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ALLAN HANCOCK FOUNDATION
PUBLICATIONS PS
OF wee fio? hy
THE UNIVERSITY OF SOUTHERN CALIFORNIA
First SERIES
ALLAN HANCOCK PACIFIC EXPEDITIONS
VoLuME 13
1946-1950
THE UNIVERSITY OF SOUTHERN CALIFORNIA PRESS
LOS ANGELES 7, CALIFORNIA
1950
ALAN HAN COCK) FOUNDATION
PUBLICATIONS
ALLAN HANCOCK PACIFIC EXPEDITIONS
VoLuME 13
1946-1950
THE UNIVERSITY OF SOUTHERN CALIFORNIA PRESS
LOS ANGELES 7, CALIFORNIA
1950
CONTENTS
1. The Bryophyta of the Allan Hancock Expedition of 1939, by
William,’ Campbell Steere... .2..52-1-0.22.5 et ee 1- 4
2. Land Plants collected by the Velero III, Allan Hancock Pacific
Expeditions, 1937-1941, by Howard Scott Gentry, (Plates 1-15,
10 IE Sa [eee eee oe OE AP Nee oo A Tu Soe tet Tes eco 5-246
3. Plant Ecology of the Channel Islands of California, by Meryl
Byron Dunkle;. (Figures: 1-12, Plates. 1-6)2.2.0.52 eee 247-386
Index for Land Plants of Allan Hancock Pacific Expeditions
Fe PRN one Sire eA ER ND UTE. ted eT mE Seen ENCE LMI RENEE SE Ace Se 237-246
Index for Plant Ecology of Channel Islands of California.......................- 381-386
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REPORTS ON THE COLLECTIONS OBTAINED BY ALLAN HANCOCK PACIFIC EXPEDITIONS OF
VELERO III OFF THE COAST OF MEXICO, CENTRAL AMERICA, SOUTH AMERICA,
AND GALAPAGOS ISLANDS IN 1932, IN 1933, IN 1934, IN 1935,
IN 1936, IN 1937, IN 1938, IN 1939, IN 1940, AND IN 1941
THE BRYOPHYTA-OF THE
ALLAN HANCOCK EXPEDITION OF 1939
By WILLIAM CAMPBELL STEERE
THE UNIVERSITY OF SOUTHERN CALIFORNIA PUBLICATIONS
ALLAN HANCOCK PACIFIC EXPEDITIONS
VOLUME 13, NUMBER 1
IssuED May 27, 1946
THE UNIVERSITY OF SOUTHERN CALIFORNIA PRESS
Los ANGELES, CALIFORNIA
THE BRYOPHYTA OF THE
ALLAN HANCOCK EXPEDITION OF 1939
By WILLIAM CAMPBELL STEERE
The collection of bryophytes brought back by the Allan Hancock
Expedition of 1939 is much smaller than that resulting from the 1934
Expedition,1 and contains no species new to science. However, since Dr.
Wm. Randolph Taylor and Mr. Francis H. Elmore collected the speci-
mens in areas little known by botanists, such as the west coast of Costa
Rica and Panama, and Socorro Island of the Revillagigedo group
(Mexico), it seems worth while to report on them.
The five species of Hepaticae listed below were identified by Dr.
Margaret Fulford of the University of Cincinnati, and I wish to acknowl-
edge here my obligation to her. All specimens are deposited in the her-
baria of the Allan Hancock Foundation, The University of Southern
California, and the University of Michigan, and a set of the Hepaticae
are in the possession of Dr. Fulford.
HEPATICAE
LEJEUNEACEAE
BRACHIOLEJEUNEA CORTICALIS (Lehm. & Lindenb.) Schifin.,
Hedwigia 33 :180. 1894.
Costa Rica (West Coast): On a large smooth-barked tree in forest,
Golfo Dulce; 26 March 1939; W.R. Taylor No. 39-754.
Distribution: Florida; West Indies; Central America; northern
South America.
CAUDALEJEUNEA LEHMANNIANA (Gottsche) Evans, Bull. Torrey
Bot. Club 34:554. 1907.
Costa Rica (West Coast): On twigs in the forest, Golfo Dulce;
26 March 1939; W.R. Taylor No. 39-753.
Distribution: Florida; West Indies; Central America; northern
South America.
RECTOLEJEUNEA BERTEROANA (Gottsche) Evans, Bull. Torrey Bot.
Chibsset2s 1906;
1 Steere, Mosses of the G. Allan Hancock Expedition of 1934, collected by Wm.
R. Taylor. Hancock Pacific Expeditions 3(1):1-12. 1 pl. 1936.
es
2 ALLAN HANCOCK PACIFIC EXPEDITIONS VoL. 13
Costa Rica (West Coast): On bark of trees in the forest, Golfo
Dulce; 26 March 1939; W.R. Taylor No. 39-765.
Distribution: Florida; West Indies; British Honduras. This seems
to be the first report of the species from Costa Rica.
STICTOLEJEUNEA KUNZEANA (Gottsche) Schiffn., in Engler &
Prantl, Nat. Pflanzenfam. 1(3):131. 1895.
Costa Rica (West Coast): On bark of trees in forest, Golfo Dulce;
26 March 1939; W.R. Taylor No. 39-764.
Distribution: Andes of South America. This seems to be one of the
first collections to be reported from Central America.
STICTOLEJEUNEA SQUAMATA (Willd.) Schiffn., in Engler & Prantl,
Nat. Pflanzenfam. 1(3):131. 1895.
Costa Rica (West Coast): On the bark of trees in forest, Golfo
Dulce; 26 March 1939; F. H. Elmore No. 39-759, W.R. Taylor No.
39-760.
Distribution: West Indies; Central America; northern South
America.
MUSCI
FIsSIDENTACEAE
FissIDENS GARBERI Lesq. & James, Proc. Amer. Acad. 14: 137. 1879.
Mexico (West Coast): On soil with a small fern, three-quarters of
a mile up the canyon from the landing place, Braithwaite Bay, Socorro
Island, Revillagigedo Islands; 18 March 1939; F. H. Elmore No.
39-751.
Distribution: Southern United States; West Indies; Mexico;
Central America.
CALYMPERACEAE
CALYMPERES DONNELLI Austin, Bot. Gaz. 4: 151. 1879.
Costa Rica (West Coast): On twigs in the forest, Golfo Dulce;
26 March 1939; F. H. Elmore No. 39-757, W.R. Taylor No. 39-762.
Trinidad: On branches of Cacao plants by the side of the Manzanilla
Beach Road; 18-20 April 1939; W.R. Taylor No. 39-768.
Distribution: Southern United States; West Indies; Central
America; northern South America. In spite of its wide distribution in
tropical America, this species has not been previously reported from Costa
Rica.
No. 1 STEERE: BRYOPHYTA 3
CALYMPERES RicHaArpDI C. Miill., Syn. Musc. 1: 524. 1849.
Costa Rica (West Coast): Growing high in a tree, among orchids,
Port Baker, near Salinas Bay; 24-25 March 1939; F. H. Elmore No.
39-752.
Distribution: Southern United States; West Indies; Central
America; northern South America. Although this species is widely dis-
tributed in the American tropics, it has not been reported before from
Costa Rica.
ERPODIACEAE
ERPODIUM DOMINGENSE (Brid.) C. Miill., Bot. Zeit. 1: 774. 1843.
Mexico (West Coast): On soil with a small fern, mixed with
Fissidens Garberi Lesq. & James, three-quarters of a mile up the canyon
from the landing place, Braithwaite Bay, Socorro Island, Revillagigedo
Islands; 18 March 1939; F. H. Elmore No. 39-751a. Only one small
stem of this unmistakable moss was found, but it was enough to establish
the identification beyond any doubt.
Distribution: Cameron County, Texas; Santo Domingo; Haiti;
Puerto Rico; Yucatan; Guatemala. ‘This is the first collection and
report of what has always been considered to be a typically Caribbean
species from the Pacific side of Central America.
OrRTHOTRICHACEAE
MIcROMITRIUM FRAGILE (Mitt.) Jaeg., Adumb. 1: 435. 1872-73.
Trinidad: On branches of Cacao plants by the side of the Manzanilla
Beach Road; 18-20 April 1939; W.R. Taylor No. 39-767.
Distribution: West Indies; Mexico; Central America; tropical
South America; Galapagos Islands. Although this species is known from
the West Indies, I do not believe that it has been reported previously
from Trinidad.
LEUCODONTACEAE
LEUCODONTOPSIS FLORIDANA (Aust.) E. G. Britton, Bryologist
£55 26,4912,
Trinidad: On branches of Cacao plants by the side of the Manzanilla
Beach Road; 18-20 April 1939; W.R. Taylor No. 39-769.
Distribution: Florida; West Indies; Mexico; Central America;
northern South America.
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4 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 13
PTEROBRYACEAE
ORTHOSTICHOPSIS TETRAGONA (Hedw.) Broth., in Engler &
Prantl, Nat. Pflanzenfam. 1(3): 805. 1906.
Panama (West Coast): In forest, Bahia Honda; 26 March 1939;
F. H. Elmore No. 39-755.
Distribution: West Indies; Mexico; Central America; tropical
South America.
METEORIACEAE
PAPILLARIA NIGRESCENS (Hedw.) Jaeg., Adumb. 1: 169. 1875-76.
Trinidad: On branches of Cacao plants by the side of the Manzanilla
Beach Road; 18-20 April 1939; WV. R. Taylor No. 39-766.
Distribution: Florida; West Indies; Mexico; Central America;
tropical South America. ‘This is a common and very widely distributed
species.
METEORIOPSIS PATULA (Hedw.) Broth., in Engler & Prantl, Nat.
Pflanzenfam. 1(3) : 825. 1906.
Trinidad: On branches of Cacao plants by the side of the Manzanilla
Beach Road; 18-20 April 1939; W.R. Taylor No. 39-768.
Distribution: Florida; West Indies; Mexico; Central America;
tropical South America; Galapagos Islands.
PILOTRICHACEAE
PILOTRICHUM AMAZONUM Mitt., Journ. Linn. Soc., Bot., 12: 387.
1869.
Costa Rica (West Coast): On delicate twigs in the forest, Golfo
Dulce; 26 March 1939; W.R. Taylor No. 39-756; on the bark of
trees, W.R. Taylor No. 39-763.
Distribution: Amazon region of South America, extending northward
through Panama to Guatemala. ‘This is apparently the first report of the
species from Costa Rica.
REPORTS OF THE COLLECTIONS OBTAINED BY ALLAN HANCOCK PACIFIC EXPEDITIONS OF
VELERO III OFF THE COAST OF MEXICO, CENTRAL AMERICA, SOUTH AMERICA, AND
GALAPAGOS ISLANDS IN 1932, IN 1933, IN 1934, IN 1935, IN 1936, IN 1937, IN 1938,
IN 1939, IN 1940, AND IN 1941
LAND PLANTS COLLECTED BY THE
VELERO III, ALLAN HANCOCK PACIFIC
EXPEDITIONS 1937-1941
(Pirates 1-15, Maps 1-3)
By HOWARD SCOTT GENTRY
THE UNIVERSITY OF SOUTHERN CALIFORNIA PUBLICATIONS
ALLAN HANCOCK PACIFIC EXPEDITIONS
VOLUME 13, NUMBER 2
IssUED JULY 22, 1949
THE UNIVERSITY OF SOUTHERN CALIFORNIA PRESS
Los ANGELES, CALIFORNIA
PARLE OF CON EE NTS
LisT Ge ME LUSTRATIONS ~ ©. sah) vd: fer otal wrk
GENERAL INTRODUCTION
New Names Proposed
Introduction to the Catalogues
CHANNEL ISLANDS
Introduction .
Catalogue of Collections .
Literature Cited .
CEDROS AND SAN BENITO ISLANDS .
Introduction .
Catalogue of Collections .
Literature Cited .
REVILLA GIGEDO ISLANDS
Introduction
Catalogue of Collections
Literature Cited
Tres MariAs IsLANDS
San Juanito
Maria Madre
Maria Magdalena
Maria Cleofa
Literature Cited .
CALIFORNIA GULF REGION
General Physiography
Postinsular Localities
Climate .
Colleehion Pacatities® 0 2) So fe ee
Summary of Insular Floras
Catalogue of Collections .
Literature Cited .
JALISCO AND OAXACA
Introduction
Catalogue of Collections .
CosTA RICA
Introduction
Catalogue of Collections .
PLATES
INDEX
re
PAGE
it7
204
237
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LIST OF ILLUSTRATIONS
Moringa oleifera Lam.
Fig. 1. section of branchlet with leaf x¥4.
Fig. 2. pod x.
Moringa oletfera Lam.
Fig. 3. flower at anthesis x3.3.
Fig. 4. stamen x11.
Fig. 5. bud'x5.
Fig. 6. sepal x6.7.
Echinopepon peninsularis Gentry
Fig. 7. habit x4.
Fig. 8. node x4.
Fig. 9. fruit prickle x6.5 to compare with.
Fig.
Fig.
Fig.
Fig.
Fig.
Fig.
Fig.
Fig.
Fig.
Fig.
Fig.
Fig.
Fig. 22.
10.
11,
20.
21.
fruit prickle x6.5 of Echinopepon minimus.
View on the north end of Santa Rosa Is!and. Grassland covers the
more level slopes, while bushy perennials are spotted on the bluff.
(Photo from the Los Angeles Museum Channel Island Survey)
. Braithwaite Bay, Socorro Island on a calm cloudy day in March.
. Punta Frailes, Cape District, Baja California. ‘The arborescent
growth is widely dispersed on the steep rocky slopes, dense on the
outwash fans.
. Vegetation above Frailes Bay, Cape District. On the basic rock slope
the vegetation is sparse and stunted.
. Dense Thorn Forest vegetation in a broad wash near Frailes Bay,
Cape District, Baja California.
. View southward near Puerto Escondido, Baja California, over-
looking a narrow coastal plain with the scarp of the Sierra Giganta in
the background. The foreground shows a xerophytic grass ground
cover with scattered tree of Bursera microphylla and Lemaireocereus
Thur bert.
. Canyon above Escondido, Baja California. The steep slopes are
brecciated lavas; the palm, Erythea Brandegeet.
. Angel de la Guardia Island. Typically sparse desert vegetation on
washes and fans with a scattered grove of Pachycereus Pringlet.
. Angel de la Guardia Island. The effect of wind on the sarcophytic
tree Pachycormus discolor pubescens along a rocky crest.
Angel de la Guardia Island. Sparse Desert Shrub on an east exposure
with Pachycereus Pringlei on the lower gentler slopes.
Tiburon Island. Low Desert Shrub on the granitic terrain of the
southeast coast.
San Pedro Nolasco Island, showing the “raw” rock surfaces, almost
no soil, and adventive or pioneering perennials.
[9]
10.
1
12.
14,
15:
= oo
233s
. San Pedro Nolasco Island. A clump of Echinocereus grandis.
. San Pedro Nolasco Island. A succulent vegetation of Agave, Opuntia,
and Pachycereus on very rocky terrain.
. San Pedro Nolasco Island. Agave chrysoglossa and Lemaireocereus
Thurber in foreground.
. San Pedro Nolasco Island. A dense colony of the succulent low shrub,
Pedilanthus macrocarpus.
. Espiritu Santo Island. A dispersed shrub formation with scattered
trees of Pachycereus Pringlei.
. Espiritu Santo Island. Detail of branch and fruit of Opuntia cholla.
. Tenacatita Bay, Jalisco. The subtropical forest is close upon the
beach.
. Chacahua Bay, Oaxaca. The scrubby vegetation on the hill in the
background shows evidence of having been cut over.
. Lowland coastal vegetation of the tierra caliente in Costa Rica near
Port Culebra.
Close lowland forest of Costa Rica with a dense tangle of trunks,
limbs, and clambering stems, crooked to semi-straight.
Forest of the tierra caliente in the Golfo de Dulce, Costa Rica. The
varied tree forms indicate the richness of the flora.
[10 ]
LAND PLANTS COLLECTED BY THE VELERO [i],
ALLAN HANCOCK PACIFIC EXPEDITIONS 1937-1941
(PLATES 1-15, Maps 1-3)
By Howarp Scott GENTRY
GENERAL INTRODUCTION
The complete itinerary of the voyages of the Velero III on the Allan
Hancock Pacific Expeditions is given by Fraser (1943). An outline of
the land plants secured are given in Table 1. Since the expeditions were
primarily concerned with marine biology and especially the collection of
marine faunas, the land plant collections were only incidental and are
not large. They are samplings of several distinct floral elements of west-
ern North America.
(1) Those from the Channel Islands belong to the unique California
flora, in one of the five regions of the world having a Mediterranean
type of climate. This climate is characterized by winter rainfall, dry
summers, and maritime influence conducive to equable temperatures, on-
shore winds, and regular seasonal fogs. Cedros Island, off the west coast
of middle Baja California, contains in its high elevations a southern out-
post of the California flora.
(2) The Sonoran Desert flora is generally peripheral to the Gulf of
California. It extends farther south on the peninsula (to the Cape Dis-
trict) than it does on the mainland (to about Guaymas, Sonora). In its
area an arid contintental type of climate competes with an arid maritime
one, the former most evident in the northern part of the region around
the lower Colorado River basins, while the latter is particularly stead-
fast in the middle and southern outer coastal part of the peninsula.
While both types have low and irregular rainfalls, the maritime desert
differs in having more equable annual and daily temperatures, higher
relative humidity, and summer rainfall is more common in the southern
latitudes. This latter feature is a tropical factor in the situation.
(3) The Sinaloan subtropical flora is the great transitional element
between deserts and tropics. Rainfall is about 90% summer. The high
temperatures are ameliorated, particularly through the spring, by on-shore
westerlies. The dominating life form is the tree of short to medium
pia
12 ALLAN HANCOCK PACIFIC EXPEDITIONS VoL. 13
stature, densely spaced, with epiphytes common in the more humid locali-
ties. On the mainland of Mexico, the Sinaloan flora occupies the low
and middle elevations from southern Sonora south at least to Nayarit.
Farther south it is local or transitional with the Central American floral
element. The Velero III collections from the Tres Marias Islands, the
Revilla Gigedo Islands, and the Cape District of Baja California are
referable to the Sinaloan flora.
(4) The Central American flora is distinctly tropical under medium
to high rainfalls. It contains a very great number of species and is domi-
nated by both evergreen and deciduous trees of medium to tall stature.
It is further characterized by broad leaf blades and an abundance of epi-
phytes. Ihe Pacific part of the area is distinctly arid as compared to the
Atlantic, and its coastal forests are mostly deciduous, of medium stature,
and are interspersed with areas of savanna. ‘There is a long dry season
from November to May. From the standpoint of vegetation there is
little to separate the Pacific coast of Costa Rica from the Pacific coast
of southern Mexico, since the dominating plant forms and associations
apparently extend throughout with but little modification as far north
as Nayarit. The Velero III collections from coastal Jalisco, Oaxaca, and
Costa Rica reflect this general relationship.
The report has been organized according to geographic regions under
the following headings: “The Channel Islands of California, Cedros and
San Benitos Islands, Revilla Gigedo Islands, Tres Marias Islands, The
California Gulf Region, Jalisco and Oaxaca, Mexico, and Costa Rica.
The desirability of so enumerating these scattered collections, representa-
tive of several regions and several floras, is so obvious it is unnecessary
to recount them here. Each section is introduced by a general discussion
of the physiography, the climate, and the plant geography with special
emphasis on the historical or developmental aspects of the flora involved.
I have also attempted to evaluate the botanizing that has been done to
date on the respective areas, the islands in particular. The discussions
are opinionated summaries, according to my experiences and observa-
tions in the fields or to reports read, rather than documented conclusions.
It is hoped that they will stimulate interest and activity in the richly re-
warding botanical field of northwestern Mexico.
