODERMA VULGARE AND ITS IOWA ALLIES 411
SCLERODERMA VULGARE AND ITS IOWA ALLIES.
GUY WEST WILSON.
The Sclerodermitaceae, or so-called hard puffballs, have been
very inadequately studied by American mycologists. Tndeed it
has been too common a custom to group all the material together*
as Scleroderma vulgare Hornem, without regard to external
markings, the thickness of the periderm, or the mode of rupture
for spore dispersal. Probably one of the most comprehensive
treatments of the American forms is that by Lloyd1 in connection
with his studies on Australian species. His treatment has been
followed with some variations by Hard2 and by Mcllvane3, each
adding variations to the treatment of species. Several of the
eastern forms have ben figured by Murrill in Mycologia. How-
ever, no systematic account of the American forms has come to
the notice of the writer.
As treated by Ed. Fischer4 the American members of the family
fall under three genera, Scleroderma, Pisolifhus, and Sclerang-
ium. Of these the first and second rupture irregularly for the
dispersal of the spores, while in the third the periderm breaks
into stellate lobes as in Geaster. Usually the spore mass is ex-
posed directly, but occasionally specimens arc found with a very
delicate and evanescent inner periderm. In Scleroderma the
periderm varies in thickness in different species but it is always
more permanent than in Pisolithus. The hynienial, (glebal)
characters are also of considerable interest and subject to a wide
range of variability. At first the hymenial surface is broken up
into a series of closed chambers which are irregulary disposed
among the sterile tissues of the sporophore. In Scleroderma
these lose their individuality with the maturity of the sporophore,
although they frequently remain as distinct lines of hyphae which
gives the spore mass the appearance of being contained in num-
erous small pockets. In Pisolithus these chambers are persistent
in the mature sporophore as peridioles quite similar in appear-
aTlie Lycoperdonacese of Australia, New Zealand and neighboring islands,
1905. pp. 12-15, pi. 29-31.
2The Mushroom, 1908, pp. 555-558. 567.
3One Thousand American Fungi, Revised edition. 1912, pp. 615-618.
♦Engler & Prantl, Naturl. Pflanzenfam., 1899-1900, l1** : 334-338.
412 IOWA ACADEMY OF SCIENCE
ance to those of the Nidularacese. This character is subject to a
very wide range of variation so that in some eases it is necessary
to rely entirely on the peridium to determine to which genus a
given specimen should be referred.
KEY TO THE SPECIES.
Distinct peridioles absent at maturity; periderm rather persistent.
Periderm rupturing irregularly.
Periderm thick.
Periderm conspicuously warty or scaly
1. Scleroderma aurantium
Periderm smooth, or smoothish 2. Scleroderma Caepa
Periderm thin.
Periderm rather firm and flexible, smooth or scaly
3. Scleroderma Bovista
Periderm fragile above, warty 4. Scleroderma verrucosum-
Periderm rupturing stellately.
Spore-mass light colored 5. Sclerangium flavidum
Spore-mass appearing almost black 6. Sclerangium polyrhizon
Distinct peridioles present at maturity; periderm very fragile
7. Pisolithus arenarius
I. SCLERODERMA Persoon.
Sporophore subglobose, with rhizomorphs and frequently
rhizoids, or even a stalklike base ; peridium single, usually thick,
rather firm, opening irregularly; gleba homogeneous, capillitium
none, the boundaries of the spore cavities remaining as more or
less distinct lines of hyphas; spores globose, roughened.
1. SCLERODERMA AURANTIUM (L.) Pers. (S. vulgare Hornem.)
Subglobose, subsessile, radicate or not, 2.5 — 8 cm. in diameter ;
periderm thick, corky, usually pale with shades of yellow or
orange, or sometimes brownish, usually covered with large warts
which are more or less deciduous; gleba at first white, changing
through various shades to blue-black and finally greenish gray;
lines of trama yellowish ; spores dark, globose, warted, 7 — 12 f1 in
diameter.
Johnson county (Macbride, Shimek, Miss Jewett), Linn county
(Shimek), Muscatine county (Shimek).
The commonest species in our territory and one of the largest.
It presents a considerable variation in the size and pattern of the
warts on the periderm. The specific name is frequently incor-
rectly written "aurantiacum."
SCLERODERMA VULGARE AND ITS IOWA ALLIES 413
2. SCLERODERMA CAEPA Pers.
Subglobose or depressed, 3 — 8 cm. diam. ; peridium smooth or
only slightly roughened, never truly tuberculate, thick and firm ;
gleba at first white, finally ferruginous; trama lines light yel-
lowish; spores dark, globose, tuberculate, 7 — 12m in diameter.
Johnson county (Shimek), Hesper, Winneshiek county
(Shimek).
Very similar to 8. aurantium but with a slightly thinner peri-
derm which is essentially smooth or only slightly roughened.
3. S. BOVISTA Fries.
Sporophore subglobose, 3 — 5 cm. diameter, yellowish in color;
periderm rather thin and firm, flexible, smooth or somewhat
scaly ; gleba at first white, at last brownish ; lines of trama ochra-
ceous; spores globose, verrucose, 7 — 12 m diameter.
Johnson county (Macbride, Shimek), Muscatine county
(Shimek).
A very distinct form which appears to be fairly common. It
is easily distinguished by its firm, flexible periderm.
4. S. VERRUCOSUM (Bull.) Pers. (S. tenerum Berk.)
Sporophore subglobose, 2.5 — 7 cm. diameter, ochraceous, pur-
plish, or dingy brown; periderm thin and fragile above, firmer
beneath, covered with more or less angular warts, continued be-
low into a more or less stemlike base ; gleba white, then very aark
vinous or almost black, at last umber ; lines of trama white ; spores
globose, dark, warted, 7 — 12 p- in diameter.
Unionville, Appanoose county (Shimek), Hesper, Winneshiek
county (Shimek), Mason City, Cerro Gordo county (Shimek).
A widespread and rather common species which might easily
be passed over as immature specimens as it ranges quite small in
our territory. The thin, fragile periderm distinguishes it readily
from S. aurantium. The white trama lines also are quite dis-
tinctive. Probably second only to S. aurantium in common-
ness.
II. SCLERANGICM Leville.
Similar to Scleroderma except that the periderm ruptures
stellately, sometimes exposing a thin inner periderm.
- EENGE
" S 7_ :.ym. nor. i Scleroderma ilaridum
rophore depressed-globose, yellowish : periderm thick and
firm. - - .'Ay above, splitting stellately into three to eight
triangular lobes: spore-ma- ombraeeous s ling
tows: s — ie trama light oehraeeoi> - - glo-
s rougher^ 7 — 13 - in diam
^nson county "W _ ; .
:-rrs hr::_ v I . a its i f rapt
and from Sctenwgium polyrhizon in its small- . ts lighl
S] rophore - - - -7 em low-
sh brown to g - periderm thi s th. splitting
Stella- six r_ner periderm if pres
- ::: :.:: . :r.j__- si :- ::ias< ~-:y .;-:•:. ?.-..'. -:_:._ a_:_ -: .;-. :-k :
- of trai_ tis spores g - - arted,
1- — I- -
Johnson county Ma
At and striking species which upon rupture bears
erf - ice 1 th si
III PI-"LITHT S . - «cemn :
odfrma. but with a thin and
astent
5 Alb. ie Sehw. (I Pisiean Fries
rophore depresse - rootlike s
-:<th. dark brown a and soon breaking i:
eeomnu. - polygonal or
d brown or red-brow: spores rucose
-
This s] - e passed ov in the field as
''tut. but - minationsh. ts irked
-.__-_ - _ ?. This is
provis sis of a
rbarium bearing the locality data
8 probably eolleete
- : mek. Its
5 to be looked : rable in*
-
PILEATE HYDNACEAE FROM IOWA 415
NOTES ON SOME PILEATE HYDNACEAE FROM IOWA.
GUY WEST WILSON.
The Hydnaceae, or spine fungi, is one of the smaller families of
the Agarieales, or. as they were known to the older mycologists,
the Hynienomyeetes. numbering as it does only about five hun-
dred species. Of these some are widely dispersed and rather
common while others are quite sporadic or even local in their
occurrence. Only a few members of the family are common in
our state, yet their number is more considerable than the pub-
lished accounts would indicate, as but four species appear to nave
been recorded from Iowa. Greene in his Plants of Iowa does not
even mention the family, while two other papers, one by Hess
and Yandivert1 and one by Shimek2 include a single species each.
The most considerable list of Iowa species is given by Banker'
who includes references to three. The present paper includes
fifteen species, all but one of which are represented in the her-
barium of the State University.
The taxonomic treatment of the Hydnaceas, in common with
that of related families, has been subject to various vicissitudes
both as to extent of the group and as to the arrangement of the
species. Under the old concept two types of pileate forms were
included. Those forms having the teeth at least approximately
terete were all referred to the genus Eydnum, while those with
decidedly flattened teeth were designated as the genus Irpex.
The present paper is concerned only with the pileate species of
the first group. Numerous attempts have been made to segregate
the old genus Hydnum. As might be expected these have met
with varying degrees of success or failure according to the grasp
which their author had upon the relative importance and tax-
onomic value of the characters which were employed. Perhaps
the most rational attempt at a revision of the group is that of
Banker3 who in his careful treatment of the American sp<
iHess and Yandivert, Bacidiomycetes of central Iowa : Proc. Iowa Acad.
Scl., VII, 1900, 183-186, pi. 16.
2Shimek, The Plant geography of the Lake Okoboji region: Bull. Labs. Nat.
Hist. Univ. Iowa. 72. 1915, 1-90, pi. 1-S and map.
3Banker. A contribution to the revision of the Xorth American Hydnaceae.
Mem. Torrev Club, 12, 1906, 99-194.
416 IOWA ACADEMY OF SCIENCE
has laid the foundation for a satisfactory revision of the entire
family. The primary characters used are not merely colors and
superficial external resemblances which might be accidental, but
a series of correlated characters so based upon the entire fungus
as to insure a workable and logical grouping of species. Those
members of the group which have smooth spores also hare light
colored flesh and lend themselves to further segregation on the
basis of habit, of hymenial structure, and of habitat, while those
species with roughened spores have darker flesh and may be
further segregated on the basis of spore markings, spore color,
texture, and habit. This classification is accordingly adopted in
the present paper as it represents a grouping of species on the
basis of relationships and in a manner such as to make the family
more easily studied than to follow some of the earlier writers.
KEY TO SPECIES.
Hymenophore usually light colored, white to reddish or gray;
spores smooth, hyaline.
Terrestrial; hymenophore stipitate, fleshy. . . .1. Hydnum repandum
On wood; hymenophore sessile, dry or fleshy (in No. 6 some-
times stipitate, but not fleshy).
Hymenophore more or less tuberculiform or branched, fleshy
to sub-fleshy, white or yellowish.
Pileus more or less branched from the base.
Teeth uniformly distributed over the entire under sur-
face of the branches 2. Martina flagellum
Teeth so distributed as to leave a bare region at the
base of the branches 3. Manina coralloides
Pileus more or less massive and tubercular, unbranched
4. Manina cordiformis
Hymenophore pileate to resupinate, sessile or stipitate.
Substance dry.
Pileus sessile and decurrent to resupinate, more or less
gregarious and confluent 5. Steceherinum ochraceum
Pileus more or less stipitate or subsessile.
Hymenophore large and complicated, even stipitate
forms often confluent; teeth straight
6. Steceherinum adustum
Hymenophore smaller and simple, rarely totally con-
fluent, teeth flexuose 7. Steceherinum pusillum
Substance fleshy.
Surface densely strigose to tomentose, gummy when dry
8. Creolophus puleherrimus
Surface rather smooth, white, not drying gummy
9. Creolophus cirratus
PILE ATE HYDNACEAE FROM IOWA 417
Hymenophore usually dark colored, terrestrial; spores roughened.
Hymenophore normally pileate and stipitate.
Stipe central; spores coarsely tuberculate, colored.
Surface of pileus obscurely or not at all zoned, more or
less uniform in color.
Brown; pileus obscurely zonate, more or less deformed
■. . . . 10. Hydnellum scorbiculatum
Cinnamon-colored 11. Hydnellum velutinum
Surface of pileus zonate.
Small; pileus less than 4 cm. wide, very thin
12. Hydnellum parvum
Larger; pileus 3-15 cm. wide, rather thick
13. Hydnellum sonatum
Stipe lateral; spores hyaline 14. Auriscalpium vulgare
Hymenophore sessile to resupinate, of branched processes,
clothed with a dense coat of branched hairs
15. Gliodon strigosus
I. HYDMM L.
According to the present treatment this genus is limited to
those stipitate, terrestrial species with smooth, light colored or
hyaline spores and light to yellowish or reddish flesh. We have
a single species.
1. H. REPANDUM L.
A cosmopolitan species of extreme variability which is found
on the ground in woods from midsummer to autumn. "When
growing the fungus is light in color, varying from creamy to
tawny. Both collections listed here appear to belong to this
species, although the second does not agree in all respects with
the first, as the individuals are a trifle more robust and the teeth
slightly more slender.
Johnson county (Macbride), Ilesper. Winneshiek county
(Shimek).
II. MANIXA Scop.
Characterized by having a fleshy tuberculiform or branched,
laterally sessile or subsessile pileus; the teeth pendant; spores
smooth ; the sporophore always light colored, varying from white
to creamy, with a more or less coralline or beardlike appearances
always on wood.
We have three species, the nomenclature of which is very
much involved owing to the widespread misinterpretation of
27
418 IOWA ACADEMY OF SCIENCE
specific limits. The confusion has heen increased by the fact that
the genus has been thrice named, and each time confusion intro-
duced into the synonomy of the species. The synonomy is
Manma Scopoli 1772, Hericiwm Persoon 1794, and Medusina
Chevelier 1826. The synonomy of our American species has
been discussed by Banker.4
2. M. FLAGELLATUM Scop. {Hydnum laciniatum Leers,
H. coralloides "Ant.")
One of our commonest and most variable species. The speci-
mens range from large and rather stout to comparatively slender
and delicate forms, probably fairly well representing the vari-
ations of the species in Iowa. This species is easily distinguished
from the next by the distribution of the spines on the branches
of the pileus. In the present species they are evenly distributed
from tip to base of the branches while in the next they are
grouped at the tip, leaving the under side of the branch bare
at the base. However, this is the species which is commonly re-
ferred to by American mycologists as Hydnum coralloides and
figured under that name by Hess and Vandivert,5 The
confusion arises from the fact that two closely related species
have been assigned the same binomial by different authors, nor
is its persistence a matter of surprise as the present species
is decidedly more coralline in appearance than is the next.
Johnson county (Macbride) ; Wildcat Den, Muscatine
county (Shimek); Highlandville, Winneshiek county (Shimek).
?>. M. CORALLOIDES (Scop.) Banker. {Hydnum coralloides Scop.)
Apparently a much less common species than the preceding.
This may be due to a failure to discriminate between species
in the field, but this appears improbable as one would expect
equally common species to be more equitably represented even
though their distinctive characters might have escaped notice
at the time of collection. American mycologists have sometimes
confused this species with the more massive Hydnum Caput-
ursi. But two specimens seen, one of them from an oak stump.
Iowa City, Johnson county (Wilson); Hesper, Winneshiek
county (Shimek).
4Banker, Type Studies in the Hvdnaeeae : I. The Genus Martina. Mycologia,
4, 1912, 271-278.
sLoc. cit.. p. 186, pi. 16, fig. 2.
PILEATE HYDXACEAE FROM IOWA 419
4. M. CORDIFORMIS Scop. (Hiidnum Erinaceus Bull.)
A common species, at least locally, which differs from our
oilier species of the genus in its unbranched, tubercular pileus
and shaggy spines which give the fungus a rather pronounced
heardlike appearance. This fungus cannot well be confused
with any other Iowa species. On living and recently cut oak,
causing a serious heart rot which finally results in a hollow
trunk. All our material appears to be local.
Johnson county (Macbride, Shimek, Wilson).
III. STECCHERINUM S. F. Gray.
A group of species of exceptional variability in form and
habit, ranging from pileate to laterally sessile, or even resupi-
nate. The spores are smooth and light-colored, while the con-
text is tough and fibrous. Always on wood. We have three
species. i
5. S. OCHRACEUM (Pers.) S. F. Gray. (Hydnum oehraceum Pers.)
A common and variable species which appears to be confined
to dead oak wood. The sporophores may be single or imbricate,
often confluent, sessile to decurrent or even resupinate. The
surface of the cap suggests a polypore of close relationship with
Polyporus pergammus, while the ocher-colored spines are equally
characteristic. This is the only species which the writer has
found twice referred to in literature as having been collected in
Iowa. Banker6 records it among the species which Holway col-
lected, and Shimek7 records it from the Okoboji region. These
citations would indicate that it is well distributed throughout
the state.
Iowa City. Johnson county, (Macbride. Wilson) ; Okoboji re-
gion, Dickinson county (Shimek).
6. S. ADUSTUM (Schwein.) Banker. (Hydnum adustum Schwein.)
A very peculiar and interesting species which shows a wide
range of variability in form and habit. The hymenophore may
be sessile or stipitate, separate or more or less laterally con-
nate, or even developing a '•two-story" habit of imbricate pelei.
"Mem. Torrey Club, 1906, 12, 1-'.".
7Loc. cit, p. 54.
420 IOWA ACADEMY OF SCIENCE
With such a range of variability the form of the pileus could
scarcely be expected to show a considerable degree of regu-
larity. The surface is more or less distinctly zonate. The dried
specimens are buff or with a tinge of blue above while the
teeth have a pronounced bluish tinge in most specimens. All
our material is local, although Banker8 records it as being
among the Holway material. On decaying branches.
Johnson county (Macbride, Shimek).
7. S. PUSILLUM (Brot.) Banker. (Hydnum pusillum Brot.)
A species quite similar to the preceding, but more conspicu-
ously zonate and with noticeably smaller teeth. Two collec-
tions have been seen, both from dead wTood, in one instance with
fragments of charcoal adhering to the fungus. Previously re-
ported only from New York and New Jersey.
Johnson county (Macbride).
IV. OREOLOPHUS P. Karsten.
The species of this genus differ from Steccherinum primarily
in their fleshy texture as distinguished from the dry and tough
character of the members of that genus. "We have two species.
8. C. PULCHERRIMUM (Berk. & Curt.) Banker. (Hydnum
pulcherrimum Berk. & Curt.)
Two specimens in the University herbarium labelled "im-
mature" and referred questionably to Hydnum flabelUforme
Berk, are apparently identical and are to be referred here. If
this identification is correct we have a considerable extension
of range for the species to the northwest. These specimens
have a pronounced tawny-colored, gummy pileus. Two speci-
mens which are much larger and with spines a trifle longer, but
with very little of the gummy character of the pileus are also
referred here provisionally. As it may be that two closely re-
lated species have been confused the two series are listed sep-
arately, the gummy ones being designated I, and the others II.
I. Johnson county (Macbride). II. Iowa City, Johnson
county (Macbride), Dubuque county (Shimek).
9. C. CIRRATUS (Pers.) (Hydnum cirratus Pers.)
Not uncommon in Johnson county on oak. The form is easily
separable from C. pulcherrimum by the lack of gum on the
dried pileus, and from C. septentriomlis by its less fleshy tex-
ture. It also differs in form from these species. When fresh
8Loc. cit., p. 132.
PILEATE HYDXACEAE FROM IOWA 421
the pileus is subfleshy, becoming fragile on drying. The sporo-
phore is broadly effused, approaching resupinate, and not truly
imbricate. The statement by Banker9 concerning " H. cir-
ratum Pers. often written incorrectly cirrhatum" that £iit seems
probable that the plants thus reported are H. pulcherrinium or
II. septentrionale" needs no further comment than his previous
statement that he has seen none of the specimens so referred.
Certainly our own material could never be confused with either
of these nor does it agree with any other species listed by
Banker.
Johnson county (Shimek, "Wilson).
V. HYDXELLUM P. Karsten.
.V well defined group of species having coarsely tuberculate,
colored spores, and a central stipe which is always duplex in
texture, the central region being quite hard while the cortical
layers are feltlike. The pileus is fibrous and tough. All four
of our species are terrestrial.
10. S. SCORBICULATUM (Fries.) Banker. {Hydnum scorbiculatum
Fries.)
The collection referred here contains two specimens which
are somewhat zonate, but with the teeth decidedly decurrent on
the stipe. The pileus is quite noticeably deformed on the upper
surface and has a broad sterile margin. The sporophores are
rather small.
Johnson county (Macbride).
11. S. VELUTINUM (Fries.) P. Karsten. (Hydnum velutinum Fries.,
H. spongipes Peck.)
Two collections of a large cinnamon-colored species with a
very pronounced felty layer about the stipe are very evidently
this species. The pileus is quite thick, the surface very uneven,
and the outline quite irregular. The teeth are only slightly de-
current.
Johnson county (Macbride).
12. H. PARYl'LUM Banker.
A single collection of five very small sporophores is the sole
representative of this species seen. The very small and extreme-
ly thin pileus distinguishes this species from //. -.omitum with
9Loc. cit., p. 135.
422 IOWA ACADEMY OF SCIENCE
which it is usually confused. The recorded range is New York,
Michigan and Alabama.
Coufal, Johnson county (Miss Macbride).
13. H. ZOXATUM (Batsch) P. Karsten (Hydnum zonatum Batsch.)
Also represented by a single collection which includes but one
sporophore. While apparently very close to the last species
it is very easily distinguished from it by the larger and thicker
pileus.
Hesper, Winneshiek county (Shimek).
VI. Al KISCALPIUM S. F. Gray.
In the present genus the pileus has a deep sinus on one side
with the stipe so inserted in the sinus as to give it a lateral ap-
pearanee while the stipe continues on the top of the pileus as
a. distinct ridge which runs out gradually, but extends well
a cress the pileus. A very interesting monotypic genus.
14. A. VULGARE P. Karsten. (Hydnum Aurisealpium L.,
A. Aurisealpium S. F. Gray.)
This species is recorded from Iowa by Banker10 who gives
its habitat as "decaying cones of Conifers." Our specimens
are probably from the same collection as his Iowa material,
but do not show the substratum further than that the base
of the stipe is covered with moss. The label reads "On the
ground. Rare." Not to be confused with any other species of
the family on account of the peculiar insertion of the stipe.
Iowa (Macbride).
VII. GMODON P. Karsten.
A very distinct genus characterized by the papillate, light-
colored spores and the sessile or resupinate branched pileus.
Monotypic. j
15. G. STRIGOSUM (Swartz) P. Karsten. (Leaia piperata Banker,
Hydnum strigosum Swartz.)
Not represented in the University herbarium but recorded
by Banker11 as being collected in Iowa by Holway.
Department op Botany,
State Universitv.
1(,Loc. cit., p. 178.
"Banker, loc. cit., p. 176.
PIONEER PLANTS ON A NEW LEVEE 42;
PIONEER PLANTS OX A NEW LEVEE— IT.
FRANK E. A. THONE.
A year ago the writer presented before the meeting of the
Academy at Iowa City a paper under the above title1 describ-
ing the vegetation appearing during the first growing season
on a newly built embankment in Des Moines. It was his in-
i< nt ion to make this the first of a series of studies following
the development of the flora on this area until a permanent
balance of power had been established.
Unfortunately, however, several circumstances intervened to
prevent the carrying out of this plan. The writer was able
to visit the area only a few times after the completion of the
first paper, and the information gleaned on these flying visits
covers only the most salient facts. In the second place, the
river itself has made a number of changes in the terrain. The
level space that originally lay between the foot of the embank-
ment and the edge of the channel has been entirely eaten away,
and in one place a portion of the levee itself has slid into the
river. On the opposite shore the erosion has been even more
rapid ; the entire face of the sand heaps described in the pre-
vious paper has disappeared, and on the continually slipping,
almost perpendicular wall of sand that remains no living thing
has so far been able to establish a foothold. And since the two
bridges which formerly connected the newly made island on
which these sand heaps lie with the mainland have been de-
stroyed, the reverse slopes are as much of a terra incognita as
the other side of the moon. Finally, the western end of the
Levee lias been graded and everything there is reduced to hopeless
chaos.
There remains, then, only the actual embankment of the
Levee proper in anything like its original shape, and here alone
conditions have taken their normal course, so that it is only on
this part of the entire original area that any observations at all
were worth while.
]See Iowa Academy of Science Proceedings, Vol. XXII, p. 135.
4 24 IOWA ACADEMY OF SCIENCE
On this area the weeds have succeeded very well for one
year's work, and have made conditions much more comfortable
for themselves. They have bound at least the surface soil with
their roots, so that there is much less washing than there was
during the preceding season. The presence of algae and mosses,
and of a few specimens of Equisetum arvense, testify to im-
proved moisture conditions. Some of the plants first observed
(notably the survivors of the former cultivated state) have
disappeared: lack of time for careful botanizing has prevented
the preparation of a list of the missing. Most of the plants
still remain and thrive, however, and a few new arrivals may
be reported. Two of them. Salsola tragus and Lepidium vir-
ginicum, were probably rolled in as tumbleweeds from the rail-
road embankment against which one end of the levee abuts;
the remainder (listed below) were probably wind-sown.
The main point of interest in this year's observation, how-
ever, is concerned with the changes of dynasty which are tak-
ing place in this little corner of the vegetable kingdom. In
the first paper the pigweed. Amarcmtliiis retroflexus, was re-
ported as the dominant plant. A prolific seeder, holding more-
over a goodly proportion of its offspring until well into the
following growing season before launching them on their colon-
izing ventures, it was well prepared to become master of the
situation presented by the newly bared soil exposed after spring
was well advanced. With it, as noted before, went the goose-
foot. Chenopodium album, which possesses some of the same
characteristics. A considerable sprinkling of this plant was in-
- >ersed with the dominant amaranth, but the amaranth re-
mained after all the king of the colony during the first season.
But with the arrival of the second spring the situation was
radically changed. The Chenopodium proved to be an early
riser, and thus got the start of its cousin weed. During the
latter part of March the writer went over the ground, and the
principal sign of life on the levee was the presence of Chena-
podium seedlings all over the place. They were as ubiquitous
as the Amaranthus had been during the preceding season, and
in places formed dense sods. Xo seedlings of the pigweed were
as yet to be seen. Observations a couple of months later showed
the logical result. The dominant plant was now the Chenopo-
PIONEER PLANTS ON A NEW LEVEE 425
(Ham, and specimens of Amaranthus were few and far between.
Handicapped from the start, only a scattering stand had de-
veloped, and these poor individuals were having a hard fight
for existence. Shouldered and smothered by their neighbors,
they showed little trace of the sleek prosperity that had been
the lot of their parents the summer before : the kingdom of the
amaranth was at an end.
But even then a new race was beginning to rear its head
among the ranks of the Chenopodiuni; a possible rival that
might drive it. in its turn, into extinction. During the second
summer a few specimens of Lactuca scariola were observed on
the area. They maintained their place and bore their seed.
so that by the latter part of the summer the winter rosettes
of this plant were showing themselves wherever there was an
inch of free ground, and they even established themselves be-
tween the stalks of the Chenopodiuni where it was not too thick.
Long after the early frosts and snows had killed the last of
the goosefoot these rosettes of the wild lettuce held their color,
and before the seedlings of the third year made their appear-
ance they were again at work. "Where Chenopodiuni had taken
but a few weeks' advantage of Amaranthus, Lactuca profited by
nearly half a year's handicap. At the 'beginning of the present
season (1916) the wild lettuce shows very strong evidence that
it is going to give the goosefoot a hard fight for its position as
the dominant plant. It is the most eloquent sermon on prepar-
edness that one can imagine.
One other factor thrusts itself into the situation. In the
first paper note was made of the dominance of the tall rag-
weed. Ambrosia trifida. on a small area, the reverse slope of
the levee at its extreme eastern end. During the si seas
this weed added to its original territory the river side of the
same part of the embankment and at the beginning of the third
season its seedlings are in evidence in advanced positions on
other portions of the area. It may be that this invasion will cut
off the feud between Chenopodium and Lactuca before they have
a chance to carry the contest to a finish.
426
IOWA ACADEMY OF SCIENCE
It is not likely that Chenopodium can hold its own against
this army; Ambrosia has the same advantage of fecundity and
early germination of seed. Whether Lactuca also will be swept
down remains to be seen. It will be an interesting fight.
NEW SPECIES APPEARING DURING THE SEASON OF 1915.