As is usual in works of this kind, the author is indebted to many
people for their willing assistance in making the report possible. ‘Io all
of them he extends his sincere thanks. Ira L. Wiggins of Stanford Uni-
NO. 2 GENTRY: LAND PLANTS 13
versity, E. Yale Dawson and Kenneth O. Emery of the Allan Hancock
Foundation and The University of Southern California, and P. A. Munz
of the Santa Ana Botanical Garden all read various sections of the
manuscript and made valuable criticisms and suggestions. ‘he following
taxonomists made determinations in certain genera or families:
S. F. Blake National Arboretum Compositae
Elzada Clover University of Michigan Cactaceae
L. Constance University of California Hydrophyllaceae
E. Y. Dawson Allan Hancock Foundation Cactaceae
L. H. Harvey Montana State University Gramineae
C.V. Morton National Herbarium Pteridophytes
Hugh O’Neill Catholica University of America Cyperaceae
R. C. Rollins Stanford University Cruciferae
L. C. Wheeler University of Southern California Euphorbiaceae
I. L. Wiggins Stanford University Malvaceae
New Names PROPOSED IN THIS PUBLICATION
A gave costaricana Gentry sp. nov.
A gave Shawii sebastiana (Greene) Gentry new comb.
Lyrocarpa linearifolia Rollins sp. nev.
Calliandra Brandegeei (Brit. & Rose) Gentry new comb.
T ephrosid hamata (Rydb.) Gentry new comb.
Dalea variegata (Rydb.) Gentry new comb.
Pachycormus discolor V eatchiana (Kell.) Gentry new comb.
Pachycormus discolor pubescens (Wats.) Gentry new comb.
Echinopepon peninsularis Gentry sp. nov.
V aseyanthus Palmeri (Wats.) Gentry new comb.
INTRODUCTION TO THE CATALOGUES
In the plan of the catalogues of species collected by members of the
Allan Hancock Expeditions, families are listed according to the sequence
of the Engler and Prantl system. The genera and species are listed alpha-
betically under each family. The first entry under the species heading is
the citation of collection together with any note that the collector may
have left upon his field label. It will be noted also that I have included
the date of collection, which I estimate of some importance because it
gives a record of the time of flowering or fruiting. In cases where the
specimen is sterile, it is either so indicated in parentheses along with speci-
men citation or is noted in the following paragraph.
14 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 13
TABLE 1
LAND PLANTS COLLECTED BY THE VELERO III
Collector and *No. Sp.
Locality and Date his numbers Col.
1937
Baja California (outer coast)
Manuela Lagoon near Lagoon Head Anchorage,
ols PEL ONE (abahes Dik el spe Soe Mc Ane aires Beak aN Rempel 1-22 25
San juameo Bay, Wearch 2202 Rempel 24-52 50
Cubeza Ballena;s (March 3.225 00e a ee Rempel 54-74 26
Sclands\an.Pond Tapoon, July Ps ee Rempel 350-355 6
Gulf of California
Ensenado de los Muertos, Cape District, Baja
Calitornaas larch 52205 too. ee Se - Rempel 76-78 +
San Gabriel Bay, Espiritu Santo Island,
LL GT 1 ght ebb a BG Fall OND eRe aan a 2 he ea 8 Rempel 80-100 30
San Prancisco Fsland, March 9:2:.::.2-22- 23 Rempel 101-112 16
Agua Verde Bay, Baja California, March 10........... - Rempel 114-140 34
Puerto Escondido, Baja California, March 13.......... Rempel 141-170 40
Bideronso island | Wiareds 25.28 es ed Rempel 170a-170b 2
West Cove in Concepcion Bay, Baja
Catirorniay March 15.50 5s see Rempel 171-186 17
Island in Concepcién Bay, Baja
California’ March: 16.52.2255 oe ahi ek Rempel 188-209 25
Mareiea island Whareiy 2 Je. 80 Ae ee Rempel 210-230 23
Los Angeles Bay, Baja California, March 19, 20....... Rempel 231-250 21
North end of Los Angeles Bay, Baja
Caltorma, Mare 2005. obese) Le ee le Rempel 251a-262 12
Puerto Refugio, Angel de la Guardia Island,
LS Er | ea a MRS a ag. 0 ad aE We Rempel 262-280 24
Willard Point, Gonzaga Bay, Baja
Calriornras Wharcly 2360 0 ae ee Rempel 283-285 3
North of Point Lobos, Sonora, March 26.............-.------ Rempel 287-288 2
ates 'sland iar 26.6 a ase Rempel 290 if
Sanebstepan Island, Marchi272. 262 fe a 8 Rempel 291-294 6
South end of Tiburon Island, March 27................--.. . Rempel 295-298 6
San Pedro Nolasco Island, March 29................---.------- Rempel 300-307 10
Ensenado de San Francisco, Sonora,
[s/f Tel A SO ee CR A OF ne Br epee ENE eee Rempel 311-315 8
Fraile Bay, Cape District, Baja California,
Ugh ily | le Haan AGS Seed OREM UNE YF RRR YUN RH Mirae et Fens . Rempel 317-328 12
Cedros and San Benito Islands
Hast side ot Cedros Island, Fuly 10-2. Rempel 330-348 19
Sait Benita Isianas July: 142 eee ee Rempel 356-362 15
West San Benito Islands, July 15...) Rempel 364-371 8
1938
Channel Islands
Middle Island of Anacapa Group, August 1............. Elmore 220-252 40
Becher Bay, Santa Rosa Island, August 2.................- Elmore 170-215 50
Santa Barbara Island, August 12.20.02. Elmore 295-310 20
San Miguel Island, Tylers Bight, August 3
and Point Bennett, September 12................-------------- Elmore 312-341 47
San Clemente Island, February 18, 19......................- Elmore 381-428 53
Santa Catalina Island, February 28............--......--------- Elmore 3
NO. 2 GENTRY: LAND PLANTS 15
TABLE 1—Continued
LAND: PLANTS ‘COLLECTED BY THE VELERO iF
Collector and *No Sp.
Locality and Date his numbers Cal
1939
San Clemente Island, February 18, 19......................... Elmore 312-341 47
Santa Catalina Island, February 28..02—.20.22-. Elmore 430-439 15
1941
Santa Cruz Island:
Between Pelican Bay and Prisoners
Blarbor, cA pael V7 ee Ny Be Elmore 254-293 45
Hill west of Prisoners Harbor, April 17................. Elmore 440-468 30
1939
Mexico
Cedros Island, “Cannery Bay,” March 14.................. Elmore A1-A37 80
Revilla Gigedo Islands.
Sulphur Bay, Clarion Island, March 16.................. Elmore B1-B15 50
Braithwaite Bay, Socorro Island, March 18........... Elmore C1-C11 40
Chacagua Bay,Oaxaca,. Match) 21.2.2 .2.nne Elmore D1-D25 130
Penacatita Bay, Jalisco, May) S$.) cee Bee Elmore 1A1-1A24 90
Magdalena Island, Tres Marias Group, May 9......... Elmore 1B1-1B3 10
1939
Costa Rica
Port Parker, Salinas Bay, March 24, 25............-------- Elmore E1-E-25 £15
Golfo-de Duleé, Match 26.2420). 2 ee es Elmore F1i-F28 150
Southwest island of Secas Group, March 27.............- Elmore G1-G2 10
1940
Gulf of California, Mexico
(Giayinas, Sonoda, \aWUAEY, 29-0 ene ee Sate et Dawson 1000-1009 45
Pabucow Fsland. Janwary, 256 cncccc000 et Dawson 1010-1020 28
Puerto Refugio, Angel de la Guardia Island,
dpetinenairy 2 Geo loy bane Phd eR te A ee ele oS . Dawson 1021-1032 50
San Pedro Nolasco Island, February 6.........-------------- - Dawson 1033-1036 20
Pond) island. \Nepruany. «866 el ed Dawson +
san Bstepan Island, February... 20... Dawson 6
san Carlos Bay, Sonora, February 3_........___. Dawson 1050-1073 90
Near Guaymas, Sonora, February 9.22... Dawson 1074-1084 60
Puerto Escondido, Baja California, February 11....... Dawson 1085-1109 50
Punta Frailes, Baja California, February 16.............. Dawson 1111-1149 100
San Jose del Cabo, Baja California, February 17...... Dawson 1150-1225 180
Table 1. The land plant collections made by members of the Allan Hancock
Foundation Expeditions in the Eastern Pacific on the Velero III, 1937 to 1941.
*No. Sp. Col.=number of specimens obtained, approximate.
16 ALLAN HANCOCK PACIFIC EXPEDITIONS voL. 13
In the following paragraph I have noted the distribution of each
species generally, drawing upon my notes and travels, upon notes and
records furnished me by Dr. Forrest Shreve of the recent Carnegie
Desert Laboratory, upon manuscript copy of the “Flora of the Sonoran
Desert” under preparation by Dr. Ira Wiggins of Stanford University
and which he was generous enough to loan, upon information furnished
by Dr. Dawson of the Allan Hancock Foundation regarding cactus dis-
tributions, and upon information in publications. The type locality is
given if it is known or specific enough to mean anything. Some taxonomic
notes on the species or specimen at hand are also offered and in this I
have often tried to clarify some of the important characters for specific
recognition. The list, however, makes no attempt to be a descriptive
flora. I have tried to add to, rather than merely duplicate, information
already carried in earlier publications.
‘The abbreviations used are those that are well established in taxo-
nomic literature with but two exceptions. ‘The first is C.N.H. for Con-
tributions from the United States National Herbarium, rather than
Contr. U. S. Nat. Herb., as has been frequently used. In employing this
abbreviation I have followed Riley of the Royal Botanic Gardens at
Kew (cf. Flora of Sinalao, Kew Bull. 1923-1924).
Proposed here is the abbreviation Brge. for Townsend Seth Brande-
gee, who did so much pioneer work on the Flora of Baja California, and
K. Brge. for Katherine Brandegee, his coworker and wife. I. S. Brande-
gee has been abbreviated in various ways, viz., I. S. Brandeg., Brandg.,
and Brand. The first is too long to function as an efficient abbreviation,
two digits only having been stricken out, one of which is replaced by the
period, leaving a net gain of only one digit. The third is easily confused
with Brand. According to the recommendations in article 49 of the In-
ternational Rules of Nomenclature, Brandegee should be contracted to
Brande. However, as an abbreviation this is ineffective since it has elimi-
nated only two digits of a long name. Since none of the above abbrevia-
tions are short enough to carry the functional advantage of brevity, Brge.
stands for I. S. Brandegee in the following pages.
Trinomials have been briefed to the citation of the varietal author,
or authors, only, and are not designated as to subspecies, variety, or form.
With very few exceptions the authors have regarded them as varieties.
The criteria used to differentiate subspecific entities is quite variably
subjective, and particularly meaningless in dealing generally with a wild
and incompletely known flora. Subspecific entities can be used effectively
No. 2 GENTRY: LAND PLANTS 17
when genetic values are obtained. Hence, pending the genetic stages of
taxonomic inquiry into the plants of the regions considered, the nomen-
clature has been kept simple.
Synonomy is given when required in proposing new names and also
in a few cases of special significance.
CHANNEL ISLANDS
INTRODUCTION
The southern California coast from Point Arguello southeastward
describes a long shallow irregular curve. ‘The outer margin of the con-
tinental shelf, trending more nearly southward, accordingly broadens.
Its submarine surface is irregular with submarine valleys and ridges;
the topography suggesting land surface rather than sea bottom. The
greatest heights of the shelf rise above the sea and form the Channel
Islands, bearing the appellations cast upon them by the early Spaniards,
San Miguel, Santa Rosa, Santa Cruz, Anacapa, Santa Catalina, Santa
Barbara, San Nicolas, and San Clemente. ‘They comprise a residual area
of considerable antiquity, which, according to Reed (1933) and other
geologists, dates from the Cretaceous. The ratio of sea to land area over
the shelf has varied greatly, but during much of the Tertiary this shelf
segment actually formed a large land body, known as Catalinia. In the
early Miocene and again in the Pleistocene, if not also at other times,
Catalinia appears to have been bridged to the continent.
Structurally the islands are separated into two groups. The northern
consists of San Miguel, Santa Rosa, Santa Cruz, and Anacapa, repre-
senting disjunct segments of the Santa Monica Mountains, which ap-
pear to have been more variably emerged and submerged in the sea than
has the southern group. The southern group, consisting of Santa Bar-
bara, Santa Catalina, San Nicolas, and San Clemente, have been part
of a more consistent land area and are structurally tied to the San Pedro
peninsula. The present islandic configuration is the result of geologically
recent submergence of all but the higher elevations. The biota of such
a land area can be expected to differ considerably from that of the near
mainland and actually the evolution of the plants and animals is to be
correlated with that of the land. Behind the present configuration of
flora and fauna the elusive steps of evolution can be discerned.
The climate of the Channel Islands is Mediterranean in type, semi-
arid, and, of course, maritime. The average annual rainfall is around
12 inches, about 90% of which is precipitated in winter (November
18 ALLAN HANCOCK PACIFIC EXPEDITIONS VoL. 13
through March). The dominating factor is the northwest winds, which
pour around the islands for the majority of the days of the year. ‘This
increases aridity over what might be expected on the basis of rainfall
and temperature (60°F. mean annual) only. However, transpiration
and general aridity are tempered by high humidity and frequent fogs.
The climate borders on a fog or maritime desert over the southern por-
tion of San Clemente Island, the southern-most of the group.
There is considerable variation in climate locally, both on individual
islands and between different islands. This is explainable primarily in
terms of the predominating direction of air flow. Physical conditions
vary greatly whether a given area is on a windward or leeward side.
This is expressed by the vegetation. Windward slopes commonly are
covered with grass and forbs (PI. 4, fig. 11), or stunted wind-tolerant
shrubs, while protected slopes support shrub and tree communities. Some
of the smaller islands that have been greatly disturbed by man have been
nearly denuded of cover and top soil by the erosive action of wind.
This is true of San Miguel, which catches the full force of the north-
westers, and its sterile mobile sands are being discharged into the lee sea.
The vegetation of the islands has been greatly altered by man. Both
the aborigine, who burned and cut the native plants, and the modern
European segregates, who burned, cut, cleared, and pastured, have left
only remnants of the virgin cover. Many of the native plants are intoler-
ant to grazing, and as they were destroyed, the aggressive weeds were
introduced and have persistently spread. While considerable has been
published about the flora of the islands, very little is on record regarding
the vegetation. The only study of the plant ecology, that I have been
able to find, which gives an adequate account of the vegetation is a doc-
toral thesis by M. B. Dunkle (1944). Between 1939 and 1943 he made
repeated visits to the islands and his introductory statement (1944:128-
129) is a concise general picture of the island vegetation.
“Varied as are the different islands in topography and climate, they
possess certain basic similarities. ‘The western slope of all the islands,
except San Nicolas which consists of barren sand dunes in this area, are
covered with grasses, low forbs, suffrutescent perennials, and a few low
wind-tolerant shrubs. The eastern slopes, except on the smaller islands,
are quite generally covered with chaparral, or shrub and tree savannas.
The canyons, which afford protection from the wind, usually have more
or less shrubby growth on their slopes. This varies from an Opuntia lit-
toralis association, through various facies of the coastal sage brush associa-
tion, to chaparral on the larger islands. On these larger islands, and on
NO. 2 GENTRY: LAND PLANTS 19
Anacapa, there may be occasional trees in the canyons, and where there
is a continuous supply of running water there may be a riparian com-
munity with trees or arborescent shrubs. The seaward bluffs have a
varied growth of succulents, forbs, suffrutescent perennials, and occa-
sional shrubs. Sand dune vegetation, very similar to that of mainland
areas, is present on low dunes back of the few sandy beach areas. On
the larger islands the protected north and northeast slopes support
scattered groves of trees, while Santa Cruz has an extensive area of
woodland.”
It is to be expected that such a residual area, representing a con-
siderable area of long though interrupted isolation, would have many
endemics in its flora. Of the approximately 950 species and varieties
that have been catalogued from the ilsands, 80 of them are endemic. The
original endemic element was undoubtedly reduced during times of the
land bridges and migratory exchanges appear to have been made in both
directions. Hence, if the apparent migrants from the islands to the main-
land were included, the total island endemics would be about 100 species
and varieties. Many of the endemics make up the unique plant com-
munities known only on the islands, as the Pinus and the Lyonothamnus
associations among the trees, the shrubby or suffrutescent communities,
as the Coreopsis-Artemisia association, the A triplex-Hemizonia-Lotus-
Astragalus community, the Echevaria-Eriogonum-Opuntia community,
and the Eriogonum-Eriophyllum association forming a low tangle of
suffrutescents. As on the mainland, the grasslands are dominantly com-
posed of aggressive introductions and indicate little of the natural virgin
climax.
The most exhaustive flora published on the islands is that of Mills-
paugh and Nuttall (1923) on Santa Catalina Island. Subsequent papers
have stressed other islands, as Hoffman (1932) and one has recently
catalogued the plants from all of the islands (Eastwood 1941). The fol-
lowing annotated catalogue is based upon the collections secured by Mr.
Francis H. Elmore on voyages of the Velero III of the Allan Hancock
Foundation in 1938, 1939, and 1941, as outlined in Table 1. The com-
plete itinerary of the Velero III voyages is given by Fraser (1943). On
these and several other works as well, the author has drawn in formu-
lating the collections. Philip A. Munz, an authority on southern Cali-
fornia botany (1935), of the Rancho Santa Ana Botanical Garden, has
read considerately and criticized the manuscript. No new plants are re-
ported but the collections confirm and add to the distributional knowl-
edge of plants in and about the Channel Islands.
20 ALLAN HANCOCK PACIFIC EXPEDITIONS voL. 13
CATALOGUE OF COLLECTIONS
POLYPODIACEAE
PELLAEA ANDROMEDAEFOLIA (Kaulf.) Fee, Gen. Fil. 129. 1850-52.
San Clemente Island, February 18, 19, Elmore 383, 413.
In maritime climate up to 4000 feet elevation from Oregon to
northern Baja California, and known from the adjacent islands of Santa
Catalina, Santa Rosa, and Santa Cruz.
SELAGINELLACEAE
SELAGINELLA BicELovi’ Underw., Bull. Torr. Bot. Club 25:130.
1898.
San Clemente Island, February 18, 19, Elmore 398.
Southern half of California west of the deserts and adjacent islands
of Santa Rosa, Santa Cruz, and Catalina. Probably also in northern
Baja California.
PINACEAE
PINUS RADIATA Don, Trans. Linn. Soc. 17:441. 1836.
Santa Cruz Island, Prisoners Harbor, August 2, Elmore 284.
Maritime of central coastal California from Pescadero to Santa
Cruz; type from Monterey.
The Santa Cruz Island pines have recently been reviewed by Howell
(Leafl. West. Bot. 3:1-7.1941), who recognized only P. remorata Mason
in varying forms. Of the authors of California floras, Jepson and McMinn
& Maino attribute P. radiata to Santa Cruz Island, while Abrams and
Munz do not, excepting the doubtful status of P. radiata binnata
(Engelm.) Lemmon. Hence the Elmore collection was considered criti-
cally. The 3-needled leaf fascicles and the light brown, slightly assyme-
tric, open cone specimens appear to belong definitely to P. radiata.
Regarding his Santa Cruz Island pine collection, Mr. Elmore has re-
cently written, “I remember well collecting the pine specimens, but as
the trees were in a regular grove and near a fence line, I remember
thinking at the time that they were probably exotics, having been planted
there.” (Letter dated February 2, 1948).
PINUS REMORATA Mason, Madrono 2:8-10. 1930.
Santa Cruz Island, Prisoners Harbor, August 2, Elmore 290.
Known only from Santa Cruz and Santa Rosa Islands.
NO. 2 GENTRY: LAND PLANTS Ah
GRAMINEAE
DISTICHLIS sPICATA (L.) Greene, Bull. Calif. Acad. Sci. 2:415.
1887.
Santa Cruz Island, Prisoners Harbor, September 14, Elmore 289.
On both coasts of North America through the temperate and sub-
tropical regions in saline soils and marshes; type from the north Atlantic
coast. Also known on Catalina, San Nicolas, San Miguel, and Santa
Rosa Islands.
ELYMUS TRITICOIDES Buckl., Proc. Acad. Phil. 1862 :99.
San Miguel Island, Tyler Bight, August 3, Elmore 317.
Widely distributed in the western United States; type from the
Rocky Mountains. Known from San Miguel, Santa Cruz, Santa Rosa,
and Santa Catalina Islands.
FESTUCA MEGALURA Nutt., Jour. Acad. Phil. II, 1:188. 1848.
Santa Cruz, hill west of Prisoners Harbor, April 17, Elmore 444.
Mostly maritime from British Columbia and Idaho south to Baja
California; type locality, Santa Barbara, California. On the islands it
is known from Santa Cruz, Santa Rosa, San Miguel, and Catalina.
FESTUCA PACIFICA Piper, C.N.H. 10:12. 1906.
Santa Cruz Island, hill west of Prisoners Harbor, April 17, Elmore
454,
Maritime from British Columbia to Baja California and the Chan-
nel Islands of San Miguel (Hoffman ??) and San Nicolas.
MONANTHOCLOE LITTORALIS Engelm., Trans. Acad. St. Louis 1 :437.
1859.
San Miguel, Tyler Bight, August 3, Elmore 318.
Littoral in salt marshes, tidal flats, and strands throughout tropical
America and north on the Pacific coast to Santa Barbara; type from
Texas. The only other records from the Channel Islands are from
Catalina.
POLYPOGON MONSPELIENSIS (L.) Desf., Fl. Atlant. 1:67. 1798.
Santa Rosa, Becher Bay, August 3, Elmore 193. Santa Cruz, Pris-
oners Harbor Canyon, September 14, Elmore 267.
_ Introduced from Europe, common now from Alaska to Mexico along
the coast. Also on Santa Catalina, San Miguel, San Nicolas, and Santa
Cruz Islands.
22 ALLAN HANCOCK PACIFIC EXPEDITIONS voL. 13
CYPERACEAE
ScIRPUS CALIFORNICUS (Meyer) Brit., Trans. N. Y. Acad. 2:80.
1892.
Santa Cruz Island, Prisoners Harbor, September 14, Elmore 293.
From California to Florida across southern United States and south
through tropical America to South America; type from California. It is
not known from any other of the Channel Islands.
LILIACEAE
BRODIAEA CAPITATA Benth., Pl. Hartw. 339. 1857.
San Clemente Island, February 18, 19, Elmore 391.
Common through the coast ranges from southern Oregon to northern
Baja California. On all the Channel Islands.
FAGACEAE
QUERCUS AGRIFOLIA Nee, Anal. Cien. Nat. 3:271. 1801.
Santa Cruz, Prisoners Harbor, September 14, Elmore 273.
Maritime climate of the coast ranges from Mendocino County, Cali-
fornia south to San Pedro Martir Mountains of northern Baja Cali-
fornia. Also known from Santa Rosa Island.
Quercus puMosA Nutt., Silva 1:7. 1842.
Santa Cruz, Prisoners Harbor Canyon, September 14, Elmore 283.
Mostly in the chaparral of the Lower Sonoran Life Zone from
northern California south into Baja California; type from Santa Bar-
bara. Also on Santa Rosa and Catalina Islands.
URTICACEAE
UrTICA HOLOSERICEA Nutt., Jour. Acad. Phil. IT, 1:183. 1847.
Santa Cruz, Prisoners Harbor Canyon, August 2, Elmore 258, dry
river bed.
From Washington and Idaho south to Baja California; type locality,
Monterey, California. Also on Santa Catalina Island.
POLYGONACEAE
ERIOGONUM ARBORESCENS Greene, Bull. Calif. Acad. Sci. 1:11.
1884.
Middle island of Anacapa group, August 1, Elmore 234, steep rocky
slope.
Canyon walls and steep slopes on the California Islands of Santa
Rosa, Santa Cruz, and Anacapa; type from Santa Cruz Island.
ERIOGONUM GIGANTEUM Wats., Proc. Am. Acad. Sci. 20:371. 1885.
Santa Barbara Island, August 12, Elmore 306, dry hillside.
NO. 2 GENTRY: LAND PLANTS 23
In canyons and on bluffs on the islands of Santa Cruz, San Clemente,
and Santa Catalina; type from the latter. Elmore’s collection from
Santa Barbara is apparently the first citation for that island.
ERIOGONUM GRANDE Greene, Pittonia 1:38. 1887.
Middle island of Anacapa group, August 1, Elmore 232, steep rocky
slope.
Southern California and the Channel Islands; the type from Santa
Cruz. It appears to be lacking only on San Nicolas Island.
ERIOGONUM RUBESCENS Greene, Pittonia 1:39. 1887.
San Miguel Island, Tyler Bight, August 3, Elmore 321. Point Ben-
nett, September 12, Elmore 334. San Miguel Island, August 10, Elmore
325.
Known only from the Channel Islands of Santa Cruz, Santa Rosa,
Santa Catalina, San Clemente, and San Miguel.
This plant is closely related to E. grande Greene, to which it has
been referred as a variety by some authors. Numbers 325 and 334 are
atypical in the densely flocculose tomentum of the involucres and the
compact cymose head-like inflorescences. “They may represent a hybrid
form, a condition also indicated by the tendency of the mature involucres
to double their number of teeth.
The interesting genus Eriogonum shows considerable specific and
subspecific variation and in this it appears to be expressive of environ-
mental differences. Hence, since environments have varied in the geolo-
gic past, the present segregates of Eriogonum would be reactive products.
A cytogenetic study of the genus might find physiographic correlatives
in insular evolution. Who will make it?
POLYOGONUM AVICULARE L., Sp. Pl. 362. 1753.
Santa Rosa Island, Becher Bay, August 2, Elmore 213.
A cosmopolitan weed native of Eurasia; on Santa Rosa and Santa
Catalina Islands also.
CHENOPODIACEAE
ATRIPLEX LEUCOPHYLLA (Mog.) Dietr. in DC., Prodr. 132:109.
1849,
Middle island of Anacapa group, August 1, Elmore 237, steep rocky
slope.
A littoral halophyte from Humboldt Bay, California to Vizcaino
Bay, Baja California; type from California.
24. ALLAN HANCOCK PACIFIC EXPEDITIONS voL. 13
SALICORNIA SUBTERMINALIS Parish, Erythea 6:87. 1898.
San Clemente, February 18, 19, Elmore 402.
Salt marshes along the coast from San Francisco Bay, California to
Sinaloa, Mexico; occasional in saline soils of the interior valleys; type
from the San Jacinto River, California. On the Channel Islands of San
Miguel, Santa Rosa, Santa Cruz, Santa Catalina, and San Clemente.
Also collected at Avila, Port San Luis, near San Luis Obispo, August 4,
Elmore 402.
SUAEDA CALIFORNICA Wats., Proc. Am. Acad. Sci. 9:89. 1874.
San Clemente Island, February 18, 19, Elmore 403.
Salt marshes from San Francisco, California to northern Baja Cali-
fornia; type from San Francisco Bay. On Santa Cruz, Santa Catalina,
Anacapa, and San Nicolas Islands.
SUAEDA TAXIFOLIA Standl., N. Am. FI. 21:91. 1916.
Santa Barbara Island, August 12, Elmore 302, dry hillsides.
Salt marshes along the coast from Santa Barbara County to Los
Angeles County; type from Playa del Rey.
Some of the collections reported from the islands as S. californica
may rightly belong to this species. It has not previously been listed from
the islands. Elmore’s collection compares favorably with mainland ma-
terial reviewed by the author.
CHENOPODIUM MURALE L., Sp. PI. 219. 1753.
Santa Rosa Island, Becher Bay, August 2, Elmore 178.
A cosmopolitan weed naturalized from Europe. On all of the Chan-
nel Islands.
NYCTAGINACEAE
ABRONIA ALBA Eastw., Proc. Calif. Acad. Sci. III, 1:97. 1898.
San Miguel Island, Tyler Bight, August 2, Elmore 232. Point Ben-
nett, September 12, Elmore 339. San Miguel Island, August 10, Elmore
330a.
Insular. In addition to San Miguel Island it is also known from
San Nicolas, Santa Rosa, and San Clemente Islands.
ABRONIA MARITIMA Nutt. ex Wats., Bot. Calif. 2:4. 1880.
Middle island of Anacapa group, August 1, Elmore 243. San Cle-
mente Island, February 18, 19, Elmore 381. San Miguel Island, Point
Bennett, September 12, Elmore 340.
Sandy sea strands from San Luis Obispo County south to Baja Cali-
fornia and Sinaloa, Mexico; type from San Pedro, California.
No. 2 GENTRY : LAND PLANTS 25
HESPERONIA LAEVIS (Benth.) Standl., C.N.H. 12:363. 1909.
San Clemente Island, February 18, 19, Elmore 415, 328.
Coast ranges and adjacent islands from Monterey County south to
central Baja California; type from Magdalena Bay, Baja California.
AIZOACEAE
MESEMBRYANTHEMUM CHILENSE Molina, Sagg. Chile ed. 2:133.
1810.
San Miguel, Tyler Bight, August 3, Elmore 316.
Coastal, common on bluffs and sandy soils from Oregon to northern
Baja California; type from Chile. Also reported from Australia and
‘Tasmania.
MESEMBRYANTHEMUM NODIFLORUM L., Sp. Pl. 480. 1753.
San Clemente Island, February 18, 19, Elmore 406. Santa Barbara
Island, August 12, Elmore 310.
Native of South Africa and the Mediterranean region; introduced
and now common along the shores of southern California and northern
Baja California. It has been collected on all the Channel Islands except
Santa Cruz. This small mat plant is the least conspicuous and showy of
the adventive Mesembryanthemum.
PORTULACACEAE
MonmTIA PERFOLIATA (Donn.) Howell, Erythea 1:38. 1893.
San Clemente Island, February 18, 19, Elmore 418.
A hydrophytic shade-tolerant herb widely distributed through western
North America north of Mexico.
CARYOPHYLLACEAE
SILENE GALLICA L., Sp. Pl. 417. 1753.
Santa Cruz Island, hill west of Prisoners Harbor, April 17, Elmore
456.
A common weed naturalized from Europe; known on all the Chan-
nel Islands.
SILENE LACINIATA Cav., Ic. Pl. 6:44. 1801.
Santa Rosa Island, Becher Bay, August 2, Elmore 206. Middle island
of Anacapa group, August 1, Elmore 239.
Widely distributed in the mountains of western North America from
central California and western Texas south to southern Mexico; type
from Mexico. In addition to the above cited islands, it is also known on
Santa Cruz and San Miguel Islands.
26 ALLAN HANCOCK PACIFIC EXPEDITIONS voL. 13
SPERGULARIA MACROTHECA (Hornem.) Heynh., Nomen. 2:689.
1840.
Santa Rosa Island, Becher Bay, August 2, Elmore 189.
Saline soils near the coast from Washington to Baja California;
type from California.
PAPAVERACEAE
EsCHSCHOLTZIA CALIFORNICA Cham. var., in Nees Hor. Phys. Ber.
73.1920.
Santa Rosa, Becher Bay, August 2, Elmore 187, on dry hillsides.
The material is not sufficient for certain identification. It may be the
same as the collection annotated by Hoffman (Bull. So. Calif. Acad. Sci.
31:102. 1932) as Eschscholtzia sp. He stated that it is. an annual with
clear yellow flowers on Santa Cruz Island. On the basis of fruit and re-
ceptacle, however, I have no hesitancy in assigning it to the FE. californica
complex, which is so well known for its variability. It differs from £.
californica maritima, the common variety of the islands, in the non-
glaucous and longer-lobed leaves, and the reduced stature.
EsCHSCHOLTZIA CALIFORNICA MARITIMA Jep., Man. FI. Pl. Calif.
402. 1925.
San Miguel Island, August 10, Elmore 329. Tyler Bight, August 3,
Elmore 320. Point Bennett, September 12, Elmore 337.
Endemic to the Channel Islands where it is known from Santa Cruz,
Santa Rosa, and San Miguel, the latter island, according to Hoffman,
having the most widely dispersed population.
PLATYSTEMON CALIFORNICUS Benth., Trans. Hort. Soc. Lond. II,
1:405. 1835.
Santa Cruz Island, hill west of Prisoners Harbor, April 17, Elmore
458.
Widely distributed in western United States; also in northern Baja
California.
CRUCIFERAE
LEPIDIUM LASIOCARPUM Nutt. in Torr. & Gray, N. Am. Fl. 1:115.
1838.
San Clemente Island, February 18, 19, Elmore 401.
Widely distributed in the southwestern United States and northern
Mexico; type from near Santa Barbara, California. It has been collected
on nearly all of the other Channel Islands. ‘The above cited collection
consists of several depauperate specimens, 6-8 cm high, fruiting, and are
the first taken from San Clemente.
NO. 2 GENTRY : LAND PLANTS 27
CAULANTHUS INFLATUS Wats., Proc. Am. Acad. Sci. 17 :364. 1882.
Santa Cruz Island, hill west of Prisoners Harbor, April 17, Elmore
453.
‘The known range of this plant is from the Mojave Desert in Cali-
fornia and Nevada and thence westward to the more arid localities in
the San Joaquin Valley and Monterey County; type from the Mojave
Desert, California. It has never before been reported from the Channel
Islands, and in so far as it is a desert plant, Elmore’s collection from
the maritime habitat is open to question. There was no accompanying
note of locality in the field sheet, as there was in the majority of them,
but it was in with the sheets in the pacquet of plants marked from Santa
Cruz Island.
CRASSULACEAE
DuDLEYA GREENEI Rose, Bull. N. Y. Bot. Gard. 3:17. 1903.
Santa Rosa Island, Becher Bay, August 2, Elmore 180.
Rocks and cliffs near the sea in southern California and on Santa
Cruz, Santa Rosa, and San Miguel Islands.
DUDLEYA FARINOSA (Lindl.) Brit. & Rose, Bull. N. Y. Bot. Gard.
Se27.-1903.
San Miguel Island, Tyler Bight, August 3, Elmore 314, dry hill-
side.
Along the coast of northern and central California. The above cited
collection is the first known record of the species in the Channel Islands.
It agrees well with mainland material.
CROSSOSOMATACEAE
CROSSOSOMA CALIFORNICUM Nutt., Jour. Acad. Phil. IT, 1:150. 1847.
Santa Catalina Island, February 29, Elmore 437.
Southern California, Baja California and adjacent islands; type from
Santa Catalina Island. Also on San Clemente.
ROSACEAE
LYONOTHAMNUS FLORIBUNDUS ASPLENIFOLIUS (Greene) Brge.,
Zoe 1:136. 1890.
Santa Cruz Island, ranch yard in Central Valley, August 2, Elmore
255;
Endemic to the islands, Santa Cruz, Santa Rosa, and San Clemente.
PHOTINIA ARBUTIFOLIA (Ait.) Lindl., Trans. Linn. Soc. 13:
1821.
28 ALLAN HANCOCK PACIFIC EXPEDITIONS VoL. 13
Santa Cruz, Prisoners Harbor Canyon, September 14, Elmore 269.
Santa Rosa Island, Becher Bay, August 2, Elmore 210.
Widely distributed in the Upper Sonoran Zone of California; type
from Monterey, California. Known also from the islands San Miguel,
Santa Catalina, San Nicolas, and San Clemente. Elmore 269 from Santa
Cruz Island has small, subentire, proximate leaves on short diffuse twigs
making a compact crown of foliage indicative of an arid situation.
PHOTINIA ARBUTIFOLIA MACROCARPA Munz, Bull. So. Calif. Acad.
Sci. 31:64. 1932.
San Clemente Island, February 18, 19, Elmore 421.
Known previously only from Santa Catalina Island.
Prunus Lyoni (Eastw.) Sarg., Pl. Wilson. 74. 1911.
Santa Cruz Island, Prisoners Harbor Canyon, September 14, E/more
271, rocky hillside.
Endemic to the islands, Santa Cruz, Santa Rosa, Santa Catalina, and
San Clemente; the type from Santa Catalina.
ROSA GRATISSIMA Greene, FI. Fran. 73. 1891.
Santa Cruz Island, hill west of Prisoners Harbor, April 17, Elmore
447. :
Central Sierra Nevada to southern California; type from the moun-
tains of Kern County. Not previously credited to the Channel Islands,
but the few weak straight spines, the spatulate-tipped sepals, and the
nature of the stipules appear to relate the above-cited collection with the
R. gratissima complex rather than with R. californica.
LEGUMINOSAE
ASTRAGALUS LEUCOPSIS Torr. & Gray, N. Am. Fl. 1:344. 1838.
Middle island of Anacapa group, August 1, Elmore 252, steep rocky
slopes. San Miguel Island, Tyler Bight, August 3, Elmore 319.
Upper and Lower Sonoran Life Zones from Santa Barbara County
south into northern Baja California; type from Santa Barbara, Cali-
fornia. Also reported from Santa Barbara and Santa Catalina Islands.
AsTRAGALUS Nevinut Wats., Proc. Am. Acad. Sci. 21:412. 1886.
San Clemente Island, February 18, 19, Elmore 395.
Known only from the Channel Islands of Santa Catalina, Santa
Barbara, Anacapa, and the type locality, San Clemente.
LoTUS DENDROIDEUS (Greene) Greene, Pittonia 2:148. 1890.
Santa Rosa Island, August 2, E]more 196, dry canyon wall.
Endemic to the Channel Islands of Santa Catalina, Santa Cruz, Santa
Rosa, and Anacapa; type from Santa Cruz.
NO. 2 GENTRY: LAND PLANTS 29
Lotus NIvEus (Greene) Greene, Pittonia 2:148. 1890.
San Clemente Island, February 18, 19, Elmore 409.
Known only from Santa Cruz and San Clemente Islands.
Referred here is Elmore 410, a sterile shrubby perennial 2-4 dm high
with silvery sericeus twigs, spikoid foliage, also densely silvery tomentose,
with 3 ovate-lanceolate leaflets 10-15 mm long.
Lorus oRNITHOPUS Greene, Bull. Calif. Acad. Sci. 1:185. 1885.
San Clemente Island, February 18, 19, Elmore 392.
Southern California, northern Baja California and adjacent islands;
type from Guadelupe Island off Baja California.
LUPINUS SPARSIFLORUS Benth., Pl. Hartw. 303. 1848.
Santa Cruz Island, hill west of Prisoners Harbor, April 17, Elmore
446.
Widely scattered in southern California and in adjacent Baja Cali-
fornia.
TRIFOLIUM MICROCEPHALUM Pursh, Fl. Am. Sept. 2:478. 1814.
Santa Cruz Island, hill west of Prisoners Harbor, April 17, Elmore
441.
Open grassy slopes from British Columbia to Baja California and
east to Nevada; type from Bitter Root River, Montana. On San Miguel,
Santa Rosa, Santa Catalina, and San Clemente Islands.
TRIFOLIUM TRIDENTATUM ACICULARE (Nutt.) McDermott, N. Am.
TP ritol.-26.. 1910.
Santa Cruz Island, rock slide between Pelican Bay and Prisoners
Harbor, April 17, Elmore 465.
Central valley of California, cismontane southern California, and
adjacent islands; type from Santa Barbara. Also on Santa Rosa and San
Clemente Islands.
OXALIDACEAE
OXALIS CERNUA Thunb., Diss. Oxal. 14. 1781.
San Clemente Island, February 18, 19, Elmore 423.
Naturalized from southern Africa and now common in cismontane
southern California; on the Channel Islands it has previously been listed
from Santa Catalina only.