Equisetum arvense.
Elymus robustus.
Sisymbrium officinale.
Polygonum aviculare.
Polygonum erectum.
Salsola Tragus.
Lepidium virginicum.
Potentilla monspeliensis.
Trifolium repens.
Verbena hastata.
Erigeron canadensis.
Antbemis Cotula.
Artemisia biennis.
Lactuca scariola.
Botanical Laboratory,
Grinnell College.
THE FLORA OF SITKA, ALASKA 12'
NOTES ON THE FLORA OF SITKA, ALASKA.
JACOB PETER ANDERSON.
INTRODUCTORY REMARKS.
On February 1, 1914, the writer began his duties in connec-
tion with the United Stairs Agricultural Experiment Station
at Sitka, Alaska. This math' necessary a change in thesis sub
jeet and at the suggestion of Dr. Pammel, in whose department
the major work was taken, the above subjed was chosen.
The matter presented is based <>n collections, observations,
ami research during a period of two years. The facilities of
the Experiment Station have been at the disposal of the writer,
but these are quite limited, both as to literature and equip-
ment. The region covered is that within easy walking or -motor
boat distance of the town of Sitka, but owing to the limited
time for the purpose, this region has not been as thoroughly
explored as it should be.
The Experiment Station has an herbarium containing sev-
eral hundred specimens, but it is far from complete, except in
the grasses, of which there is a good collection. The specimens
from the vicinity of Sitka in said herbarium were collected by
Professor C. C. Georgeson, head of the Alaska Experiment
Station, and Drs. W. 11. Evans and C. V. Piper of the De-
partment of Agriculture at Washington. To these will lie
added the collections of the writer.
This thesis, as originally planned, was to consist of three parts:
pari one, to contain notes on the general aspect of the flora
with special reference to ecology and economic plants; pari
two, to be a systematic list of the Pteridophytes and Sperma-
tophytes; while part tin was to deal with the fungus flora.
Owing to inability to gel determinations on some plants, part
two is omitted for the present. bu1 will he presented later, as
will also notes on groups of parasitic fungi not taken up in
detail in part three of the [.resent paper.
In the preparation of these notes, special acknowledgements
are due In Dr. L. II. Pammel of Iowa State College, at Ames.
428 IOWA ACADEMY OF SCIENCE
under whose general supervision they have been prepared, to
Mr. E. W. Merrill, of Sitka, who has kindly furnished the ex-
cellent series of photographs for the plates, many of which
were taken expressly for this purpose, and to Dr. J. C. Arthur,
oi Lafayette, Indiana, who has identified the rust fungi.
THE FLORA IN GENERAL.
TOPOGRAPHY AND CLIMATE.
Sitka is located on the west, or seaward side of Baranoff
Island in latitude 57° 3' North, and longitude 135° 20' West.
It is built partly on gravelly soil, which is an old beach de-
posit, and partly on some low hills. In the rear of the town
is a peat bog or Muskeg, beyond which are some low hills alter-
nating with Muskeg until the base of the mountain is reached,
which is less than a mile from the shore line. In most places
in the region around Sitka, the distance from the sea to the
base of the mountains is much less, as in many places the sea
actually beats against the steep slopes of the mountain sides.
Except some small areas at the mouths of streams and on the
Muskeg the region is all heavily timbered up to about 2,500
feet elevation. The mountains rise to elevations of from 1,800
feet to more than 4,000 feet, with some peaks in the interior
of the island about 5,000 feet in height. On some of the higher
slopes small glaciers occur.
The shore line is very irregular and the sea in the vicinity
is studded with islands. All except the smallest of these islands
are forested.
The soil along the shore line consists of coarse gravel mixed
with a black material composed mostly of decayed organic mat-
ter. Farther in we find some orange-colored soils supposed to
he ancient volcanic ash from Mount Edgecombe. This of itself
seems almost absolutely sterile to plant growth. This volcanic
ash is covered with a layer of muck and peat, varying in thick-
ness. Moss prevails nearly everywhere. At many places, espe-
cially on the steeper mountain slopes, there is scarcely any-
thing that could be called soil.
The climate of Sitka is moist and equable. The precipita-
tion averages about 85 inches per annum. Spring and summer
are drier than autumn and winter. June is the driest month,
with an average rainfall of 3.46 inches, while October is the
THE FLORA OF SITKA, ALASKA 429
wettest with 11.64 inches. The absolute minimum precipita-
lion recorded at Sitka is .45 inches for July and the absolute
maximum is 25.52 inches for September.
The average temperature is about 44 F. with only 23° dif-
ference between the averages for January and July. The av-
erage for the former is between 32° and 33° F., while for the
latter month it is between 55° and 56° F. The absolute mini-
mum ever recorded is — 4° F., while the maximum is 87° F.
There is but little sunshine. There may be weeks at a time
when the sun shines every day, and again there may be weeks
at a time when the sun is not seen at all. The actual sunshine
for the year is probably not smore than one-fourth the possible
amount. During the growing season, the days are long. Near
the summer solstice they are nearly eighteen hours long, the
sun dipping only about 91/2° below the horizon. Twilights
are long.
HISTORICAL.
Sitka having been the Russian capital, as well as the American
capital until 1906, it is but natural that more or less collecting
of botanical material should have been done in the vicinity. The
writer has not had the opportunity to examine into this phase
of the subject, but a few facts have been gleaned incidentally.
It appears that Henry Mertens of Lriitke's expedition and H.
G. Bongard1 in 1832 described a number of species of plants
from Sitka, C. B. Trinius describing the grasses. A. Kellogg
visited Sitka in 1867.
Since the American occupation a number of collectors, in-
cluding A. S. Hitchcock, H. C. Cowles and others, have visited
Sitka, including the Harriman Alaska Expedition in 1899. Co-
ville, Trelease and Saunders were of this expedition. The
specimens in the Experiment Station herbarium were collected
by C. V. Piper, W. H. Evans and C. C. Georgeson. A number
of other collectors have been in the vicinity but the writer does
not, at present, have definite information concerning them.
The following list of type species is incomplete. It is largely
gleaned from Professor Piper's work, which includes only such
species as are found in the state of "Washington.
430 IOWA ACADEMY OF SCIENCE
Agrostis aequivalvis Picea sitchensis
Alnus sitchensis Poa leptocoma
Arnica latifolia Pteridium aquilinum pubescens
Bromus sitchensis Pyrus diversifolia
Carex mertensii Romanzoffia sitchensis
Carex sitchensis Salix sitchensis
Cassiope mertensiana Saxifraga bongardi
Cladothamnus pyrolaeflorus Saxifraga mertensiana
Claytonia asarifolia Scorzonella borealis
Corallorhiza mertensiana Sorbus sitchensis
Elymus borealis Trisetum cernuum
Festuca subulata Tsuga mertensiana
Juncus mertensiana Valeriana sitchensis
Lycopodium sitchense Washingtonia purpurea
LIFE ZONES REPRESENTED.
There are three of the life zones represented. These are the
Canadian, Hndsonian and Arctic-Alpine. Owing to the moist
and equable conditions the limits of these zones are not well
defined. "While characteristic Canadian species, such as Corn us
Canadensis and Sanguisorba latifolia, occur down to the sea
level, we find a liberal admixture of species generally classed
as Humid Transition. These, indeed, include some of our com-
monest species such as Rubus spectabUis and Ecliinopanax hor-
ridum. On the other hand, some of the characteristic Hud-
sonian plants are also found near sea level and growing freely
in company with the Humid Transition and Canadian species.
Among these may be mentioned NephropKyllidiwm crista-galli.
Even some Arctic-Alpine plants grow freely near sea level and
among these may be mentioned Emp( trum mgrwm, which is the
most abundant and characteristic of all the higher plants grow-
ing on the peat bogs or Muskeg.
The characteristics of the Arctic-Alpine zone appear at about
2.500 feet elevation. Plants properly belonging to the Hud-
sonian zone may reach an elevation of nearly 3,000 feet, while
the Canadian species may reach 2,000 feet.
HABITAT GROUPS.
In considering the ecological aspects of the flora one finds
that the plants can be segregated into a number of habitat
groups. These are quite well defined, corresponding to their
physical environment. Mixtures generally occur only in in-
termediate situations. The typical habitats are five, as follows:
Littoral, Forest, Muskeg, Aquatic and Alpine. To these might
be added a sixth — the weed habitat. These will now be taken
up separately.
THE FLORA OF SITKA, ALASKA
431
LITTORAL FLORA.
(PLATE XT I.)
Included in this group are the species that are found only,
or most abundantly, on the sea beaches or their immediate
vicinity. Some of these species thrive on rocks where there is
scarcely any soil visible. Others occur on gravelly soil. Nearly
all the soil found in the immediate vicinity of the sea is com-
posed largely of coarse gravel, while in many places the shore
is composed of bowlders, or large rocks, in the crevices of which
the plants may find some decayed matter and obtain a foot-
hold. The Mowing list includes the more typical plants found
in this environment :
Ammodenia peploides
Atriplex littorale
Campanula sp.
Cochlearia officinalis
Draba sp.
Elymus mollis
Fritillaria camtschatcensis
Glaux maritima
Ligusticum scoticum
Pedicularis sp.
Plantago maritima
Polygonum paronychia
Polygonum viviparum
Potentilla villosa
Rhinanthus crista-galli
Sisyrinchium sp.
Triglochin sp.
Vicia gigantea
In addition to the group given above there are certain plants
that, while not strictly littoral in their habits, are seldom found
at any great distance from the sea and are not properly forest,
marsh, or aquatic plants. These include several of the grasses,
prominent among which are two species of Calamagrostis — C.
aleutiea and C. langsdorfii. Other plants of this habit are the
following :
Achillea borealis
Anaphalis margaritacea
Aster peregrinus
Barbarea vulgaris
Conioselinum gmelini
Epilobium affine
Epilobium angustifolium
Geum macrophyllum
Lepidium sp.
Malus diversifolia
Mimulus langsdorfii
Monarda sp.
Pinus contorta
Potentilla anserina
Ranunculus sp.
Ranunculus tenellus
Rosa nutkana
Salix sitchensis
Sanguisorba latifo'.ia
Sorbus sitchensis
Tissa marina
Veronica americana
-
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434 IOWA ACADEMY OF SCIENCE
MUSKEG FLORA.
(PLATE XXI I.)
The term Muskeg, as here used, includes the formations
variously called peat bogs, marsh and tundra. The last name,
however, should uot be used, as the Muskeg is quite different
from the true Tundra which surrounds the Arctic Ocean.
This formation consists of peat covered by a layer of moss,
mostly Sphagnum. The layer of living and dead, but still
undecomposed moss is often a foot in thickness. The depth
of the peat varies from a few inches to many feet. On the
Muskeg north of the town of Sitka, a hole twelve feet in depth
failed to reach the bottom. Scattered about are pools, the
surface areas of which vary from a few square feet to several
square rods. These pools are generally shallow, but their bot-
toms are exceedingly soft. In walking over even the firmer
portions of the formations one mires a few inches.
Conspicuous features also include the tree growth and small
stumps. Except along the edges and the water courses these
trees seldom exceed five or six feet in height and are old and
decrepit looking. Finns contorta is the most abundant but
Tsuga hcterophylla is common and Chumaccyparis nootkatensis
is occasional. There is a tendency for the formation to be
built up around the base of these trees and especially around
the stumps. This gives rise to slight elevations on which such
forest species as Cornus canadensis, Menzeisia ferruginea,
h'uhiis pedatus, and Vaccinium vitis-idaea are generally found.
The most abundant and characteristic plant of the Muskeg
other than mosses is the Crowberry (Empetrum nigrum). It
occurs from sea level to well above timber line. The Ericaceae
are well represented. Andromeda polifolia, Kalmia glauca,
Ledum groenlahdicum, Vaccinium Oxycoccus and Vaccinium
uliginosum are common at the lower altitudes and Chamaecystis
procumbens occurs locally. Buous chamaemorus is one of the
commonest species as is also the interesting little sundew, Drosera
rotundi folia. A few species of sedges (Carex spp.) are found
growing on the Muskeg, but the majority of species prefer the
wet soil along the banks of streams or lakes. The cotton grass
(Eriophorum polystachyon) is very conspicuous when in fruit.
THE FLORA OF SITKA, ALASKA 435
Other plants found in this habitat arc as follows:
Coptis trifolia Limnorchis leucostachys
Dodecatheon sp. Parnassia palustris
Gentiana douglasiana , Pinguicula villosa
Juncus balticus Pinguicula vulgaris
Juncoides campestre Scirpus caespitosus '
Lycopodium annotinum Tofieldia intermedia
Lycopodium elavatum Trientalis arctica
Limnorchis dilatata
AQUATIC FLORA.
(PLATE XXIII.)
So far as the higher forms of plant life are concerned, this
is the smallest division of the flora. Only one species has been
noted as occurring in salt water and that is Zostera marina.
The fresh water forms are a water lily (Nymphaea polysepala),
two species of Potamogeton (P. natans and P. heteropkyllus) ,
Cdllitricht verm, and Myriophyllwm sp., Menyanthes trifolia.
Comarwm palustre, Spcvrganium sp., and Co rex spp. represent
the semiaquatic species.
ALPINE FLORA.
Under this head are included all species that reach their
maximum abundance at or above the ordinary line of timber,
which in some cases may be somewhat less than 2.500 feet.
Most of these belong to the Arctic-Alpine life zone, but some
lludsonian species are included. Their typical habitat is the
Alpine meadows or the crevices of rocks. A very few extend
down to sea level and several others are found occasionally be-
tween sea level and timber line. The soil at this elevation is
largely of a peaty nature but drier and witli less moss than the
Muskeg. Empetrum nigrum is still very abundant and members
of the Ericaceae are among the commonest forms. The following
list includes the species of this group so far as observed.
Anemone narcissiflora Hieracium gracile
Arctoranthis cooleyae Lupinus nootkatensis unalaskensis
Artemisia borealis Lutkea pectinata
Campanula sp. Lycopodium sitchensis
Cassiope mertensiana Nephrophyllidium crista-galli
Cladothamnus pyrolseflorus Pedicularis sp.
Cryptogramma acrostichoides Phyllodoce glanduliflora
Epilobium sp. Saxifraga spp.
Erigeron sp. Sieversia calthifolia
Gentiana sp. Tsuga mertensiana
Harrimanella stclleriana Valeriana sitchensis
436 IOWA ACADEMY OF SCIENCE
WEED FLORA.
Of all the weeds that occur in the area covered by this paper,
there is one that stands out pre-eminent as causing more trouble
than all others combined. That species is the common chick-
weed, Alsine media. The spurry (Spergula arvensis) probably
would rank second in importance with sorrel (Rumex acetosella)
third. The following list includes all the species that have
as yet become important in this habitat group. It includes
several introduced species as well as a few that are included in
other lists.
Brassica arvensis Montia fontana
Bursa sp. Plantago major
Cardamine sp. Ranunculus repens
Cerastium spp. Rumex obtusifolius
Epilobium angustifolium Rumex occidentals
Epilobium affine Senecio vulgaris
Matricaria matricaroides Taraxacum officinale
Mimulus langsdorfii Veronica americana
Monarda sp. Veronica serpyllifolia
In addition to the foregoing, the following have been found,
having been introduced with seed, packing, etc. They are, as
yet, quite rare and of almost no importance from an economic
standpoint. Some may in time become established.
Agrostemma githago Saponaria Vaccaria
Anthemis cotula Sisymbrium officinale
Camelina sativa Solanum nigrum
Cbenopodium album Soncbus asper
Polygonum convolvulus Vicia angustifolia
Polygonum pennsylvanicum
Mention might also be made of a parasite, Razoumofskya
douglasii tsugensis (Plate XXIV), which causes much damage
to the Western hemlock (Tsuga Jietcropltylla) . It attacks the
branches causing them to enlarge and proliferate. Scarcely a
host tree of any size is free from the parasite.
ECONOMIC PLANTS.
The economic plants of Alaska naturally arrange themselves
in three groups: 1. Forest trees. 2. Grasses and forage plants.
3. Fruit-bearing plants. These will now be taken up in their
order.
FOREST TREES.
Of all the plants native to the coast region of Alaska, the
Sitka or Tideland spruce (Picea sitchcnsis) is by far the most
THE FLORA OF SITKA, ALASKA
valuable. It dominates the foresl from Dixon Entrance to
Prince Williams Sound. In the vicinity of Sitka it extends
from sea level to 2,500 feel elevation. It attains lai
Logs, six feet in diameter, are sometimes received by the saw-
mill at Sitka, but the average for the butl Logs probably would
be about four feet. Three of the larger standing trees near
the Experiment Station, as measured by the writer, were L9
feet 2 inches, 18 feet 5 inches, and 16 feel 4 inches, res] tively,
in circumference about six feet from the base. It furnishes
very good saw timber. The wood is Light, soft, from tine to
moderately coarse-grained. Its color is generally pale brown,
often with a fine tinge of red. It is a long-lived species and
the larger trots may be several centuries old. According to
Sudworth3 this species may attain a diameter of 12 ft -t and an
age of probably 800 to 850 years. In addition to furnishing
nearly all the native Lumber used in the region of its occur-
rence there is a large probability that in course of time it will
furnish the basis for a wood pulp industry.
In size and number of individuals the Western hemlock
(Tsuga heterophylla) is second only to the Sitka spruce. It
may dominate the forest locally. A mature tree which was
already dead measured 14 feet J inches in circumference, but
it was not possible to reach high enough to get clear of the
buttressed trunk. Close by a typically mature tree measured
10 feet 9 inches in circumference. The wood is rather light,
soft, fine-grained, pale yellowish brown with slightest tinge
of red. The bark is claimed to contain a larger percentage of
tannin than that of the Eastern hemlock (Tsuga can<i<l< ■
It is our most shade-enduring tree and the young plants may
be found growing in the moss covering the earth, old trunks.
rocks, etc.
Mountain or Black hemlock (Tsuga mert( i has com-
paratively little value. It is really an Alpine tree and reaches
its greatest number of individuals at or above the limit reached
by the other conifers. Above 2,500 feet, it is the only tree
found and here it is usually Low and sprawling. Well grown
trees of moderate size occur in the forests, but the sp
comes rare as one approaches sea level.
The third forest tree in point of importance is Ghamaecyparis
nootkatensis, locally called Yellow cedar, or simply cedar. It
438 IOWA ACADEMY OF SCIENCE
occurs from sea level up to above 2,000 feet. It is not so
large as the Sitka spruce or Western hemlock, the largest trees
observed by the writer being somewhat less than two feet in
diameter. The wood is sulphur-yellow in color, very fine-
grained, and comparatively heavy for its class. It is remark-
ably durable, works easily, and is valuable for interior finish.
Firms contorta occurs mainly on the Muskeg where it is a
stunted shrub. Well grown trees of moderate size occur in
favorable locations, but they are infrequent. The wood is hard
and resinous.
Red alder (Abuts oregona) is largely confined to the banks
of water courses, where it may reach a diameter of one foot or
more. The wood is pale reddish brown, light, and fine-grained.
It is sought locally for fuel.
The Sitka alder (Abuts sitchensis) has a wider range of
habitat than the Red alder, but does not grow so large.
GRASSES AND FORAGE PLANTS.
A large number of grasses are native to the region but there
are three species that are outstanding from an economic point
of view. These species are the Beach rye (Elymus mollis) and
two species of Calamagrostis (C. aleutica and C. langsdorfii) .
The first is rather large and coarse but is claimed to make fine
feed and silage. It occurs on the beaches and tide flats. The
species of Calamagrostis attain a height of from three to six
feet and are often called Alaska redtop.
Sedges are not generally so palatable or nutritions as grasses
but may be used for feeding stock. Sedges are especially
abundant on the borders of lakes (Plate XXIII).
Only one native legume is abundant enough to be of any
value whatever as a forage plant. That one is Vicia gigantea.
It occurs only near the sea.
FRUIT-BEARING PLANTS.
The majority of the fruit-bearing plants of Alaska belong
to three genera, Ribes, Rubus, and Vaccinium. Several other
groups are represented by one or two species.
Of the five species of Ribes native to Alaska, only two are
found in the vicinity of Sitka. These are R. bracteosum and R.
laxi [lor um. Ribes bradteosum (Pint.' XXV) is very abundant
and one of the most valuable of the native fruits. The bush
THE FLORA OF SITKA, ALASKA 439
has a tendency to be straggling, but the growth is very stout.
The diameter of a season's growth often equals one-half inch.
The racemes are long but the berries are rather scattered. In
size it compares quite favorably with the garden black currant
(Ribcs nigrum) and has that same aroma, but to a more marked
degree. The fruit is black, covered with a dense white bloom.
All parts of the plants contain glands. Under favorable con-
ditions it is very vigorous and the writer has found racemes
12 14 inches in length, while the leaves may reach an extreme
length and width of about eight inches, a leaf of this size hav-
ing been measured.
The fruit of the wild plant is utilized to a considerable ex-
tent. This species is quite promising for use in plant breed-
ing. Crosses with Ribes nigrum show a vigorous growth the
first year, with no appreciable difference between reciprocal
crosses.
Ribes laxiflorwm is a much more slender plant than R. brac-
teosum with a tendency for the canes to become prostrate and
take root. It has a fetid odor while the taste of the fruit is
rather sweetish and insipid. The clusters and berries are about
the same size as that of the common garden currant (Ribes
rubrum), but the fruit is black with whitish bloom and raised
glands. It is of little value.
Of seven species of Rubus known to occur in Alaska five
are found in the vicinity of Sitka. These will be taken up in
order of their importance.
The Salmonberry (Rubus spectabilis) (Plate XXVI) forms
dense jungles near the sea, along water courses, and in open
forests. The canes are perennial, often attaining a diameter
of one inch or more and a height of ten to twelve feet. Canes
one inch in diameter often show five or six annual rings. Flow-
ers are rose pink and come out very early. The fruit begins
to ripen by the middle of June and continues until August,
being at its height about July 1st. It is twice the size of ordi-
nary raspberries, and consists of rather large, soft drupelets.
The color varies from lemon yellow to dark red. It can be had
in large quantities and is utilized to some extent. The flavor
is different from that of any other berry. Crosses with the
red raspberry (R. strigosus) have proven almost entirely
sterile, as the pistils and stamens do not seem to develop
properly.
440 IOWA ACADEMY OF SCIENCE
The Thimbleberry (Rubus parviflorus) is only locally com-
mon. It is in cultivation for its large white flowers. The
canes are imperfectly perennial, but are seldom more than four
to five feet high. The fruit is depressed hemispheric, composed
of numerous drupelets, red when ripe and of fair quality.
Rubus Chamaemorus, the Cloudberry, known among the Rus-
sians as Maruski, is common all over the Muskeg. It is her-
baceous with creeping rootstock and erect branches. Each
branch has one or two leaves and often a white flower. The
fruit is the size of a large raspberry and consists of few but
large drupelets which are amber to red when ripe. The natives
are very fond of it and often gather it before it has thor-
oughly ripened. The quality is quite good.
Rubus stellatus resembles R.' chamaemorus in habit, but pre-
fers better drained locations and is not so abundant. The
flower is pink. The red fruits are of good quality.
Rubus pedatus is a delicate creeping vine with five-foliate
leaves found in abundance in forest and brushland. The fruit
consists of from one to six rather large, distinct, red drupelets.
While the quality is fair, it has but little value.
The strawberry (Fragaria chiloensis) though abundant in
many places in the coast region of Alaska seems to occur around
Sitka only as an escape from former cultivation. The fruit is
quite large for a wild berry, and of excellent flavor.
The Crab apple {Mains diversifolia) (Plate XXVII) is a
shrub or small tree which bears round to oblong fruit varying
in size from that of a pea to three-fourths of an inch in length.
In quality it is pleasantly, though rather strongly acid, without
any trace of astringency. The fruit is used for making jelly
and it also has value for the plant breeder.
The Vacciniacea3 are represented by not less than seven
species, every one of which has some value.
Vaccinium ovalifolium, the earliest species to ripen, is very
abundant and produces a fruit which averages about three-
eighths of an inch in diameter, dark blue, with bloom and of
good quality. It begins to ripen in June and continues through
July. It is much used, especially for pies.
Vaccinkim parvifolium (Plate XXVIII), the Huckleberry,
is also very abundant, and reaches its maximum development
THE' FLORA OF SITKA, ALASK \ 441
in the dense shade near the base of Ihe mountains. It is of a
clear, bright, almost transparent red and of aboul the same
size as the Early blueberry, although occasionally bushes bear
much large fruits and the writer noted one the pasl season
where the berries averaged better than one-half inch in diam-
eter. It is of good quality and much used. It ripens in Augusl
and September.
Vaccinium chamissonis (Plate XXIX, is another Bighbush
blueberry that is abundant. It bears the largesl fruit of any
member of the genus, bu1 the quality is nut equal to thai of
the other species and many of the fruits are wormy; hence,
it is not used to any great extent. The Fruit is round to pyri-
form. purplish black, with scarcely any to very dense bloom.
Berries five-eighths of an inch in diameter are sometimes l'"nnd.
The forms included under this head may form mere than one
species. The pyriform, black, bloomless fruit is quite distinct
from the round to slightly depressed fruit with heavy bloom,
but intermediate forms occur.
Vaccinium uliginosum is a low growing species common on
the Muskeg'. The blue berries are somewhat oblong in shape
and ripen late. It is often gathered for use.
Vaccinium caespitoswm (Plate XXX), is another low -row-
ing form and extends from sea level to above timber line. Tie
fruit is somewhat smaller than that of the Bighbush blueberries,
but it excels them all in quality. While fairly common it is
not abundant enough to he gathered economically.
Vaccinimi vitis-idaea (Plate XXXI. figure 1 . He' .Mountain
cranberry, is our most valuable species of the -roup, h Is dark
red and is borne in small clusters at the end of the branches. It
is an evergreen species with creeping stem and semi-ered
branches. While the fruit is rather small it occurs in abundance
and is used to a greater extenl than any other native fruit.
It is considered superior in quality to the cranberry of the
states (Vaccinium macrocarpon) and was formerly shipped
from Sitka in considerable quantities, but, of late years the
native women have found other lines of work more profitable
and the export of these berries has dwindled to a very small
amount. It is often kept for months in a fresh state in cold
water.
ic~ v s::z>:
Plate XXXI. figure "2 Swamp
ranberry _ - States
t the s t s aller and Yaria"
l almost hidden in the
skeg. It is rnon ai: - 1 ex-
-
ligrum is abundant
_ ts t is t us s 1 is
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Lental s rub.
food
Alaska.
- -
DESCRIPTION OF PLATES
Plates are all from photogr. rrilL
PLATE XVI.
Scene on a small island near Sitka. Near the rock just below the
center may be seen some Blue bells {Campanula sp.). The white-
flowered plant with finely divided leaves is Achillea borealis; the one
with ternately decompound leaves is Conioselinum gmelini; the fern is
Polypodium vulgare; the grass is Hordeum boreale, while the species
that is so dominant at the top is Fireweed (Epilobiiim angustifoUum) .
Some leaves of a native Currant (Ribes bracteosum) may be seen
near the center.
Iowa Academy Science
Plate XVI
■.:,.'. ■
PLATE XVII.
View along a stream showing jungle-like growth along banks. This
growth is composed mostly of Salmonberry (Rubus spectabilis) .
The large-leaved shrub is Devil's Club (EcJiinopanax horridum) .
Mixed in are Vacciniums and Currant (Ribes bracteosum), but these
do not show in the plate. Note the Witches' brooms on the hemlock
[Tsuga Heterophylla) , leaning out over the stream, also the moss and
lichens hanging from the branches of this and the spruce just back
of it. A young plant of Alder {Alnns sp.) appears in the lower left,
while a- plant of Kruhsia streptopoicles is seen at the lower right
corner.
PLATE XVIII.
Scene at 800 feet elevation showing dense growth of Vacciniums in
the foreground. The two trees in the center (one of which is dead),
are Hemlock (Tsuga TieteropJiylla). Spruce (Picea sitchensis) may-
be seen in the background.
Iowa Academy S
Plate XVI II
PLATE XIX. •
Heavy timber at 800. feet elevation. The large trees in the fore-
ground are Sitka spruce (Picea, sitchensis). In the left background
are Western hemlock {Tsuga heterophylla) . The large-leaved plant
is Skunk cabbage (LysicMton camtschatcense) . The shrubs are
species of Vaccinium. Cormis canadensis may be .seen at the base of
the large tree in the foreground, and immediately to the left is a
plant of a species of Streptopus.
Iowa Academy Science
1'I.ATE XIX
ered -
old grow:
7 - .
- vrium eycloeorum
? I
PLATE XXI.
An open formation at 1800 feet elevation. The most prominent
species on the Muskeg here is Cotton grass (Eriophoriim polystachyon) .
A dying cedar (Chamaecyparis nootkatensis) appears on the extreme
right and other cedars, spruce, and hemlock are seen to be growing in
association.
PLATE XXII.
View of Muskeg ncrth of Sitka. Note the water holes and stunted
trees. These trees are mostly Pine (Pinus contorta), but a few
Hemlock (Tsuga heterophyHa) are visible. The trailing bushes to
the left of the central water hole are Vaccinium uliginosum. Clumps
of Sedge (Carex spp.) and leaves of Cloudberry (Rubus chamaemorus)
are also in evidence.
PLATE XXIII.
Scene on Swan Lake, north of Sitka. Xote the Water lilies (Xym-
pJiea polysepala) to the left of which Potamogetons may be seen with
Menyanthes trifoliata at extreme left. On opposite shore is a dense
growth of Carex. The nest containing twro eggs is that of the Red-
Throated loon and is built on a floating mass of vegetation.
Iowa Academy Science
Plate XXlll
PLATE XXIV.
A branch of Western hemlock (Tsuga heterophylla) showing a
severe infection of Razoumofskya douglasii tsugensis. This causes
the branch to proliferate and form a Witches' broom.
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PLATE XXV.
A branch of Currant {Ribes bracteosum) , showing typical fruiting
habit.
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Bag- . ■ Set P
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XXVI
- -
PLATE XXVII.
A branch showing fruit of native Crab apple (Malus divcrsifolia) .
Iowa Academy Science
Plate XXVI r
PLATE XXVJ1I.
Branches of Huckleberry (Yaccinium parvifolium)
-
PLATE XXIX.
Branches of the Late blueberry (Vaccinium chamissonis) .
Iowa Academy .-
Plate X X I X
PLATE XXX.
A Low bush blueberry (Vaccinium cacspitosum) .
Iowa Academy Sciem e
Plate xxx
PLATE XXXI.
Fig. 1. — The Mountain cranberry (Vaccinium vitis-idaea).
Fig. 2. — The Swamp cranberry (Vaccinium Oxycoccus) .
THE FLORA OF SITKA, ALASKA 477
THE FUNGUS FLORA.
"Work on the fungus flora has been largely confined to para-
sitic forms or those appearing on particular hosts shortly after
the death of the plant. Of the groups to which little attention
has been paid, the Agaricacese should receive mention on ac-
count of their abundance in both species and individuals. Sev-
eral species arc gathered and used as food.
During- the past two years, during which time the writer
has been at Sitka, a collection of nearly 300 numbers of fungi
has been made. In this collection imperfect forms and Pyre-
nomycetes greatly predominate. While many of the species are
known, there are so many unidentified forms in most orders and
families that it is deemed advisable, at this time, to consider
only two groups — the Erysiphacese and the Uredinales — leav-
ing the other groups until further identifications may be made,
when it is hoped to present the same in considerable detail.
ERYSIPHACEjE.
The Erysiphacea?, commonly called Powdery mildews, are not
so abundant as they are in many other localities. They were
collected on only about fifteen different host plants, whereas the
writer found them to occur on at least 186 hosts in the State
of Iowa,4 and Salmon5 enumerates a host index of much more
than 1,200 species.
In this list, and also the one that follows, on the Uredinales,
the numbers in parentheses which follow the name of the host
plant refer to the collection number.
Sphaerotheca humuli (DC.) Burr. Hop Mildew.
On Epilobium affine Bong. (72). On this host the mildew-
seems very destructive at times, and is quite widespread.
On Fragaria chiloensis (L.) Duchsne. What appears to be
the conidial stage of this mildew is troublesome in the
greenhouse on young plants which are hybrids of this
species.
On Fragwria platypetala Rydb. This species also is affected
in the greenhouse.
On Ribes aurcum Pursh. (248). Only one slight infection
observed on this cultivated species.
On Ribes bractcosum Dougl. (73 and 188). Not widespread
but sometimes quite severe on this native currant. Some
478 IOWA ACADEMY OF SCIENCE
young hybrid seedlings of this species and the garden black
currant (B. nigrum) became severely infected during the
fall of 1915. It has not been observed on B. nigrum.
On Bibes rubnum L. (190). Does not seem to be severe on
this host and there seems to be a great deal of difference
in the resistance of the different varieties. Of the red cur-
rants grown at the Station, Perfection seems to be most
susceptible.
On Bubus speetabilis Pnrsh. (187). Infection seems to be
severe, but local.
Spaerotheca mors-uvae (Schw.) B. & C. Gooseberry mildew,
this can be distinguished from the preceding by its dark,
dense, felted mycelium. It is abundant on the fruits while
S. liumuli is mostly confined to the leaves, petioles and young
stems.
On Bibes lacustre (Pers.) Poir. (74). During 1914 this
species was very abundant and destructive, being found
on berries, leaves and stems. Scarcely a fruit escaped its
ravages. During 1915 it did but little damage. Two thor-
ough sprayings with Bordeaux mixture helped to keep it
in check. The host is native to Alaska, but ddes not occur
near Sitka.
On Bibes uva-erispa L. (75). Very abundant and destructive
on some varieties of the English gooseberry, while other
varieties (e. g. "Whitesmith) seem nearly immune.
Sphaerotheca pannosa (Wallr.) Lev. Rose mildew.
On Bosa sp. (180). This mildew is common and troublesome
on many of the tea roses grown indoors.
Erijsiphc graminis DC. Grass mildew. This species is not
abundant, but the conidial stage occurs sparingly on a few
grasses.
On Agrostis exarata Trin. (191).
Erysiphe sp. The conidial stage of a mildew has been collected
on Achillea borealis Bong., and on Banunculus sp. The for-
mer may be E. dehor aeearum, DC., while the latter probably
is E. polygoni DC.
Microsphacra alni (Wallr.) Wint, Alder mildew. This species
does not seem to be common.
THE FLORA OF SITKA, ALASKA 479
On Alnus sitchensis (Regel) Sarg. (213).
Uncinula solids (DC.) Wint. The Willow mildew was collected
at Skagway, by the writer, July 13, 1915, on Popuhis tricho-
carpa T. & G. (192), but has not been observed at Sitka.
UREDINALES.
This interesting group of obligate parasites is quite well rep-
resented, and most of the species are of more or less economic
importance. Following the general usage the Roman numerals
are used in the following notes to designate the three main
stages in the life cycle of the rust. These are as follows : I — ■
Aecia; II — uredinia; III — telia. Small bodies known as pyemia
are generally found in association with the aecia and sometimes
in association with the other forms. This stage is designated
by 0.
All the species here enumerated have been determined by
Dr. J. C. Arthur of Lafayette, Indiana, who is recognized as
one of the leading authorities on the group.
melampsorace;e.
Melampsora biglowii'Tlmm.
II — On Salix sitchensis Sanson. (193). The writer collected
this at Skagway, July 13, 1915. It has not been observed
at Sitka and probably does not occur, as the alternate host
is Larix and this tree is not found in the vicinity.
Pucciniastrum myrtilU (Schum.) Arth.
II, III — On Vaccinium caespitosum Michx. (69).
II, III — On Vaccinium ovalifolium J. E. Smith. (196).
This rust seems to be rather infrequent.
Pucciniastrum pustulatum (Pers.) Diet.
II, III— On EpiloUum affine Bong. (173), (271).
Common and quite destructive.
Melampsoropsis ledicola (Peck.) Arth.
II, III — On Ledum groenlandicum Oeder. (68).
Common, but only moderately destructive.
Melampsoropsis pyrolae (DC.) Arth.
II, III — On Moneses uniflora (L.) A. Gray. (70).
Common and sometimes locallv destructive.
480 IOWA ACADEMY OF SCIENCE
Hyalosora aspidiotis (Peek) Magn.
II. Ill — On Phegopteris dryopteris (L.) Fee. (67).
This is quite common.
Peridermium coloradense (Diet.) Artli.
I— On Picea sitchensis (Bong'.) T. & M. (57).
This is very common around open places, hut does not
seem to be found in the denser forest. It is sometimes
quite destructive to small trees, as it causes a loss of a
large portion of the leaves. It is included under the
family Melampsoracece as probably it is genetically con-
nected with one of the foregoing species.
PUCCINIACE^E.
Phragmidium occidentale Arth.
On Bubus parviflorus Nutt. (50 and 51).
On the Station grounds this rust is abundant enough to be
decidedly injurious to the host.
Phragmidium, rosae-acicularis Liro.
On Rosa hemisphaerica Herrm. (19). This host seems some-
what more susceptible than B. rugosa and its hybrids.
On Bosa n utkana Presl. (52 and 53) . This is our native rose.
It seems very susceptible.
On Bosa rugosa (267) and hybrids (195).
Xenodochus minor Arth.
On Sanguisorba latifolia (Hook.) Coville. (54, 113 and 202)
This rust is very common. All the forms occur. Dr. Arthur,
in a letter to the writer, says concerning some material be-
longing to this species, which was sent to him September,
1915, "Your material gives the first collection of a?cia be-
longing to Xenodochus minor, which has come to hand."
Gymnosporangium sorbi (Arth.) Kern.
0, I — On Pyrus {Mains) diversifolia Bong. (56).
This rust is common on the native crab apple and is some-
times injurious locally.
0, I— On Sorbus sitchensis Roem. (55). During 1914, this
species was badly affected, but in 1915 it had suffered to
such an extent from attacks of Entomosporium that but
few leaves were left to be attacked by the rust.
THE FLORA OF SITKA, ALASKA 481
f'romyces carophyllinus (Schrank.) Wint.
II, III — On Dianthus carophyllus L. (186). This rust de-
veloped rather sparingly on the common greenhouse car-
nation.
Puccinia acuminata Peck.
Ill — On Cornus canadensis L. (58). This rust forms dense,
black, circular spots on the under surface of the leaf, 1 to
2 mm. in diameter. Infect inn is not general, hut it is
abundant in places.
Puccinia circaea Pers.
On Circaea alpina L. (203). Common wherever the host is
found.
Puccinia epilobii-tetragoni (DC.) "Whit.
I — On Epilobium affine Bong. (59). Common on young
plants shortly after starting growth in the spring.
Puccinia grossulariae (Schum.) Lagerh. This species is by all
odds our most abundant and destructive species of rust.
Forms 0 and I occur on species of Ribes while forms II
and III infect species of sedges belonging to the genus
Carex. Of the fourteen species of Ribes growing on the
Experiment station grounds in 1915, exactly one-half were
affected. The different species differ very much in the de-
gree of infection, as is noted under the remarks on each.
On Ribes alpiniim (65). This host suffered a rather mod-
erate infection, in both 1914 and 1915.
On Ribes bracteosum Dougl. (60). This species seems to suf-
fer quite severely when exposed to infection from nearby
sources of Carex, but plants growing in the forest away
from sources of infection are nearly or entirely free.
On Ribes lacustre (Pers.) Poir. (61). This seems to be the
most susceptible species of all. In 1914, the infection was
severe indeed. In 1915, control measures were largely suc-
cessful.
On Ribes laxiflorwm Pursh. (63). The writer has observed
plants of this species along the edge of the Muskeg where
Carex stygia was abundant, so badly infected that they lost
most of their leaves while a few rods away the infection was
moderate to light.
31
482 IOWA ACADEMY OF SCIENCE
On Ribes oxycanthoides L. (66). Varieties of gooseberry de-
rived from the American species show moderate infection
while some of its hybrids with the European gooseberry
show light infection.
On Ribes rubrum L. (64). The common red currant seems
to be rather lightly infected.
On Ribes sanguiucum Pursh. (178). This species was planted
on the station grounds in 1914. The first season it was
scarcely infected at all, but in 1915 the infection was very
severe.
On Ca-rex macrocfiaeta C. A. Meyers. (251).
On Carex mertensii Prescott. (250).
On Carex sitchensis Prescott. (252) . This and the two species
above are moderately to rather severely infected.
On Carex stygia Fries. (197). This sedge is very abundant
all over the Muskeg, and seems always to be heavily in-
fected with the rust. From an economic point of view, it
is by far the most important Carex host of the Puccinia
under consideration, and from it most of the infection of
the Ribes on and near the Experiment Station grounds
probably takes place.
Puccinia poarum. Niessl.
II — On Poa pratensis L. (166). Not very common.
Puccinia pygmaea Erikss.
II — On Calamagrostis aleutica, Bong. (201 and 218). Fre-
quent, but only a small portion of the host plants seem
to become infected.
REFERENCES.
1. Mem. Acad. St. Petersb., VI, 2, 1832.
2. Piper, C. 7., Flora of the State of Washington: Cont. U. S. Nat'l
Herb., XI, 1906.
3. Sudworth, Geo. B., Forest Trees of the Pacific Slope. U. S. Dept.
Agri., Forest Service, 1908, p. 93.
4. Anderson, J. P., Iowa Erysiphaceas: Proc. Iowa Acad. Sci., XIV,
1907.
5. Salmon, E. S., A Monograph of the Erysiphaceae: Mem. Torrey
Bot. Club, IX, 1900.
United States Agricultural Experiment Station,
Sitka, Alaska.
INSECT POLLINATION IN COLORADO 483
INSECT POLLINATION OP TIMBERL1XK FLOWERS
IN COLORADO.
L. A. KENOYER.
Nageli attributes the fact that alpine flowers are more showy
that those of the lowlands to the greater scarcity of insects
on the mountain tops and the greater efforts thereby necessary
on the part of flowers to secure their visits.
Bonnier states that insect visitors are quite rare on mountain
flowers, and uses this as an argument to indicate that flower
color plays a relatively unimportant roles in the attraction of
insects.
Midler after extensive study of the subject states in his book,
"The Fertilization of Alpine Flowers," that although there
are long periods in which the weather of the mountain top
does not favor the activities of insects, he is unable to convince
himself that on the whole the flowers of the Alps are relatively
less visited and crossed by insects than are those of the low-
lands.
Schroeter in his consideration of the subject is inclined to
deny Midler's proposition and to assert that in the Alps and
on mountains in general the relative number of insects that
effect cross pollination is less than in the lowlands.
Little investigation seems to have been made on the abun-
dance and effectiveness of insect visits to flowers in our Rocky
Mountain region. Mrs. Soth, who has written on the flora of
Pike's Peak, states that insects are rare on mountain flowers,
only an occasional bumble-bee being seen. Therefore I took
advantage of a vacation in Colorado in the summer of 1915
to do a little work on alpine flowers and their visitors.
During the month from June 18 to July 18, I went ten times
from my camp at Tolland, Colorado, to the parts of the con-
tinental divide above timber line, between James Peak and
Corona. The insects collected on these trips were identified by
Dr. T. D. A. Cockerell of the University of Colorado.
The most apparent recipients of the visits of bees are the
mountain clovers. These plants sometimes occupy mountain
areas almost to the exclusion of other plants. It seemed to me
that in sunny weather when the wind is not too strong, bumble
484 IOWA ACADEMY OF SCIENCE
bees are as numerous on these clover fields of the mountains as
one "would expect to find them on a field of red clover at ordi-
nary altitudes. Sometimes a dozen could be seen in a walk of
a hundred feet.
Trifolium nanum is a dwarf plant coming into bloom in
earliest summer. On it "were found:.
Bombus kirbyellus Curtis. Numerous.
Bombus edwardsii bifarius Cresson. Numerous.
Bombus (a small species).
Trifolium dasypliyllum is a larger plant and blooms a little
later. Its visitors are
Bombus kirbyellus Curtis. Numerous.
Bombus edwardsii bifarius. Cresson.
Bombus appositus Cresson.
Bombus flavifrons Cresson.
Prosopis eoloradensis Cockerell.
Osmia kenoyeri Cockerell (n sp.).
A blue butterfly.
Perhaps next in importance is Polemonium confertum, a plant
contrasting in its erectness to the caespitose vegetation, so
abundant on the mountains, and bearing a conspicuous cluster
of dark purple blossoms with a inusky odor. It is visited by
Bombus kirbyellus Curtis.
Halictus rasiphora? Cresson.
also numerous flies, among which are species of Eristalis and
the Anthomyinea?.
Mcrtensiu bakeri is another bee flower. Its guests include
Bombus edwardsii bifarius Cresson.
Bombus flavifrons Cresson.
Eristalis sp. among the flies.
Silene acaulis, the well-known Mountain Pink. w7as visited by
Bombus edwardsii bifarius Cresson.
A small gray bee.
Melittia (a butterfly).
A moth.
H. Midler in the European Alps found this plant visited pre-
vailingly by Lepidoptera. L. H. Pammel found Lepidoptera
abundant on the same plant in the Medicine Bow region of our
Rockies.
INSECT POLLINATION IN COLORADO 4S5
On Primula angustifolia was seen a Bombus; on Frasera steno-
sepala, rare above timber line, was found
Halietus rasiphorae Cresson.
Halietus regis Cockerell (n. sp.).
On Castilleja sulphurea was a. Bombus kirbyellus Curtis, which
had just visited Trifolium dosyphyllum; on Alsimopsis obtusiloba
was apparently a species of the little red parasite, Sphecodes ; on
Hcuchera parvifolia a small bee; on Phlox caespitosa a small bee;
on Sievcrsia turbinata, a species of Prosopis; on Arenaria fend-
leri, Prosopis coloradensis Cockerell; on Thlaspi coloradense,
Halietus sisymbrii Cockerell; on Erigcron pinnatisectus, Prosopis
coloradensis Cockerell and Prosopis personatella Cockerell
(n. sp.).
The plant most conspicuous and visited by the greatest number
of insects is the sunflower-like Rydbergia grandiflora. The only
bee noticed on it was a green form, probably Angocholora, seen
three times. There were numerous butterflies, among them Melit-
tia, Lycaena, and a white form. Among the very many flies are
Syrphidae and Anthomyineae. Butterflies seem to take a greater
fancy to it than to any other plant of the region.
The plant which seemed most noticed by flies is the very com-
mon Sievcrsia turbinata. Among these ever-present guests are
Anthoniyineae and Empididae. Ants also are found here.
There are several other flowers that seem open to the ap-
proaches of flies and ants. The most important are Dryas
octopetala, Potentilla uniflora. Lloydia serotina, Micranvthes
rhomboidea, Caltha, Polygonum bistortoides, Oreoxis alpina,
Arenaria fendlefi, Eriysimum wheeleri, Ranunculus adoneus
and Heuchcra par vi folia. Some of these flowers are very con-
spicuous and others but slightly so, but all agree in having the
nectar practically exposed and in the reach of all comers. The
Anthonryineas are easily the prevailing forms among the flies,
although Syrphidae are quite common. Aliiller finds Caltha,
Dryas, the Potentillas and the Ranunculi visited mainly by flies
in the Alps.
A bumble bee, probably Bombus cdwardsii bifarius, was seen
entering a hole among the rocks above timber line, doubtless
leading to its nest." A male specimen of Osimia abnormis Cres-
son, was taken from the rocks where it was apparently seek-
ing shelter from the wind. I desired to learn the extent to
which the alpine flowers are dependent upon insects for their
486 IOWA ACADEMY OF SCIENCE
pollination, so I stretched cheese cloth and mosquito netting
over wire domes, which by means of stakes driven into the
ground I attached securely over plants just prior to their
blooming season.
My stay was too brief to permit me to obtain definite results
in all cases, but I can report as follows :
1 — No seeds on covered plants, seeds on uncovered: Polemon-
ium confertum, Trifolium dasyphyllum, Silene acaulis.
2 — Practically as many seeds on covered as on uncovered
plants: Ranunculus inamoenus, Oreoxis alpina, Sieversia tur-
birVataj Erysimum ivheeleri.
It is worthy of notice that the flowers that require insect
visits for pollination are mainly the bee flowers, while those
that get along without them are principally the fly flowers.
Perhaps the real reason for this difference is the relative ar-
rangement of the floral parts. The bee-flowers are long-tubed
and are apt to have stamens and pistils relatively remote from
one another. On the whole the flowers of the two groups are
about equal in showiness.
Of course when the wind is quite strong or when rain or
snow is falling or the clouds are dense there is a scarcity of
insects in sight. But selecting comparable weather and exclud-
ing the honey bee, which does not live at high altitudes, it seems
to me that the flowers above timberline are as much visited by
insects as are those of lower altitudes, and I have no reason to
suppose that they are any less dependent for pollination upon
their insect visitors.
Dr. L. H. Pammel, who has given some attention to Alpine
flowers in various sections of the Rocky Mountain region, thinks
that insects are practically as abundant on Alpine as on low-
land flowers.
I must express my appreciation to Dr. Francis Ramaley for
extending to me the courtesies of the Colorado University La-
boratory at Tolland.
LITERATURE CITED.
Nageli, C. Von, Entstehung und Begriff der naturhistorischen Art,
Miinchen, 1865.
Bonnier, Gaston, Les Nectaires. Annates Des Sciences Naturelles (Bot-
anique), Paris, VIII, 1879.
Miiller, Hermann, Die Alpenblumen, ihre Befruchtung durch Insecten
und ihre Anpassungen an dieselben, Leipzig, 1S81.
Schrbter, C, Das Pflanzenleben der Alpen, Zurich, 1904.
INSECT POLLINATION OF FRASERA STENOSEPALA 487
INSECT POLLINATION OF FRASERA STENOSEPALA.
L. A. KENOYER.
One of the largest of herbaceous plants growing- at Tolland,
Colorado, 9,000 feet above sea level, is the green gentian, Fras-
era stenosepala. X rosette of basal leaves gives rise to a coarse
stalk, three to four feet high, with whorls of large leaves and
a leafy panicle of rather large flowers of a light green color.
Singularly the color is about as inconspicuous as can be
imagined. The flowers are rendered rather noticeable by the
size and isolation of the plants, but much less so by color. Yet
it appeared to surpass all other flowers of the region in the
number and variety of insect visitors. The yellow Thermopsis
ddvaricata or mountain pea is abundant where Frasera grows.
It has a color that renders it visible at a much greater distance
than is Frasera, yet it is much less frequently visited by in-
sects.
A casual study of the Frasera blossom showrs, as its principal
attraction to bees, two trough-like nectaries which lie on the
inner face of the petal, extending almost half its length, and
protected against the weather and against small insects by a
fringe of hairs on either side of each trough. Bumble bees that
visit the flower pass successively to its nectaries, passing the
tongue through each. In so doing they rub against the stamens
and the pistils in such a way that they could easily effect pol-
lination.
At a number of times during the latter part of June and
the early part of July, 1915, insects were captured from the
blossoms. Determinations made through the courtesy of Dr.
T. D. A. Cockerell of the University of Colorado, show them
to be as follows:
Bombus edwardsii bifarius Cresson.
Bombus edwrardsii kenoyeri Cockerell (n. var.)
Bombus rufocinctus astragali Cockerell.
Bombus appositus Cresson.
Psithrus insularis Smith.
IOWA ACADEMY OF SCIENCE
Psithrus latitarsus Morrill.
MegacMLe wootoni caligaster Cockerell.
Monurnetha albifrons Kirby.
Uetes salieola geranii Cockerell.
Colletes kineaidi Cockerell.
Colletes — two unidentified species.
Chelynia nitida Cress
Andrena lewisii Cockerell.
Halictus inconditus Cockerell (n. sp.)
Halietus frasera? Cockerell (n. sp.)
Halictus rasipkora? Cockerell.
Halietus regis Cockerell (n. sp.)
Odynerus sp.
The latter two species of Halictus were collected from a dwarf
plant, about eight inches high, just above timber line. All of
the others are from larger plants at Tolland, which is one or
two thousand feet below timber line.
A plant was covered with cheese cloth to determine whether
self pollination could occur without insects. Observations on
3 plant and on three average untreated ones were taken a
month later by Miss Helen Leonard. Unfortunately, the cov-
ered plant had become badly affected by aphids before the seeds
set.
The following is the numerical result :
Total Xo. of j No Ux- pEB cE>-T U>-.
FXOWEBS j POLLINATED POLLINATED
1. Covered plant 145
2. Plant not covered
3. Plant not covered 547 116 21
4. Plant not covered 368 ' 81 22
The evidence points pretty clearly to the fact that, while
pollination may occur without bees, it is much more effectively
done when their visits are permitted.
Department of Botany,
Iowa State College.
THE WEEDS OF CALIFORNIA
NOTES ON THE WEEDS OF CALIFORNIA.
L. H. PAMMEL.
During the month of A" . I Mrs j'am-
mel spent a month visiting California. Our journey took us
the Western Pacific railroad from S
railway \ sses ver the Sierra divide and down the Pe
river canyon, down the Yuba and Sacramento flood plains,
thence into San Francisco. At several points along the line
- were made and some collecting was done. From S
Francisco we went over the Southern Pacific to B:_ - 3
-inta Barbara and Los Angel — : m the
latter point over the Santa F to S Dieg
San Bernardino. At each of these places we-
an opportunity to collect plants and make notes on the more
common wee -
Dr. Hilgard some years ago published some notes on the weeds
of California1. He states that the broad : t 1 t first -:rikes
the new-comer in California is that a number of plants that
are objects of careful culture east of the Re tains as
well as in Europe, and that when depriv
succumb, in California thrive and are persistenl - and
many weeds which are conspicuous on the Atlan:::-
absent in California. He mentions the beet, celery, radish and
carrot as conspicuous weeds. Some of the smartweeds so com-
mon in the east do not maintain themselves in California,
casionally one finds the Pennsylvania smart- I aum
Pennsylvanicum) in low grounds. The Spergula arvensis is
common in moist places along the coast. The E
um and E. moschatum are common plants everywhere in I
forma. The Oxalis cornkuhita is rather common in places. In
some places there is an abundance of Glycyrrh ■
nel (Anethum gran - is common in many places and so
is the Conium maculatum and the caraway {Carvum ca
and there in the vicinity of San Francisco one may ob-
serve the Teasel (Dipsacus] . The Madia saiiva is quite widely
distributed and generally is regarded as a troublesome weed.
KJarden and "
490 IOWA ACADEMY OF SCIENCE
It secretes a substance that is decidedly objectionable. The
Amsickia intermedia and A. lycopsoides is most troublesome.
The aspect of a California field is entirely different than an
Iowa or an Illinois field. Broad acres are covered with the
Yellow Knapweed or Tocalote of the Mexicans (Centaurea
melitensis) and C. solstitialis are among the most troublesome
weeds of the meadows. In the Sacramento Valley and in the
foothills and valleys there is an abundance of the California
P°PPy (Eschscholtzia calif omica). The roadsides are covered
with one of the numerous species of Tarweed (Hemizonia luzu-
laefolia). The great Star Thistle (Silybum mariamim) and an-
nual grasses like Wild barley (Hordeum murinum) cover wide
stretches of the fertile fields. The two species of Prickly let-
tuce (Lactuca Scariola and the variety integrata) are common
everywhere in waste places. Certain weeds like the Greater
Ragweed (Ambrosia trifida) are missed entirely. The Foxtails
(Setaria glauca and S. viridis) are not common as with us.
Hilgard notes that S. glauca is a formidable weed in the foot-
hills of the Sierras and that Bromus mollis is a formidable weed.
The Russian thistle (Salsola Kali, var. tenui folia) is a common
weed. "White sweet clover (Melilotus alba) is common in places.
The Black medick (Medicago lupulina) and the Bur clover
(Medicago dentiadata) and Wild oats (Avena fatua) are com-
mon weeds.
In the Feather river canyon at an altitude of 4,000 feet there
is comparatively little land that can be cultivated. In fields
and waste places in the vicinity of Portola the writer observed
Lactuca scariola and the var. integrata, Mayweed (Anthemis
Cotula,), Eschscholtzia calif omica var. tenuifolia; Sisymbrium
altissimum, Sisymbrium sp., Polygonum aviculare, Hordeum
jubatum, Sitanion elymoides, Achillea Millefolium, Gayophy-
tum sp., Hemizonia sp., Pteris aquilina, Bumex Acetosella and
Wyethia. This sunflower or rosin weed (Wyethia) of the open
meadows in the mountains occupies waste places in streets and
along roadsides.