30 ALLAN HANCOCK PACIFIC EXPEDITIONS VoL. 13
EUPHORBIACEAE
EREMOCARPUS SETIGERUS (Hook.) Benth., Bot. Voy. Sulph. 53.
1844.
Santa Cruz Island, Prisoners Harbor Canyon, August 2, Elmore
259, dry river bed.
Common in wasteland and fallow fields from Washington to south-
ern cismontane California. Known also on Santa Rosa, Santa Catalina,
and San Clemente Islands.
ANACARDIACEAE
RHUS INTEGRIFOLIA (Nutt.) Benth. & Hook. ex Wats. in Wheeler,
Rep. U.S. 100th Merid. 6:84. 1878.
Santa Catalina Island, February 29, Elmore 439. San Clemente,
February 18, 19, Elmore 394. Santa Cruz Island, Prisoners Harbor
Canyon, September 14, Elmore 275. Anacapa Island, August 1, Elmore
224.
Maritime southern California and northern Baja California and
adjacent islands from Santa Barbara to Cedros Island; type from San
Diego, California. Known from all the Channel Islands except San
Nicolas.
‘TOXICODENDRON DIVERSILOBIUM (Torr. & Gray) Greene, Leafl.
1:119. 1905.
Santa Cruz Island, Prisoners Harbor Canyon, September 14, Elmore
265, dry rocky hillside.
Common along the Pacific coast below 4000 feet from Washington
through California and south in the mountains of northern Mexico to
Sinaloa. Known also from San Miguel, Santa Rosa, and Santa Catalina
Islands.
MALVACEAE
LAVATERA ASSURGENTIFLORA Kell., Proc. Calif. Acad. Sci. 1:14.
1854.
Santa Catalina Island, Indian Rock in Emerald Cove, February 29,
Elmore 435. Santa Rosa, Becher Bay, August 2, Elmore 191, dry hill-
side.
Native of the Channel Islands, apparently originally lacking only
on San Nicolas, escaped and cultivated on the adjacent mainland.
SIDALCEA MALVAEFLORA (DC.) Gray ex Benth., Pl. Hartw. 300.
1848.
Santa Rosa Island, Becher Bay, August 2, Elmore 181, wall of wet
ravine.
Cismontane southern California to northern California and on the
islands of Santa Rosa, San Miguel, Santa Cruz, and Catalina.
NO. 2 GENTRY: LAND PLANTS 31
FRANKENIACEAE
FRANKENIA GRANDIFOLIA C. & S., Linnaea 1:35. 1826.
Middle island of Anacapa group, August 1, Elmore 250.
Along the coast from central California south to northern Baja Cali-
fornia and on the adjacent islands of Anacapa, San Miguel, Santa Rosa,
Santa Cruz, and Santa Catalina.
CACTACEAE
OPUNTIA LITTORALIS (Engelm.) Cockr., Bull. So. Calif. Acad. Sci.
4:15. 1905.
San Clemente Island, February 18, 19, Elmore 382. Santa Cruz,
Prisoners Harbor Canyon, September 14, Elmore 279, rocky hillside.
Middle island of Anacapa group, August 1, Elmore 245, steep rocky
slope.
Along the coast from Santa Barbara to northern Baja California
and on the adjacent islands; the exact type locality is not known. East-
wood (1941:67) also reports it from Santa Barbara, San Nicolas, and
Santa Rosa Islands.
The above series of specimens, particularly Elmore 382 from San
Clemente, are atypical of the mainland plants in the more orbicular pads
(rather than ovate) and in the straightness of their spines.
ONAGRACEAE
OENOTHERA CHIERANTHIFOLIA Hornem. ex Spreng. Syst. 2.228
San Miguel Island, August 10, Elmore 331. Tyler Bight, August 3,
Elmore 313. Point Bennett, September 12, Elmore 335. Santa Rosa
Island, Becher Bay, August 2, Elmore 209, sandy hill slope.
Sea beaches from Oregon to southern California and adjacent islands.
Not listed from San Clemente and Anacapa, but apparently common on
all the others.
ZAUSCHNERIA CALIFORNICA VILLOSA Jeps., Man. FI. Pl. Calif. 667.
1925.
Santa Rosa Island, Becher Bay, August 2, Elmore 183, dry hillside.
Stated by Jepson to be in southern California. It is known from the
islands of Santa Cruz, San Clemente, and Santa Catalina, and may
originally have been an island endemic.
UMBELLIFERAE
FoENICULUM VULGARE (L.) Gaertn., Fr. Sem. 1:105. 1788.
Santa Cruz Island, Prisoners Harbor Canyon, August 2, Elmore
254, dry river bed.
A naturalized weed from Europe and now widely dispersed in west-
ern North America and in South America. It is also listed from Santa
Rosa and Santa Catalina Islands.
32 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL.13
SANICULA ARGUTA Greene ex Coult. & Rose, C.N.H. 7:36. 1900.
Santa Cruz Island, hill west of Prisoners Harbor, April 17, Elmore
462.
Southern California and the adjacent islands of San Nicolas, Santa
Catalina, San Clemente, and Santa Cruz.
PRIMULACEAE
ANAGALLIS ARVENSIS L., Sp. Pl. 148. 1753.
Santa Rosa Island, Becher Bay, August 2, Elmore 208, grassy hill-
side.
Weed naturalized from Europe and widely scattered in western
North America. Known on the Channel Islands of San Miguel, Santa
Cruz, Santa Catalina, and Santa Rosa.
GENTIANACEAE
CENTAURIUM VENUSTUM (Gray) Robs., Proc. Am. Acad. Sci. 45:
397. 1910.
Santa Rosa Island, Becher Bay, August 2, Elmore 204, grassy hill-
slope.
From northern Baja California to Butte County, California where
it is common along the coast and rarely in the desert. Known also from
Santa Cruz and Santa Catalina Islands. Elmore’s collection appears to
be the first from Santa Rosa Island.
CONVOLVULACEAE
CONVOLVULUS OCCIDENTALIS CYCLOSTEGIUS (House) Jeps., Man.
FL &P)-Calit.' 776. 1925:
Santa Barbara Island, August 12, Elmore 313, climbing on shrubs
in dry canyon. San Clemente Island, February 18, 19, Elmore 396.
Santa Cruz Island, Prisoners Harbor, August 2, Elmore 282.
Coastal from San Francisco Bay to southern California. Its insular
distribution has previously been reported only on Santa Catalina Island.
POLEMONIACEAE |
GILIA AFF. MULTICAULIS Benth., Bot. Reg. 19: t. 1622. 1833.
Santa Cruz Island, hill west of Prisoners Harbor, April 17, Elmore
440)
Common in cismontane southern California and reported also from
Catalina.
BORAGINACEAE
AMSINCKIA INTERMEDIA Fisch. & Mey., Ind. Sem. Hort. Petrop.
2:26. 1836.
Santa Rosa Island, Becher Bay, August 2, Elmore 212, dry hillside.
Widely scattered in California, northern Baja California, Arizona,
and on the Channel Islands.
NO. 2 GENTRY: LAND PLANTS 33
CRYPTANTHA CLEVELAND! Greene, Pittonia 1:117. 1887.
San Miguel Island, Tyler Bight, August 3, Elmore 312.
Maritime, from northern Baja California to Santa Barbara, Cali-
fornia and the Channel Islands of Santa Catalina, Santa Cruz, and San
Miguel; type from the hills above San Diego, California.
HELIOTROPIUM CURASSAVICUM L., Sp. PI. 130. 1753.
Middle island of Anacapa group, August 1, Elmore 222, steep rocky
slope. Santa Cruz Island, Prisoners Harbor Canyon, September 14, E/-
more 277, rocky edge of salty pool. San Miguel Island, August 10, El-
more 328.
Widely dispersed in saline lowland soils of tropical and subtropical
America.
PECTOCARYA LINEARIS FEROCULA Jtn., Contr. Arn. Arb. 3:95. 1932.
Santa Cruz Island, hills west of Prisoners Harbor, April 17, Elmore
463.
Cismontane southern California from Ventura south into Baja Cali-
fornia and the adjacent islands.
VERBENACEAE
VERBENA ROBUSTA Greene, Pittonia 3 :309. 1898.
Santa Cruz Island, Prisoners Harbor, September 14, Elmore 291,
along edge of swamp.
San Diego County and the Channel Islands of San Miguel, Santa
Rosa, Santa Cruz, Santa Catalina, and San Clemente. Apparently origi-
nated on Catalinia and migrated to the mainland.
LABIATAE
MARRUBIUM VULGARE L., Sp. Pl. 583. 1753.
San Clemente Island, February 18, 19, Elmore 417.
Weed naturalized from Europe, widely scattered across North
America and on all the Channel Islands except San Nicolas and Anacapa.
SALVIA BRANDEGEI Munz, Bull. So. Calif. Acad. Sci. 31:69. 1932.
Santa Rosa Island, Becher Bay, August 2, Elmore 194, dry canyon
wall.
Endemic to Santa Rosa Island.
SOLANACEAE
LycIuM CALIFORNICUM Nutt. in Gray, Bot. Calif. 1:542. 1876.
Santa Barbara Island, February 12, Elmore 295, forming thickets
in dry fields. San Clemente Island, February 18, 19, Elmore 397.
34 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 13
Cismontane southern California and south along the coast to central
Baja California, type from San Diego. In addition to the above listed
Channel Islands it is also reported from Santa Catalina. Dunkle (1944)
reports it as characteristic of the grassland on Santa Barbara Island,
where it forms a biome with Suwaeda and the gull Larus.
PETUNIA PARVIFLORA Juss., Ann. Mus. Paris 2:216, t. 47. 1803.
Santa Rosa Island, Becher Bay, August 2, Elmore 170, sandy hills.
Widely distributed in the moist sandy soils of southern United States
and tropical America. On the Channel Islands it is known only from
Santa Rosa.
SOLANUM CLOKEYI Munz, Bull. So. Calif. Acad. Sci. 31:69. 1932.
Santa Cruz Island, rock slide between Pelican Bay and Prisoners
Harbor, April 17, Elmore 467.
Endemic to Santa Cruz Island.
SoLANUM Douctasu Dunal, in DC., Prodr. 13, 1:48. 1852.
Santa Catalina Island, February 28, Elmore 438.
Cismontane southern California and the Channel Islands of San
Miguel, Santa Rosa, Santa Cruz, Santa Catalina, and San Clemente.
SOLANUM VILLOSUM (L.) Mill., Gard. Dict. ed. 8, n. 2.
Santa Rosa Island, Becher Bay, August 2, Elmore 200, dry canyon
walls. San Clemente Island, February 18, 19, Elmore 420.
A European weed adventive in southern California. Not previously
reported from the Channel Islands.
SCROPH ULARIACEAE
CASTILLEJA ANACAPENSIS M. B. Dunkle, Bull. So. Calif. Acad.
Sci. 41 :135. 1942.
Middle island of Anacapa group, August 1, Elmore 230, steep rocky
slope.
Endemic to Anacapa Island.
CASTILLEJA HOLOLEUCA Greene, Pittonia 1:38. 1887.
Middle island of Anacapa group, August 1, Elmore 226, steep rocky
slope.
Endemic to the islands of San Miguel, Santa Rosa, Santa Cruz, and
Anacapa.
NO. 2 GENTRY : LAND PLANTS 35
CASTILLEJA LATIFOLIA Hook. & Arn., Bot. Beech. Voy. 154. 1839-
40.
Santa Rosa Island, Becher Bay, August 2, Elmore 172, 174, sandy
hills.
From Monterey County to northern California and on the islands of
Santa Rosa and Santa Cruz. The flowers are reported as being normally
red, but No. 174 was noted by the collector as having yellow flowers.
CASTILLEJA MOLLIS Penn., Proc. Acad. Nat. Sci. Phil. 99 :185. 1947.
San Miguel Island, August 10, Elmore 333. Point Bennett, Septem-
ber 12, Elmore 341.
CASTILLEJA SP.
San Clemente Island, February 18, 19, Elmore 384, 411.
The material is too young for certain determination. It is a low
shrubby or suffrutescent plant with sordid pubescence, linear attenuate
bracts and leaves, both of which are irregularly lobed.
DIPLACUS LONGIFLORUS Nutt. in Taylor’s Ann. Nat. Hist. 1, 1:139.
1838.
Santa Cruz Island, Prisoners Harbor, August 2, Elmore 261, rocky
hillside.
Common on the cismontane and chaparral slopes of southern Cali-
fornia and on Santa Rosa, Santa Cruz, and Catalina Islands. Also in
northern Baja California.
DIPLACUS PARVIFLORUS Greene, Pittonia, 1:36. 1887.
Santa Rosa Island, Becher Bay, August 2, Elmore 185, dry hillside.
Santa Cruz Island, rock slide between Pelican Bay and Prisoners Har-
bor, April 17, Elmore 464.
Apparently limited to Santa Cruz and Santa Rosa Islands.
MIMULUS GUTTATUS DEPAUPERATUS (Gray) Grant, Ann. Mo.
Bot. Gard. 11:170. 1924.
Santa Cruz Island, Prisoners Harbor Canyon, August 2, Elmore 257,
dry stream bed.
Widely dispersed in the western United States. This variety has not
previously been reported from the islands and the fragmentary material
is doubtfully referred here.
36 ALLAN HANCOCK PACIFIC EXPEDITIONS voL. 13
LINARIA CANADENSIS TEXANA (Scheele) Penn., Proc. Acad. Phil.
7a2502.° 1922.
Santa Cruz Island, hill west of Prisoners Harbor, April 17, Elmore
461.
Widely distributed in both North and South America. On the Chan-
nel Islands it is known from San Miguel, Santa Rosa, Santa Catalina,
and Santa Cruz.
ORTHOCARPUS PURPURASCENS Benth., Scroph. Ind. Introd. 13.
1835.
Santa Cruz Island, hill west of Prisoners Harbor, April 17, Elmore
459, 460.
Common along the coast from central California to northern Baja
California and the adjacent islands of San Nicolas, San Miguel, Santa
Rosa, Santa Cruz, and Santa Catalina.
CUCURBITACEAE
MarRAH FABACEA (Naud.) Greene, Pittonia 2:129. 1890.
San Clemente Island, February 18, 19, Elmore 422, 386.
The Channel Islands and mainland from Monterey north to Sonoma
County, California.
CoMPOSITAE
ACHILLEA MILLEFOLIUM LANULOSA (Nutt.) Piper, Mazama 2:97.
1901.
Santa Barbara Island, August 12, Elmore 308, dry hillside.
From the mountains to the coast in southern California and northern
Baja California and on all the Channel Islands.
ARTEMESIA CALIFORNICA Less., Linnaea 6:523. 1831.
Middle island of Anacapa group, August 1, Elmore 228, steep rocky
slope.
Common and widespread on slopes and mesas of the Upper Sonoran
from central California to northern Baja California and the adjacent
islands. It is one of the strongly successful elements in and about chapar-
ral. With a stable population it is quickly adventive on new habitats, and
was doubtless migratory on the Tertiary land bridges.
BaccHaris Douctasi DC., Prodr. 5:400. 1836.
Santa Cruz Island, Prisoners Harbor Canyon, September 14, Elmore
281, dry stream bed.
NO. 2 GENTRY: LAND PLANTS ov
Mostly coastal from San Francisco south to northern Baja Cali-
fornia and the adjacent islands of Santa Rosa, Santa Cruz, and Santa
Catalina. It is tolerant of new immature soils and apparently has a
strong potential as a migrant in new areas of Mediterranean climate
type.
BACCHARIS PILULARIS CONSANGUINEA (DC.) O. Kuntze, Rev.
Gen. Pl. 13319. 1891.
Prisoners Harbor Canyon, Santa Cruz Island, September 14, Elmore
285, dry rocky hillside.
Coastal from Oregon to southern California and the adjacent islands
of Santa Rosa, Santa Cruz, and Catalina.
BACCHARIS PLUMMERAE Gray, Proc. Am. Acad. Sci. 15:48. 1880.
Prisoners Harbor Canyon, September 14, Elmore 287, dry rocky
hillside.
Santa Cruz Island and the adjacent mainland.
BAERIA CHRYSOSTOMA GRACILIS Hall, U. C. Publ. Bot. 3:170. 1907.
Hill west of Prisoners Harbor, Santa Cruz Island, April 17, Elmore
468. San Clemente Island, February 18, 19, Elmore 400.
Common on Pacific slopes from Oregon south to northern Baja Cali-
fornia and listed (by Eastwood 1941:75 under Baeria Palmeri clemen-
tina) from San Nicolas, San Miguel, Santa Rosa, Santa Cruz, and San
Clemente Islands. A quick annual in a genus developmentally responsive
to the semi-arid climates of both maritime and continental types.
CoREOPSIS GIGANTEA (Kell.) Hall, U. C. Publ. Bot. 3:142. 1907.
Santa Barbara Island, August 21, Elmore 297, dry canyon walls and
rocky hillside. Catalina Island, February 28, Elmore 436.
Coastal bluffs from San Luis Obispo County south to the Santa
Monica Mountains and on all the Channel Islands. Apparently evolved
on Catalinia and recently migratory to the mainland.
CORETHROGYNE FILAGINIFOLIA ROBUSTA Greene, Pittonia 1:89.
1887.
Middle island of Anacapa group, August 1, Elmore 220, steep rocky
slope.
The variety is endemic to the islands San Miguel, Santa Rosa, Santa
Cruz; not previously known from Anacapa.
38 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 13
ENCELIA CALIFORNICA Nutt., Trans. Am. Phil. Soc. II, 7:357. 1841.
San Clemente Island, February 18, 19, Elmore 393.
Common on the semi-arid coastal slopes from Santa Barbara, Cali-
fornia south into northern Baja California and on the adjacent islands
of Santa Cruz, Santa Catalina, and San Clemente. An adaptive species
of maritime climate which has responsively evolved into varietal popu-
lations.
ERIGERON FOLIOSUS Nutt., Trans. Am. Phil. Soc. II, 7:309. 1841.
Becher Bay, Santa Rosa Island, August 2, Elmore 177, dry hillside.
Mainly coastal from Humboldt County, California south into south-
ern California. The typical form of the species has not been reported
from the islands. However, the variety, stenophyllus (Nutt.) Gray, is
reported by Eastwood (Leafl. W. Bot. 3:74. 1941) for San Miguel,
Santa Rosa, and Santa Cruz Islands. Elmore’s collections lack the fili-
form leaves of the variety, being up to 5 mm wide.
ERIGERON GLAUCUS Ker., Bot. Reg. 1: pl. 10. 1815.
Point Bennett, San Miguel Island, September 12, Elmore 336. Tyler
Bight, San Miguel Island, August 3, Elmore 315, dry sandy hill slope.
San Miguel Island, August 10, Elmore 332.
Common along the shores from Oregon south to Monterey County
and on the Channel Islands of San Miguel, Santa Rosa, and Santa Cruz.
ERIOPHYLLUM NEVINI Gray, Syn. FI. I, 2:452. 1886.
Santa Barbara Island, August 12, Elmore 300, dry hillside.
Apparently endemic to the islands Santa Catalina, San Clemente,
and Santa Barbara; not previously reported from the latter.
GNAPHALIUM BENEOLENS Davidson, Bull. So. Calif. Acad. Sci.
yA 4908: ;
Becher Bay, Santa Rosa Island, August 2, Elmore 215, dry hillside.
Southern California east to ‘Texas and northern Mexico.
GNAPHALIUM BICOLOR Bioletti, Erythea 1:16. 1893.
San Clemente Island, February 18, 19, Elmore 407.
Coastal and inland valleys from Monterey and Tulare Counties
south to Baja California and on the adjacent islands of Santa Rosa,
Santa Catalina, and Santa Cruz; not previously reported from San
Clemente.
NO. 2 GENTRY: LAND PLANTS 39
GNAPHALIUM PALUSTRE Nutt., Trans. Am. Phil. Soc. II, 7:403.