Near Belden, at an altitude of about 2,800 feet, the following
weedy plants were observed : Erigeron canadense, Common
mullein (Vcrbascum Thapsus), Anthemis Cotula, Cow herb
(Saponaria Vaccaria), Mexican tea (Chenopodium ambrosi-
oides), Russian thistle (Salsola Kali var. tenuifolia) , (Lactuca
THE WEEDS OF CALIFORNIA 491
Scariola and the var. integrata), Sour Dock (Rumex crispits),
Dooryard Knotweed (Polygonum aviculare) , Tumbling Mustard
(Sisymbrium altissimum), the Iowa Tumbleweed (Amaranthus
graecizans), Shepherd's Purse (Capsella Bursa-pastoris) .
The following- weeds are abundant in the vicinity of Yuba
City in the Yuba bottoms: The European Morning glory (Con-
volvulus arvcnsis), Prickly lettuce (Lettuce Scariola and the
var. integrata), Johnson grass (Soi^/hum halcpense) a very per-
nicious weed. Bermuda grass (Cynodon Dactylon), Lamb's
quarters (Chenopodium album) and our Iowa pigweed (Am-
aranthus retroflexus) were abundant. The Spiny clotbur
(Xanthium spinosum) and a species of Croton were common in
fields. The roadsides also contained an abundance of Sunflower
(HcUanthus annuus and H. lenticularis) . The Russian thistle,
as in other parts of central and northern California, was abund-
ant. The Yellow Starflower or Knapweed (Ccntaurea melit en-
sis) occurred not only along the roadsides but the harvested
grain fields were yellow with the flowers of this species. The
Polygonum aviculare and Lippia sp. w7ere common in yards.
Chcnopodium ambrosioides, Eeliinochloa crusgalli, Rumex
crispus, Verbascum Thapsus, Marrubium vulgare, Sisymbrium
altissimum, Avena fatua, Erigeron canadense, Cicliorium Inty-
bus, Melilotus alba, Eschscholtzia californica and Grindelia sp.
were all common in fields and along roadsides.
In the Bay region, Oakland, San Francisco and other points
weeds of the mustard family (Cruciferae) are common. The
common Mustard (Brassica campcstris), Hedge Mustard (Si-
symbrium officinale), the Common radish (Rapluutus sativus)
and the Jointed Charlock (R. Raphanistrum) are two of the
most common weeds of the Bay region. The California poppy
(EscJiscJwltzia californica) is common, as well as the Sow
thistle (Sonchus asper) ; the Bull thistle (Cirsium lanceolat u m)
and the May weed (Anthemis Cotula) occur sparingly. Gray
observed in 18762 "sparingly found along roadsides; intro-
duced but not yet common." Dill (Anethum gravcolens) is com-
mon in Oakland. Evidently it was not established in California
in 1876 as it is not mentioned by Brewer and Watson.3 Celery
(Apium graveolens) in 1876 was reported by the same authors
as occurring from Santa Barbara to San Diego in salt marshes.
2Botany of California 1: 401.
3Bot. of California 1: 252.
49 i IOWA ACADEMY OF SCIENCE
Doctor Hilgard in 1891 stated it was common in the Bay
region. It is not a common weed except, perhaps, in the salt
marshes. Hemlock (Conium maculatum) was a sparingly in-
troduced plant in waste places about cities in 1876. It is com-
mon in many places now in the vicinity of Oakland and else-
where. Other weeds in this Bay region are Hollyhock (Althoea
rosea), Beet (Beta vulgaris), Buckhorn (Plantago lanceolata),
Jimson weed (Datura Tatula), Verba-scum Thapsus, Lactuca
Scariola and the variety integrata, Carrot (Daucus Carota),
Wild barley (Hordeum murinum and Hordeum nodosum). The
H. murinum was evidently not common in California in 1876.
Melilotus alba, Medicago denticulata and M. lupulina were com-
mon in the region as well as the Silybum marianum.
Santa Cruz in the Monterey Bay region on the coast, south
of San Francisco and west of the coast range contains many
of the weeds found further north. The roadsides in places are
lined with tarweed (Hemizonia Sp.) and Rosin weed (Grin-
delia), Radish (Raplianus sativus), jointed charlock (R. Raphan-
istrum), Russian thistle (Salsola Kali var. tenuifolia), Medi-
cago lupulina, M. denticulata, Melilotus indica. The latter oc-
curs abundantly and is a troublesome weed. The Alfilaria
(Er odium cicutarium) is an abundant weed on roadsides and in
fields. Sometimes it is used most effectively to cover waste
places. Brassica campestris and Rumex crispus, Hordeum
murinumi and Centaurea melitensis are quite as common as in
the Sacramento Valley, Pacific Grove and the Monterey penin-
sula on the other side of the Bay. In one place the dodder
(Cuscuta Epitliymum) has practically destroyed alfalfa.
In the city of Pacific Grove and outside I saw an abundance
of the Poison Hemlock (Conium maculatum) and Hordeum
murinum everywhere on the sand dunes. The Polygonum avi-
culare and occasionally some P. convolvulus are present in grain
fields to the east of Pacific Grove. At Salinas where some of the
soil is more or less salty I saw an abundance of caltrop (Tribu-
lus terrestris). The Hemizonia luzulaefolia as elsewhere in the
valley is a troublesome weed. The odor is most objectionable,-
stock do not forage on the weed. At Santa Barbara, further
south on the coast, one finds again the tarweeds in abundance.
I noticed two species of Hemizonia abundant. In some cases
fields were fairly yellow with it. The Eschscholtzia calif ornica
THE WEEDS OF CALIFORNIA 493
was common and the Lippia covered great stretches and here it
is used quite effectively to cover banks and waste places.
In Los Angeles, south of Santa Barbara, I observed Erigeron
canadensis, Datura Tatula and a great deal of D. meteloides,
Franseria sp., Lactuca Scariola, Melilotus alba, Xanthium can-
adense, Radish (Raphanus sativus), Iowa Tumbleweed {Amar-
anth us graccizans), Pigwreed (A. retroflexus) , Convolvulus
arvensis, Brassica campestris, Sorghum lialepense, Marrubium
vulgare, TJrtica holosericea, Ricinus communis, Nicotiana glauca,
Solanum nigrum, Helianthus animus, Dill (Anethum grave-
olens).
The San Diego region in the extreme southern portion of
California is much more arid than Los Angeles, where irriga-
tion is practiced. A number of northern weeds occur. "We
note, however, that in waste places, there is an abundance of
Nicotiana glauca and N. attenuata and some Ricinus communis,
Digitaria sanguinalis and Setaria glauca though Digitaria and
Setaria are nowhere abundant in California. Erigeron can-
adense, Xanthium canadense, Amaranthus graecizans, Chenopo-
dium album, Avena fatua, Helianthus annuus, Polygonum
avicidare, Hordeum murinum, Plantaga lanceolata, Cosmos
bipinnatus, Cucurbita foetidissima are some of the other weeds
which occur in southern California. There is a great deal of
Datura meteloides as well.
A list of weedy plants might be greatly extended. The out-
standing fact is that many of the weeds like Salsola, Centaurea,
Raphanus, Beta, Daucus, Datura, Chenopodium and Hordeum
are European, while a relatively small number are of tropical
origin like Amaranthus, Nicotiana, Ricinus and Cosmos. The
conspicuous native weeds are Hemizoma, Gayophytum, Helian-
thus and Croton. It is a striking fact that so few of the peren-
nial native plants have become weeds. The seeds of most of the
weeds germinate during the rainy season and rapidly mature
their seeds, leaving the landscape seer and brown. The yellow
composites like Hemizonia, Grindelia are in strong contrast to
the dead annual grasses that mark the California landscape in
August.
494 IOWA ACADEMY OF SCIENCE
SOME NOTES ON CALIFORNIA FOREST FLORA.
L. H. PAMMEL.
Not much that is new can be presented on the forest flora of
the state of California. The interesting forest flora of Cali-
fornia has been worked over most carefully by a large number
of eminent botanists ; of the later contributions we may mention
a few of the more recent: namely, the work of Willis Linn
Jepson, "The Trees of California"1 and by the same author
"The Silva of California,"2 published in 1914, which is the
most complete and exhaustive treatise on trees of any given
local region; the work of Sudworth, "Forest Trees of the Pa-
cific Slope;"3 the work of Sargent, "Manual of the Forest Trees
of North America Exclusive of Mexico"4 and his monumental
work, "The Silva of North America" in fourteen volumes, and
Britt on's "North American Trees."5
Many botanists have, of course, contributed to our knowledge
of the trees of California. Of the earlier botanists and ex-
plorers mention may be made of Kellogg, Brewer, Parry, Doug-
las, Nuttall, Fremont, Bolander, Watson, Gray and Torrey. Of
the later botanists mention may be made of H. M. Hall, W. R.
Dudley, Baker, Green, S. B. Parish, Heller, Macbride, Cleveland
and Orcutt.
Our visit during the summer of 1915 included stops at Por-
tola and Belden in the Feather river canyon, at Yuba City, the
Bay region around San Francisco, Big Trees region near Santa
Cruz and Monterey, Santa Barbara, Los Angeles, San Diego
and San Bernardino. Representative types of trees were col-
lected and herbarium material prepared.
Those who are familiar with the topography of California
know that there are two rugged chains of mountains, the Sierra
Nevada in the eastern part of the state and the Coast Ranges
near the coast. Between these ranges a "Great Valley" as it
is called contains the Sacramento Valley, the northerly valley
in which the Feather, Yuba and other rivers join the Sacra-
*228 pp. figs. 115. Cunningham, Curtiss and Welch, 1909.
^Memoirs of the University of California, 2: 1-4S0, 85 pi., 10 figs., 3 maps.
3Ut S. Department of Agriculture, Forest Service, 411 pp. figs., October 1,
1908.
4S46 pp. ; 61/2 figs., 1 map.
BN. L. Britton and John A. Schafer, S04 pp. ; 781 figs.
CALIFORNIA FOREST FLORA 495
mento. The valley to the south is known as the San Joaquin
within which the river of that name receives the waters of many
small streams. Jepson calls attention to the fact that the north
coast ranges differ in a marked degree from the south coast
ranges. The former are marked by the development of the red-
wood belt, the tan oak and Douglas fir. These forest tree species
are some of the marked features of this region. This region,
too, has a large rainfall. Jepson gives the normal seasonal rain-
fall as 45.59 inches with the highest recorded temperature as
84° above freezing and the lowest as 20° above freezing. These
data are for Eureka. In the southwest ranges, the region lying
below San Francisco is characterized by long, dry, rainless
summers and a low rainfall. In the Santa Cruz mountains fac-
ing the ocean an abundance of redwood, tan oak, sycamore,
Douglas fir, madrona and maple grows. The Monterey bay
region contains an interesting peninsula with a number of
conifers of restricted ranges. Jepson terms the region an
"aboreal island." Here are found the Monterey pine (Pinus
radiata), Bishop's Pine (Pinus muricata), Monterey cypress
(Cupressus macrocarpa) and the Gowen cypress (Cupressus
goveniana) . In the moister valleys of the coast range near Los
Angeles such deciduous trees as the large leaved maple, syca-
more, alder, maul oak and Douglas fir occur.
In the San Diego district the valleys contain the cottonwood
(Populus Fremontii) , the arroyo willow (Salix lasiolepis) and
• the black willow (Salix nigra). On the coast north of San Diego
about twenty-six miles, at a point known as the Torrey pine
hill, is the Torrey pine, of very restricted distribution.
The forest province designated as the Sierra Nevada includes
the area in eastern California from the base of the San Joaquin
and Sacramento valleys and the east slope of the range. The
Lake Tahoe district and the low foothills approaching the Feather
river divide belong to this area. The annual rainfall in the
foothills is low and the tree vegetation is small. The most char-
acteristic tree at the mouth of the Feather river canyon is the
digger pine (Pinus sabiniama) which is associated with the blue
oak (Quercns Douglasii). This is followed further by the belt
of yellow pine (Pinus ponderosa) and incense cedar (Liboccdrus
decurrens). Then come the Jeffrey Pine (Pinus ponderosa,
var. Jeffreyi) and the Silver Pine (Pinus mo nt kola) . Profes-
sor Jepson gives the precipitation in inches for Blue canyon for
IOWA ACADEMY OF SCIENCE
s 1907-08 as 49.05 3; ] "the pre-
cipitation was 100.47 inches. Blue canyon is in the Yellow pine
belt and sonth of the Feather river canyon.
The mountains of south California, such as the San Bernar-
dino, blend with t' - st ranges The mountains about
San Bernardino contain the yellow pine, sugar pine and large
fruited fir Pst lacrocar the map>
•ophyUum), alder Al >■ rhc . sycamore {Flat
ilifornia black c. Kelloggii and maul
oak (Q. chryscilei
PIKACEJE I
The following conifers of the genus g rved.
Sugar ] Doug This is 1 rgesi
and finest of the white pines, with pendulou- les 12 1
inches long. It - n the high points about Belden and
la. The wril some fine specimens in the mountains
San Bernard:: r the s -
Western White Pine or Silver
is common in some p ts the Sierras Jeps - s the alti-
tude from to 8 feet - ind near the
rn Pacific- Railroad Station of Belden. which 3 less than
4.000 feet above sea. It is. howeve - "ered through the for-
th only a 1 g in a plae< I I - int.
Yellow Pine Pinus pc a - - : the
st important of the pines of California. It is abundant in
the vicinity of Portola. Quiney and Belden. also abundant in
southern California in the San Bernardino mountains
land and occurs in the S ruz mountains.
Jeffrey Pine Pinus ponderosa var. Jeffr - ommonly
g Larger cones, [tis mmon near Portola ass th the
species.
Big Cone Pine Pi - Cc Iteri Don was not collected, but
was observed in the San Bernardino Mountains along ti
Fe railroad.
Digger Pine Pinus > ,: ■ lana Dougl.) was observed in the
foothills of the Sierra mountains at altitudes of a few hundred
feet in the Feather river canon near Oroville.
CALIFORNIA FOREST FLORA
497
Pine / Parry' . This pine \ s
covered by I». Parry, botanist of the Mexican Boundary
Survey, who was a resident of Davenport. Iowa. This pine
is resl ts distribution. It occurs on the San Diego
coast near the mouth of the Soledad river, south of the
1 1 Mar and north of La Jolla. Santa K — [s - - the only
other locality from which the - - reported. A few cul-
tivated trees were observed in San Diego. The tree in its looks
is very disappointing but it is unique. Xo other tree species are
found growing with it.
18 — Characteristic broad • "id hilly open forest
i at junction of Alpine creek with Little Kern river. Forest consists
of Jeffrey pine, 2; 0 trees per acre, and the region has been heavily
grazed bv cattle and sheep. There is evidence also of fire, -which has
helped to bare the surface. Sequoia National Forest, Tulare County,
ia. Courtesy U. S. Forest Service.
Bishop's Pine Don.) occurs at Montere;
Monterey Pine /' - radiata Don.), a beautiful symmetri-
cal tree with a trunk one to four feet in diameter, tan or cin-
namon colored cones, is abundant on the Monterey peninsula.
The trees are protected by a private corporation which owns
much of the land.
32
498 IOWA ACADEMY OF SCIENCE
Douglas Fir (Pseudolsuga mucronata Suclw.). The Douglas
fir is widely distributed in California from Porto-la to Beldetn
in the Feather river canon, Santa Cruz mountains, Big Trees
and Sierra Madre.
"White Fir (Abies concolor Lindl. and Gord.). Common in.
the Feather river canyon between Portola and Bel den. A large
tree with smooth bark.
Redwood (Sequoia scmpervirens Endl.). Isolated groves are
found in the vicinity of San Francisco, Muir Valley, Santa
Cruz mountains, Big Trees. The Muir woods contain some fine
trees. The Sequoia in the Santa Cruz mountains is associated
with the beautiful Chamisso's fern (Aspidium minutum), Um-
bellularia calif ornica, Quercus chrysolepsis, Acer macrophyllum
and Alnus rhombifolia. On some of the stumps of the redwood
three generations may be seen. Unlike the pines this species
sprouts abundantly and reproduction is plentiful in the canyons
and moist slopes.
Incense Cedar (Libocedrus decurrens Torr.). The tree re-
sembles an arbor vitae with minute leaves. It is abundant on
the mountain slopes associated with the white fir, Douglas fir
yellow pine and Purshia tridentata. This is true for Feather
river canyon about Portola. It was common between Portola
and Belden, also near San Bernardino in the mountains of that
name and at the summer resort known as Skylands.
Monterey Cypress (Cupressus macrocarpa Hartw.) is com-
monly planted in California. It occus on the ocean shore at
Monterey from Pescadero Point to Cypress Point, a strip about
two miles long and one-eighth of a mile wide. There is also a
little grove at Point Lobos.
Gowen Cypress (Cupressus goveniana) occurs on the coast on
the west slope of Huckleberry Hill.
California Juniper (Juniperus calif ornica Carr). The Cal-
ifornia juniper is a low tree, often a shrub, found at lower alti-
tudes of the San Bernardino mountains, where it is common.
Western Juniper (Juniperus occidcntalis Hook.). Not common
in the Feather river country. Near Portola a few isolated trees
were found.
CALIFORNIA FOREST FLORA 499
SALICACE& Willow Family.
Yellow Willow (Salix lasiandra Benth.). This willow is com-
mon along streams, Feather river canyon, Portola and Belden.
Black Willow (Salix nigra Marsh.)- Along streams, Yuba,
Feather river and in the "Great Valley."
Arroya Willow (Salix lasiolepis Benth.). This is common
in the bottom of streams in southern California. San Diego.
Nuttal Willow (Salix flavescens Nutt.). Along the sea coast,
San Francisco Bay region.
Cottonwood (Populus Fremontii Wats.). This is common
along the streams in the Great Valley, Yuba City, southern
California, San Diego.
Black Cottonwood (Populus trichocarpa T. and G.) is a beau-
tiful tree resembling the balm of Gilead. It is common in the
Feather river canyon near Belden, growing in the bottoms.
JUGLANDACE^E Walnut Family.
California Walnut (Juglans calif omica Wats.). The Cali-
fornia walnut is common in the lower parts of the canyons of
the San Bernardino mountains. It is a low branching tree.
Trees occur in the great northern valley of California. The
wood of this species makes beautiful lumber. This form has
been called the var. Ilindsii by Jepson.
BETTJLACE2E Birch Family.
White Alder (Alnus rJiombifolia Nutt,). Common every-
where in the lower Sierras. Abundant along the Feather river
m the canyon near Belden, Muir woods and Mill valley, Santa
Cruz Mountains, San Lorenzo canyon, Big Trees, mountains
near Los Angeles, and the canyons of San Bernardino moun-
tains.
FAGACEM Oak Family.
Valley Oak (Quercus lobata Nee). The valley oak is one of
the most striking trees of the "Great Valley," Sacramento,
Marysville, Yuba City, Live Oak, etc. Large trees are found
about Yuba City. The trees of the Valley Oak are sometimes^
eight to ten feet in diameter. The crown is round topped and
has pendulous branches.
500 IOWA ACADEMY OF SCIENCE
Oregon Oak (Quercus Garryana Dougl.). This oak, of wide
distribution on the Pacific Coast reaching up into Oregon, Wash-
ington and British Columbia, was observed in the Santa Cruz
mountains.
Blue Oak (Quercus Vouglasii II. and A.). This is an abundant
species in the lower Feather river canyon about Belden.
Maul Oak (Quercus chrysolepis Liebm.) is another oak of
wide distribution, with toothed or entire leaves. Beautiful spec-
imens occur in the Feather river canyon about Belden, Mill
Valley, Muir woods and the San Bernardino Mountains in
Southern California.
Coast Live Oak (Quercus agrifolia Nee). A tree sometimes
seventy feet high with short trunk and spreading branches.
Found at Berkeley and in the coast ranges southward. Com-
monly found on the low hills, giving them a unicrue appearance.
Live Oak (Quercus Wislizeni ADC). Yuba and Feather
river valleys, Live Oak.
California Black Oak (Quercus Kelloggii Newb.). This
species approaches the eastern black oak. A good sized tree on
high ridges at Portola at an altitude of 4,500 feet.
Tan Bark Oak (Pasania dcnsiflora Oerst.). The tan bark oak
has erect staminate flowers resembling Castanea, and the fruit
is like Quercus. The bark of the tree is used extensively for
tanning. At Mill Valley it occurred with redwood (Sequoia
senipervirens).
PLAT A~N ACE 2E Sycamore Family.
Sycamore (Platanus racemosa Nutt.). The California Syca-
more resembles our eastern species but with fruit racemose
and widespreading branches. The species occurs in the great
valley near Yuba City but is more common southward in the
Coast ranges like the Santa Cruz mountains near Big Trees,
Santa Barbara and San Bernardino mountains.
LAURACEM Laurel Family.
California Laurel or Bay Tree (JJ nib ellul aria calif ornica
Nutt.). Common and abundant everywhere in the lower Feather
river canyon, Belden, near Berkeley, in the canyons, and in
the Santa Cruz mountains.
CALIFORNIA FOREST FLORA 501
ROSACEA Rose Family.
Cherry (Prunus emarginatus walp.) Belden, Feather river
canyon.
"Western Choke Cherry (Prunus demissa Walp.). Common in
the Feather river canyon, Belden.
ACERACEM Maple Family.
Large Leaved Maple (Acer macrophyllum Pursh). Hand
some tree with large leaves, sometimes with a trunk four feet
in diameter, sixty-five feet in height. Abundant at Belden,
Muir woods, Mill valley, Big Trees, Santa Cruz mountains and
San Bernardino mountains.
Box Elder (Acer negundo L. var. Calif oniicum Sarg.). Com-
mon in foothills, Feather river, Yuba City, Marysville and San
Bernardino mountains.
CORNACEJE Dogwood Family.
Flowering Dogwood (Comas Nattallii Aud.). Feather river
canyon, Belden.
ERIC ACE M Heath Family.
Madrone (Arbutus menziesii Pursh). The Madrone has a
wide range from southern California to Vancouver Island and
British Columbia. Lower Feather river canyon, Belden, Big
Trees, in the Santa Cruz mountains.
OLEACEJE Ash Family.
Oregon Ash (Fraxinus Oregona Nutt.). Common in lower
Feather river canyon, Belden, where it occurs on the mountain
sides and valleys.
CAPRIFOLIACE& Honey-Suckle Family.
Blue Elderberry (Sambacus glauca Nutt.). Lower Feather
river canyon, Belden, Big Trees, in the Santa Cruz mountains.
I am indebted to the Western Pacific Railway for Plates
XXXII A, XXXIII and XXXIV from the Feather river Can-
yon and to the Southern Pacific Railway for Plates XXXV and
XXXVI. Plate XXXV shows the Redwood in the big tree grove
in the Santa Cruz mountains.
For photographs illustrating the Libocedrus, the Valley Oak
and Jeffrey Pine, I am indebted to the U. S. Forest Service.
Department op Botany.
Iowa State College.
-
- "
fc. O
- r
33
Iowa Academy Science
Plate XXXVII
Incense cedar, Librocedrua decurn ns, El Dorado county, California.
U. S. Foresl Service.
Courtesy
-
i
SOME NORTH AMERICAN CONIFERS 519
NOTES ON SOME NORTH AMERICAN CONIFERS
BASED ON LEAF CHARACTERS.
L. W. DURRELL.
Leaf characters, unlike stem characters, are as a rule sub-
ject to such variations that they form an unreliable basis of
comparison between plants. Conifer leaves on the contrary,
because of their simplicity as compared with other leaves, show
a large degree of uniformity, particularly in those characters
seen in cross section.
In preparing material for a class in dendrology it occurred to
the writer to make sections of conifer leaves to show these leaf
characters that they might be used, not wholly as a means of
identification in themselves, but to supplement other identify-
ing characters. Leaves of all the arboreal conifers of North
America bearing needle leaves (except Pinus) were examined and
the characters of the same species were found to be constant
even though the specimens come from widely separated locali-
ties. With this in mind camera-lucida drawings were made of
representative sections taken from the middle of mature leaves
from different points on the branch, and the drawings supple-
mented by a description of the section when treated with re-
agents to differentiate the histological elements.
As the leaf characters of conifers have frequently been dis-
cussed and used in identification, the following drawings rather
than the keys or description are of most importance, as a means
of quick and vivid portrayal of these characters. The drawings
endeavor to show all the characters seen in cross section both as
a whole and in detail, except in the case of the stomata, which,
because of their alternate arrangement in their rows, do not
appear in the regular number in any one section.
The scale of magnification for each plate is the same — the
drawing of the whole section in each case is enlarged to 40
diameters while the detailed drawings are enlarged to 260 di-
ameters, except in the case of Plates XL and LXVI, which are
reduced one-third more than the other plates.
520 IOWA ACADEMY OF SCIENCE
It is interesting to note, in comparing the series of sections,
the presence of dichotomy, as manifest in the double vascular
bundles, and its disappearance in the higher conifers, — also the
development of palisade parenchyma in all flat leaves. Some-
thing of phyletic relationship is shown in some of the sections,
as for instance, the deeply infolded parenchyma walls of the
Larches, linking them with the preceding Pines; with the de-
crease of the same character to mere corrugations in the paren-
chyma walls of some of the Spruces. The presence and de-
crease of a conspicuous bundle sheath as advance is made through
the group, is also notable.
Note: Throughout the descriptions it has been the aim to
describe all the characters seen in section. Most reliance, how-
ever, can be placed in the appearance of such characters as the
vascular bundles, bundle sheath, resin ducts and hypodermai
cells, as they show most constancy.
The characters of the parenchyma and the pithlike cells of
the vascular bundles can not be considered as reliable, though
the infolding of the walls of the former appear to be uniform.
Throughout the Plates it has been the aim to use uniform
means of portrayal. The shaded space without the epidermal cells
represents cutin except where this is very thin, where only a line
is used to represent its boundaries. In representing the phloem
in the bundles single lines are used to distinguish it from the
thick walled xylem though in many cases the walls are as thick
as those of the xylem cells, though not lignified as is the xylem.
The numbering of the figures of the plates is the same approx-
imately in each case — Figure 1 shows the leaf section as a whole.
Figure 2, section of epidermis. Figure 3, section of resin duci
if present. Figure 4, section of vascular cylinder.
SOME NORTH AMERICAN CONIFERS 521
ARTIFICIAL KEY TO CONIFERS BASED ON LEAF SECTIONS.
I. Leaves 3 to 4-angled, or if compressed without a dorsal groove.
Vascular cylinder surrounded by a conspicuous
bundle sheath. Vascular bundle obscurely divided.
Resin ducts present or absent.
2. Walls of parenchyma deeply infolded /
2. Walls of parenchyma not infolded, smooth or only
slightly corrugated Picea
I. Leaves more or less flattened, usually grooved above.
2. One central resin duct.
3. Two vascular bundles Tsuga
3. One vascular bundle, leaves very small, resin duct
inconspicuous Taxodium
3. One vascular bundb . haves very large, resin duct
large Tu m ion
2. Two lateral resin duets.
3. Vascular cylinder surrounded by a conspicuous
bundle sheath. One vascular bundle. . . Pseudotsuga
3. Vascular cylinder .surrounded by a group of pith-
like cells or an inconspicuous bundle sheath.
Two distinct bundles ibies
2. Three resin ducts Sequoia sempervirens
2. No resin ducts. One vascular bundle. Walls of epi-
dermal cells and cutin deeply mammillated Taxus
KEY TO LARIX.
Leaves 3-angled or keeled.
2. Leaves distinctly 3-angled. Obscure resin ducts in
lateral edges of leaf L. arm i'v ana
2. Leaves slightly 3-angled or flat with keel on ventral side.
No resin ducts L. occidentalis
Leaves 4-angled L. Lyallii
522 IOWA ACADEMY OF SCIENCE
LARIX AMERICANA Michx. Tamarack, Larch.
Leaves decidedly three-angled.
Resin ducts obscure, but present at extreme edges of leaf. They
consist of an opening in a cluster of hypodermal cells.
Vascular bundles surrounded by a definite sheath of round un-
lignified cells. Xylem bands small and divided. A very
few isolated lignified cells present in pith.
Hypodermal cells present in small groups at lateral edges of leaf,
also one layer along dorsal and ventral midrib. Not lignified.
Epidermal cells small, round and unlignified.
Walls of parenchyma deeply infolded.
Material from trees on Campus of Iowa State College.
LARIX OCCIDENTALS Nutt. Tamarack.
Leaves more or less flat, keeled below.
Resin ducts none.
Vascular bundle surrounded by a definite sheath of round, lig-
nified, loose joined cells. Xylem in excess of phloem with a
band of lignified cells extending from xylem through phloem
to a group of lignified strengthening cells below. Xylem bands
slightly separated.
Hypodermal cells in a small group at lateral angles, also one
layer present along dorsal and ventral midrib. Lignified.
Epidermal cells large, round and lignified.
Parenchyma walls infolded.
Material from University of Washington.
Plate XXXIX.
Figure 1'. — Section of leaf of Larix americana.
Figure 1". — Section of leaf of L. occidentalis.
Figure 2".— Section through stoma of L. occidentalis.
Figure 3'. — Section through resin duet of L. americana.
Figure 4'. — Section of vascular cylinder of L. americana.
Figure 4". — Section of vascular cylinder of L. occidentalis.
Iowa Academy Sciem i
Plate XXXIX
524 IOWA ACADEMY OF SCIENCE
LARIX LYALLII Pari. Tamarack.
Leaves 4 angled, 1 — iy2 in. long.
Kesin ducts absent.
Vascular bundle surrounded by a definite bundle sheath of
round unlignified cells. Lignified cells extending in a band
across the vascular cylinder comprise the xylem.
Hypo-dermal cells present at angles of leaves — those at lateral
angles in a double layer — lignified epidermal cells small, round,
un-uniform in size and unlignified.
AValls of parenchyma not deeply unfolded.
Material from California.
Plate XL.
Figure 1. — Section of leaf of Larix Lyallii.
Figure 2. — Section through lower epidermis of leaf of Larix
Lyallii.
Figure 3. — Section through lateral angle of leaf of Larix
Lyallii.
Figure 4. — Section of vascular cylinder of leaf of Larix
Lyallii.
Iowa Academy Science
Plate XL
526 IOWA ACADEMY OF SCIENCE
KEY TO PICEA.
1. Without resin ducts.
2. Leaves 4-angled. Three to four rows of stomata on
each side of leaf. Parenchyma walls smooth
P. canadensis
2. Leaves flattened. Two to three rows of stomata on
each side of mid-rib on lower surface. Numerous
stomata on upper surface P. sitchensis
1. With resin ducts.
2. Resin ducts more or less touching lateral angles
Leaves 4-angled. Four to seven rows of stomata
on each surface P. parryana
2. Resin ducts touching ventral sides.
3. Leaves more or less 3-angled. Four to five
rows of stomata on each upper surface, no
stomata on lower surface P. Breweriana
o. Leaves 4-angled.
4. Resin ducts very large, as large as vascu-
lar cylinder (in some leaves one or
both wanting). Three to five rows of
stomata on each surf ace... P. Englemanni
4. Resin ducts small.
5. Two layers of cells lining resin
ducts. Four rows of stomata on
each upper surface. Two rows
on each lower surface P. ruhens
5. One layer of cells lining resin ducts.
Four to five rows of stomata on
each upper surface. Two to
three rows on each lower sur-
face P. mariano
PICEA MARIANA B. S. & P. Black Spruce
Leaves 4-angled, 14 to 3/4 inch long.
Resin ducts 2, small, lateral, touching ventral epidermis, one
layer of lignified cells lining the duct.
Vascular bundles — Xylem obscurely separated, cells of pith
largely lignified, several large lignified strengthening cells be-
low phloem. Cells of bundle sheath lignified at their junc-
ture.
Hvpodermal cells in one layer around entire periphery, ligni-
fied.
Epidermis lignified on inner wall.
Parenchyma walls corrugated.
Stomata 2 to 3 rows on lower side
4 to 5 rows on upper side.
Material from Campus of Iowa State College.
Plate XLT.
Figure 1. — Section of leaf of Picea mariana.
Figure 2. — Section through epidermis and stomata of leaf of
P. mariana..
Figure 3. — Section through resin duct of leaf of P. mariana.
Figure 4. — Section through vascular cylinder of leaf of P.
mariana.
Iowa Academy Science
rr.ATE xr.i
528 IOWA ACADEMY OF SCIENCE
PICE A IWBENS Sarg. Red Spruce.
Leaves 4-angled, y2 to % inch long.
Resin ducts 2, small, lateral, touching strengthening cells on
ventral side below the angles, ducts lined by two layers of
lignified cells.
Vascular bundle — Xylem very slightly divided, a group of thick
walled lignified strengthening cells below phloem. Xo ligni-
fication of pith, cells of bundle sheath lignified where joined.
Hypodermal cells around entire periphery, thick walled except
along stomata bands, one layer thick and lignified.
Parenchyma walls slightly corrugated.
Stomata 4 rows on each upper side.
2 rows on each lower side.
Material obtained from C. S. Sargent,
Jamaica Plains, Massachusetts.
Plate XLII.
Figure 1. — Section of leaf of Picea rubcns.
Figure 2. — Section through epidermis and stomata of leaf of
P. rubcns.
Figure 3. — Section through resin duct of leaf of P. rubens.
Figure 4. — Section through vascular cylinder of leaf of P.
rubens.
Iowa Academy Science
Plate XLII
34
530 IOWA ACADEMY OF SCIENCE
PICEA CANADENSIS B. S. & P. White Spruce.
Leaves 4-angled, 1/3 to % inch long.
Resin ducts none or rarely one.
Vascular bundles — Xylem bands separated by one row of thin
walled cells, cells of pith lignified below phloem, also a few
thick walled lignified cells below phloem, bundle sheath not lig-
nified.
Hypodermal cells in one layer around entire periphery ligni-
fied.
Parenchyma walls smooth.
Stomata in 3 to 4 rows on each side of leaf.
Material from Campus of Iowa State College.
Plate XLIII.
Figure 1. — Section of leaf of Picea canadensis.
Figure 2. — Section through epidermis and stomata of leaf of
P. canadensis.
Figure 4. — Section through vascular cylinder of leaf of P.
canadensis.
Iowa Academy Science
1'i.ate XL1II
533 IOWA ACADEMY OF SCIENCE
PICEA ENGELMANNI. Engelm. Engelman Spruce,
White Spruce.
Leaves 4-angled, 1 inch to 1% inches long.
Resin ducts 2 (in some leaves 1 or both are missing), very large
(as large as vascular cylinder), touching epidermis on ventral
side, lined with 2 layers of lignified cells.
Vascular bundles — Xylem most noticeably undivided, pith cells
above xylem lignified, large irregular cells in pith below
phloem lignified, cells of bundle sheath lignified where joined.
Hypodermal cells present around entire periphery in 1 layer
with increases to 2 to 3 layers at angles, heavy walled and
lignified.
Parenchyma walls slightly corrugated.
Stomata in 3 to 5 rows on each side.
Material from Herbarium of Iowa State College.
Plate XLIV.
Figure 1. — Section of leaf of Picea Engelmanni.
Figure 2. — Section through epidermis asd stomata of leaf of
P. Engelmanni.
Figure 3. — Section through resin duct of leaf of P. Engel-
manni.
Figure 4. — Section through vascular cylinder of leaf of P.
Engelmanni.
Iowa Academy Science
Plate XLIV
534 IOWA ACADEMY OF SCIENCE
PICEA PARRYANA Sarg. Blue Spruce.
Leaves 4-angled, 1 inch to iy8 inches long.
Eesin ducts 2, large, at lateral angles of leaves or slightly below
the angles, 2 rows of cells lining ducts, inner layer of lignified,
irregular flat cells.
Vascular bundle — Xylem bundles separated by two rows of
long narrow lignified cells, large irregular cells above xylem
lignified, also the large irregular cells below phloem lignified,
cells of bundle sheath lignified where joined.
Hypodermal cells lignified, in 1 row around entire periphery,
thickening into 2 rows at upper and lower angles of leaf.
Parenchyma walls smooth.
Stomata in 4 to 7 rows on each side of leaf.
Material from Campus of Iowa State College.
Plate XLV.
Figure 1. — Section of leaf of Picca parryana (pungens).
Figure 2. — Section through epidermis and stomata of leaf of
P. parryana.
Figure 3. — Section through resin duct of leaf of P. parryana.
Figure 4. — Section through vascular cylinder of leaf of P.
parryana.
Iowa Academy Science
Tlate XLV
536 IOWA ACADEMY OF SCIENCE
PICEA BREWERIANA Wats. Weeping Spruce.
Leaf flat, 3-sided. (The lower side is the flat side), % incn to
l*/o inches long.
Resin ducts 2, large, lateral, touching ventral epidermis, lined
with 2 layers of flat cells, inner layer lignified.
Vascular bundle — Xylem bundles very small, separated by 2 rows
of irregular, lignified cells. Phloem band large, cells of pith
largely lignified, cells of bundle sheath lignified where joined
to each other.
Hypodermal cells very pronounced around entire periphery ex-
cept on upper side along bands of stomata, 2 rows deep, 3
rows deep at angles.
Epidermis cutinized in thick outer walls, inner wall lignified.
Stomata in broad bands on upper surface only, 4 to 5 rows in
each band.
Parenchyma deeply corrugated.
Material from State House grounds, Sacramento, California.
Plate XLVI.
Figure 1. — Section of leaf of P. breweriana.
Figure 2. — Section through epidermis and stomata of leaf of
P. breweriana.
Figure 3. — Section through resin duct of leaf of P. brew-
eriana.
Figure 4. — Section through vascular cylinder of leaf of P.
breweriana.
Iowa Academy Science
Plate XL VI
538 IOWA ACADEMY OF SCIENCE
PICE A SITCHENSIS Carr. Sitka Spruce.
Leaves flat. 12 inch to l1- inches long.
Resin duets none.
Yascular bundles — Xylem not apparently separated, cells of
pith above xylem and below phloem lignified. lignified
strengthening cells present below phloem, bundle sheath some-
what lignified.
Hypodermal cells lignified. in one layer except at lateral edges
of leaf and in dorsal and ventral angles where there is an
increase of 2 to 3 layers. Thinner walled hypodermal cells
below epidermis between the angles of the leaf on ventral
side.
Parenchyma walls deeply corrugated.
Stomata occasionally in 2 to 3 rows on each side of midrib on
lower surface, numerous stomata on upper surface.
Materials from University of Washington and from State House
grounds. Sacramento. California.
Plate XLYII.
Figure 1. — Section of leaf of Picea sitchensis.
Figure 2. — Section through epidermis and stomata of leaf of
P. sitchensis.
Figure -i. — Section through vascular cylinder of leaf of P.
sitchensis.
Iowa Academy Science
Plate XL VI I
540 IOWA ACADEMY OF SCIENCE
KEY TO TSUGA.
1. Leaves flat.
2. Five to six rows of stomata on each side of midrib
T. canadensis
2. Seven to eight rows of stomata on each side of midrib.
Cells of upper palisade not deep. Cells of parenchyma
along lower surface irregular, or in shallow palisade
arrangement. Secretory cells of resin duct not con-
spicuously one-layered T. caroliniana
2. Seven to nine rows of stomata on each side of midrib.
Deep and narrow palisade on upper surface. Cells of
parenchyma on lower surface having greatest length
laterally. Secretory cells of resin duct conspicuously
one-layered T. heterophylia
1. Leaves concave above.
Stomata on both surfaces. Eight rows on each side of
midrib on ventral surface T. mertensiana
TSUGA CANADENSIS Carr. Hemlock.
Leaves flat, grooved on top, 1/3 to 2/3 inch long, edges tend to
turn up.
Resin duct 1, large, central, on ventral side touching epidermis,
lined with 1 layer of thin flat lignified cells.
Vascular bundles enclosed in an inconspicuous sheath of large,
round, loosely joined cells. Xylem bundles very small,
scarcely separated. Xo other cells except those of xylem lig-
nified.
Hypodermal cells sometimes present along dorsal groove. Epi-
dermis not lignified, guard cells and those cells adjacent lig-
nified.
Stomata on lower surface, 5 to 6 rows each side of midrib.
Material from Campus of Iowa State College.
Plate XL VIII.
Figure 1. — Section of leaf of Tsuga canadensis.
Figure 2. — Section through epidermis and stomata of leaf of
T. canadensis.
Figure 4. — Section through vascular cylinder and resin duct
of leaf of T. canadensis.
Iowa Academy Science
Plate XL VI II
542 IOWA ACADEMY OF SCIENCE
TSUGA CABOLINIANA Engelm. Hemlock.
Leaf flat, straight, 1/3 to % inch long.
Resin duet 1, small, central, touching hypodermal cells adjoin-
ing epidermis; lined with a layer of flat lignified cells.
Vascular bundle enclosed in a sheath of large, round, loosely
joined cells. Xylem bundle small and separated by a layer
of large thin walled cells. Two groups of lignified cells at
each side of phloem.
Hypodermal cells in angles formed by epidermis and resin duct
at edges of leaf and a few scattered singly on dorsal side.
Stomata in bands of 7 to 8 rows each on ventral side either
side of midrib.
Material from Biltmore, North Carolina.
Plate XLIX.
Figure 1. — Section of leaf of Tsuga caroliniana.
Figure 2. — Section through epidermis and stoma of T. caro-
liniana.
Figure 4. — Section through vascular cylinder and resin duct
of leaf of T. caroliniana.
Iowa Academy Science
Plate XLIX
544 IOWA ACADEMY OF SCIENCE
TSUGA HETEROPHYLLA Sarg. Hemlock.
Leaves flat, edges tending downward, 14 to % inch long, grooved
top.
Resin duct 1, large, lined with. 2 layers of cells, inner layer con-
sisting of large, round, unlignified cells.
Vascular bundles enclosed in a sheath of large loose cells ; within
the sheath, in addition to vascular bundle, lie a few lignified
cells below and at each side of phloem.
Hypodermal, lignified cells present along lateral edges of leaf
and along dorsal groove. Walls of guard cells lignified.
Stomata in bands of 7 to 9 rows along each side of midrib.
Parenchyma along ventral surface of leaf, having cells arranged
with greatest length laterally.
Material from University of Washington, Seattle.
Plate L.
Figure 1. — Section of leaf of Tsuga lieterophylla.
Figure 2. — Section through epidermis and stomata of leaf of
T. heterophylla.
Figure 4. — Section through vascular cylinder and resin duct
of leaf of T. keterophyUa.
Iowa Academy Science
Plate L
546 IOWA ACADEMY OF SCIENCE
TSUGA MERTENSIANA Sarg. Mountain Hemlock.
Leaves flat, grooved on top, edges tending down, 1-12 to 1 inch
long.
Resin duct 1, small, central, on ventral side touching epidermis ;
cells lining duct not in a definite layer.
Vascular bundle enclosed in an obscure sheath of large, round,
loosely joined cells, xylem bundles small, separated by 1 or 2
rows of unlignified cells, groups of cells in pith on each side
of phloem lignified.
Hypodermal cells present only at edges of leaf, cells lignified
also at point where duct and epidermis touch; guards cells
lignified.
Stomata on both surfaces, 8 rows on each side of midrib on
ventral surface.
Material from Jamaica Plains, Massachusetts.
Plate LI.
Figure 1. — Section of leaf of Tsuga mertensiana.
Figure 2. — Section through epidermis and stomata of leaf of
T. mertensiana.
Figure 4. — Section through vascular cylinder and resin duct
of leaf of T. mertensiana.
Iowa Academy Science
Plate 1. 1
548 IOWA ACADEMY OF SCIENCE
PSEUDOTSUGA MUCRONATA Sudw. Douglas Fir.
Leaves flat, notched above and keeled below, % inch to l1^
inches long.
Resin ducts, 2, lateral and touching epidermis on ventral side,
ducts lined with 2 layers of cells, lignified where touching
epidermis.
Vascular bundle surrounded by a most pronounced bundle
sheath of lignified cells. Xylem bundles appearing as one,
cells below phloem and above xylem lignified.
Hypodermal cells present in 1 to 3 layers along dorsal and ven-
tral midrib, heavily lignified.
Epidermis cells mammillated, mammillation most pronounced on
ventral surface.
Walls of parenchyma corrugated.
Stomata on lower surface.
Material from Campus and herbarium of Iowa State College;
Jamaica Plains, Massachusetts; University of Washington,
Seattle ; State House grounds, Sacramento, California ; and
University of California.
Plate LII.
Figure 1. — Section of leaf of Pseudotsuga mucronata.
Figure 2. — Section through epidermis and stoma of leaf of
P. mucronata.
Figure 3. — Section through resin duct of leaf of P. mucro-
nata.
Figure 4. — Section through vascular cylinder of leaf of P.
mucronata.
Iowa Acailemy Science
Plate L1I
550 IOWA ACADEMY OF SCIENCE
PSEUDOTSUGA MACBOCARPA Mayr. Hemlock.
Leaves flat, grooved above, keeled below, edges tending down-
ward. % inch to li/4 inches long.
Resin ducts 2, lateral, lignified where touching ventral epidermis.
Vascular bundle surrounded by a most pronounced bundle
sheath, cells of sheath lignified. Xylem appears as one bundle
with only a slight demarcation. Lignified strengthening cells
present below phloem and a wide band of lignified cells ex-
tend from xylem through center of phloem.
Hypodernial cells present in one layer around entire peri-
phery. Walls lignified and very thick.
Cells of epidermis mammillated.
Stomata on ventral surface.
Material from Herbarium of Iowa State College ; from San Ber-
nardino. California, and from State House grounds,
Sacramento, California.
Plate LIII.
Figure 1. — Section of leaf of Pseudotsuga macrocarpa.
Figure 2. — Section through epidermis of leaf of P. macro-
car pa.
Figure 3. — Section through resin duct of leaf of P. macro-
carpa.
Figure 4. — Section through vascular cylinder of leaf of P.
macrocarpa.
Note : The distinguishing feature between the leaves of the
two species of Pseudotsuga consists in the presence of a continu-
ous band of heavy walled, lignified, hypodermal cells in the leaf
of P. macrocarpa and the absence of the same, except along the
midrib, in P. mucronata. This fact tallies with the environ-
mental conditions under which the trees grow, as P. macrocarpa
lives under more xerophytic conditions than P. mucronata.
Iowa Academy St ience
Tlate L1II
552 IOWA ACADEMY OF SCIENCE
KEY TO SPECIES OF ABIES.
1. Leaves flat.
2. Resin duct lateral and interparenchymal.
3. Hypodermal cells not present, stomata 4 to 8 rows
on lower side A. balsamea
3. Hypodermal cells present.
4. Stomata on lower surface only, 8 to 12 rows
A. Fraseri
4. Stomata on upper and lower surfaces, 8 to 10
rows below, indefinite number above
A. lasiocarpd
2. Resin ducts lateral, touching lower epidermis.
3. Hypodermal cells present on dorsal side in con-
tinuous layer, or around entire periphery,
except along bands of stomata.
4. Stomata not present on dorsal surface.
5. Leaf small, deeply grooved. Margins
curving up. Stomata in bands of 6
to 8 rows each A. amabilis
5. Leaf very long, flat or slightly rounded
on upper side. Eight to sixteen rows
of stomata in each band A. venusta
4. Stomata present on both dorsal and ventral
surface, leaf deeply notched above.. A. nobilis
3. Hypodermal cells present only in lateral angles of
leaf, and along ventral midrib or in
groups of 2 or 3 along dorsal side.
4. Stomata on ventral surface only A. grandis
4. Stomata on both dorsal and ventral surfaces
A. concolor
1. Leaves 4-angled or rounded.
2. Bundle sheath obscure. Vascular bundles close together.
The same number of rows of stomata on all sur-
faces A. magnified
2. Bundle sheath distinct. Vascular bundles far apart.
Rows of stomata more numerous on lower surface. . .
A. nobilis
ABIES FEASERI Poir. Balsam Fir.
Leaves flat, edges tending down, y2 to 1 inch long.
Resin ducts large, lateral and more or less touching ventral epi-
dermis, lined with two rows of cells.
Vascular bundles small, enclosed in a sheath of large, round,
loosely joined cells; xylem bundles small and close together,
separated by a band, of thin walled cells, one row wide. The
thin walled irregular cells present below and between phloem
are lignified.
Hypodermal cells present in angles made by ducts and epider-
mis, and in small number along midrib.
Epidermis not lignified.
Stomata present on lower surface in band of 8 to 12 rows each
side of midrib.
Material from Jamaica Plains, Massachusetts.
Plate LIV.
Figure 1. — Section of leaf of Abies fraseri.
Figure 2. — Section of epidermis and stomata, leaf of A. fraseri.
Figure 3. — Section through resin duct of leaf of A. fras< ri.
Figure 4. — Section of vascular cylinder, leaf of A. fraseri.
Iowa Academy Science
Plate LIV
554 IOWA ACADEMY OF SCIENCE
ABIES BALSAMEA Mill. Balsam Fir.
Leaves flat, edges tending down, y2 inch to 1*4 inches long.
Eesin ducts interparenchymal, lined by two layers of unlig-
nified cells.
Vascular bundle surrounded by a slightly differentiated bundle
sheath of large, loose cells, lignified where joined together;
most of cells in pith below phloem lignified.
Hypodermal cells not present or seldom so. No lignification of
epidermis except guard cells.
Stomata in 4 to 8 rows each side of mid rib on lower surface.
Material from Cass Lake, Minnesota.
Plate LV.
Figure 1. — Section of leaf of Abies balsamea.
Figure 2. — Section through epidermis and stomata of leaf of
A. balsamea.
Figure 3. — Section through resin duct of leaf of A. balsamea.
Figure 4. — Section through vascular cylinder of leaf of A.
balsamea.
Iowa Academy Science
Plate LV
556 IOWA ACADEMY OF SCIENCE
ABIES AMABILIS Forbes. White Fir.
Leaves flat, edges turned up, % inch to 1% inches long.
Resin ducts lateral, touching epidermis on ventral side, lined
with two layers of unlignified cells.
\ ascular bundles surrounded by a sheath of large, round, loosely
joined cells, xylem bundles small, separated by a band of 2
to 3 rows of lignified cells ; a group of large cells below phloem
lignified.
Hypodermal cells present around entire periphery except along
bands of stomata. Walls of these cells very thick and lig-
nified; the inner walls of the epidermis lignified.
Stomata on lower surface, 6 to 8 rows each side of midrib.
Material from Jamaica Plains, Massachusetts.
Plate LVL
Figure 1. — Section of leaf of Abies amabilis.
Figure 2. — Section through epidermis and stomata of leaf of
A, amabilis.
Figure 3. — Section through resin duct of leaf of A. amabilis.
Figure 4. — Section through vascular cylinder of leaf of A.
amabilis.
Iowa Academy Science
Platk LVI
558 IOWA ACADEMY OF SCIENCE
ABIES GRANDIS Lindl. White Fir.
Leaves flat, edges tending down, 1% to 2*4 inches long.
Resin ducts small, lateral, touching epidermis on ventral side,
lined with 2 layers of cells.
Vascular bundles surrounded by a sheath of large, round, loosely
joined cells. The large irregular cells separating the bundles
and those below lignified.
Hypodermal cells present within epidermal layer between bands
of stomata on lower side, at the edges of the leaf, and scat-
tered in groups of 1 or 2 along upper surface. Epidermal
cell walls not lignified.
Stomata present on lower surface of leaf, 7 to 10 rows each side
of midrib.
Material from Jamaica Plains, Massachusetts.
Plate LVII.
Figure 1. — Section of leaf of Abies grandis.
Figure 2. — Section through epidermis and stomata of leaf of
A. grandis.
Figure 3. — Section through resin duct of leaf of A. grandis.
Figure 4. — Section through vascular cylinder of leaf of A.
grandis.
Iowa Academy Science
Plate LVII
560 IOWA ACADEMY OF SCIENCE
ABIES LASIOCAEPA Nutt. Balsam Fir.
Leaves flat, 1 inch to 1% inches long.
Resin ducts large, interparenchymal, and lateral; lined by 2
rows of thin cells.
Vascular bundles small and near upper margin of vascular cyl-
inder. The large loose cells below phloem are lignified.
Hypodermal cells present below epidermis at lateral edges, and
between the bands of stomata on lower surface. Inner Avails
of epidermis lignified.
Stomata present, in 4 to 5 rows each side of midrib on dorsal
side and 7 to 8 rows each side of midrib on ventral side.
Material from Jamaica Plains, Massachusetts.
Plate LVIII.
Figure 1. — Section of leaf of Abies lasiocarpa.
Figure 2. — Section through epidermis and stoma of leaf of
A. lasiocarpa.
Figure 4. — Section through vascular cylinder of leaf of A.
lasiocarpa.
Iowa Academy Science
Pi ATE LVIII
562 IOWA ACADEMY OF SCIENCE
ABIES CON CO LOR Lindl. and Gord. White Fir.
Leaves flat, straight, 2 to 3 inches long.
Resin ducts ventral, touching epidermis; lined with 2 layers of
cells; not lignified. except where ducts touch epidermal wall.
Vascular bundles very far apart, cells between lignified, no trace
of a bundle sheath.
Ilypodermal cells present on lateral edges and on lower side of
leaf between bands of stomata.
Guard cells and heavy cells in epidermis above them lignified.
Stomata in 6 to 7 rows each side of midrib above, in
5 to 6 rows each side of midrib below.
Material from Campus of Iowa State College and from
Jamaica Plains, Massachusetts.
Plate LIX.
Figure 1. — Section of leaf of Abies concolor.
Figure 2. — Section through epidermis and stoma of leaf of
A. concolor.
Figure 3. — Section through resin duct of leaf of A. concolor.
Figure 4. — Section through vascular cylinder of leaf of A.
concolor.
Iowa Academy Science
Plate L1X
564 IOWA ACADEMY OF SCIENCE
ABIES VENUSTA K. Kosh. Silver Fir.
Leaves flat, straight, lanceolate iy2 — 214 in. long, y8 in. wide,
liesin duets small, ventral, touching epidermis, lined with 2 lay-
ers of thin walled cells.
Vascular bundles — surounded by a slight bundle sheath of loose,
round cells ; heavy walled irregular cells between bundles, lig-
nified ; phloem extending far around the sides of bundles.
Hypodermal cells present in double or triple layers below epi-
dermis around entire periphery, except along stomata bands,
strongly lignified ; heavy layer of cutin over epidermis.
Stomata on lower surface only in bands of 8-16 rows each side
of mid-rib.
Material from California.
Plate LX.
Figure 1. — Section of leaf of Abies venusta.
Figure 2. — Section through lower epidermis and stoma of leaf
of Abies venusta.
Figure 3. — Section through epidermis and resin duct of Abies
venusta.
Figure 4. — Section through vascular cylinder of leaf of Abies
venusta.
Iowa Academy Science
Plate LX
566 IOWA ACADEMY OF SCIENCE
ABIES NOBILIS Lindl. Red Fir.
Leaves flat and deeply grooved above, on sterile branches; 4-
angled on fertile shoots. U inch to iy2 inches long.
Resin ducts lateral, touching ventral epidermis, lined with 2
layers of unlignified cells.
Vascular bundles surrounded by a bundle sheath of round,
loosely joined cells: cells below phloem lignified.
Hypodermal cells present in lateral angles of leaf and along
dorsal and ventral midribs in 1 to 2 layers, cells thick walled
and lignified. In the 4-angled leaves they are more or less
present around entire periphery.
Stomata present on both surfaces. 8 rows on upper surface and
10 rows on lower surface.
Material from Herbarium. Iowa State College.
Plate LXI.
Figure 1. — Section of leaf of Abies nobilis.
Figure 2. — Section through epidermis and stoma of A. no-
bilis.
Figure 3. — Section through resin duct of leaf of A. nobilis.
Figure 4. — Section through vascular cylinder of leaf of A.
nobilis.
Iowa .-. - a
5«8 IOWA ACADEMY OF SCIENCE
ABIES MAGNIFICA A. Murr. Red Fir.
Leaves 4-angled, % inch to iy2 inches long.
Resin ducts, large, lateral, touching epidermis on ventral side,
lined by 2 layers of unlignified cells.
Vascular bundles large and close together. Vascular cylinder
not surrounded by a definite sheath ; 2 large groups of ligni-
fied cells present each side of phloem.
Hypodermal cells thick walled and lignified, located in lateral
angles, dorsal angles, and adjoining resin ducts, also scattered
in groups of 2 and 3 along ventral side of leaf.
Stomata in bands of 6 to 8 rows on each of the four sides of the
leaf.
Material from Jamaica Plains, Massachusetts.
Plate LXII.
Figure 1. — Section of leaf of Abies magnified.