1841.
Hill west of Prisoners Harbor, Santa Cruz Island, April 17, F-
more 443.
Widely distributed in western North America from British Co-
lumbia to Mexico; on the islands Santa Cruz, Santa Catalina, and San
Clemente.
HAPLOPAPPUS VENETUS VERNONIOIDES (Nutt.) Munz, Man. So.
Calif. Bot: 522; 601.- 1935.
Middle island of Anacapa group, August 1, Elmore 246, steep rocky
slope.
Common on dry slopes at low elevations from San Francisco south
into Baja California and on all the adjacent islands. |
HEMIZONIA CLEMENTINA Brge., Erythea 7:70. 1899.
Santa Barbara Island, August 12, Elmore 299, dry hillside. San
Clemente Island, February 18, 19, Elmore 408.
Endemic to the islands Santa Catalina, San Clemente, Santa Bar-
bara, and Anacapa.
A perennial herb with dimorphic inflorescence; the early flowers in
larger heads on simple leafy peduncles, the later in diffuse corymbose
panicles. Elmore’s collection from San Clemente is in the early flower-
ing stage and differs from typical material also in the long villous
pubescence of branches and foliage. It may be in need of varietal or
possibly even specific segregation.
HEMIZONIA FASCICULATA (DC.) Torr. & Gray, N. Am. FI. 2:397.
1841-43.
Becher Bay, Santa Rosa Island, August 2, Elmore 175, dry hillside.
Common from southern California south through Baja California
to Cedros Island; also on San Miguel, Santa Rosa, Santa Catalina, and
San Clemente Islands. It is tolerant of immature soils and apparently is
aggressive on local wastelands.
LayYIA PLATYGLOSSA (F. & M.) Gray, Pl. Fendl. 103. 1849.
Becher Bay, Santa Rosa Island, August 2, Elmore 202, dry hillside.
Hill west of Prisoners Harbor, April 17, Elmore 442.
Widely scattered in southern California and on San Miguel, Santa
Rosa, Santa Cruz, and Santa Catalina Islands.
40 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL.. 13
MALACOTHRIX CLEVELANDII Gray, Bot. Calif. 1:433. 1876.
Santa Barbara Island, August 12, Elmore 370.
Aggressive on disturbed areas in cismontane southern California and
on the islands Anacapa, Santa Cruz, and on the above new extension of
range, Santa Barbara Island. Apparently migratory on the mainland.
MALACOTHRIX FOLIOSA Gray, N. Am. FI. ed. 2, 1, pt. 2, suppl. :455.
1886.
Point Bennett, San Miguel Island, September 12, Elmore 338.
On the islands Santa Cruz, San Clemente, Santa Barbara, and the
above extension of range, San Miguel.
MALACOTHRIX INCANA (Nutt.) Torr. & Gray, N. Am. FI. 2:486.
1841-43.
Tyler Bight, San Miguel Island, August 3, Elmore 322. San Miguel
Island, August 10, Elmore 327.
Channel Islands of Santa Rosa, Santa Cruz, San Miguel, and the
adjacent coast.
MALACOTHRIX SAXATILIS IMPLICATA (Eastw.) Hall, U. C. Publ.
Bot. 3:269./ 1907.
Middle island of Anacapa group, August 1, Elmore 248, steep rocky
slope.
Channel Islands of San Miguel, Santa Rosa, Santa Cruz, San Ni-
colas, and Anacapa.
The evolution of the genus Malacothrix, judging from the numerous
segregates of varying rank that are known from the islands, has ap-
parently been highly responsive to the stimulation of successive disjunc-
tions and conjunctions of populations as induced by physiographic evo-
lution.
PEREZIA MICROCEPHALA (DC.) Gray, Pl. Wright. 1:127. 1852.
Prisoners Harbor Canyon, Santa Cruz Island, August 2, Elmore
263, dry rocky hillside.
Open arid slopes of the chaparral belt from San Luis Obispo County
south to Baja California and the adjacent islands of Catalina, Santa
Rosa, and Santa Cruz. The limited island distribution of this strongly
successful perennial of the mainland, indicates at least recent appearance
on the islands.
NO. 2 GENTRY: LAND PLANTS 41
PerITYLE Emory Torr. in Emory, Rep. N. Mex. Bound. Sur. 142.
1848.
San Clemente Island, February 18, 19, Elmore 414, 385.
Widespread from southern California to Arizona south in Mexico
to southern Sonora and throughout Baja California; also on Santa Cata-
lina, Santa Rosa, Santa Cruz, San Clemente, and Cedros Islands. It
is an aggressive winter annual with white rays in the arid maritime
climates.
SeNEcIO Lyonu Gray, Syn. Fl. I, 2:456. 1886.
San Clemente Island, February 18, 19, Elmore 404, 399.
On the Channel Islands of San Clemente, Santa Barbara, Santa
Cruz, and in Baja California. j
SILtyBuUM Marianum (L.) Gaertn., Fruct. 2:378. 1791.
Santa Cruz Island, August 2, Elmore 264.
Common weed in California naturalized from Europe; also on Santa
Catalina Island.
SONCHUS OLERACEUS L., Sp. PI. 794. 1753.
Santa Barbara Island, August 12, Elmore 304, dry hillside.
Common weed in wasteland, naturalized from Europe; widespread
on the islands and probably on all of them.
4? ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 13
LITERATURE CITED
DUNKLE, M. B.
1944. Investigations of the plant ecology of the Channel Islands. Ph.D. thesis,
264 pp. Univ. of So. Calif.
Eastwoop, ALICE
1941. The islands of Southern California and a list of the recorded plants.
Leaflet West. Bot. 3:27-35, 54-78.
FRASER, C. MCLEAN
1943a. General account of the scientific work of the Velero III in the Eastern
Pacific, 1931-41, Part I. Historical introduction, Velero III, Personnel.
Allan Hancock Pacific Exped., 1(1) :1-48, pls. 1-16.
1943b. General account .. Part II. Geographical and biological associations.
Ibid., 1(2) :49-258, pls. 17-128.
1943c. General account .. Part III. A ten-year list of the Velero III collecting
stations. Ibid., 1(3) :259-432, charts 1-115.
HoFFMAN, RALPH
1932. Notes on the flora of the Channel Islands off Santa Barbara. Bull. So.
Calif. Acad. Sci. 31:46-60, 101-120.
? Flora of San Miguel Island. Typed list of plants in Santa Barbara
Museum of National History; ca. 150 species and varieties.
MILLSPAUGH, C. F. AND THOMAS NUTTALL
1923. Flora of Santa Catalina Island. Field Mus. Pub. Bot. 5:1-413, pls. 1-14,
map.
Muwnz, Puiuip A.
1935. Manual of Southern California botany. Published by Claremont College,
642 pp.
REED, RALPH D.
1933. Geology of California. Published by Am. Assoc. Pet. Geol., Tulsa,
Okla. 355 pp. (State Minerologist, Ferry Bldg., San Francisco, Calif.)
NO. 2 GENTRY: LAND PLANTS 43
CEDROS AND SAN BENITO ISLANDS
Cedros Island is a partially submerged mountain that stands about
midway along the coast of Baja California across the broad Vizcaino
Bay. North to south it is about 38 kilometers long, averages about 8
kilometers wide, and contains about 300 square kilometers of rugged
land. It has several peaks, the highest of which is about 1200 meters
above the level of the Pacific Ocean. Dissected by numerous canyons,
some of which dip steeply to the sea, it contains several physiographic
habitats; peak, ridge, hill slope, mesa, canyon, cliff, and brief narrow
beaches. Alluvial slopes and valleys are notably minor. Salty and other-
wise highly mineralized and unpalatable water is reported to stand in
the lower reaches of the canyons. Near the south end of the island,
about 3 miles from what was formerly known as Bernstein’s abalone
camp and at about 600 to 900 meters elevation, is a good fresh water
spring. Fishing has recently been developed by the construction of a
large cannery in the locality and a village has grown up around it.
The island is composed mostly of sedimentary rocks. ‘The south end
shows fossiliferous marine sediments of Cretaceous shales, Miocene
shales and sandstones, and Pliocene sands and conglomerate. Near the
middle of the east side of the island, “Grand Canyon” cuts back deeply.
G. Dallas Hanna, paleontologist on the California Academy of Science’s
expedition to the Eastern Pacific islands in 1922 and 1923, wrote in
reference to the middle section, as follows (1926:88): “It was found
that a fault line crosses the island following approximately the course
of the canyon. To the south only, Jurassic cherts, supposedly Franciscan
in age, were found. To the north there is a block of Cretaceous shales,
200 or more feet thick, with a generally westward dip of about 30°.
—Our studies convinced us that Cedros Island is a zone of intense
block faulting and disturbance. At the present time, except for a com-
paratively recent post-Pleistocene uplift of little significance, the island
is in a period of depression. In other words, at no very distant period
geologically, the island was a part of a much higher land mass.” He
found igneous rocks only at the two extremities of the island. “At the
southwestern corner of the island there has been some volcanism and at
the north end the land is greatly disturbed with intrusions of serpentine”
(1925 :268).
Since the axis of Cedros Island is aligned with that of Sierra Viz-
caino to the south on the western edge of the peninsula, and because
soundings show the intervening channel to be only 9 to 12 meters in
44 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 13
depth, it appears that the two land masses were continuous at times in
the geologic past. If this is true, the floras of the two mountains should
show much in common and a comparison would contribute evidence for
the historical problem. Unfortunately, the flora of Sierra Vizcaino is
quite unknown, except by what may be inferred from neighboring locali-
ties of collections, the nearest being northwest of the mountains on San
Bartolome Bay, or, as it is now commonly known, Tortuga Bay. Three
collecting parties have visited this locality: Hinds on H.M.S. Sulphur
in 1839, Pond on the U.S. ship Ranger in 1889, and Brandegee on the
Wahlberg in 1897. The latter on his spring visit found, “the region was
perfectly dry and seemed not to have been rained upon for years. A few
plants were recognized that were before known only from Cedros Island,
and made it evident that an accurate knowledge of the distribution of
neighboring island forms cannot be obtained without a more thorough
examination of the adjacent mainland.” The isolated position of Sierra
Vizcaino, sitting out by itself across a broad low desert plain about 60
miles wide, indicates that it too was for indeterminant periods in the past
an insular body and that like Cedros it may possess its own relic biotic
elements.
There are no meteorological data for Cedros Island nor for the
adjacent peninsula. Rainfall is probably under 8 inches annually on the
average for the lower slopes and most of the island area, something over
that for the highlands. The rainfall incidence is irregular, judging from
oral accounts of peninsular natives, and years may pass without effective
precipitation. There is apparently only one source of rainfall and that
is in the cyclonic winter storms of the northern latitudes which occasion-
ally extend to Cedros. According to the natives, the convectional sum-
mer storms rarely reach Cedros Island. The moist westerlies are reported
by the inhabitants of the adjacent peninsula to be the dominant and
persistent winds. A fog desert similar to that found along the western
border of the peninsula may exist over some of the island. Visitors re-
port that fog drips from the trees in the higher elevations to such an
extent that it causes little rivulets of water and that these have been
mistaken for springs.
Few botanists appear to have visited the western margin of Cedros
and very little has been published regarding its plant life. According to
accounts left us by visitors, most of the island is covered with a dis-
persed formation of Desert Shrub. Suffrutescents in Eriogonum, Fran-
NO. 2 GENTRY : LAND PLANTS 45
seria, Atriplex, Viguiera, and Encelia are common. Succulents are repre-
sented in Agave and cacti and semi-succulents by such shrub and tree
forms as Euphorbia misera and Pachycormus discolor. ‘The sclerophyl-
lous shrubs of Rhus and Simmondsia appear to be prevalent and Greene
mentions (1888:197) two evergreen shrubs, Gilia Veatchii and Harfor-
dia fruticosa, “which grow on these lower hills in sufficient quantities to
impart an appearance of verdure.” Io Greene the most conspicuous tree
was the corpulent xerophyte, Pachycormus discolor, endemic to Baja
California and adjacent islands. A scrubby juniper, Juniperus cerrost-
anus, he reported as growing throughout all elevations. ‘Towards the
summits of the mountains, Pinus muricata cedrosensis is accompanied by
Arctostaphylos bicolor.
George O. Hale and Lee Haines, as two students of botany at the
University of California at Los Angeles, spent six weeks in the early
spring of 1939 on the island and made an ecologic study of the vegeta-
tion. Hale (1941) reported about 97% of the island is covered through
all elevations with Desert Shrub. It has a uniform growth as a regularly
dispersed open formation of low bushy shrubs spotted with large shrubs
or dwarf tree forms; among the latter, that of Pachycormus discolor
being the most ubiquitous. He found differences in composition between
the higher elevations and the lower elevations, and divided the Desert
Shrub accordingly into ‘‘High Altitude Desert” (650 to 1300 meters
elevation) and “Low Altitude Desert” (below 650 meters elevation).
As dominants of the former he listed Eriogonum fasciculatum, Pachy-
cormus discolor, Haplopappus propinguus, and Franseria camphorata
leptophylla and for the latter he listed as most abundant Harfordia
fruticosa, Euphorbia misera, Pachycormus discolor, Franseria chenopodt-
folia, and Encelia californica asperifolia.
The only other low altitude assocation he reported is “Maritime
Dune Scrub,” occupying a small dune area on the southwest coast.
Dominated by Atriplex julacea and Frankenia Palmeri, it is also charac-
terized by Brodiaea, Abronia, Achyronchia Cooperi, Oenothera, and Ly-
cium Andersoni.
The highland vegetation, other than High Altitude Desert Shrub,
occupies limited areas at middle and high elevations.
A Closed Cone Pine Forest (250 to 900 meters elev.) occurs in
two widely separated areas on western and northern slopes, in the
central and northern parts of the island. The pines usually occur in
pure stands and have an average mature stature of about 50 feet. Hale
46 ALLAN HANCOCK PACIFIC EXPEDITIONS VoL. 13
concluded that they are coincident with the elevations and tracks of
regular fog ingressions.
A local Chaparral, dominated by Arctostaphylos, Adenostema, Quer-
cus, Eriogonum, and Juniperus, occurs on the northern slopes of the
highest peaks, above the pine forest. This is a most interesting ecologic
find with considerable historical significance. Small patches of Coastal
Sagebrush and Juniper Woodland border the pine stands irregularly.
These formations show little or no natural transitional grading, but
are sharply one or the other. Where the pine forest begins, the desert
shrub leaves off. Chaparral occupies higher elevations than the pines and
both formations appear largely dependent upon the upsurging fogs from
the westward, especially the latter. IThese are aspects peculiar to the
island, and while the vegetations show climatic qualities, they are inter-
esting instances of what climate and soil types have generated out of the
limited plant materials available.
The flora of the island is now known to consist of about 182 species
of vascular plants and has recently been annotated by Eastwood (1929)
and Howell (1942). Around 600 numbers have been taken by 14 col-
lectors, but little collecting has been done in summer, only one small
one made in winter (Pond, 15 numbers), and none at all during the
fall (Table 2). Considering this, the fact that little or no collecting
has yet been done on the western side, the areal nature of the island,
and the irregular rainfall, I would estimate that some, perhaps 10%,
of the island flora is still unreported. In addition to the unknowns, more
material of many of the known plants, and more field work are needed
for a thorough evaluation of the Cedros flora.
The plant collections of the Allan Hancock Expeditions to Cedros
Island were made in 1937 by P. J. Rempel and in 1939 by Francis H.
Elmore. They are enumerated below together with Rempel’s collection
from the neighboring San Benito Islands. Their collections add three
genera and four species to the Cedros Island flora: Aristida adscensionis,
Eschscholtzia minutiflora, Fagonia laevis, and Euphorbia bartolomaet.
NO. 2 GENTRY: LAND PLANTS 47
TABLE 2
Cedros Island San Benito Islands
Year Collector Cae S Sori S
pring ummer pring ummer
1859 Veatch 28
1876 Streets 11 10?
1882 Belding 10
1885 Greene 82
1889 Pond 15 24
1889 E. Palmer 87 18
1897 T. S. Brandegee 100? 50?
1905 Stewart ff
1911 J.N. Rose 97 44
1922 Hanna Z
1925 Mason 63
1932 Howell 41
1937 Rempel 19 15
1939 Elmore 38
1939 Hale and Haines 150
Table 2. Plant collectors and collections on Cedros and San Benito Islands.
Estimated numbers are followed by a question mark.
The San Benito Islands consist of three small islands, East,
Middle and West, lying about 24 kilometers from the north end of Cedros
Island. Although they rest upon the continental shelf, they are separated
from Cedros Island by a channel 180 to 190 fathoms deep. This is more
than enough to prevent junction during low eustatic sea levels of the
Glacial Periods. Whether they were ever land-bridged to Cedros or the
peninsula is not presently known. The highest elevation of 200 meters
(661 feet) is attained on West Island, the largest of the three. Fraser
(1943 :65) speaks of them as “‘all rocky and barren,” but Greene (1889:
261), the first chronicler of the islands, described them in glowing terms.
“Lieutenant Pond judges the San Benito Islands to be of much older
formation than the large island of Cedros near by. The surface is not
sharply rocky ; the slopes are not abrupt; there is good depth of soil almost
everywhere, and vegetation is abundant, the whole group presenting, on
near approach, a picture of freshness and verdure at the showery season
of the year, the months from December to February, during which
several visits were made (by Pond). At this time sweet flowing water
was found in most of the canyons and ravines; a condition not likely to
obtain during the dry summer season.” Such opposing impressions in
addition to the personal factor of prejudice appear to be conditioned by
the lack or presence of seasonal rains.
48 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL.-13
Before Pond’s collection of 1889, Streets had collected, among other
plants the endemics Lavatera venosa, and Hemizonia Streetsit. Follow-
ing Pond the next important collection is that of the remarkable pereg-
rinating botanist, Edward Palmer, who visited the San Benitos in March
of the same year that Pond did. His collections were reported by J. N.
Rose (1890:20-21). No additions to Greene’s first published list of 25
species were made, however, until Brandegee visited the San Benito
Islands on the voyage of the Wahlberg in 1897 and published (1900:
22-23) a small supplementary list, bringing the known flora of the San
Benitos to 40 species. Rose and Rempel appear to complete the roster
of collectors on San Benito Islands (‘Table 2).
Except for the five plants which still appear to be endemic to the
San Benito Islands, the flora is almost completely repeated on Cedros
Island, the exceptions being common wide-spread species, as Lepidium
lasiocarpum, which may have been passed by collectors on Cedros. Be-
cause of the striking lack of the genera Astragalus and Eriogonum in
the San Benito flora, Greene saw a straight relationship between the
San Benito flora and that of Guadalupe Island 150 miles westward,
and not at all between San Benito and Cedros. The absence of these
genera, so conspicuous on the peninsula and on Cedros Island, is, of
course, interesting, and the explanation of it could easily lead one into
many conjectures. However, because so many Cedros genera and species
are represented on the San Benito Islands and so few of the Guadalupe
Island species are, Greene’s statement now appears rather meaningless.
The position and character of the San Benito flora, however, does re-
main in part anomalous.
The collection of 15 numbers by P. J. Rempel from the San Benito
Islands during July on the 1937 voyage of the Velero III, is apparently
the first to be made in summer. Although no novelties are added, the
collection provides fruiting and flowering records and one addition,
Mesembryanthemum nodiflorum, as annotated below in the catalogue
of species.
NO. 2 GENTRY: LAND PLANTS 49
CATALOGUE OF COLLECTIONS
GNETACEAE
EPHEDRA ASPERA Engelm. ex Wats., Proc. Am. Acad. Sci. 18:157.
1883.
Ephedra peninsularis Jtn., U. C. Publ. Bot. 7:437. 1922.
East side of Cedros Island, July 10, 1937, Rempel 340, alluvial fan.
Widely distributed in the southwestern United States and northern
Mexico; type apparently from Frontera, Texas. Rempel’s collection is
sterile and not certainly determinable, but aspera is the only species
known from Cedros Island. Hale, (1941:56) reports that the plants
are broad and bushy, scarcely exceeding a foot in stature.
GRAMINEAE
ARISTIDA ADSCENSIONIS L., Sp. Pl. 82. 1753.
Cannery Bay on east side of Cedros Island, March 14, Elmore 46,
in dry wash.
A xerophytic grass commonly scattered throughout southwestern
United States and southward into Mexico; also in warmer parts of the
Old World. The collection is a single depauperate plant, but it adds
another species to the published flora of the island.
AMARYLLIDACEAE
AGAVE SHAWII Engelm., Trans. Acad. St. Louis 3:314. 1875.
West San Benito Island, July 14, 15, 1937, Rempel 364 (sterile),
on southerly exposures with wind appearing to prevail from north.
Typical 4. Shawii is abundant from San Diego, California south to
Rosario in northwestern Baja California, where it commonly forms
dense stands along the slopes facing the moist sea air. The type was
described from Point Loma near San Diego. The short ovate-lanceolate
blades with strong crooked, closely set, marginal prickles of the San
Benito plant pretty certainly align it with the peninsular plant.
Agave Shawii Engelm., var. sebastiana (Greene) Gentry new comb.
A gave sebastiana Greene, Bull. Calif. Acad. Sci. 1:214. 1885.
East side of Cedros Island, July 10, Rempel 330, general.
The variety is known certainly only from Cedros Island. Greene
first collected and described it as a distinct species. T'release (C.N.H.
23:110, 124. 1920) maintains 4. Shawii and A. sebastiana as distinct
species, separating them in his key on the basis of sinuous (Shawii) or
straight (sebastiana) terminal spine. The sebastiana population appears
50 ALLAN HANCOCK PACIFIC EXPEDITIONS voL. 13
also to differ from typical Shawii by its less robust form and by fewer,
more remote, and smaller marginal spines, characters which appear to
have subspecific rather than specific value.
Agave Shawii sebastiana may also occur on the San Benito Islands.
Brandegee reported an Agave from the San Benito Islands (1900)
which he considered the same as on Cedros. Palmer (Rose 1890:20)
spoke of two species of Agaves on San Benito Islands.
POLYGONACEAE
ERIOGONUM FASCICULATUM Benth., Trans. Linn. Soc. 17:417.
1837.
Cannery Bay on east side of Cedros Island, March 14, Elmore A24,
sandy rocky slope in dry wash, flowers white.
Generally distributed on the maritime and desert slopes and valleys
from Santa Barbara, California south to central Baja California and
on adjacent islands. This collection appears to be related to the variety
flavoviride Munz and Johnston, but differs in the pubescent peduncles
and larger stature.
ERIOGONUM INTRICATUM Benth., Bot. Voy. Sulph. 46, t. 22. 1844.
East side of Cedros Island, July 10, Rempel 337.
Known only from Cedros Island and the adjacent peninsula; the
type from San Bartolome Bay, Baja California. The above material is
very young, but a few young flowers at the base of the plants with
wine-red strigulose sepals in sessile involucres and the pubescent leaves
limited to the basal node are diagnostic.
Er10oGONUM Ponpu Greene, Pittonia 1:267. 1889.
Cannery Bay on east side of Cedros Island, March 14, Elmore A106,
A25, dry rocky wash.
In and along arroyos in sandy and coarse detrital soils on Cedros
Island and the adjacent peninsula near Tortuga Bay (San Bartolome
Bay) ; type from Cedros Island. Elmore reports in his notes that the
flowers on No. 416 were pink, and white on No. 425. A very low
wide-spreading suffrutescent bush.
CHENOPODIACEAE
ATRIPLEX DILATATA Greene, Pittonia 1:264. 1889.
West San Benito Island, July 14, 15, Rempel 366, west side of
island; small-leaved plant all over island. San Benito Islands, July 14,
15, Rempel 361, general distribution.
No. 2 GENTRY: LAND PLANTS 51
Known only from the San Benito Islands to which it is apparently
confined. The species is related to 4. Barclayana, but differs in the
woody branches, the thicker fruits with less tuberculation on the sides.
The shrubby nature of the plant is apparent in the above cited collec-
tions. On the sheet of Rempel 361 even the terminal branches are woody,
the leaves reduced, while Rempel 366 shows new herbaceous shoots from
a thick woody branch, the leaves uncommonly wide and herbaceous, the
broad ovate blades 3-4 cm long, mostly 2-2.5 cm wide; petioles 5-10
mm long.
ATRIPLEX PACIFICA A. Nels., Proc. Biol. Soc. Wash. 17:99. 1904.
Cannery Bay on east side of Cedros Island, March 14, Elmore 437,
sandy, rocky soils of alluvial fan.
Southern California and adjacent islands to Cedros Island; type
from San Diego, California. Elmore reports only a few plants observed
and the collection consists of a single small plant. I have seen no collec-
tions of this species from northern Baja California, but it probably occurs
there, since it is a weedy type that is often passed by collectors.
SUAEDA SP.
San Benito Islands, July 14, 15, Rempel 358 (sterile).
NYCTAGINACEAE
HESPERONIA CEDROSENSIS Standl., C.N.H. 12:362. 1909.
Cannery Bay on east side of Cedros Island, March 14, Elmore A15,
alluvial fan with sand and pebbles.
On coarse arid soils from Cedros and San Benito Islands, along the
northern coast of Baja California, and on San Clemente Island in the
Channel group; type from Cedros Island. Elmore noted but a few
plants; flowers purple.
AIZOACEAE
MESEMBRYANTHEMUM CRYSTALLINUM L., Sp. Pl. 480. 1753.
Cannery Bay on east side of Cedros Island, March 14, Elmore 426,
gentle slope of pebbly alluvial fan.
Naturalized along the coasts of the Californias and adjacent islands
from Santa Barbara, California south into northern Baja California;
type from Cape of Good Hope.
MESEMBRYANTHEMUM NODIFLORUM L., Sp. Pl. 480. 1753
West San Benito Island, July 14, 15, Rempel 369, 371, north side
of island.
52 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 13
This Mediterranean adventive is abundant on the coast through the
northern part of Baja California and is also common farther north as
far as Oregon. Rempel’s collections are the first records from San
Benito Islands.
PORTULACACEAE
CALANDRINIA MARITIMA Nutt. in Torr. & Gray, N. Am. Fl. 1:197.
1838.
Cannery Bay on east side of Cedros Island, March 14, Elmore 428,
gentle slope of a rocky alluvial fan; flowers purple.
From Santa Barbara County, California south along the coast to
central Baja California. Locally on Cedros the plant is known as “ver-
dolaga” and was regarded by Elmore’s informant as edible.
EsCHSCHOLTZIA MINUTIFLORA Wats., Proc. Am. Acad. Sci. 11:122.
1876.
Cannery Bay on east side of Cedros Island, March 14, Elmore 417,
gentle slope of rocky alluvial fan.
From southern Utah south through the Sonoran Desert to middle
Baja California. The above collection is a considerable extension of
range for the species and an addition to the known flora of the island.
CRUCIFERAE
SIBARA PECTINATA Greene, Pittonia 3:11. 1896.
Cannery Bay on east side of Cedros Island, March 14, Elmore 432,
on gentle rocky slope of alluvial fan; flowers light purple.
Central Baja California and Cedros Island; type from San Bart-
olome Bay (Tortuga Bay). A delicate and rarely collected winter an-
nual, slender, erect, with dissected leaves 4-6 cm long, the lobes remote
and narrowly linear, spreading.
CAPPARIDACEAE
IsOMERIS ARBOREA Nutt. in Torr. & Gray, N. Am. Fl. 1:124. 1838.
Cannery Bay on east side of Cedros Island, March 14, Elmore 414,
dry wash and fans on exposed, sandy, pebbly, gentle slopes; flowers
yellow.
Widely but irregularly distributed in the deserts of California, So-
nora, and Baja California; type from San Diego, California. Forms a
low bushy shrub on the island and flowers through February and March
after rainy winters.
NO. 2 GENTRY : LAND PLANTS 53
LEGUMINOSAE
ERRAZURIZIA BENTHAMI (Brge.) Jtn., Proc. Calif. Acad. Sci. IV,
12:1043. 1924.
Dalea Benthami Brge., Proc. Calif. Acad. Sci. II, 2:148. 1890.
Cannery Bay on east side of Cedros Island, March 14, Elmore A20,
on rocky, sandy, exposed, gentle slope of alluvial fan. East side of Cedros
Island, July 10, Rempel 341, alluvial fan and hill side.
Known only from the Sierra Vizcaino area and the neighboring
islands; type from Santa Margarita Island.
This is a low stiff shrub with short intricate branches, gray twigs,
and conspicuously gland-dotted light gray leaves, the whole often matted
into a low rounded crown. Both Johnston and Rydberg have indicated
the advisability of separating this species (together with the related F.
megacarpa from the California Gulf Region), with its regular non-
papilionaceous corolla, from the genus Dalea, having a typical papili-
onaceous corolla; a view with which the writer thoroughly agrees. Un-
fortunately, Phillip’s awkward name, Errazurizia, (Ann. Univ. Chile
1872:688) has priority over Rydberg’s Psorobatus (N. Am. FI. 24:41.
1919). It was reported to Elmore by local informant as edible to human
beings, but caused insanity among animals. The informant may have
been confusing the plant with members of the genus Astragalus.
Lotus HUMILIS Greene, Pittonia 2:140. 1890.
Cannery Bay on east side of Cedros Island, March 14, Elmore 427.
A low prostrate winter annual common to the sands of central Baja
California and Cedros Island; type from San Bartolome Bay.
Lupinus Ponpi Greene, Pittonia 1:288. 1889.
Cannery Bay on east side of Cedros Island, March 14, Elmore A1,
a few plants in a dry wash.
Central and northern Baja California and Cedros Island; type from
San Bartolome Bay, Baja California. It is a low annual herb with
spreading stems, sparse, coarse, long pubescence, and the flowers glomer-
ate along the rachis of the inflorescence, according to the specimen at
hand.
ZYGOPHYLLACEAE
FAGONIA LAEVIs Standl., Proc. Biol. Soc. Wash. 24:249. 1911.
Cannery Bay on east side of Cedros Island, March 14, Elmore 418,
gentle slope with rocky sandy soil on alluvial fan; flowers light purple.
54 ALLAN HANCOCK PACIFIC EXPEDITIONS voL. 13
Widely distributed around the upper half of the Gulf of California
in California, Arizona, Sonora, Baja California, and on intervening and
adjacent islands. This is a rather dense form of the usually more open
habit of the species, which is characterized by the 3 small very narrow
leaflets and the short spreading stipules.
EUPHORBIACEAE
EUPHORBIA BARTOLOMAEI Greene, Pittonia 1:290. 1889.
Cannery Bay on east side of Cedros Island, March 14, Elmore A29,
rocky sandy soil in dry wash; flowers white.
One of the small finely cut prostrate spurges nies the arid
soils on Cedros Island and adjacent. Baja California; type from San
Bartolome Bay.
EUPHORBIA MISERA Benth., Bot. Voy. Sulph. 51. 1844.
Euphorbia Benedicta Greene, Pittonia 1:263. 1889.
Cannery Bay on east side of Cedros Island, March 14, Elmore 419,
gentle slope on sandy rocky alluvial fan. San Benito Islands, July 14,
15, Rempel 370, north side of West Island (flowering).
Irregularly distributed through the deserts of southern California,
Baja California, and perhaps in the Thorn Forest of central Sinaloa
(Gentry 7001, near Culiacan) ; type from San Diego, California.
Eastwood (1929:432) reported it tentatively as collected by Mason,
his material being too poor for certain identification. Elmore’s number
agrees well with typical material from the peninsula. The San Benito
Island plants are apparently more succulent and dwarfed in stature,
and are perhaps worthy of varietal distinction.
BUXACEAE
SIMMONDSIA CHINENSIS (Link) Schneider, Il]. Handb. Laubholzk
2:141. 1907.
Simmondsia californica Nutt., Lond. Jour. Bot. 3:400, t. 16. 1844.
Simmondsia pabulosa Kell., Proc. Calif. Acad. Sci. 2:21. 1860.
Cannery Bay on east side of Cedros Island, March 14, Elmore 43,
dry wash. East side of Cedros Island, July 10, Rempel 331 (sterile).
Widely scattered upon the arid slopes on the mountains and in the
canyons of the Sonoran Desert from southern California and southern
Arizona south into Sonora and through Baja California to the Cape
District ; the type is probably from San Diego, California, although the
describer attributed it to China, due to error in labeling or sorting by
the collector who visited both California and China on the same voyage.
No. 2 GENTRY : LAND PLANTS 55
It is a leathery-leaved evergreen shrub with acorn-like fruits, which,
although it may assume a dominant role in the vegetation, is more often
widely scattered as individual plants.
Although somewhat bitter the seeds are eaten by the desert peoples
as they ripen, either raw or roasted, and a kind of coffee has been made
of them by the Mexicans in times of coffee shortages. Elmore reports
that it is employed locally as a pomade by women for their eyelashes
and by men for their moustaches. The family affinities of the plant are
uncertain.
ANACARDIACEAE
Pachycormus discolor Veatchiana (Kell.) Gentry new comb.
Rhus Veatchiana Kell., Proc. Calif. Acad. Sci. 2:24. 1860.
Veatchia discolor Veatchiana (Kell.) Jtn., Proc. Calif. Acad. Sci.
IV, 12:1081. 1924.
Cannery Bay on east side of Cedros Island, March 14, Elmore 413,
on wash walls and fans. East side of Cedros Island, July 10, Rempel
344 (with young leaves and budding inflorescence).
This variety, which according to Johnston is distinguished by its
larger, more colored, coarser, and more conspicuously pubescent flowers,
is known definitely only from Cedros Island. However, it likely will be
found to occur also on the adjacent island of Natividad and the Sierra
Vizcaino part of the mainland. Elmore collected it at 75 feet elevation
where he noted a few trees or shrubs up to 10 feet high, trunks as much
as two feet in diameter and with peeling papery bark, known locally as
“Copalquin.” Hale (1941:68) reports it as “Abundant throughout the
desert formation, and reaches its best development as to size in Grand
Canyon, where on the lateral alluvial fans it reaches tree size——On the
west coast near the ocean it is often of low stature, not two feet tall.”
This remarkable plant with its massive, smooth, round, paper-barked
trunk and branches together with the pinnate leaves make it appear
much like the Burseras, which abound in Mexico. ‘The massive stems
accommodate the enlarged water-storing tissues, which serve to carry
the plant over the extended and regular drought periods of the peninsu-
lar desert, and which in extreme times are known to last for several
years. Bentham first described it under Schinus (Bot. Voy. Sulph. 11,
pl. 9. 1844), while later authors have assigned it to Veatchia and Rhus.
Were not the name Veatchia preoccupied, it would have priority over
Pachycormus of Coville.
56 ALLAN HANCOCK PACIFIC EXPEDITIONS vou. 13
Ruvus Lentu Kell., Proc. Calif. Acad. Sci. 2:16. 1863.
Cannery Bay on east side of Cedros Island, March 14, Elmore 44,
on sandy gentle slope with pebbles on alluvial fan.
On outer coast of middle Baja California and adjacent islands; type
from Cedros Island. It forms a dense green shrub or even a small tree,
flowering in the early spring. Elmore noted that it was used locally for
wood and that the fruits are three to four times larger than our “Jemon-
ade berry.”
MALVACEAE
LAVATERA VENOSA Wats., Proc. Am. Acad. Sci. 12:249. 1877.
Middle island of the San Benito Islands, July 14, 15, Rempel 362,
near shore on south side.
It is known only from the San Benito Islands. The collection is in
full leaf, flower, and fruiting.
SPHAERALCEA FULVA Greene, Pittonia 1:201. 1888.
Cannery Bay on east side of Cedros Island, March 14, Elmore A11,
gentle slope of alluvial fan.
Commonly in washes along the outer coast of middle Baja Cali-
fornia and on Cedros Island, the type locality. Elmore noted that the
flowers are orange-colored, that it is known locally as ‘‘malva silvestre,”
and a decoction of the herbage is made and applied to the back for fevers.
LOASACEAE
MENTZELIA HIRSUTISSIMA Wats., Proc. Am. Acad. Sci. 12:252.
137 (
Cannery Bay on east side of Cedros Island, March 14, Elmore A5.
sandy pebbly soil of alluvial fan; flowers light yellow.
Infrequently scattered in the mountains of the mid Baja California
Desert and on some of the adjacent islands; type from Angel de la
Guardia Island. The single collection contains two depauperate plants
6-7 cm high with the dry corollas 12-15 mm long.
FRANKENIACEAE
FRANKENIA PALMERI Wats., Proc. Am. Acad. Sci. 11:124. 1876.
West San Benito Island, July 14, 15, Rempel 368. San Benito
Islands, July 14, 15, Rempel 359 (sterile).
A halophyte on either salty or “‘sweet”’ soils of the arid coastal slopes
and flats throughout northern Baja California and adjacent southern
California. It forms low brittle woody bushes 2-6 dm high, rather dense,
NO. 2 GENTRY : LAND PLANTS 5/7
and often forming dispersed pure stands over considerable area in some
localities.
CACTACEAE
CocHEMIEA Ponpit (Greene) Walton, Cact. Jour. 2:51. 1894.
East side of Cedros Island, July 10, Rempel 332 (sterile).
Known only from Natividad and Cedros Islands, the type locality
being the latter.
ECHINOCEREUS MARITIMUS (Jones) Schuman, Gesambt. Kakteen
21. 1898.
East side of Cedros Island, July 10, Rempel 333 (sterile).
West coast of Baja California and adjacent islands; type from En-
senada.
FEROCACTUS CHRYSANTHUS (Orcutt) Brit. & Rose, Cactaceae 3:
T1922.
East side of Cedros Island, July 10, Rempel 331 (sterile).
Northwestern Baja California and the adjacent islands; the type
from Cedros Island. ‘The numerous, curved, light brown to gray, an-
nular spines in the closely set areoles identify this insular plant.
MAMMILLARIA GooprIDGEI Scheer in Salm-Dyck, Cact. Hort. Dyck.
1849 :91. 1850.
West San Benito Island, July 14, 15, Rempel 364.
West coast of middle Baja California and the adjacent islands of
Cedros, San Benito, and Guadalupe; type from Cedros Island. Some of
the Rempel specimens are fruiting. The series show all low plants tend-
ing to be obovate in outline, 5-10 cm high, woody at base, and one plant
is branched.
OPUNTIA SP.
San Benito Islands, July 14, 15, Rempel 357, infrequent—mostly top
and north sides.
This is a sterile Cylindropuntia, showing affinities to the section
Imbricatae. The inflated straw-like sheaths of the spines suggest O. cal-
malliana, but the joints are too thick, the spines too few, too long, and
the areoles too remote for that species. It is neither O. tesselata nor O.
prolifera, the only two Opuntia which have been reported (Brandegee
1900:20) for the San Benito Islands. The collection probably repre-
sents an undescribed species, but is insufficient for diagnosis.
58 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 13
HYDROPHYLLACEAE
PHACELIA IXODES Kell., Bull. Calif. Acad. Sci. 1:6. 1884.
East side of Cedros Island, July 10, Rempel 335, damp place in
canyon.
Known only from Cedros Island, the species is readily recognized
by its coarse stems, long scorpioid cymes, and heavy glandular pubescence.
BoRAGINACEAE
CRYPTANTHA MARITIMA Greene, Pittonia 1:117. 1887.
Cannery Bay on east side of Cedros Island, March 14, Elmore 49,
sandy soils of wash and alluvial fans.
In coarse sandy soils apparently throughout the Sonoran Desert in
California, Arizona, Baja California, and on adjacent islands.