Figure 2. — Section through epidermis and stoma of leaf of
A. magnified.
Figure 3. — Section through resin duct of leaf of A. mdg-
nifica.
Figure 4. — Section through vascular cylinder of leaf of A.
nni unified.
Iowa Academy Science
Plate LXII
570 IOWA ACADEMY OF SCIENCE
SEQUOIA SEMPERVIRENS Endl. Red Wood.
Leaves (secondary and lower branches) flat, lanceolate, *4 to V2
inch long.
Kesin ducts 3, lined with unlignified cells.
Vascular bundle one. No bundle sheath. Cells adjoining bundle
slightly lignified.
Hypodermal cells present along upper surface and extending
around edges of leaf to resin ducts, lignified and thick
walled.
Epidermal cells not lignified.
Stomata on dorsal surface in 2 narrow bands, ventral surface
stomatiferous on each side of midrib.
Material from University of California.
Plate LXIII.
Figure 1. — Section of leaf of Sequoia sempervirens.
Figure 2. — Section through upper epidermis of leaf of S.
sempervirens.
Figure 3. — Section through lateral resin ducts of leaf of S.
sempervirens.
Figure 3 (lower). — Section showing stoma and underlying
parenchyma of S. sempervirens.
Figure 4. — Section through vascular cylinder and central
resin duct of leaf of S. sempervirens.
Iowa Academy Science
Plate LXIII
IOWA ACADEMY OF SCIENCE
TAXODIUM DISTICHUM Rich. Bald Cypress.
Leavt-s small. :_ to % inch long. flat, notched on top.
Kesin ducts not present.
Vascular bundles obscure. Xyleni consists of 6 or more small
lignified cells, the remainder of bundle composed of a group
of small undifferentiated, round cells. At each side of bundle
lie 3 to 4 large cells slightly lignified.
Hypodermal cells not present.
Epidermal cells not lignified.
Parenchyma walls corrugated.
S1 aata on lower surface of leaf.
State House grounds, Sacramento. California.
Plate LXIV.
Figure 1. — Section of leaf of Taxodium distichum showing
resin du I
Figure 1 . — Section of the same showing a leaf not having
resin duct.
Figure 2. — Section through lower epidermis and stoma of
leaf of T. distichum.
Figure 2'. — Section through upper epidermis of same.
Figure 4. — Section through vascular cylinder and resin duct
of leaf of T. distichum,
Iowa Academy Science
Plate LX1V
>K-/
574 IOWA ACADEMY OF SCIENCE
TUMION TAXIFOLIUM Green, Torreya. Stinking Cedar.
Leaves very broad and flat. V/2 inches long, edges tending down.
Resin duet 1, large, ventral, central, below vascular bundle but
not touching epidermis. Lined by several irregular concentric
layers of cells.
Vascular bundle single, not enclosed in a sheath. Xylem bundle
thin and crescent shaped, often a few strengthening fibers
present at sides of phloem.
Hypodermal cells not present.
Epidermis shallow, heavy walled and lignified, lower epidermal
cells slightly mammillated.
Stomata borne in 2 broad, shallow grooves on ventral side of
leaf, one groove each side of midrib. Stomata flanked by long
forked pillars, guard cells lignified.
Palisade parenchyma not very deep, composed of broader shal-
lower cells than Tumion californicum.
Material from Tallahasse, Florida.
Plate LXV.
Figure 1. — Section of leaf of Tumion taxifolium.
Figure 2. — Section through a ventral groove, on leaf of T.
taxifolium, showing stomata and pillar-like cells.
Figure 2'. — Section through epidermis of leaf of T. taxi-
folium.
Figure 4. — Section through vascular cylinder and resin duct
of leaf of T. taxifolium.
Iowa Academy Science
Plate LXV
576 IOWA ACADEMY OF SCIENCE
TUMION CALIFOBNICUM Greene. California Nutmeg.
Leaves flat, 1 inch to 3^ inches long, edges tend down.
Resin duct one, large, central, on ventral side, not touching epi-
dermis, lined by several irregular concentric layers of cells.
Vascular bundle one, not enclosed in a definite bundle sheath.
Hypodermal cells not present. Epidermis deep, very thick
walled and lignified, lower epidermis decidely mammillated.
Stomata borne in deep narrow grooves on ventral side of leaf,
one groove each side of midrib. Stomata flanked by long
forked suberized pillars.
Palisade parenchyma very deep, composed of long narrow cells.
Material from University of California.
Plate LXVI.
Figure 1. — Section of leaf of Tumion californicum.
Figure 2'. — Section through upper epidermis of leaf of T.
californicum.
Figure 2". — Section through lower epidermis of leaf of T.
calif or n't i ma.
Figure 2'". — Section through a ventral groove on leaf of T.
californicum, showing stomata and pillar-like cells.
Figure 4. — Section through vascular cylinder and resin duct
of leaf of T. californicum.
Iowa Academy Science
Plate LXVT
37
578 IOWA ACADEMY OF SCIENCE
TAXUS BREVIFOLIA Nutt. Yew.
Loaves broad and flat, Vo to % inch long.
No resin ducts.
Vascular bundles not large, surrounded by a group of round,
loosely joined cells; a group of lignified cells present in pith
at each side of xylem band.
No hypodermal cells.
Epidermal cells very large and spherical, covered by a thick cut-
in, cutin deeply mammillated on lower side of leaf; guard cells
lignified.
Palisade parenchyma not deep nor cells so narrow as in case of
Taxus floridana.
Material from University of Washington.
Plate LXVII.
Figure 1. — Sections of leaves of Taxus brevifolia.
Figure 2. — Section through lower epidermis and stoma of
loaf of T. brevifolia.
Figure 4. — Section through vascular cylinder of leaf of T.
brevifolia.
Iowa Academy Science
Plate I.XVII
*"^#
IOWA ACADEMY OF SCIENCE
TAXUS FLOMDANA Chapm. Yew.
Leaves broad and flat. 34 to 1 inch long.
Resin duets none.
Vascular bundles large, not surrounded by a sheath but by a
mass of loosely joined cells. Xylem in narrow band, lignified
cells present in pith at each side of xylem.
Hypodermal cells not present.
Cells of epidermis flattened, smaller than in Taxus b re vi folia.
heavily eutinized. cutin deeply mammillated on lower surface ;
guard cells lignified.
Palisade parenchyma deep, composed of long narrow ceils.
Material from State House grounds. Sacramento. California.
Plate LXVIII.
Upper figure. — Section of leaf of Taxus floridana.
Figure 2. — Section through upper epidermis and palisade
parenchyma of leaf of T. floridana.
Figure 2'. — Section through lower epidermis of leaf of T.
floridana.
Lower figure. — Section through vascular cylinder of leaf of T.
tana.
Iowa AcafJerr.y Science
I'i.ate LXVIII
582 IOWA ACADEMY OF SCIENCE
For assistance and advice in the above work acknowledgment
is respectfully made to Dr. L. H. Pammel and Dr. J. N. Martin.
For specimens used the writer is indebted to Dr. C. S. Sargent,
Doctor Setchel, Mr. 0. W. Newman, Dr. T. C. Fry, Prof. H. M.
Hall, Mr. II. D. Petheram and Mr. E. Peck Greene.
LITERATURE CITED.
Sargent, Charles Sprague, Manual of the Trees of North Ameri-
ca, pp. 35-101.
i'ngdmann, George, A Synopsis of the American Firs. Trans.
Acad. Sci., St. Louis, III, pp. 593-602.
Bertrand, C. E., Anatomie des Gnetacee's et des Conifers. Ann.
Sci. Nat. Bot., 20, 1874, pp. 5-153.
McNdb, W. It., Remarks on the Structure of Leaves of Certain
Conifers : Proc. Irish Acad., II, 1875, 209-213.
Sharp, Seymour S., Notes on the Determination of Rocky Mt.
Conifers: Torreya, 15, No. 1, 1915.
Coulter, J. M., and Bose, J. N., Synopsis of American Pines,
based on leaf anatomy: Bot. Gaz., Vol. II, 1886, 256-262
and 302-309.
Botanical Laboratory,
Iowa State College.
LATE POTATO BLIGHT IN IOWA 5S3
LATE POTATO BLIGHT EPIDEMICS IN IOWA AS COR-
RELATED WITH CLIMATIC CONDITIONS
A. T. ERWIN.
At least three pronounced outbreaks of the late blight of the
potato, Phytophthara infestans, have occurred in Iowa within
the past forty-five years. These were in 18851, 1903, and 19152.
The northern limits of the region generally designated as the
corn belt seems to represent in a general way the southern lim-
its of this disease under normal climatic conditions. This is in-
dicated by the fact of its frequent occurrence in the region just
north of us.
From these regions of the north we receive our annual seed
supply and this disease is therefore probably introduced into
some portions of the state every year. The fact that under nor-
mal climatic conditions in Iowa it does not survive even when
so introduced and yet in occasional years breaks forth in a vir-
ulent form, presents an interesting problem.
In many parts of the New England states late blight, usually
is an ever present disease and fails to develop only in dry years.
In Iowa the conditions are reversed. It is normally absent and
its presence in every known instance has been accompanied by
abnormal weather conditions. This fact indicates an interre-
lationship between these outbreaks and the atmospheric condi-
tions. In the following pages is presented a study of the cor-
relations between climatic conditions and late blight epidemics
in this state.
The relationship existing between many diseases and certain
climatic factors is well known. It is usually difficult, however.
to separate out the operative and nonoperative factors and to
determine which are finally causative. The fact that in Iowa
the outbreaks of this potato blight have always been accompan-
ied by abnormal conditions permits of a careful study of its re-
lation to those conditions and hence presents an approach to the
JThe outbreak for 1885 was reported by I lalsted, B. D. (Bot. Dept. Bull.
la. Agrl. College, 95, Feb., 1SSS), and tbose for 1903 and 1915 came under the
observations of the writer.
Specimens for the years of 1903 and 1915 are filed in the Bot. Dept. her-
barium of this institution and are identified by L. H. Pammel.
584
IOWA ACADEMY OF SCIENCE
problem from a direction the reverse of that iu the New Eng-
land states, where considerable attention has been given to this
disease.
Notable studies of late blight have been made under labora-
tory conditions, the most recent being those of Melhus3. These
have contributed important information relative to the life his-
tory of the fungus and cleared away a number of erroneous
conclusions based upon its supposed similarity to other mildews
whose life histories were well known. Laboratory studies, how-
ever important, recpiire confirmation under field conditions cov-
ering long periods of time and different sections of the country.
FIELD OBSERVATIONS IN IOWA.
In the following pages the writer has endeavored to supply
these field data for Iowa conditions. It is particularly inter-
esting to note the close parallelism between the actual condi-
tions of the field and the findings of the laboratory, a fact which
emphasizes the value of laboratory investigations for the correct
interpretation of field data.
MOISTURE SUPPLY.
One of the vital factors affecting the growth of diseases is
moisture supply. "When present in excessive quantities, the
plant growth is apt to be very succulent and sappy thus afford-
ing ideal feeding grounds for the parasite and these conditions
also augment spore production.
The rainfall by months for the years of 1885, 1903.. and 1915,
is presented in the following table :
Rainfall for Iowa.
TEAR
• UNE
JULY
AUGUST
TOTAL
DEPARTURE
FROM
NORMAL
TOTAL
PERCENTAGE
EXCESS
Normal
1885
1903
1915
4.38 in.
5.03 in.
2.86 in.
4.16 in.
3.92 in.
6.55 in.
4.83 in.
8.32 in.
2.91 in.
6.10 in.
6.64 in.
2.81 in.
—6.47 in.
—2.84 in.
—3.27 in.
52.05
22.85
26.30
It will be noted that the rainfall was deficient for June in
two of these years. July and August were very wet for 1885,
-Melhus, I. E., Jour. Agrl. Res. V— 2, Oct., 1915.
LATE POTATO BLIGHT IX IOWA
the total ss for the three months being 52 per cent. July
and August of 19 als -s amounting
to 23 per cent.
July of 1915 was very wet. in fact with one exception the
ttest July in the climatological history of the state. A s
of 1915 was dry but the total excess of rainfall for the three
months was approximately 26 per cent.
3 nee there is a vital relationship between weather conditions
covering the period of incubation and since that period also
bears a direct relationship to the time of final outbre;.
ondary period of infection, we have presented the rainfall
data in the following table in ten-day periods which we shall
call decades.
Raixfall fob Svmmee Moxths or 1903 by Decades ex Ixch -
(Des Moines Station.)
rcAx
?.TVEE
June :
First decade
•
"
— : B
ad decade
1.56
72
— .16
Third decade
.91
— •
Juxt:
-: decade
1.57
24
—
nd decade
.
1.31
—
Third decade
3
1.31
— -_
Aug" s
First decade
-
1
— : •
.
—1.25
Third decade
Total
!
1
— - -
13.40
12.43
— -
In two instances, the first decade of June was wet and in one
The second decade of June in two of the years was dry
and wet in one. The third decade of all three Junes was dry.
These conditions point to the fact that an — st ire in
June is not a requisite fa r the development of this
- and that even a normal June moisture supply g
In brief, the moisture supply for June would not s
to be a limit:: _ tor for the development of late blight under
Iowa conditions.
July for all three decades of the three years - with one
exception wet. The third decade of July was in all instances
586
IOWA ACADEMY OF SCIENCE
very wet. The excess in two of them was quite pronounced. The
conditions in this third decade of July are without doubt sig-
nificant in relation to the outbreaks which occurred during this
period in at least two of the epidemics. The decade in which
the outbreak of 1885 occurred was not recorded, but judging
from analagous climatic conditions it also occurred probably
during the third decade of July and during early August.
1903
1865
1813
June TulV Auqy*T
Fig. 49 — Rainfall by decades of each month. Des Moines station.
The first decade of August was wet in all three years. This
third of the month was also covered in at least two of these
outbreaks by a period of secondary infection. The second de-
cade of August was dry in all three instances. Since the vines
were dead by this time, the atmospheric conditions for the sec-
ond and third decade of August would not be significant in
relation to foliage destruction.
HUMIDITY.
Humidity and rainfall are usually closely associated though
such is not necessarily the case. From the standpoint of the
host plant, rainfall is the more important factor while humidi-
ty bears a direct relationship to the growth and development
of foliage diseases. A liberal supply of atmospheric vapor and
dew combined with the right degree of temperature provides
ideal conditions for spore production and germination. In the
following table are presented the humidity data for the three
years in question.
LATE POTATO BLIGHT IN IOWA
llrumnv Table.
(Des Moines st<ition.)
June
Per Cent
July
Per Cent
-
' 'I.N 1
Total Pehcentage
depaki ctbe from,
Normal
Normal
1885
1903
68.0
76.6
71.1
74.0
67.6
79.8
72.2
71.1
71.4
79.7
78.0
75.4
—29.1
—14.::
—19.5
It will be noted from this table that the humidity fa
is much more constant than thai of rainfall. In all of the
months in all three years, the humidity runs abnormally high
even in the months in which the rainfall was deficient.
The conditions with regard to humidity are more clearly
brought out in relation to the different stages of the develop-
ment of the disease when presented by decades.
-1903
?\8BS
1915
Jur\e lultj Auqust
Fir. 50 — Per cent of humidity by decades of each month. Pes Moii
Without reviewing the decades of each month in detail, spe-
cial attention is called to the high degree of humidity for the
third decade of July in 1885 ami 1915. For tie' year 1903.
this high stage of humidity came a little later and was re)
during1 the first decade of August.
58S
IOWA ACADEMY OF SCIENCE
TEMPERATURE.
Probably but few parasitic fungi are more sensitive to tem-
perature conditions than late blight. Its occurrence in Iowa
is dependent upon comparatively cool weather and in the cool
'climate of Maine upon comparatively warm weather. In both
instances the thermal mean for the years of its recurrence is
probably much the same. In one territory, its growth is limited
by too low a normal and in the other by one too high.
The mean temperature in Iowa by months is given in the
table below:
Mean Temperatures for Iowa.
fe
'-
rj
i CO
> CD
f- GO
Total
Totae
• a
—
a g
— —
n
< |
Departure
Degree^ F.
Percentage
Departure
Normal
69.1
74.1
71.8
1885
69.0
75.9
68.7
—1.4
.65
1903
64.6
70.9
69.1
10.7
4.83
1915
65.1
69.5
65.9
14.5
6.74
1885. The temperature was .l3 below normal for June and
3.1" deficient for August. July averaged 1.8° above normal.
1903. June — :'The month just closed was the coldest June on
record for the period of 144 years." The daily mean was 5.6°
below normal. July — Daily mean 2° below normal. August —
3.1° below normal.
1915. June — I3 below normal. "The coldest June since
1903. At numerous stations the monthly mean and absolute
maximum temperature for the month was lower than ever *oe-
fore recorded in June." July — "With one exception the cold-
est July of record." ''August. 1915. was the coolest month of
that name in the climatological history of the state. The month-
ly mean temperature and the monthly extremes were all lower
than was ever before recorded and the daily means were below
the normal means on all but four or five days during the
month." Frost occurred in some part of Iowa in every month
of the year 1915.
Taken as a whole, the years of outbreaks were distinctly cool
seasons. Subnormal temperatures were very pronounced for
4The climatological data of this bulletin are based upon the records of the
Iowa Weather Bureau. Thanks are due the director, G. M. Chappel.
LATE POTATO BLIGHT IX IOWA
5S9
the summers of 1903 and 1915. The same is true for lv<>
with the exception of the third decade of July. During this
decade the humidity, however, was above normal and gave one
of the highest readings on record.
^-^1903
Jur>« Jj"lv^ August
Fig. 51 — Mean temperature by decades of each month. Des Moines station.
The deduction is clear that the normal mean temperatures
for the summer months are too high for the development of
late blight in Iowa and are limiting factors.
The exact optimum between the upper and lower tempera-
tures at which this disease thrives under field conditions is dif-
ficult to determine. Selby3 in laboratory tests found that tem-
peratures ranging from 65° Fahrenheit to 75 Fahrenheit pro-
dueed favorable conditions for the disease and Galloway states
that "A normal temperature of from 72° Fahrenheit to 74"
Fahrenheit accompanied for any considerable time by moist
weather furnishes the best conditions for the spread of the
diseas
since the normal mean in Iowa for July is 74.1c Fahrenheit
and for August 71.8° Fahrenheit and as the disease has oc-
curred here only in the seasons of subnormal temperature dur-
_ These months, it would seem that the last named figures are
perhaps high.
'Selby, A. D., Ohio Naturalist, Feb.,
19 :
590
IOWA ACADEMY OF SCIENCE
The average of the means for July and August for the three
years in question is 70° Fahrenheit. This temperature would
seem to represent the danger line. So far as the temperature
conditions are a factor, a mean below 70° Fahrenheit for the
latter part of July and early August provides favorable condi-
tions for an outbreak of late blight. In this connection it is
interesting to note the statement made by Smith0 that "The
critical districts (for late blight) would be along the line of
70° Fahrenheit."
Conversely, regions lying within a mean above 70°, which in-
cludes Iowa, would be but little affected. The study of its his-
tory in this state supports this conclusion.
Since the disease is always more or less present through the
introduction of infected seed, there is always the probability
of an outbreak at a mean temperature below 70° Fahrenheit
provided the humidity factor is also favorable.
SOIL TEMPERATURES.
The initial growth of the mycelium in an infected tuber is
probably largely a matter of temperature conditions as moisture
is supplied directly by the tuber.
1914
1915
Fig. 52 — Mean soil temperatures, Ames, Iowa. Readings taken at a depth
of six inches.
The soil temperatures for the season of 1915 in comparison
with those for 1914 are presented in the following table.
6Smith, J. W.( Monthly Weather Review, 43-5-234, May, 1915.
LATE POTATO BLIGHT IN IOWA
591
These readings were taken in the experiment station potato
field at a depth of six inches, whieh probably represents the
main zone of tuber development for the potato. It will be
noted that soil temperatures for 1915 are strikingly low as com-
pared with 1914. It is to be regretted that this comparison
cannot be made with a normal established over a long period
of years. Orton7 reports that in the outbreak of 1893 in Penn-
sylvania, the soil temperatures for the summer were notably
low, and suggests that the soil temperatures are probably the
prinary factor in developing an epidemic. It is readily con-
ceivable that the soil temperature is a limiting factor in the
initial growth of the mycelium. However, once it reaches the
foliage and sporulation begins the controlling factors would
seem to be atmospheric rather than those of the soil. In fact,
the study of our field conditions leads to the suggestion that
through the planting of new seed the disease frequently makes
a start but fails to sporulate due to unfavorable atmospheric
conditions. Being unable to propagate it quickly perishes.
Through the courtesy of Professor J. G. Hosier of the Illi-
nois Experiment Station we have the soil temperature rec-
ords for the year 1915 in comparison with a normal, covering
a ten year period at that station.
Soil Temperatures at a Depth of Three Ixches.
(Champaign, Illinois.)
1Q1_ Actual
1910 Degrees F.
Normal
Degrees F.
Degree
Departure
Percentage
Departure
July
71.13
74.06
70.23
72.00
75.80
75.80
— .87
— .74
—4.57
—1.21
— .98
—603
In the following Sunshine Chart is shown the percentage
of possible amount of sunshine for the years 1903 and 1915 as
compared with the normal.
TQrton, C. R., Contributions from Dept. Bot. Pa. St. Coll., 191G.
592
IOWA ACADEMY OF SCIENCE
1915
1903
lune July August
Fig. 53 — Per cent of sunshine by decades of each month. Des Moines station.
Particular attention is called to the period covering the third
decade of July and the first decade of August of this table in
its relation to the period of secondary infection.
Unfortunately the sunshine records for 1885 are not avail-
able as they were not taken in this form by the Weather Bureau
at that time.
As expressed in terms of clear, partly cloudy and cloudy
days, the record for 1885 was as follows:
Clear
Partly
Cloudy
Cloudy
July
4
5
11
21
15
11
5
11
9
The germicidal properties of sunshine are well known. The
delicate thin walled conidia are quickly destroyed by exposure
to bright sunshine. The predominance of cloudy days was
therefore an important aid in the propagation of the disease.
SUMMARY.
Climatic conditions in Iowa are generally unfavorable to the
development of Phytophthora infestans.
The seasons in which it did occur were characterized by sub-
normal temperatures, high humidity, heavy dews, excessive
rainfall and a predominance of cloudy weather.
Iowa Agricultural Experiment Station.
FORMALIN TREATMENT FOR OAT SMUT 593
THE FORMALIN TREATMENT FOR CONTROLLING
OAT SMUT.
JOHN A. KRALL.
INTRODUCTION.
Five million dollars is a conservative estimate of the annual
loss incurred by the oat smut disease in Iowa. That this loss
can be controlled is indicated by the following statements from
farmers over the state of Iowa.
Reports from 5,300 farmers representing over 15,000 acres
of farming- land, showed that 7.5 per cent of their oat crop
was destroyed by this disease. On the other hand, reports from
054 farmers who had treated their seed oats showed that their
loss was only 1.4 per cent.
To insure more definite knowledge of the control methods
?or oat smut, and to determine if possible a practical and efficient
method for the farmer has been the purpose of our work. In
the results which have been secured the writer wishes to
acknowledge the co-operation and assistance which was accorded
from time to time by Dr. L. II. Pammel. Prof. II. I). Hughes
and others interested in the work.1
EARLY HISTORY OF OAT SMUT CONTROL MEASURES.
Selby (47) from review of early literature makes mention of
two articles which are interesting from a historical standpoint.
In the September 29th issue of the American Farmer, Balti-
more, 1820, page 215, a correspondent tells of oats so badly
smutted that the eraddlers were nearly as black as colliers. The
crop was allowed to lie on the ground for curing, in the old
manner, and was turned after showers some four or live times
before binding and gathering. The same oats sowv.l the next
season gave a crop free from smut. The value of washing the
grain no doubt was early recognized. In a later publication of
the Cultivator. May. 1856, page 139, the editor recommends
to one of his correspondents that "he wash the grain thoroughly
1This work was done in the botanical and farm crop laboratories Iowa
State College.
38
594 IOWA ACADEMY OF SCIENCE
iii water, or still better, in brine (or giving the last washing in
brine), and then rolling it well in dry powdered, water-slacked,
fresh lime, some hours before sowing."
An article published in the Cultivator, 1837, Vol. 11, page
107, mentions a method which no doubt was in vogue at that
time. The grain was soaked in a brine solution for twelve hours
after which it was rolled in fresh slacked lime before sowing.
After 1856 the records indicate that copper sulphate was
used to some degree with varying success. In 1887 and 1888
Jensen (29) published the results of his experiments with hot
water — a method which still bears his name. Following the in-
troduction of the Jensen method, Kellerman and Swingle (33) in
1889, published a rather complete treatise of the history and
methods of control. As a result of their experiments potassium
sulphide proved an efficient preventive. The treatment con-
sisted in soaking the oats in a % per cent solution of potassium
sulphide (l1/^ lbs. of salt in 25 gallons of water) for a period
of 24 hours. From this time on there is a noticeable interest in
the oat smut problem. As a result sundry methods of control
have been tried in an effort to secure one that would be conven-
ient, efficient, and cheap. Of the many materials experimented
with for the control of the smut disease the following have come
to the attention of the writer. Kellerman and Swingle (33) have
tried various combinations of copper sulphate, copper nitrate,
potassium sulphate, mercuric chloride, potassium bichromate,
sodium hyposulphate, sodium hydrogen carbonate, corrosive
sublimate, chloroform vapors, carbon bisulphide, ether vapor,
ammonium hydrate vapors, verdigris, sulphur, salicylicid acid,
castile soap, hot water. L. H. Pammel (17) experimented with
ammonieal carbonate, ferrous sulphate, bordeaux mixture. By
others, ceres pulver or powder, soap, tar dips and various other
products have been tried.
Since it is the purpose of the writer to follow the history and
the use of formalin for the control of the oat smut, other treat-
ments will not receive consideration in this paper only as they
have a bearing on the subject at hand.
Early History of Formalin.
Goff (25") in his treatise on the use of formalin mentions that
formalin was first discovered by a German scientist who had
produced the gas from wood alcohol. Its germicidal properties
FORMALIN TREATMENT FOR OAT SMUT 595
seem first to have been discovered by Trillat in 1888. In 1895
Gruther published a paper stating that formalin was capable
of destroying the germination of smut spores without injury
to the grain.
The first use of formalin in the United States is credited to
Professor Bolley of the North Dakota Station. After three
years of investigational work the author made his first publica-
tion in March, 1897. During the same year Professor C. P.
Close of the New York Station published the results of that
season's experiments in Bulletin 131, 1897. During the next
year Professor M. B. Thomas of the Indiana Station read a
paper before the American Academy of Science regarding ex-
periments with formalin. In this paper the author considers
the effect of formalin on the germination of seed oats, and sug-
gests that it might be well to try this substance upon the spores
ci smut as a possible prevention.
Arthur (1) in 1891 in his publication on loose smut of oats
mentions the use of formalin. In this article the author states
that various men have studied the action of this solution on
seeds and spores but only in a subsidiary way. Its first applica-
tion for the control of smut in a practical wray is credited to
Bolley. In the earlier publications of Bolley the wTriter failed
to find any mention of the use of formalin. In his publication
(6b) on the treatment on wheat smut (1895) he mentions only
the use of hot water, and copper sulphate, which had been in
use for many years prior to that time. However, in a later pub-
lication (6°), of 1897, he mentions the use of corrosive sublimate,
sulphur dioxide, hot water, and formalin, and their effect upon
the germination of wheat, oats, and barley. These experiments
are quite extensive and are tabulated to show the effect of the
treatment on the per cent of germination, the per cent of smut
and the yield. The data are worthy of the attention of any
investigator along similar lines of work. As a conclusion of his
work Bolley sets forth the following treatment: "Thoroughly
saturate a large pile of the grain with a solution made at the
rate of one pound of formalin to 50 gallons of water. Shove]
over rapidly so that the pile shall become evenly and thor-
oughly wet. Iu this treatment the grain should be Lefl wet in
the pile for two or more hours, or else dipped for two hours."
The author also mentions the practical use of the solution and
596 IOWA ACADEMY OF SCIENCE
its cheapness $1.20 per pound) as compared with potassium
sulphide which would cost approximately $3.60 to treat 50
bushels.
In a later publication 0 1910, the author reduces the water
in the solution to 45 gallons. He also recommends that the
grain should be soaked or covered for two hours after treatment.
Two bushels of dry grain will equal approximately 2l-2 bushels
after the treatment and due allowance should be made when
seeding.
Arthur (1) in 1691 recommends, after reviewing the litera-
ture published by Bolley and after local experiments, that the
formalin be used at the rate of one pound to 60 gallons of water.
Immerse seed two hours or wet the pile thoroughly and let
stand covered in a pile for two hours.
Goff (25) made first mention of the formalin treatment in
1901. After three years of experimenting on various treat-
ments and methods of application the formalin treatment was
considered efficient.
The following table shows the effect of the various formalin
solutions on the growth of the plants under field conditions.
THE EFFECT OF VARIOUS FORMALIN SOLUTIONS ON THE
GERMINATION, GROWTH AXD YIELD OF OATS.
Table I. Showing Average Height oe Plants ox Dieeerext Dates.
Trp„TTT1pnt Avg. Height | Avg. Height Avg. Height
1 in mm., May 14 in mm., May 22 in mm., July 30
Untreated 58l> 133.7 5L6
Formalin, 1 pint to 5C
gal. of water 55.4 134.2 50.9
1 pint to 36 gal. water 63.8 138.7 52.6
1 pint to 25 gal. water 55.4 124.9 51.3
1 pint to 10 gal. water 26.2 80.7 54.7
Table II. Weight of Plants at Harvest.
Untreated 83.6 lbs.
Formalin, 1 pint to 50 gal. water 96.7 lbs.
Formalin, 1 pint to 36 gal. water 82. 7 lbs.
Formalin, 1 pint to 25 gal. water 82.0 lbs.
Formalin, 1 pint to 10 gal. water 54.3 lbs.
The plots were seeded April 29th, a quantity of seed from
each lot was planted on well prepared ground with a garden
FORMALIN TREATMENT FOR OAT SMUT
" ;
seed drill. The - - - na thickly in rows fourteen inches
apart and with a uniform depth of two inch-- As the plants
appeared they were thinned out so as to si s part
in the rows except in the 1 — 10 Treatment where the plants
averaged eight inches apart, owing to lack of germination.
May 11th. and again on May 22d. the height in millinv I -
determined on 500 plants in each lot. At harvest time the
height of the plants was determined in inches.
Table III. Effect of Formalin Treatments ox Yield.
Treatment
Ami of Seed
per Acre
Wt. of Entire
Plant
Cleaned Grain
Bu. per Acre
lbs.
lbs.
Untreated
"
". "
1 pt. to 50 gal. . . .
"
575.0
• -
1 pt. to 36 gal
"
399.0
1 pt. to 25 gal. . . .
■
1 pt. to 10 gal. . . .
-
"
16%
Note: The above plots were 1/40 acre in size. The seed
thoroughly dried before seeding, being seeded at the rate of TO lbs.
per acre -with a garden drill. The drill rows were four inches a
and the grain seeded at a depth of two inches.
As a result of these field I sts Gfoff concludes that under
practical field culture the yield of grain is not appreciably
fected by treating with a solution as strong as one pint of
formalin to 36 gallons of water.
Clinton 12 1895-1898, after comparing the relative value of
hot water, formalin, copper sulphate, potassium sulphate, and
ceres pulver. concludes that hot water and formalin proved most
efficient.
Table IV. Thf Effect of Formalix ox the Percentage of Smvt.
Treatment
Smutted
Per cent
Snv.
Formalin, 1 lb. to 25 ga water.
Formalin, 1 lb. to 50 gal. water.
Formalin. 1 lb. to 100 gal. water.
Untreated — check plot
N " a smutted panicle 0
21 smutted on plot
out of 4 12.7
out of 4 11.0
For general use the author recommends the sprinkling method
with formalin having a strength one pound to 40 to 50 gallons
598 IOWA ACADEMY OF SCIENCE
water. Sprinkle the grain at the rate of 1 to 2 gallons per
bushel, thoroughly stirring the oats. The treated grain is then
left in sacks for a few hours and then planted.
W. Saunders (45) in 1899 recommended the following for-
malin method: Soak the grain for one hour in a formalin solu-
tion made up to a strength of one pint formalin to 36 gallons of
water. This treatment has been found equal to the copper sul-
phate solution consisting of one pound of copper sulphate to
live gallons of water.
Wilcox (61) of the Montana Station (1899) states that oats
treated with a solution of formalin (1 lb. to 50 gallons of water)
and soaked for two hours were free from smut, This method
is to be preferred to the copper sulphate treatment, which is
injurious to the vitality of the seed.
Moore (37). 1901, after careful investigation, recommends
the use of one pound of formalin to 36 gallons of water. For-
malin with a guaranteed strength of 40 per cent. The method
suggested is to immerse the oats in sacks for ten minutes, then
place on a floor in a thin layer to encourage drying. The seed
nrny be sown in one to two days, setting the drill to seed one
bushel more than normally recpiired.
Henderson (27) in his work at the Idaho Station in 1906
experimented with various formalin solutions to determine their
effect on germination of wheat and oats. His conclusions are
as follows: (Idaho Bulletin 53, page 107). "1. Seed treated
with solution at strength of one pint of formalin to 16 gallons
of water and covered for nearly one day. was injured but little.
2. Seed treated as above, and covered nearly two days was de-
cidedly injured. 3. When treated with solution of one part
to 50 gallons, one to 40 gallons, or even one to 25 gallons, the
seed was not injured, though covered for two days. 4. When
wheat has been treated in piles on the floor, do not cover at all,
since germination is delayed, even though the grain is not in-
jured. 5. When farmers complain of seed being injured it is
the result of too strong a solution — (below 1-50 or 1-40) or to
covering for too long a period — two or more days.''
Mackey (41) of the Canadian Experiment Station at Indian
Head makes first mention of the formalin treatment in 1898. At
this time experiments were conducted to compare the relative
value of formalin, bordeaux mixture, and copper sulphate solu-
FORMALIN TREATMENT FOR OAT SMUT
599
tion. The solutions used were 3 ounces and 41- ounces of for-
malin to 10 gallons of water. The oats were soaked for two
hours in the formalin solution, while in the bordeaux and cop-
per sulphate solutions the grain was steeped for four hoars.
The result indicated that the formalin solutions were both
efficacious — no disease being found in the resulting crop from
the treated seed.
R. S. Shaw after, three years' work at the Montana Station
in 1903 (48) recommends a formalin solution consisting of
one pint formalin to 40 gallons of water. Treat the grain either
by dipping or sprinkling. In either ease the grain should re-
main covered for two hours, after which it should be dried.
Shutt (49) in his report of 1906 remarks that the use of for-
malin for treating smut in cereals is increasing rapidly, due
to its ease of application and effectiveness. Two strengths then
in use were three and four ounces of formalin to 10 gallons of
water. The grain was immersed for five minutes or sprinkled.
In the majority of cases the weaker solution has proven as ef-
fective, and thorough sprinkling equal to immersion.
Stevens (52) in 1906 and 1907 conducted some extensive ex-
periments to determine the influence of various formalin solu-
tions on the germination of oats, especially when covered for
different periods of time. Other experimenters have suggesl
strong solutions of formalin, but the effect on the vitality of
the grain was often quite marked. The following table g
the results of the first series of experiments in which solutions
of one ounce of formalin were used with one-half, one, two and
three gallons of water.
EFFECT OF FORMALIN UPON GERMINATION.
Table V. Solution of Different Concentrations.
Strength, Amt.
Solution, Amt.
formalin
of water
1 oz.
-\-j gal.
1 oz.
1 gal.
1 oz.
2 gal.
1 oz.
3 gal.
Covered 12 hrs. after treat-
ment then seeded imme-
diately
Seeded immediately after
treating
Dried 48 hours before seed-
ing
Covered 12 hours, dried
with lime before seed-
ing
Average
Per cent
25
47
43
Per cent
95
99
96
94
96
Per cent
97
SS
9S
94
94
Per cent
93
89
94
96
93
600 IOWA ACADEMY OF SCIENCE
The author concludes that the strongest solution is decidedly
injurious, either when seeded immediately or after covering
12 hours, as in either case the formalin was kept in contact
with the seed much longer as compared with the other treat-
ments. "While it is apparent that the solution (one ounce to
one gallon) had no apparent affect field tests have demonstrated
that at times even this solution may cause a decreased stand.
The variability in results might be attributed to other causes,
which raised the following questions:
Do different varieties of oats offer different degrees of resist-
ance to formalin ? What percentage of the seed is killed by for-
malin of the strengths usually employed? Does formalin have
any stimulating affect upon germination? Are the seeds of in-
ferior quality more susceptible than those of medium or excel-
lent quality? Does the fatality increase with the increase of
the time of application? "While many tests have been made
bearing upon these points, they have usually been made with
only one or two factors in mind, and the results are neither
concordant nor conclusive. In order to determine some of these
factors a series of crucial experiments were planned with the
hope of gaining conclusive answers.
In all cases 1,000 seeds of average quality were taken and
treated for twelve hours. They were treated with formalin of
the strength indicated and one cc. of the solution was employed
to 9.3 cc. of seeds, this being equivalent to the usual practice of
using one gallon of liquid to one bushel of seed. The seeds,
after being thoroughly wetted by the solution, were placed in
glass capsules, of suitable size, to prevent loss of formalin by
evaporation. Great care was taken to have the lots exactly
alike, except as regards the factor under observation. After
treatment the seeds were planted in flats in clean sifted sand
in rows one-half inch apart, with the seeds evenly distributed
in the rows. In this manner, it was possible to account for
every seed. The final record of germination was taken two
weeks after planting, since experience showed that all available
seeds germinated in that time.
All seeds designated as average quality were secured by dis-
carding from a clean commercial sample of considerable size,
all foreign seeds and empty chaff, but retaining all actual oat
seeds, each of which, in case of any possible doubt, was inspected
FORMALIN TREATMENT FOR OAT SMUT
601
as to its integrity. This sample was thoroughly mixed and the
1,000 seeds for the test were taken absolutely without selection
by always taking the seed lying nearesl at hand, be it large or
small. The strengths mosl used in practice, .26 per cent, .39
per cent, and .78 per cent of formalin, or as more commonly
designated, one ounce to three gallons, one ounce to two gal-
lons, and one ounce to one gallon, were employed ; also a weaker
solution, one ounce to four gallons (2 per cent formalin). The
first of these is mostly used, the second often, the third rarely.
Several varieties were used in this experiment to determine
whether there was any noticeable difference in their ability to
withstand certain treatments. These results are indicated in
the following tables.
INFLUENCE OF DIFFERENT STRENGTHS UPON WHITE SPRING,
RED RUST PROOF, VIRGINIA WINTER GRAY, APPLE I,.
BURT, BLACK SPRING OATS OF AVERAGE
QUALITY TREATED TWELVE HOURS.
Table VI. Test of the White Spring Oat, 1,000 Seeds.
Flat No.
Strength of Solution
Number
Germinated
Per cent
Germinated
Per cent
due to
Treatment
11
14
15
13
12
Control
1 ounce to 4 gal.1
1 ounce to 3 gal.2
1 ounce to 2 gal.3
1 ounce to 1 gal.4
998
996
993
985
941
99.8
99.6
99.3
98.5
94.1
.2
.5
1.3
5.7
*.2 per cent formalin,
2.26 per cent formalin,
3.39 per cent formalin,
4.78 per cent formalin,
.08 per cent formaldehyde.
.104 per cent formaldehyde.
.156 per cent formaldehyde.
.312 per cent formaldehyde.
Table VII. Test of Red Rust Proof Oat, 1,000 Seeds.
Flat No.
Strength of Solution
Number
Germinated
Per cent
Germinated
Per cent
due to
Treatment
16
17
20
19
18
Control
1 ounce to 4 gal.
1 ounce to 3 gal.
1 ounce to 2 gal.
1 ounce to 1 gal.
989
984
984
973
925
98.9
98.4
98.4
97.3
92.5
.5
.5
1.6
6.4
603 IOWA ACADEMY OF SCIENCE
Table VIII. Test of Virginia Gray Oat, 1,000 Seeds.
Flat No.
Strength of Solution
Number
Germinated
Per cent
Per cent ! due to
Germinatedi Treatment
30
Control
895
89.5
29
1 ounce to 4 gal.
883
88.3
.2
28
1 ounce to 3 gal.
855
88.5
.4
27
1 ounce to 2 gal.
821
82.1
7.4
26
1 ounce to 1 gal.
790
79.0
10.5
Table IX. Test of Appler Oat, 1,000 Seeds.
Flat No.
Strength of Solution
Number
Germinated
Per cent
Germinated
Per cent
due to
Treatment
10
8
9
7
6
Control
1 ounce to 4 gal.
1 ounce to 3 gal.
1 ounce to 2 gal.
1 ounce to 1 gal.
966
977
958
933
912
96.6
97.7
95.8
93.3
91.2
1.1
.8
3.3
5.4
Table X. Test of Burt Oat, 1,000 Seeds.
Flat No.
Strength of Solution
Number
Germinated
Per cent
Germinated
Per cent
due to
Treatment
1
2
3
4
5
Control
1 ounce to 4 gal.
1 ounce to 3 gal.
1 ounce to 2 gal.
1 ounce to 1 gal.
903
922
930
901
730
90.3
92.2
93.0
90.1
73.0
1.9
2.7
.2
17.5
Table XL Test of Black Spring Oat, 1,000 Seeds.
Flat No.
Strength of Solution
Number
Germinated
Per cent
Germinated
Per cent
due to
Treatment
25
Control
934
93.4
24
1 ounce
to 4 gal.
959
95.9
2.5
23
1 ounce
to 3 gal.
949
94.9
1.5
22
1 ounce
to 2 gal.
903
90.3
3.1
21
1 ounce
to 1 gal.
911
91. .
2.3
FORMALIN TREATMENT FOR OAT SUIT
603
Iii the foregoing tesl the White Spring, Red Rus1 Proof and
Virginia Gray oats gave perfectly eonsistenl results, showing
decrease, | germination with an increase in the strength of the
solution employed, the loss ranging from .2 to 5.7 per cenl with
the White Spring Oa1 and from .2 to L0.5 per cenl with the
Virginia Gray oat. The Burt oat and the Black Spring oat
(Tables X and XI i show some inconsistencies in the test. Eow-
ever, it seems evident that the Burt oat is more susceptible to
the strongest solution.
The conclusion may be drawn that solutions stronger than one
ounce of formalin to three gallons of water are questionable,
due to their appreciable effect upon the vitality of tbe oat. The
added stimulus is offset by the loss of stand.
Stevens also worked on the effect of formalin solution on
seed oats winch varied in quality. In these experiments, four
kinds of seed were used. The grain was examined individually
and divided into three classes: the largest and plumpest were
designated as "good"; the next grade as lower or "medium*';
and the smaller shrunken ones as "poor"; the average was the
sample as found. In each instance 1,000 grains were used for
each grade. All grades were treated with the same solution,
namely one ounce of formalin to one gallon of water.
EFFECT OF QUALITY OF SEED OX RESISTANCE TO FORMALIN.
Table XII. Appler Oat, 1,000 Seeds.
Flat
No.
Strength of Solution
Quality of
Seed
Number
Per cent
Germi-
Germi-
nated
nated
Per cent
Loss
due to
Treat-
ment
10
6
4.".
46
43
47
44
48
Control
1 ounce to
Control
1 ounce to
Control
1 ounce to
Control
1 ounce to
1 gal.
1 gal.
1 gal.
1 gal.
Average
Average
Good
Good
Medium
Medium
Poor
Poor
966
96.6
912
91.2
991
99.1
954
95.4
976
97.6
920
92.0
937
93.7
780
78.0
5.4
3.7
4.6
1.V7
604 IOWA ACADEMY OF SCIENCE
Table XIII. Virginia Gray Oat, 1,000 Seeds.
Per cent
Number
Per cent
Loss
Flat
No.
Strength of Solution
Quality of
Seed
Germi-
Germi-
due to
nated >
nated
Treat-
ment
30
Control
Average
895
89.5
10.5
26
1 ounce to 1 gal.
Average
790
79.0
36
Control
Good
924
92.4
32
1 ounce to 1 gal.
Good
826
82.6
9.8
37
Control
Medium
909
90.9
33
1 ounce to 1 gal.
Medium
801
80.1
10.8
38
Control
Poor
859
85.9
34
1 ounce to 1 gal.
Poor
659
65.9
20.0
From tables XII and XIII it is evident that the poorer the
grade of seed? the greater is the loss due to treating. Stevens
suggests that the beneficial results often seen after certain treat-
ments when the grain is seeded in the field is clue to the destruc-
tion of the inferior seed. The averaged run of oats in the
test indicates the presence of the inferior seed. If such re-
sults occur under all conditions it would seem advisable to grade
and fan the seed oats prior to the treatment for smut.
For general use the solution of one pint to 48 gallons of wa-
ter is recommended. The grain is either immersed for 20 min-
utes or sprinkled. Cover the grain for 6 to 12 hours. The oats
may be readily dried by mixing with air slacked lime. The
lime may be removed by a fanning mill. The seed may be stored
after being thoroughly dried without affecting its vitality. In
general one gallon of solution will treat one bushel of oats.
Willis (63), 1908, recommended in his treatments for oat
smut a formalin solution with the strength of one pint to 25
gallons of water. The grain was to be submerged for 5 to 10
minutes and sown at once. This formula would treat 20 bushels
of oats. The above mentioned solution is stronger than those
recommended for general use by any experiment station today,
yet it coincides with the results of our recent investigations.
However, the author makes no mention of covering the oats for
a period of time. Since the "time covered" element is regarded
essential by many investigators the effectiveness of this treat-
ment might be questioned.
FORMALIN TREATMENT FOR OAT SMUT 605
Wilcox (62) suggests that the oats be immersed for 10
minutes in a formalin solution made up of one pint formalin
to 30 to 40 gallons of water. After draining, cover the treated
grain for two hours, after which spread the grain out to dry.
when the sprinkling method is used the grain should be covered
after treatment for several hours or over night. Dry the grain
before seeding.
Bowman (7) recommended the sprinkling method using
a solution "one pint formalin to 40 gallons of water.'' and one
gallon of solution for each bushel of oats. Shovel the oats thor-
oughly, after which they should be covered for several hours.
Spread out in a thin layer to dry.
E. M. Freeman and E. C. Stakman (20) used a formalin solu-
tion one pint to 40 to 50 gallons of water. The treated grain
may be either immersed or sprinkled, after which it should be
covered for 12 to 24 hours. The grain should be dried so that
it can be run through a seeder.
Giissow (22) prefers the formalin treatment to that of cop-
per sulphate since it does not affect the vitality to the same de-
gree. The solution used consists of one pound or one pint of
formalin to 40 imperial gallons of water. Either immerse or
sprinkle the grain, then cover for two to three hours, after
which it should be spread out to dry.
Various other statements in regard to the formalin treatment
could be cited, but the foregoing are representative of all and
give the history and range of variation occurring in the meth-
ods of treatment.
From the above citations it is evident that no standard meth-
od even with .formalin has yet been secured. The solutions
used ranged from one pint of formalin to 25 to 50 gallons of
water. Various times for covering also are suggested, and this
last factor is of considerable importance to the farmer. The
advisability of seeding directly after covering and the amount
of grain which should be used following such treatment are
still open questions.
The Use of Vapor for Oat Sum!.
Various experimenters have worked with different vapors in
au effort to find some treatment which would eliminate the
objections so apparent in the use of solutions.
606 IOWA ACADEMY OF SCIENCE
Kellerraan and Swingle (33) in their report of 1890 show-
that vapors of chloroform, carbon bisulphide, ether, ammonium
hydrate, and sulphurous oxide were all ineffective. At that time
formalin vapor was not used in their experiments.
Prior to 1899 Bolley had secured satisfctory results with the
formalin solution (1 to 50). However, he recognized the ob-
jections that would be raised against any treatment which neces-
sitated wetting the grain. In 1897 and 1898, Bolley ascertained
that the gas treatment was effective, but was not positive of its
use on a large scale. Following later experiments the author
(6-87) concludes that for the gas to be effective it is necessary
to have it accompanied by a vapor dense enough to form a film
over the surface of every grain. The dry gas has no effect on
the smut spores. The vapor factor again brings in the objec-
tion raised against solutions; however, the gas treatment is to
be preferred for extensive work.
Clinton (1898) found that carbon bisulphide fumes were not
effective, but work with stronger solutions of formalin applied
in smaller amounts was very promising. In cases of too strong
a solution the vitality of the grain was injured.
Wheeler (60) of the South Dakota Station (1904) conducted
some preliminary experiments with various vapor treatments
for stinking smut of wheat. These experiments included for-
maldehyde, ammonia and chloroform. The apparatus used for
the gas treatment is described as follows :
It consists of a hand blower (a), a cylinder containing the
grain (c), a test tube to contain the fungicide (b) and tubes
for connection. The air is forced by means of the blower
through the liquid fungicide in the test tube. From there it is
conducted by a tube to the lower part of the cylinder contain-
ing the grain and up through the seed grain. The air permeated
with the fungicide vapor is taken up from the cylinder by the
blower and forced through the liquid fungicide. By repeated-
ly passing the same air through the fungicide, it was thought
that a saturated atmosphere would be secured and greater uni-
formity of results obtained than if the air were passed only
once through the fungicide.
The following treatments were considered in this preliminary
work: The grain was exposed to the formaldehyde vapor (40
per cent solution) for the following periods of time %, %,
\y-2, 2, 2y2, 3 hours, both with and without return current.
(See tables XV and XVI.)
FORMALIN TREATMENT FOR OAT SMUT * 607
Table XV. Formaldehyde Vapor Applied Without Return Cubbent.
Length of
Length
Date of
Total No.
No. of
Per cent
of Heads
Smutted
Treatment
of Row
Seeding
of Heads
Smutted
a Untreated
20 ft.
Apr. 16
1,136
36
2.37
1) \ i hour
40 ft.
Apr. 16
2,303
31
1.35
c T-. hour
40 ft.
Apr. 16
2,245
26
1.16
d % hour
40 ft.
Apr. 16
2,509
18
.72
e 1 U hours
40 ft.
Apr. 16
2,501
4
.16
f 2 hours
40 ft.
Apr. 16
2,570
17
.66
g 2% hours
40 ft.
Apr. 16
2,791
19
.68
h 3 hours
40 ft.
Apr. 16
2,727
16
.59
Table XVI. Formaldehyde Vapor Applied With Returx Current.
Length of
Treatment
Length
of Row
Date of
Seeding
Total No.
of Heads
No. of Per cent
Heads of Heads
Smutted Smutted
a 14 hour
40 ft.
Apr. 16
2,397
17
.7
b Vo, hour
40 ft.
Apr. 16
2,397
6
.29
c 34 hour
40 ft.
Apr. 16
2,638
5
.19
d 1 hour
40 ft.
Apr. 16
2,640
0
.00
e 1% hours
40 ft.
Apr. 16
2,571
2
.08
f 2 hours
40 ft.
Apr. 16
2,407
1
.04
g Untreated
40 ft.
Apr. 16
2,606
25
.96
Results of these trials indicate that the grain exposed to
formaldehyde vapor without the return current was only slight-
ly disinfected when compared with the check. The return
vapor current at room temperature proved much more efficient
as indicated by the declining percentage of smut in the treated
plots.
It has been observed that temperature has more or less in-
fluence on the efficiency of formalin fumes. Some investigators
recommend the use of warm water in the ordinary solution
treatments.
Wheeler also conducted a scries of experiments to determine
this factor and its relation to the gas treatment. (See Table
XVII.) Rossnan states that temperature is an importanl fac
tor in disinfect inn- with formaldehyde. The gas condenses at
20 degrees C. to the solid polymeric paraform and disinfection
should never be attempted if the temperature is under 10 de-
grees C. The action of the gas seems to be about the same be-
tween the temperature of 10 degrees C. and 27 degrees C.
QOi IOWA ACADEMY OF SCIENCE
Table XVII. Formaldehyde Vapor— Effect of Temperature.
Temperature of
Formaldehyde
Solution
Strength
of
Solution
Length
of
Treat-
ment
Date
of
Seed-
ing
Length
of Row
Total
No. of
Heads
0 -6
.O C3 3
2
•a
u * 2
* 6
a. 19° C.
b. 20° C.
c. 30° C.
d. 60° C.
e. 75° C.
f. 19° C.
g
h. Untreated
40 p. c.
20 p. c.
40 p. c.
40 p. c.
40 p. c.
20 p. c.
5 p. c.
i/2 hr.
1/2 hr.
1/2 hr.
1/2 hr.
1/2 hr.
3 hrs.
24 hrs.
4/19
4/19
4/19
4/19
4/19
4/19
4/19
4/19
20 ft.
20 ft.
20 ft.
20 ft.
20 ft.
20 ft.
20 ft.
20 ft.
1,210
1,263
1,208
1,280
1,084
1,193
1,319
1,074
0
0
0
0
0
12
3
13
0.0
0.0
0.0
0.0
0.0
1.0
.22
1.24
Iii the above table (d) was raised to 60 degrees C. at the
start and a second time after the treatment had been under
way for five minutes. Treatment (e) was maintained at 75 de-
grees for five minutes. All others were simply started at the
temperature designated. Some condensation took place on the
grain under treatment (a) which may have injured the germina-
tion.
When the formaldehyde solution was heated the gas was much
more effective. However, at the higher temperature 75 de-
grees C. for one-half hour a lowering of the germination was
noticeable, due probably to condensing of the vapor on the grain.
(See Table XVII.)
Further work with formalin vapor and formalin solution
showed both to be ineffective in killing the spores within in-
fected wheat grains. Other factors which may influence the
results are mentioned, e. g., it was found that a 30 per cent
solution of formaldehyde after air had passed through for two
hours analyzed 38 per cent of formaldehyde. New chemicals
should be used for each treatment to eliminate error.
FORMALIN TREATMENT FOR OAT SMUT
609
Table XVIII. Length of Gas Tkevimi \i we res Effei i Upon
Germination.
Chemical Used
Length of
Treatment
Per cent
Germina-
tion 6
days after
Sowing
Per cent
Germina-
tion 7
days after
Sowing
Per cent
Germina-
tion 10
days after
Sowing
Vigor of
Growth,
10 equals
Normal
Formaldehyde
Formaldehyde
Formaldehyde
Formaldehyde
Formaldehyde
Formaldehyde
Formaldehyde
Formaldehyde
Formaldehyde
None
1/3 hr.
2/3 hr.
1 hr.
1'.. hr.
2 hr.
2i/2 hr.
3 hr.
4 hr.
5 hr.
79
72
65
29
27
21
26
18
\:,
75
85
76
75
39
37
23
31
22
20
83
90
81
80
55
45
24
33
24
23
84
10
10
10
9
7
7
7
7
7
10
The germination tests show thai formaldehyde vapor from
practically standard formalin solution can be applied to wheat
for one hour without injury and is efficient in controlling the
smut. (See Table XVIII.) Whether the above conclusions
can be applied to the oat crops is still a question. The main
problem is the feasibility of applying the treatment on a large
scale for treating oats, which are of different structure and
more bulky.
At present there is no satisfactory way of treating the grain
with formaldehyde gas either on a large scale or on the farm.
And since it is necessary to have the vapor at the point of satura-
tion for efficient results, the solutions may as well be used for
practical purposes.
EXPERIMENTS WITH VARIOUS FORMALIN SOLUTIONS AND
THEIR RELATION TO THE GERMINATION AND
CONTROL OF THE OAT SMUT.
Amks, Iowa, 1915.
At the present writing the formalin treatment seems to be
the most efficient remedy for oat smut. Bowever, ii embodies
one or more objectionable features from the standpoint of the
practical farmer. These are. first, the time involved in treat-
ing; and second, the need of saturating the oa1 grain. While
its efficiency is not questioned the still presenl objections may
bear investigation.
89
610 IOWA ACADEMY OF SCIENCE
Numerous experiments have been conducted with formalin,
but as yet there is no uniformity in the results or recommenda-
tions. The solutions recommended vary from one pint of for-
malin to 25 to 50 gallons of water, the most common formula
being one pint to 40 gallons. In addition recommendations in-
clude dipping and sprinkling of the solution, the grain to be
either seeded directly or covered for various periods ot time —
from two to ten hours or more. To arrive at some definite and
satisfactory method has been the purpose of this investiga-
tion.. While one year's data are not conclusive it will indicate
the possibilities of certain methods and act as a guide for further
experimentation.