LABIATAE
SALVIA CEDROSENSIS Greene, Bull. Calif. Acad. Sci. 1:212. 1885.
Cannery Bay on east side of Cedros Island, March 14, Elmore 433,
dry wash.
Known certainly only from Cedros Island, but possibly also at Mag-
dalena Bay, Baja California. It is a low suffrutescent plant with blue
flowers. The collector reported but few plants observed and the one col-
lected is depauperate.
‘TEUCRIUM GLANDULOSUM Kell., Proc. Calif. Acad. Sci. 2:23. 1863.
Cannery Bay on east side of Cedros Island, March 14, Elmore 410,
a few plants in a wash in the bottom of a small canyon in pebbly sand,
corolla white tinged with lavender.
Ranges sparingly through middle Baja California and the adjacent
islands, the type from Cedros Island.
SCROPH ULARIACEAE
GALVEZIA JUNCEA (Benth.) Gray, Proc. Am. Acad. Sci. 22:311.
1887.
Cannery Bay on east side of Cedros Island, March 14, Elmore A430,
on alluvial fan with gentle, rocky, sandy slope.
Widely scattered through central Baja California and adjacent
islands; type locality, west coast of Baja California, probably at San
Quentin. It is a perennial herb with round, smooth, strictly ascending,
green branches and few small linear-lanceolate, glabrous, ephemeral
leaves about 1 cm long; flowers red, the sepals and peduncles strongly
glandular pubescent.
No. 2 GENTRY : LAND PLANTS 59
CUCURBITACEAE
ECHINOPEPON MINIMUS (Kell.) Wats., Proc. Am. Acad. Sci. 24:
52. 1889.
Marah minima Kell., Proc. Calif. Acad. Sci. 2:18. 1863.
Cannery Bay on east side of Cedros Island, March 14, Elmore 412,
climbing on shrubs on the sides of dry washes. ‘‘Guisapol.”
Central and southern Baja California and the outer adjacent islands;
type from Cedros Island.
It is a small scabrous vine, the leaves mostly broadly 3-lobed, small
white flowers, and solitary fruits rather strongly but flatly prickled.
CoMPOSITAE
BACCHARIS SARATHROIDES Gray, Proc. Am. Acad. Sci. 17:211. 1882.
East side of Cedros Island, July 10, Rempel 338 (sterile).
Desert washes of the southwestern United States and northwestern
Mexico; type from near Old Mission Station, San Diego County, Cali-
fornia.
BEBBIA JUNCEA (Benth.) Greene, Bull. Calif. Acad. Sci. 1:180.
1885.
East side of Cedros Island, July 10, Rempel 345, fan. Cannery Bay
on east side of Cedros Island, March 14, Elmore 435, steep rocky slope
with sandy soil.
This is a bushy broom-like shrub 1-2 m tall, long-flowering through
spring and summer, but with ephemeral reduced leaves, and found
throughout the Sonoran Desert in California, Arizona, Sonora, Baja
California, and accompanying islands. It is common to the banks and
bottoms of the desert arroyos. Type locality: Magdalena Bay, Baja
California.
ENCELIA CALIFORNICA ASPERIFOLIA Blake, Proc. Am. Acad. Sci.
49 :368. 1914.
Cannery Bay on east side of Cedros Island, March 14, Elmore A22,
dry wash.
Northern Baja California and adjacent islands; type from Cedros
Island. This forms a low spreading bush with many radiating stems from
the base. It is a more xerophytic edition of the species, characterized by
the light brittle branches and the smaller paler leaves.
60 ALLAN HANCOCK PACIFIC EXPEDITIONS voL. 13
ENCELIA STENOPHYLLA Greene, Bull. Torr. Bot. Club 10:41. 1883.
Cannery Bay on east side of Cedros Island, March 14, Elmore A7,
dry wash and fans in coarse rocky soil, flowers yellow, leaves resinous
and odorous. East side of Cedros Island, July 10, Rempel 342, fan.
Known only from Cedros Island. It is a low shrubby plant with very
narrow glutinous leaves (1-3 mm wide) and Senecio-like flowering
heads. Local name reported by Elmore is “yerba de venado.”
ERICAMERIA DIFFUSA Benth., Bot. Voy. Sulph. 23. 1844.
Haplopappus sonoriensis (Gray) Blake, C.N.H. 23:1490. 1926.
East side of Cedros Island, July 10, Rempel 346, fan.
On both coasts of middle Baja California and the adjacent islands;
type from Magdalena Bay, Baja California. The material is sterile and
doubtfully referred here. It differs from typical peninsular material in
having larger linear-lanceolate leaves as well as the typical narrow linear
ones. ‘his may be due to the late vegetative stage in which it was col-
lected. Not previously listed from Cedros Island.
FRANSERIA CHENOPODIFOLIA Benth., Bot. Voy. Sulph. 20. 1844.
Cannery Bay on east side of Cedros Island, March 14, Elmore 431,
alluvial fan.
From southern California south through Baja California to the
Cape District, Cedros Island. Type from Magdalena Bay, Baja Cali-
fornia. A low shrubby bush with crowded whitish to yellowish leaves
and rich brown stems with glutinous golden pubescence.
HAPLOPAPPUS TRIDENTATUS (Greene) Blake, C.N.H. 23:1493.
1926.
East side of Cedros Island, July 10, Rempel 348 (its flowering peri-
od is done, only a few achenes. remain in the persistent involucres ).
Known from Cedros Island and adjacent peninsula; type from
Cedros Island. It is a low suffrutescent plant with linear leaves termi-
nally tridentate.
HEMIZONIA FASCICULATA (DC.) Torr. & Gray, N. Am. FI. 2:397.
1841-43.
Cannery Bay on east side of Cedros Island, March 14, Elmore A§8,
on gentle slope of alluvial fan.
Southern California and northern Baja California.
No. 2 GENTRY: LAND PLANTS 61
HEMIZONIA STREETSII Gray, Proc. Am. Acad. Sci. 12:162.
West San Benito Island, July 14, 15, Rempel 367, north side of
island.
Known only from the San Benito Islands. It is a low suffrutescent
plant with yellow flowers, the base definitely woody and as much as a
half inch in diameter.
PERITYLE GRAYI Rose, in Coulter, Bot. Gaz. 15:117. 1890.
Cannery Bay on east side of Cedros Island, March 14, Elmore 421,
dry wash. East side of Cedros Island, July 10, Rempel 336, wash.
Southern California, Baja California and adjacent islands; type
from Guadelupe Island.
PoROPHYLLUM GRACILE Benth., Bot. Voy. Sulph. 29. 1844.
Cannery Bay on east side of Cedros Island, March 14, Elmore 434,
gentle slope with rocky soil on alluvial fan.
Found nearly throughout and limited to the Sonoran Desert in
California, Arizona, Sonora, and Baja California; type from Magda-
lena Bay, Baja California. It is a small highly ramified suffruticose plant
with small linear leaves and long pedunculate reddish involucres with
white flowers. The herbage is glandular and emits a pungent aromatic
odor when plucked or crushed. Never really abundant, it is common in
arid situations and may often be found growing up through the branches
of low shrubbery.
VIGUIERA LANATA (Kell.) Gray, Proc. Am. Acad. Sci. 17:218.
1881-82.
East side of Cedros Island, July 10, Rempel 339, wash (fruiting).
Cannery Bay on east side of Cedros Island, March 14, Elmore A22a,
dry wash.
Known only from Cedros Island. A scapose herb frutescent at the
base, white-woolly pubescent on stems, leaves, and involucres. The older
scapes shed their woolliness and show the brown-colored stems. It is a
handsome plant and worthy of cultivation.
62 ALLAN HANCOCK PACIFIC EXPEDITIONS VoL. 13
LITERATURE CITED
BRANDEGEE, T.S.
1900. Voyage of the Wahlberg. Zoe 5:19-28.
Eastwoop, ALICE
1929. Studies in the flora of Lower California and adjacent islands. Proc.
Calif. Acad. Sci. IV, 18 :420-441.
FRASER, C. MCLEAN
1943a. General account of the scientific work of the Velero III in the Eastern
Pacific, 1931-1941, Part I. Historical introduction, Velero III, Personnel.
Allan Hancock Pacific Exped., 1(1) :1-48, pls. 1-16.
1943b. General account . . Part II. Geographical and biological associations.
Ibid., 1(2) :49-258, pls. 17-128.
1943c. General acccount.. Part III. A ten-year list of the Yelero III collecting
stations. Ibid., 1(3) :259-432, charts 1-115.
GREENE, Epwarp L.
1888. Botany of Cedros Island. Pittonia 1:194-208.
1889. Vegetation of the San Benito Islands and a list of San Benito Island
plants. Pittonia 1:261-269.
HALE, GEORGE O.
1941. A survey of the vegetation of Cedros Island. Master of Arts thesis, Univ.
of Calif. at Los Angeles.
HANNA, G. DALLAS
1925. Expedition to Guadalupe Island, Mexico. Proc. Calif. Acad. Sci. IV,
14:217-275.
1926. Expedition to the Revilla Gigedo Islands, Mexico. Proc. Calif. Acad.
Sci. IV, 15 :87-89.
HoweELL, JOHN THOMAS
1942. A short list of plants from Cedros Island. Leaflet West. Bot. 3:180-185.
Rose, J. N.
1890. San Benito Island plants. Contributions of the National Herbarium,
1:20-21.
NO. 2 GENTRY: LAND PLANTS 63
REVILLA GIGEDO ISLANDS
The Revilla Gigedo Islands are small and widely scattered far off
the Mexican west coast. Southward about 380 kilometers from the tip
of Baja California is San Benedicto Island. Just south of it is the largest,
Isla Socorro, which is about 520 kilometers west by south of Jalisco.
Three hundred miles westward of Socorro is Clarion. Rocca Partida is
a barren double rock westward of San Benedicto and Socorro.
All these islands are volcanic, their geologic history obscure, and
their relationship vague. “They may be oceanic islands, but Johnston
(1931:45) considers them as continental. On the basis of bathymetrics
and flora he regards them as peaks of a submerged land mass that was
part of the Mexican mainland. The islands are in general alignment
with the Tarascanahuan Cordillera, a volcanic massif forming the
southern border of the Mexican central plateau, which breaks off in
Jalisco at the sea. Because the flora of the Revilla Gigedos is related
to both that of the Cape District of Baja California and southern
Mexico, his theory presupposes that the whole area of the California
peninsula and its periphery was once a part of the continental land
mass, more or less outlined by the bathymetric contour of 4000 meters.
This could only have been true previous to the Upper Tertiary, because
Miocene and Pliocene formations on Baja California, the Mexican west
coast, and adjacent islands show that their respective areas were covered
by salt water. Johnston’s argument is brilliantly developed, but the
entire structure of the area is in need of detailed field study before
credence of his theory can be assured.
The climate of the islands is semi-arid and maritime tropical with
a dry spring season. There are no meteorological records, but in these
latitudes rainfall should be about 80% summer and fall. The geographic
position places it in Koppen’s classification of Savanna Climate, which
is characterized by a dry winter and wet summer. The long dry spring
and the foggy montane forest of Socorro, however, make it atypical.
That the spring is dry and the winters in part wet is attested by the
five expeditions which have visited the islands between 1889 and 1939.
This is strongly indicated both by their reports and the dry quality of
the specimens collected during the spring months. Though the northern
anticyclonic storms may cause some mild precipitation during the winter
and local temperatures be productive of winter and spring fogs, the
rainfall regime belongs definitely with the tropical and appears quite
comparable to that which prevails on the west coast mainland in these
64 ALLAN HANCOCK PACIFIC EXPEDITIONS voL. 13
latitudes. The members of the California Academy of Sciences Expedi-
tion to the islands in 1922 found the vegetation dripping with early
morning fog around the summit of Mount Evermann. These fogs
ameliorate the spring aridity and help support the epiphytes of the mon-
tane forest, and even the tree growth by reducing transpiration.
The total known flora of this archipelago consists of only 120 vas-
cular plants (Johnston 1931); Socorro 102 species, Clarion 43 species,
San Benedicto 11 species, and is based upon about 325 numbers col-
lected by five men, Table 3. All of these collections but one were made
in the spring dry season. Barkelew only collected during the summer
months (May 15 to July 8) and he apparently failed to exploit fully
the opportunity to obtain representatives of the rich upper canyon flora.
It is not known if the summer rains preceded him. I have not seen his
specimens, which would indicate the condition of the vegetation at the
time of his visit. As on the Mexican mainland, collecting on the islands
should be best from August through November and the first botanist
to engage the flora at this season will undoubtedly be richly rewarded
with plants and information. Johnston (1931) has given good geo-
graphic descriptions of the islands, and with his and Hanna’s reports
(1926), I have drawn up the following brief summaries of the islands.
TABLE 3
Socorro Clarion San Benedicto
Year Collector 5 : :
spring summer spring summer spring summer
1887 Stockton (Anthony) 41 25 6
1889 ‘Townsend 19 12
1903 Barkelew 70 10? 6
1925 Mason 83 44 9
1939 Elmore at 15
‘Total known species 102 43 en i |
Table 3. Plant collectors and their collections from the Revilla Gigedo Islands.
San Benedicto Island. 48 kilometers north of Socorro, is about 5
kilometers long, averages about 1 kilometer wide, and contains in the
neighborhood of 5 square kilometers. ‘The southern half is an ash cone
about 296 meters high, the northern half a lava plateau. Physiographi-
cally it is young and little developed with a poor diversification of
habitats. The known flora consists of but 11 species of land plants.
Clarion Island. the extreme western outpost, is roughly rectangu-
lar, about 8 kilometers long, 3 kilometers wide, and 24 square kilo-
meters in area. It is surrounded by an immature coral reef (Hanna,
NO. 2 GENTRY: LAND PLANTS 65
l.c. p. 36). It has three distinct hills, the eastern being the highest
and reaching about 321 meters above sea level. “The hills are rounded
by erosion and show few canyons of any size. Over most of the island
there is a deep reddish brown soil that suggests antiquity. Undoubtedly
erosion now takes place very slowly; the rainfall is slight but the island
is well covered with vegetation” (Johnston 1931 :25). The few habitats
of two sand beaches on the south side, rocky sea cliffs, mesa, slopes, and
hill tops are not indicative of a rich flora. There is no permanent source
of fresh water. Hanna (1926:39) mentions a pool of brackish water at
the east end behind a sand beach, which he thought might be potable
during the rainy season.
The island appeared to Hanna to have been very little altered by
human interference. Such spots are so rare on the extra-polar portions
of our little earth that his remarks on this point are quoted in full
(1926:33).
“No mammals of any kind were found on the island. Fortunately,
the place has never been inhabited, even by temporary residents; hence
those curses of the isles to the northward, mice, cats, and goats, have
not become established. In fact, Clarion Island is one of the few places
remaining which has not been modified in some way through the agency
of man. The original ‘balance of nature’ still obtains. We know of only
one case of the introduction of any kind of life. In 1903 the California
Academy of Sciences sent an expedition to these islands and during the
course of the work on Socorro Island some paroquets were captured
alive. Mr. E. W. Gifford, a member of the expedition, told us that
some of these birds were liberated on Clarion Island. We saw no sign
of them during our stay and it is supposed that they perished through
lack of fruit which constitutes their chief food on their native island.”
The natural vegetation is dominated by thorny shrub under 15 feet
in stature. Hanna noted “One species of plant—, a shrub about 15 feet
high and the nearest approach to a tree found” (1926:38). One of the
most abundant shrubs was Opuntia occidentalis, which “grows very
luxuriantly in a broad zone around the shore line and more or less in
patches to the top of the island. Intertwined in it everywhere are dense
growths of vines” (1926:32). For ingress to the interior it was neces-
sary to cut trails through the dense spiny thickets. Other dominant
thorn shrubs include Zantroxylon fagara, and Euphorbia anthonyi is
probably the shrub, the fruits of which stained the parties’ clothing.
On the tops of the island they found large areas covered with grass.
66 ALLAN HANCOCK PACIFIC EXPEDITIONS voL. 13
The 43 species of vascular plants known from Clarion Island have
been discussed in some detail by Johnston. The collection and notes
obtained by Elmore on the Allan Hancock Pacific voyage to that island
are listed below together with his collections from Socorro Island. As
with other spring collections from the island, their condition reflects
the dryness of that season.
Socorro Island at about latitude 18°50’ N and longitude 111°
00’ W, stands as a rough quadrangular hulk (Plate 4, fig. 12). Fourteen
kilometers in length by about 11 kilometers in width, and with about
154 square kilometers of area, it is the largest of the Revilla Gigedo
group. Near the center is Mount Evermann, a little over 1138 meters
in elevation, a volcanic structure which Hanna (1926:56) and party
found mildly active in 1922. ‘““The whitish mud flows out in the side
of the gulch and makes a marker which is visible for a long distance—.
The fissures are very active. We had no means of measuring the tem-
perature of the steam issuing therefrom but the rush due to the high
pressure produced a great roar. Around the vents there was much
crystalized sulphur and the odor of hydrogen sulphide was very ap-
parent. The largest vents were about eight inches in diameter. In the
upper part of the gulch some of the fumaroles contained water but
this was found to be highly acid and entirely undrinkable.”’
The land form of the island is mountain broken up into ridges,
slopes, and radiating canyons. A small dry lake exists in an eastern
canyon. Recent and ancient lavas have contrasting soils and vegetations.
Permanent water is available at sea level at Grayson Cove on the south
side of the island, where a spring of fresh water comes out of a crack
in the lava rocks.
Sheep were introduced on the island in 1896 and were still running
freely about the island in considerable numbers in 1922. Grayson intro-
duced hogs at about this same time, but they have not been observed
since and it is most likely that they have expired. One species of lizzard
is known from Socorro and it is the home of numerous sea and land birds.
The vegetation apparently consists of two types determined by the
topography, soil, and the upland fogs; a maritime subtropical Thorn
Forest on the lower slopes and ridges and a maritime tropical montane
drought deciduous forest in the upper reaches of the canyons. Of the
brushy Thorn Forest, the ornithologist Anthony wrote (Auk II, 15:312.
1898) “The greater part of the island is covered with a very dense
growth of underbrush, the weather side [north and west exposure]
being especially thickly covered, making travel, except in favored spots,
NO. 2 GENTRY: LAND PLANTS 67
well nigh impossible. Trees are abundant on the weather side of the
island but on the south and east sides they are mostly confined to can-
yons, and were smaller than on the north slopes. They were nowhere
seen over forty or fifty feet in height, though usually covering consider-
able area with their broad spreading branches.”
Hanna and party found an upland section of red hills with flattened
and denuded vegetation, which they attributed to a cataclysmic wash-
out by a tropical cloud burst. On the south slopes of the mountain
above Grayson Cove, they found grass, cactus, and some shrub adventive
over the area that Grayson (1871:295) had fired 53 years earlier.
‘The montane forest is found only in the upper reaches of the canyons—
“In the canyon were many strange trees, flowers, epiphytic plants and
orchids.” Birds were excessively abundant and droves of sheep were
met with here and there all the way. ‘““The forests in the canyons were
so dense that the sunlight rarely penetrated to the ground ; hence mosses,
lichens, ferns, and orchids, were abundant on the trees and branches.
“From the top we were able to study the best means of approaching
the mountain and found it unquestionably to be from Grayson Cove.
But that route does not pass through any such interesting country as
we had traversed on the ascent. Wooded canyons are absent on the
south side but are abundant on the north, east and west. Between them
brush covered ridges radiate outward like spokes of a wheel’’ (Hanna,
1926 :48, 54, 57).
The flora of Socorro is the richest of the Revilla Gigedo Islands.