In these experiments twenty-two bushels cf Kherson oats were
used for the tests. Practically a half gallon of smut spores
were thoroughly mixed with the oats to insure infection. How-
ever, it later developed that the spores were not as virile as was
expected — the checks only showed an average of 1.83 per cent
smut. One-half bushel, by measure, of the infected oats were
used for each test. The container used in treating the oats
was a large galvanized iron pan five inches deep and four by
five and one-half feet in area. This was large enough to permit
spreading and shovelling the oats. The container was cleaned
out after each treatment.
After treating the oats were removed and piled on a muslin
sheet about six feet square, the ends of which were pulled over
the pile and tucked in around the base thus providing a good
cover. Each pile was tagged stating the nature of the treat-
ment, the time, and the various periods at which samples should
be secured for a germination test.
About one pound of oats from each treatment were used for
the germination test. In each instance the sample was secured
from the center of the pile. These were taken at stated periods
— time of treatment ; end of first and second hours ; and there-
after in two-hour periods, up to twelve hours. The sample was
placed upon a clean table until dry. then sacked in a paper bag.
after which it was stored for a period of one and one-half weeks.
when germination tests were made.
In the germination tests duplicates were run in every case
and tlie average of the two was recorded. Should the duplicate
vary to any marked degree a new test was made of the sample.
FORMALIN TREATMENT FOR OAT SMUT 611
Each test was on the basis of 200 kernels. The rag doll method
was used, since a large Dumber of tests could be taken care of
in a rather small space. When the rag doll method is used il
is advisable to place the oats on folds o\' the cloth arranged in
successive tiers. It is essential that aeration is net retarded. In
most cases the tests were ready to read within six days. Some
of the readings indicate a marked variation even in the same
Series. Inconsistent tests were checked over again, hut in some
eases the results did not improve the average of the readings.
The cause could not he determined in every case, which was il-
lustrated by good and poor readings alternating in the same
tester under identical conditions. The rag doll method is
not as accurate as a good commercial tester, unless it is given
careful observation.
The Held plots uya] were 1-5 of an acre in size. With the
exception of 45 plots in the series of 290, they were all the
same shape, being 3x33^ feet. The soil was not as uniform as
would be desirable; neither was the seed bed in as tine shape
as it should have been owing to variable climatic conditions and
lack of horse power. The resulting yields were, no doubt, in-
fluenced and will have to be discounted to a slight degree, since
variations occur which can not be attributed to the treatments.
The plots were seeded April 10th and 11th. the grain being
planted by hand in furrows one inch deep made with a hand
marker. The rate of seeding was three bushels per acre, the
grain having been previously weighed out for each row. placed
in an envelope, and labelled. As the season progressed weed
growth was kept down by frequent hoeings.
Harvesting was done by hand. The crop from each plot was
shocked and labeled. At threshing time each plot was threshed
separately in a small nursery thresher and the weight of the
grain secured.
Results of thi germination tests, based upon tables XIX and XX.
Conclusions to be drawn from Table XX — showing the effect
of various formalin solutions and time of covering on the ger-
mination of oats. For each grade of solution the amount used
per bushel of oats ranged from 1, 2. 4. 6 and 8 pints and the
treated oats were then covered up for 0, 1. 2. 4. 6, 8, 10 and 12
hours respectively.
612
IOWA ACADEMY OF SCIENCE
A. Solution — one pint formalin to three gallons of water.
1. While the germination tests do not seem to be con-
sistent there is a gradual decrease in vitality as
the amount used is increased from one pint to eight
pints, and as the time of covering increases from
none to twelve hours.
2. One pint per bushel may be used with comparative
safety.
3. Two pints apparently affects the vitality. Larger
amounts seem to have a decided affect upon the
germination and should not be used.
4. Field tests showed that all the oats receiving 4, 6,
and 8 pints per bushel were killed, except the first
two of the 4-pint treatment. The zero and 1-hour
covered seed evidently recovered from the effect of
the treatment.
GERMINATION TEST OF OATS.
Table XIX. Following Treatment with Various Kinds of Formalin
Solutions.
Pints
H
ours Coverec
0
1
2
4
6
8
10
12
Solution
per Bu.
Per
Per
Per
Per
Per
Per
Per
Per
Cent
Cent
Cent
Cent
Cent
Cent
Cent
Cent
1
100
96
99
96
91
87
91
89
1 pint formalin to
2
85
92
93
91
82
83
87
86
3 gal. of water
4
89
66
30
9
23
7
8
4
A
6
6
23
1
0
0
0
0
0
8
1
4
0
0
0
0
0
0
1
96
97
91
96
96
98
98
96
2
91
98
96
96
94
96
85
91
1 pint to 5 gal.
4
96
98
61
79
38
54
32
31
B
6
76
76
63
8
0
0
0
0
8
19
11
1
0
0
0
0
0
1
98
98
98
98
98
98
100
99
2
94
90
94
95
97
94
96
96
1 pint to 10 gal.
4
93
96
89
93
94
91
88
89
C
6
99
81
91
83
83
94
94
95
8
86
S7
84
86
66
57
47
53
1
96
96
95
94
90
94
95
92
2
96
98
95
94
92
93
91
93
1 pint to 20 gal.
4
96
94
95
93
91
91
90
92
D
6
95
95
91
95
94
92
94
96
8
98
96
94
98
91
96
95
95
FORMALIN TREATMENT FOR OAT SMUT
613
Pints
Per Bu.
Hours Covered
Solution
0
1
■>
,
6
8
10 1
12
Per
Cent
Per
Cant
Per
Ci ut
Per
Cent
Per
Cent
Per 1
Cent'
Per
Cent
Per
Cent
1
94
99
97
94
94
97
98
98
2
77
97
92
97
97
97
95
97
1 pint to 30 gal.
E
4
6
98
98
98
93
92
92
89
91
95
93
90
96
93
96
93
93
8
98
96
94
97
92
97
97
98
1
93
90
97
94
98
99
96
97
2
95
98
95
97
97
95
94
98
1 pint to 40 gal.
F
4
6
97
9G
99
98
97
97
98
98
98
96
96
95
92
94
96
8
98
97
98
97
95
95
93
95
Average of checks 95 per cent.
B. Solution — One pint formalin to five gallons of water.
1. One pint per bushel is safe for any of the hours
covered.
2. When two pints are used there is a slight decrease in
the vitality when covered for six or more hours.
3. Four pints may be used with safety when covered
not to exceed one hour.
4. Larger applications and continuous covering lower
the percentage of germination to zero, especially
after the second or fourth hour of covering.
5. Field tests showed that all plots were below the av-
erage of the checks.
The plots seeded with the grain treated with six pints
and covered zero and one hour germinated a lit-
tle slowly, showing a decrease in stand of 50 to
60 per cent. However, at harvest time the yield
was practically normal. Those plots seeded with
the other treatments of the six and eight pints
failed to germinate except occasionally could be
seen a stray plant thai had survived.
C. Solution— One pinl formalin to ten gallons of water.
1. Germination tests indicate that one pint per bushel
may be covered for a period of twelve hours with-
out any apparent injury.
614 IOWA ACADEMY OF SCIENCE
2. Two pints per bushel did not affect the vitality un-
less it be at the end of ten to twelve hours.
3. An application of four pints was followed by a slight
decrease in germination when covered eight or
more hours.
■i. When six pints per bushel were used, there was an
apparent decline in the germination from one to
six hours, after which the germination seemed to
improve. This may be due to the drying out of
the oats and consequently the lessening effect of the
formalin. Apparently there is some experimental
error incurred when dealing in quantities smaller
than several bushels.
5. Eight pints caused a gradual decrease in the germi-
nation for each hour covered. Covering for more
than one hour is questionable.
fi. Field tests showed that as the treatments per bushel
increased there was a slight irregularity in germi-
nation, especially for those covered for several
hours. No apparent accelerated germination was
noted due to stronger treatments, as has been ob-
served with the hot water treatment.
I Solution — One pint formalin to twenty gallons of water.
1. The results of the germination tests indicate that a
solution of this strength has no decided effect upon
the vitality, even when covered for twelve hours.
2. In the field work there were no apparent differences
in the plots seeded with the treatments of one and
two pints per bushel.
3. AVhen four pints were used and covered for eight
hours, there was delayed heading of one day. When
covered ten to twelve hours the heading was de-
layed at least two days.
4. The same effect was observed with the six pint treat-
ment : however, the variation was more pronounced.
5. When eight pints were used, those treatments cov-
ering eight to twelve hours showed a lack of uni-
formity and also a decrease in the yield. How-
FORMALIN TREATMENT FOR OAT SMUT 61c
ever, as was previously menti d, the yields are
not a reliable criterion in such short terra experi-
ments.
E. Solution — One pint formalin to thirty gallons of water.
1. From the germination tests all treatments are safe.
2. In the field work the low yield assigned to a pari
of the pints was due Largely to Lodging prior to
ripening. Otherwise, no particular difference was
observed between these plots and the checks.
F. Si 1 ut ii ii — One pint formalin to forty gallons of water.
1. The vitality of the oats was not injured by any of
the treatments.
2. The field records show that the crop yielded some-
what better than the cheeks. This is partly ac-
counted for in that the soil in a portion of the
series had received a heavier dressing of manure
two years previous. No increased yields should
l»e ascribed to the treatments.
Notes on Amount of Solution per Bushel.
1. When one pint per bushel was used, considerable hand-
ling made the oats damp but not wet. They were ready to plant
after the treatment. Oats were practically dry at the end of
twelve hours.
2. Two pints per bushel moistened the oats, but did not
wet them to any marked degree. The oats were ready to
after the treatment and were dry at the end of twelve hours.
3. With four pints per bushel the oats seemed to be covered
with a film of solution, but there was no excess solution left
after a thorough shovelling. The oats swelled considerably. At
the end of twelve hours the pile was only slightly damp.
4. Six pints made the oats very wet. only a comparatively
small amount of solution was left over after a thorough mix-
ing.
5. Eight pints caused the oats to drip, a small amount of
solution remaining after the oats were well mixed: evidently
being more than could he taken up by the oats.
HI 6
IOWA ACADEMY OF SCIENCE
RESULTS OF GERMINATION TESTS OF GRAIN IMMERSED FROM
ONE TO FOURTEEN MINUTES IN THE VARIOUS
FORMALIN SOLUTIONS.
Table XX. Germination of Immersed Grain.
Solution
Time Immersed in Minutes
c
G3 CO
i.i
u o
X —
1
S. W. D.
2
S. W. D.
3
S. W. D.
4
S. W. D.
1
1
1
1
1
1
5
10
15
20
30
40
4— 6— 90
25—25— 50
55—13— 32
70—14— 16
93— 4— 3
93— 4— 3
2— 2— 96
23—21— 56
5S— 14— 28
70—12— IS
93— 5— 2
95— 3— 2
0— 0—100
16—22— 62
39—22— 39
66—12— 22
94— 4— 2
92— 4— 4
0— 0—100
2— 6— 92
46—11— 43
69—14— 17
95— 3— 2
93— 3— 4
Table XX. — Continued.
Solution
Time Immersed in Minutes
a =
p -
V.
n
h z
x —
- -
8
S. W. D.
10
S. W. D.
12
S. W. D.
14
S. W. D.
l
l
l
l
l
l
5
10
15
20
30
40
0— 0—100
1— 5— 98
32— 9— 59
69—11— 20
90— 6— 4
93— 3— 4
0— 0—100
0— 2— 98
9—12— 79
68—12— 22
91— 6— 3
93— 3— 4
0— 0—100
0— 0—100
10—11— 79
38—45— 17
89— 6— 5
89— 7— 4
0— 0— 100
0— 0—100
10—12— 78
53—15— 32
85—10— 5
92— 3— 5
Note: The symbols S. W. D. stand for strong, weak and dead.
It will be noted from the above table that the stronger solu-
tions have a marked influence on the vitality of the oats. For
all solutions below one to thirty the danger resulting from im-
mersing is apparent. Even immersing for one minute in those
solutions caused more injury than the use of eight pints per
bushel of the one to ten solution and covering for two hours.
Di] ping grain in the solution of one to thirty and one to forty
caused no apparent injury, and for practical purposes these
may be recommended.
FORMALIN TREATMENT FOR OAT SMUT 617
Effects of Various Treatments upon the Smut.
In the field tests the grain was seeded on April 10th and
11th. Headin- was completed between the dates of June 22d
and 26th, and the grain was all ripe July 16th to 18th. Har-
vest was finished by July 20th. Notes on the percentage of
smut were taken at full heading. A two-foot division board
was used for spacing the plants while counting. Six counts
were made on each plot. The division stick was inserted at
given intervals on a number of check plots. In this manner
thirty-one checks were counted and the resulting average used
for the compilations. There was an average of 105 panicle-
bearing stems in the two-foot space. Only an average of 1.83
per cent of smut was noted on the checks, some ranging higher
than others. This percentage was much below the expected,
yet it served, to indicate the value of the treatments.
In counting the percentage of smut on the treated plots every
row was observed. In no instance did the formalin treated plots
show any smut. This was contrary to expectations, especially
in the case of one to forty solution when applied in small
amounts. Such results can hardly be accounted for since there
was not a check that was not infected.
The plots treated with hydrogen peroxide showed as much
smut as the cheek plots. It is no doubt safe to say that such
peroxide treatments as were used can not be relied upon to
control the oat smut.
It has been recognized for some time that, climatic- conditions
have more or less influence on the intensity of the oat smut
disease. When the seeding period is followed by warm weather
a greater percentage of smut has been observed under similar
conditions than when followed by cool weather. This is due in
part to the maximum temperature of the smut spore being com-
paratively high. This, together with the adaptability of the
oat plant to a cool moist climate, may account for the compara-
tively small percentage of smut in the test plots. The reverse
conditions would result with wheat owing to the fact that wheat
does best in a warm seed bed.
While some satisfactory results have been secured in regard
to various formalin solutions and their methods of application
it is desirable that the experiments be conducted one or more
618 IOWA ACADEMY OF SCIENCE
seasons under more favorable conditions. However, it may be
safe to conclude that solutions as strong as one pint of formalin
to twenty gallons of water when applied at the rate of six pints
per bushel and covered for a period of six to twelve hours will
control the oat smut without materially decreasing the vitality
of the seed.
BIBLIOGRAPHY.
1. Arthur, J. C, The loose smut of oats: Indiana Station Bulletin 35,
1891.
2. Arthur, J. C, Formalin for grain and potatoes: Indiana Station
Bulletin 77, pp. 38-44.
3. Beattie, R. E.. The formalin treatment for oat smut: Washington
Station Bulletin 54.
4. Bedford, S. A., Copper sulphate as a smut preventive: Canada
Exp't. Farm Rpt., 1893, pp. 237-238, Rpt. 1900'.
5. Bolley, H. L., On the relation o£ the time of seeding and the period
of development to the development of rust and smut of oats:
Proc. Soc. Promotion Agr. Sci., 1896, pp. 70-75.
6. Bolley. H. L., Studies upon the smut of small grain: N. D. Station
Bulletin 1, 1891; Bulletin 19, 1895; Bulletin 27, 1897; Bulletin
37, 1899; Bulletin 87, 1910.
7. Bowman, M. L., Treatment of smut in oats, etc.: Iowa Station
Bulletin 89.
8. Burrus, M. F„ Dissemination of diseases by means of the seed of
the host plant: Proc. Ind. Acad. Sci., 1908, pp. 113-122.
9. Brcfeld, Oscar, Untersuchungen aus dem Gesedmmtge biete der
Mykologie: Heft 11, 1895.
10. Brcfeld, O.. and R. Falck, Flower infection of smuts: Untersuch,
Gesam, Geb. Mykol., 1905, No. 13; also in Bot. Centbl., 101, 1906,
No. 8, pp. 212-213.
11. Buchanan, J. A., Treatment of grain for smut: Rpt. Ontario Agr.
College and Experiment Farm, 32, 1906, pp. 176-178.
12. Clinton, C. P.. Smuts of Illinois: Ills. Sta. Bui. 57, 1900.
13. Close, C. P., Results of the oat smut in 1892: N. Y. Station Bulletin
131.
14. Cook, M. T., Grain smuts — their causes and treatments: New Jer-
sey Station Circular 36.
15. Cory, V. L., Cooperative grain investigations at McPherson, Kan-
sas, 1904-1909: U. S. Dept. Agr.; Bur. Plant Industry, Bulletin
240.
16. Buggar. J. F.. Smut in oats: Alabama Station Bulletin 95, 175-180.
17. Flagg, C. 0„ Loose smut of oats: R. I. Station Bulletin 15, 1892.
IS. Foster, L„ On the prevention of smuts: Montana Station Bui. 10;
40-46.
FORMALIN TREATMENT FOR OAT SMUT 619
19. Fo.r. ('. P.. Methods of preventing smut of wheat and oats: Idaho
Station Bulletin 534.
20. Freemdn, E. M.. and E. ('. Stack/man, The smuts of grain crops:
Minnesota Station Bulletin 122.
21. Freeman, E. M., Minnesota plant diseases: Rpt. of the Survey.
Botanical Series, Vol. 5, 1905, pp. 59, 156, 157, 221, 22::.
22. Gussow, //. 7'.. Smut diseases of cultivated plants — their cause and
control: Canada Cent. Exp't. Farm Bulletin 73.
23. Georgeson, C. (\. Oats treated with hot water to prevent smut:
Kansas Station Bulletin 29, 1891.
24. Georgeson. C. ('.. and others, Change of soil and its relation to
oat smut: Kansas Sta. Bulletin 63, 213-226.
25. doff, E. 8., Prevention of oat smut: (a) Wise. Sta. Rpt. 1893;
228-250; (b) Bui. 50, 1896; (c) Wise. Sta. Rpt. 1909, pp. 36:',-:M7.
26. Haruood, P. M., and P. G. Holden, Hot water treatment of oats
and wheat: Mich. Sta. Rpt. 1892, pp. 280-288.
27. Henderson. L. F., Experiments with oat and wheat smut: Idaho
Station Bulletin 53.
28. Jackson, H. S.. Diseases of field crops: Del. Station Bui. S3.
29. Jensen. ./. L., Propagation and prevention of smuts in oats and
barley: Jour. Roy. Ag. Sc, S.S. 11, 1888.
30. Jensen. J. L.. Experiments with hot water for the prevention of
smut in spring grains: Lc. Cir. E: S. R. Vol. 3, pp. 309-311.
31. Jones. L. R.. Brief notes on smut of oats: (a) Vt. Sta. Rpt. 1890,
pp. 129-144; (b) Vt. Sta. Bulletin 32.
32. Johnson. C. E.. The smut of wheat and oats: U. S. Dept. Agr.
Farmer's Bui. 507.
33. Kellerman, W. A., and W. T. Svringle, Enemies of the Smut disease:
Kansas Station Report, 1889, pp. 213-288.
34. Lut man, B. F.. Life history and structure of certain smuts: Abs.
in Science New Ser. XXXI, 1911, No. 802, pp. 747-8
::.". Lawrence, W. H.. Diseases of plants: Washington Station Bulletin
7, special Ser. pp. 75-102.
36. Masse, George, Diseases of cultivated plants and trees: Edinburgh,
191 0 Edition, p. 339.
37. Moore, R. A., Oat smut in Wisconsin: (a) Wise. Sta. Bulletin No.
98, Bulletin 111; Wise. Sta. Rpt., 1903, pp. 363-367.
38. McCready, 8. B.. and C. A. Zavitz, Test of various treatments for
oat smut, vitality of spores, selection and hybridization as a
means of control: Ontario Agr. Col. Rpt. 36, 1910.
39. Pa mm el. L. H.. Prevention of oat and corn smut: (a) Iowa Sta.
Bulletin No. 20, 1893. (b) Iowa Geological Survey Bui. 1. pp.
238-243.
40. Pommel, L. H.. Experiments with fungicides: Iowa Station Bul-
letin 24, pp. 985-990." Sec. Bui. I, la. Geological Survey.
41. Maekey. Angus, The use of formalin, bordeaux mixture and blue-
stone as smut preventatives: Canada Expt. Farm Rpts. 1898,
p. 336.
620 IOWA ACADEMY OF SCIENCE
42. Mills, A. A., Treatment of oat smut: Utah St. Rpt, 1893, pp.
225, 228.
43. Raum, T. K., The influence of the time of sowing on the occur-
rence of loose smut in oats: Tidsskv. Landbor. Plateavl., 7,
1901, pp. 142-148; Synop. Expt. St. Rpt, Vol. 14, p. 877.
44. Raum, T. K., Treating oats with formalin: Prakt Bl. Pflanzenbaa
u. Schutz, N. Ser., 5, 1905, No. 11, p. 127-128; Synop. Expt. Sta.
Rec. Vol. 19, p. 251.
45. Saunders, W., Prevention of oat smut: Canada Expt. Farm Rpts.,
1899.
46. Scribner, F. Lamson, Treatment of certain fungus diseases of
plants: Tenn. Sta. Bui. "special C", 1890.
47. Selby, Augustine D., Smut of oats and its prevention: Ohio
Station Bulletin 64, 1895.
48. Shaw, R. S., Formalin treatment for grain smut: Montana Station
Bulletin 32.
49. Shutt, Frank T., Analyses and action of formalin: Canada Expt.
Farm Rpt., 1906, pp. 151, 153.
50. Sorauer, P., Disease of plants: Handbook of plant diseases, Berlin,
1908, pp. 314-316.
51. Stewart. R., and J. Stephens, The effect of formalin on the vitality
of seed grain: Utah Sta. Bulletin 108, pp. 145-156.
52. Stevens, F. L., Prevention of oat and wheat smut: N. C. Station
Rpt., 1908; also Bulletin No. 212.
53. Stevens, F. L., and J. G. Hall, Diseases of Economic Plants: 1910
Edition, pp. 319-323.
54. Tillinghast, J. A., Treatment of seed oats to prevent smut: R. I.
Station Rpt. 1898, pp. 192-203.
55. Thomas, M. B., The effect of formalin on germinating oats: Proc.
Ind. Acad. Sci., 1897, pp. 144, 148.
56. Thomas, M. B., Some field tests with formalin: Proc. Ind. Acad.
Sci., 1898, pp. 62-64.
57. Tebeuf, Karl Freiheer von. English Edition by Smith, Wm. G.
Diseases of plants: 1897, pp. 284-288.
58. Ward, H. Marshall, Diseases in plants: 1901 edition, pp. 117, 143,
162, 190.
59. Warburton, C. W., Oat smut: Field Crops, 1912, p. 202-203.
CO. Wheeler, W. A., Preliminary experiments with vapor treatments
for the prevention of stinking smut of wheat: S. D. Sta. Bulletin
89, 1904.
61. Wilcox, E. V., Smut in small grains: Montana Sta. Bui. 22, pp.
24-28.
62. Wilcox, E. M., Smuts of Nebraska Cereals: Nebraska Station Bul-
letin 131.
63. Willis, Clifford, Treatments for oat smut: South Dakota Station
Bulletin 110, 1908.
64. Wolff. E.. Der Brand des Getreides, Halle, Germany, 1874.
THE WHITE WATERLILY OF IOWA 621
THE WHITE WATERLILY OF IOWA.
HENRY S. CONARD.
Most of the known species of waterlily (Nymphaea Sni.) are
extremely variable. The student feels obliged to recognize cer-
tain extreme forms as species. These are often restricted
geographically. But where their habitats are connected by
continuous land areas, the intermediate country is usually popu-
lated by a series of waterlilies which grade insensibly from one
extreme to the other. The commoner white waterlilies of North
America illustrate these conditions.
The basic species in the United States is Nymphaea odorata
Ait. It is impossible sharply to demarcate Aiton's type form
from the smaller and pinker variety, designated by Pursh as
Nymphaea odorata var. rosea (commonly known as N. odorata
var. minor Sims). In the Atlantic coastal plain the variety
is the commoner form, from Nova Scotia to Delaware. At a
few isolated stations the whole flower is pink, giving the N.
odorata rosea of gardens. This plant may be designated as N.
odorata rosea forma rubra (cf. Rev. Hortieole 1881, p. 406).
From Delaware to Florida the var. gigantea Tricker is the com-
moner plant. The typical N. odorata is found in the New Eng-
land and Middle Atlantic states. The species ranges west-
ward to Minnesota, Nebraska, Missouri and probably to Arkan-
sas. Toward its western limits, however, it is much larger
and coarser than in the east. And it seems to be this coarse
form which runs on down into Mexico, and perhaps into Cuba
ami British Guiana.
In the region from Lake Champlain to Lake Michigan, Nym-
phaea tuberosa Paine is found. The species was first described
from plants growing in central New York, and was so named
on account of the many easily detached, tuber-like branches
found on the rhizome. I have collected unmistakeable, though
miniature, specimens at Trenton, New Jersey, where they were
discovered by C. C. Abbott. This is the extreme southeastern
limit of the species. A kindred form, probably a hybrid with
622
IOWA ACADEMY OF SCIENCE
N. odorata, occurs in Lake Hopatcong, New Jersey. MacMil-
lan states that N. odorata and N. tuberosa occur together in
Minnesota. Fitzpatriek and Shimek report N. tuberosa from
Iowa.
Unfortunately the separation of AT. odorata and N. tuberosa
is extremely difficult without fresh material and very complete
specimens or notes. Indeed, it may yet be proven that none
of the supposed distinctions are constant, and that the two
species cannot he maintained. The following table shows what
the differences are said to be.
Nymphjea odorata Ait.
NympHjEA tuberosa Paine.
Flowers — 7-15 cm. across, open
, from 6 a. m. to 12 m., very-
sweet scented.
Peduncle — purplish green, 0.3-0.5
cm. in diameter; coiled 5-£
turns in fruit.
Sepals — often purplish outside.
Petals — 23-32, ovate to elliptic-
lanceolate.
stamens — becoming linear or fil-
amentous at center of flower.
Seeds — 0.23x0.16 cm.; aril one-'
fourth longer than seed.
Leaves — usually more or less
purplish beneath; angles oJ
sinus not at all produced.
Petioles — reddish green to dark
purplish red, evenly colored.
Branches of rhizome — few, at-
tached by a base 1.3-2 cm. in
diameter.
Stipiiles?
Surface of poVcn?
Relative length of stamens and
petals:'
Flowers — 10-23 cm. across, open
from 8 a. m. to 1 (or 2-3) p.
m., odorless.
Peduncle — green, 0.5-0 9 cm. in
diameter; coiled 3 turns in
fruit.
Sepals — green.
Petals — obovate or almost spat-
ulate.
Filaments — nearly all broader
than anthers.
Seeds — 0.44x0.28 cm.; aril about
as long as the seed, or shorter.
1. races — pure green beneath, an-
gles of sinus slightly pro-
duced.
Petioles — green, with longitudi-
nal red-purple stripes.
Branches of rhizome (tubers) —
very numerous, attached by a
slender neck 0.3-0.8 cm. in di-
ameter and very readily de
taching.
Stipules?
Surface of pollen?
Of all of these distinctions the most certain test is the pres-
ence or absence of tubers. Next best is the presence of stripes
of red-purple on the petioles in N. tuberosa. I have never
THE WHITE WATERULY OF IOWA 623
known this to fail in unquestionally authentic fresh material.
hi my limited experience, the time of opening of the flowers
has been highly characteristic. The large seeds with relatively
small arils are easily recognized in .V. tuberosa. Bu1 critical
study of much material is necessary in ascertain to what extent
these features are constant and diagnostic.
In the Gray Herbarium of Harvard University and in the
private collection of Mr. J. R. Churchill T have examined ma-
terial of these species, variously labelled as A', odorata, A. tuber-
osa or A', reniformis, from Iowa (Wahonsie Slough, Fremont
county, coll. Fitzpatrick, No. -4426), Wisconsin. Minnesota. Mis-
souri and Illinois. Of all of these only one (coll. E. E. Sherff.
Wolf Lake. Chicago, June 10. 1911) has the form of flower of
X. tuberosa. But a note attached to the specimen declares that
the flowers are fragrant !
It seems highly desirable, therefore, that critical studies
should be made of the white waterlilies of all of the Great Lake
region, and the Central states. Every detail mentioned in the
table given above should be carefully examined into. Only thus
can the taxonomic value and the range of these plants be de-
termined. At present I do not place entire confidence in any
of the published names. I would be glad to serve as a medium
of exchange for observations on this subject.
Department of Botany,
Grixxell College.
3 2044 106 2o i
fKa OKI 381
Date Due
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