The larger and higher area of more diversified terrain is accompanied
by a more highly evolved indigenous flora. The five collectors who
have visited the island have given us records of 102 species of vascular
plants, Table 3. Barkelew’s collection of 70 numbers is the only one
made in the summer and he apparently failed to reach much of the
higher richer flora of the interior. To Mason goes credit for first hav-
ing brought the rich potentialities of the montane forest to our atten-
tion by his collections. Late summer and fall collections would add
more species and genera to the island flora. And, as Johnston wrote
(1931:15) “the most important botanical work now awaiting attention
on the islands concerns not species so much as the vegetation and the
living plant. The past collectors on the islands have been quite satisfied
in making a single collection of each species found on each of the islands.
No attempt has been made to make repeated collections either to show
variation of the plants or their distribution on particular islands. There
is almost nothing on record regarding the abundance, habits, stature,
68 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL.. 13
habitats, associates, flower-color, etc., of the various plants of the islands.
Few, if any, notes have been made which would permit the botanists
who have not visited the islands to visualize the living plant and see it
in relation to its environment. The plant ecology of the islands is an
untouched subject.” That is as true today as it was when Johnston
wrote it.
Elmore’s collection of 11 numbers is annotated below along with
those of Clarion.
CATALOGUE OF COLLECTIONS -
POLYPODIACEAE
CHEILANTHES PENINSULARIS INSULARIS Weatherby, Am. Fern
Jour 2 32 ).. LO Sn.
Braithwaite Bay, Socorro Island, March 18, Elmore C8, elev. 100
feet.
This variety is endemic to the Revilla Gigedo Islands, where it has
been collected from Socorro and Clarion. Elmore reports it growing in
shaded crevices of lava rocks in the side of a canyon.
GRAMINEAE
CENCHRUS MYSUROIDES H.B.K., Nov. Gen. & Sp. 1:115, t. 35.
1816.
Braithwaite Bay, Socorro Island, March 18, Elmore C1, among
boulders on upper beach.
Widely distributed in the warmer parts of North America.
JOUVEA PILOSA (Presl) Scribn., Bull. Torr. Bot. Club 23 :143. 1913.
Braithwaite Bay, Socorro Island, March 18, Elmore C4, among
lava rocks on steep slopes, elev. 10 feet.
Widely scattered along the coast from southern Baja California to
Nicaragua.
SPOROBOLUS ARGUTUS (Nees) Kunth., Enum. Pl. 1.215. 1833.
Sulphur Bay, Clarion Island, March 16, Elmore B12, on edge of
fresh water lagoon.
From Kansas to Arizona and south through tropical America.
MORACEAE
FICUS COTINIFOLIA H.B.K., Nov. Gen. & Sp. 2:49. 1817.
Braithwaite Bay, Socorro Island, March 18, Elmore C6, elev. 20
feet.
NO. 2 GENTRY: LAND PLANTS 69
In low and middle elevations from southern Baja California and
central Sonora south into Central America, especially along canyon
water courses. It is the most common and widespread fig tree in western
Mexico. Elmore notes it as growing on the island “in good red dry
volcanic soil with aerial roots from overhead branches.” Johnston (1931)
reports that these broad large trees are a favorite haunt of the untended
sheep so numerous on Socorro Island. He attributes this to their desire
for shade. ‘They may also be attracted by the edible fruits dropping
upon the ground and which are a favorite source of food for both wild
and domestic animals in Mexico. People eat them in times of hunger,
but generally as a source of food they are not desirable.
This island collection shows some minor differences in leaf vena-
tion from that of typical mainland material, but due to lack of flores-
cence it cannot be more critically compared. Its affinities are obviously
close to that of F. cotinifolia, and in spite of the apparently long isola-
tion of the Socorro Island population, it is unlikely that it would show
more than varietal distinction. Ficus is an old genus, known from the
Cretaceous.
NYCTAGINACEAE
BOERHAAVIA CARIBEA Jacq., Obs. Bot. 4:5, t. 84. 1771.
Braithwaite Bay, Socorro Island, March 18, Elmore C7, C11, elev.
100 feet, in crevices of basaltic rocks where there was sufficient dis-
integrated rock to form soil.
A low viscid perennial herb with small dark purple flowers widely
distributed in the American tropics. ‘he specimens are fragmentary
remains of plants indicating an earlier period of florescence. It normally
flowers in the summer and fall.
AIZOACEAE
SESUVIUM PORTULACASTRUM L., Syst. Nat. ed. 10, 2: 1058. 1753.
Sulphur Bay, Clarion Island, March 16, Elmore B10, clay soil around
old lagoon, flowers pink.
Widely distributed in brackish soils in the American tropics, but
not abundant on the adjacent Mexican coast and not known from other
Revilla Gigedo Islands.
LEGUMINOSAE
PHASEOLUS ATROPURPUREUS SERICEUS Gray, Proc. Am. Acad. Sci.
5:156. 1861.
Sulphur Bay, Clarion Island, March 16, Elmore B2, many plants
on upper beach, flowers dark red.
70 ALLAN HANCOCK PACIFIC EXPEDITIONS VoL. 13
On coarse arid soils in southern Arizona and western Mexico. The
densely sericeus variety is here recognized for the race inhabiting north-
western Mexico. The species ranges from southwestern United States
to Costa Rica.
SOPHORA TOMENTOSA L., Sp. Pl. 373. 1753.
Sulphur Bay, Clarion Island, March 16, Elmore B4, upper beach.
Although widely distributed in the tropical littoral of both hemi-
spheres, it is not known from the Mexican mainland, so that its pres-
ence on Clarion Island is a special problem in distribution. Native
peoples make use of the plant for supposed or actual medicinal proper-
ties, and it is possible that early seafaring people introduced the plant
on Clarion Island.
ZYGOPHYLLACEAE
TrIBULLUS cIsToIDEs L., Sp. Pl. 387. 1753.
Sulphur Bay, Clarion Island, March 16, Elmore B1, beach sand.
Widely distributed through the warmer parts of America.
EUPHORBIACEAE
EvupHorsBiA ANTHONYI Bree., Erythea 7:7. 1898.
Braithwaite Bay, Socorro Island, March 18, Elmore C9, a few
plants growing in crevices of lava rocks in side of canyon wall.
A low shrubby plant endemic to the Revilla Gigedo Islands; the
type described from San Benedicto. In Standley’s ‘Trees and Shrubs
of Mexico” (C.N.H. 23:602) the type locality is given erroneously
as San Benito Island. Dr. Wheeler, who determined the above collec-
tions, states that it is atypical, perhaps juvenile.
EUPHORBIA CF. CALIFORNICA Benth., Bot. Voy. Sulph. 49, pl. 23B.
1844.
Sulphur Bay, Clarion Island, March 16, Elmore B8, rocky loam on
gradual slope, flowers about one-quarter inch across, yellow green.
The material is insufficient for certain identification. Typical F. cali-
fornica has not been reported from these islands and is known only in
the California Gulf Region.
EUPHORBIA CLARIONENSIS Brge., Erythea 7:7. 1898 and Zoe 5:27.
1900.
Sulphur Bay, Clarion Island, March 16, Elmore B6, upper beach
in exposed dry sandy soil, flowers white, the white tips with red brown
centers.
Endemic to the Revilla Gigedo Islands.
No. 2 GENTRY: LAND PLANTS 71
STERCULIACEAE
WALTHERIA AMERICANA L., Sp. Pl. 673. 1753.
Sulphur Bay, Clarion Island, March 16, Elmore B9, among lava
boulders on dry slope. Braithwaite Bay, Socorro Island, March 18, El-
more C2, elev. 5 feet.
Widely distributed in the warmer parts of the world, common
through Mexico. A low perennial herb, often polypodial, 5-8 dm high,
very aggressive on disturbed areas, and one of the most collected weeds
of tropical America. Its presence on even the remote Revilla Gigedo
Islands is not surprising. Elmore reports that only a few plants were
observed.
CACTACEAE
OPUNTIA OCCIDENTALIS Engelm. & Big., Proc. Am. Acad. Sci.
3:291. 1856.
Braithwaite Bay, Socorro Island, March 18, Elmore C10, in ba-
saltic canyon in between boulders where there is a little soil formed by
disintegrating lava.
Southwestern California, northern Baja California, and the adjacent
islands along the maritime slopes; type from ‘‘western slopes of the
California Mountains.”
Elmore’s collection is the first identifiable material of the Platy-
opuntia which has long been noted upon the slopes of Socorro. Although
sterile, his specimens exhibit only minor differences from California
plants, as reviewed by Dr. Clover, who made the determination. The
presence of this species appears to be another bit of evidence supporting
the theory of the dissemination of migrules by oceanic currents. The
relationship of the Revilla Gigedo plants to the flora of California and
means of dispersal has been discussed by Johnston (1931).
CONVOLVULACEAE
IPOMOEA CATHARTICA Poir., Encycl. Suppl. 4:633. 1816.
Sulphur Bay, Clarion Island, March 16, Elmore B5, upper beach
in exposed sandy soil, flowers blue or purple.
Common to the American tropical lowlands; among the Revilla
Gigedo it is known only from Clarion Island.
BORAGINACEAE
HELIOTROPIUM CURASSAVICUM L., Sp. Pl. 130. 1753.
Sulphur Bay, Clarion Island, March 16, Elmore B11, on edge of
fresh water lagoon.
Common on saline or alkaline soils throughout most of tropical and
subtropical America.
2 ALLAN HANCOCK PACIFIC EXPEDITIONS VoL. 15
LABIATAE
TEucRIUM TOWNSENDII Vasey & Rose, Proc. U.S. Nat. Mus. 13:
146. 1890.
Sulphur Bay, Clarion Island, March 16, Elmore B14, on 40° slope
in lava rocks with a little soil between, flowers white.
A low succulent appearing herb with crowded ovate leaves, remotely
and irregularly crenate, thickish, inflorescence crowded at the ends of
the branches. Known only from Clarion Island.
SOLANACEAE
NICOTIANA NESOPHILA Jtn., Proc. Calif. Acad. Sci. IV, 20:93.
1931. ,
Braithwaite Bay, Socorro Island, March 18, Elmore C3, in crevices
of basaltic rocks where sufficient soil has formed.
Known only from Socorro Island. The lower leaves of the Elmore
specimens are undulate, tending to be lobed toward the base, not cren-
ate as described for the species by Johnston, but otherwise agreeing.
The flowers are reported as cream colored.
COMPOSITAE
BRICKELLIA PENINSULARIS AMPHITHALASSA Rob., Proc. Calif. Acad.
Ber LV, 20293. 1931.
Sulphur Bay, Clarion Island, March 16, Elmore B7.
Known only from Clarion and Socorro Islands, this variety is a low
brittle shrub with pale yellowish branches and prominent nodes. Mason
(in Johnston 1931:100) reported it the most dominant cover on Clarion
Island.
PERITYLE SOCORROSENSIS Rose, Bot. Gaz. 15:118, t. 13, f. 9. 1890.
Sulphur Bay, Clarion Island, March 16, Elmore B13, B3, growing
in crevices of lava boulders, partially shaded on upper beach.
Herbaceous, said to be perennial. Known only from Socorro, San
Benedicto, and Clarion Islands. Elmore B3 is a more vigorous form
with larger leaves and without ray flowers.
VIGUIERA DELTOIDEA TOWNSENDII Vasey & Rose, Proc. U.S. Nat.
Mus. 13:148. 1890.
Braithwaite Bay, Socorro Island, March 18, Elmore C5, growing
among lava boulders in decomposed lava soil at 15 feet elev.
Known only from Socorro Island.
No. 2 GENTRY: LAND PLANTS a3
LITERATURE CITED
Grayson, A. J.
1871. Exploring expedition to the island of Socorro. Proc. Boston Soc. Nat.
Hist. 14:287-302.
HANNA, G. DALLAS
1926. Expedition to the Revillagigedo Islands, Mexico, in 1925. Proc. Calif.
Acad. Sci. IV, 15 :1-113.
JounsTon, I. M.
1931. Flora of the Revillagigedo Islands. Proc. Calif. Acad. Sci. IV, 20:9-104.
74 ALLAN HANCOCK PACIFIC EXPEDITIONS VoL. 13
TRES MARIAS ISLANDS
The Tres Marias Islands are out on the steep edge of the con-
tinental shelf about sixty to seventy miles off the mainland shore of
Nayarit, opposite the port of San Blas. hey appear to have been in
existence since sometime in the Pliocene and in part much earlier. ‘They
are composed of several kinds of both igneous and sedimentary rocks.
The Miocene and Pliocene marine formations on Maria Madre and the
Mesozoic rocks on Maria Magdalena indicate local differential faulting.
To Nelson (1899 :9-11) the position of the islands upon the continental
shelf and the similarity of the vertebrate animals to those of the main-
land indicated a Quaternary land bridge. However, the seven species of
endemic mammals, the 24 species and subspecies of endemic birds and
an endemic reptile, as well as the 21 species of endemic plants known
from the islands, strongly indicate a considerable period of insular de-
velopment. A local insular biota was apparently well developed before
the Quaternary land bridge, so that aggressive mainland adventives
would have had to compete to establish themselves.
Soundings show a rather narrow submarine ridge extending out from
Punta Mita, Nayarit, toward the Tres Marias and in line with their
axis. The deepest sounding along this line shows 70 fathoms (ca. 30 m),
with greater depths to port and starboard. Glaciation ts thought to have
lowered sea levels from 80-100 m (Zeuner, 1945:248), which is suf-
ficient to cause peninsulation in this case. Probability of the land bridge
hypothesis is also dependent upon local epirogenic movements and a
study of geology still in waiting.
The climate of the Tres Marias is subhumid, tropical, maritime,
and equable with a binary pattern of seasons; rainy summer, and arid
spring. The maritime influence appears to ameliorate the long spring
dry season. (Grayson 1871:267) “In the dry season heavy dews are
frequent, the drops of which I have often seen the birds sipping, for
want of other means of quenching their thirst, there being but few
ojas de agua (springs).’”’ Summer rains are convectional in type, the
“‘chubasco”’ storms of wind-driven rain being common and making navi-
gation for small boats hazardous. Hurricanes in the fall rarely swing
in across the islands from the southwest (Schiaffino, 1939). No rain-
fall data are available for the islands but precipitation should be ap-
proximately that of San Blas on the mainland, which has an annual
average of 58.5 inches. The annual average temperature at San Blas is
24° C., with no record of frost (1939).
‘The natural vegetation of the islands is a subhumid tropical drought
NO. 2 GENTRY: LAND PLANTS 75
deciduous forest with a multiple dominance of tree species. One of the
most conspicuous dominants originally was Spanish cedar, Cedrela,
which oddly enough, although still living upon the islands, has never
been collected. The first naturalist to see these forests was Grayson in
1865, 1866, 1867, who wrote of them (1871:264). “The immense
cedar (Cedrela odorata) grows in great abundance on this island
(Maria Magdalena), not having been disturbed by the wood cutters.
This tree makes the finest lumber in the world. It is also common on
the coast of tierra caliente. Cleofa, the smallest of the three islands,
is also well wooded and has a good little port. All these islands, except
Juanito, are covered with a dense forest from the water’s edge to the
top of the highest hills. “The shape of the trees (of which there is a
great variety), is generally straight or straighter and taller than upon
the main. There is but little thorny underbrush, so characteristic of
the tierra caliente.”
Cutting of Cedrela was in progress on Maria Madre at the time
of Grayson’s visits. Later a penal colony was established on Maria
Madre by the Mexican government and disturbance of the native vege-
tation has continued. Ferris in 1925 (1927:64) found the area about
the penal colony cut over and a weedy aggressive cover advancing, many
species of which appeared to be newcomers from the mainland and
characteristic of disturbed areas about Mazatlan and San Blas. Little
agriculture has been practiced on this island.
The islands are reputed to have been uninhabited by man until the
coming of Europeans, the first of whom to inhabit the islands were
buccaneers (cf. Dampier, 1703). If it is true that the Amerindian
never inhabited the islands, it is very remarkable indeed, for traces of
man indicate that he has over-run almost every square mile of North
America at some time during his long residence on this continent. Sixty
miles of sea water is a small barrier and although the Spaniards may
have found the islands uninhabited, it is still likely that some of the
prehistoric peoples who inhabited the adjacent mainland, and some of
whom had advanced cultures, must have known of, visited, and even
inhabited the “Tres Marias for some periods. Maria Magdalena has
apparently been only partially disturbed by man, and should this frag-
ment of primeval vegetation (never affected by early man) still exist,
it would be a singular boone to all students of natural vegetation.
The known flora of the islands consists of 11 species of ferns and
313 spermatophytes. “These have been catalogued in 3 separate papers,
Rose (1899), Ferris (1925), Eastwood (1929). Over 90% of these
76 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 13
are known only from Maria Madre. In addition to a species of Cedrela,
a giant Agave, and a native cotton mentioned by authors and still un-
identified, are many other plants still awaiting collection and study.
Altogether these islands offer a most interesting subject for field research.
The job calls for a botanist of ethnographic and geologic background
in insular residence throughout the summer and fall, at least.
San Juanito Island.The Tres Marias Islands are actually four.
The odd one is San Juanito, the northwesternmost of the group, lying
across a narrow channel from Maria Madre. It is the smallest, being
about 5 kilometers long, 3 kilometers wide, 15 square kilometers in area,
and about 300 meters in elevation. Nelson and Goldman are apparently
the only biologists who have visited it and the former gives the follow-
ing short description (1899:10, 12), ‘San Juanito which is nearly flat
with a narrow border of low bluffs along the northern shore—. On San
Juanito the vegetation is largely made up of bushes and scrubby trees
8 to 15 feet high, with many Agaves on the sandy southern end. Agaves
are very numerous also on the northern end of Maria Madre.” There
are no known plant collections and it apparently has never been visited
by botanists, the accounts of other expeditions do not mention any land-
ings there.
Maria Madre Island is the largest of the Tres Marias group,
21°35’ N. by 106°40’ W. It is approximately 20 kilometers long, 10
kiolmeters wide, and 200 square kilometers in area. The peak of the
island is 616 meters above sea level.
The land forms consist of narrow beaches, cliffs, canyons, mesas, hill
slope and ridge. Arroyo Hondo is a notable intermittent water course
originating near the central peak and descending northwestward through
a deep canyon to discharge water into the sea during the rainy season.
In the past it has been difficult of access by land. Hanna (1926:67-71)
found the island to consist of a central pediment of granite with Plio-
cene marine sediments of chert, limestone, and sandstone lapped upon
it to near the top of the peak. ‘‘During a portion of Pliocene time large
coral reefs existed around this old land mass and large blocks of the
fossiliferous material, firmly cemented, having fallen from the exposures
and have rolled indiscriminately far out into the forest.’’ The island
appears to have had its inception in Miocene times, if not before, and
grew in area during the Pliocene. Maximum size was probably attained
during one of the glacial periods when sea levels were universally lower.
What is known of the vegetation has been described above. As with
nearly all of the Eastern Pacific islands, very little attention has been
NO. 2 GENTRY: LAND PLANTS 77
paid to the life histories and the ecology of the plants that live upon
them. We are still ignorant of the community make-ups and the inter-
relationships of the biota. Certainly the terrain is sufficiently diversified
to support various associations, although the elevation is not spectacular
and the present island area is not an ancient one. The area of the island,
its tropical nature, the observations of visitors, and the lack of summer
and winter collecting all indicate that the known flora of about 300
plants is probably little over half of what actually exists. Many of the
plants listed, due to inadequate material, have been determined to genus
only, others are tentative. The Euphorbiaceous genus, Calaenodendron,
appears to be endemic. Should more be found, we would have to revise
our opinion regarding the age of the island, which seems to have been
little more than a large rock until some time in the Pliocene. Until the
amount and nature of endemism and the identity of most of the species
are known, all inferences regarding the development and relations of
the flora must be very tentative. There is no group of islands in the
Eastern Pacific more worthy of thorough investigation.
Maria Magdalena Island lies about 11 kilometers across chan-
nel from Maria Madre. It is approximately 150 square kilometers
in area, 16 kilometers long, 10 kilometers wide, and with a central
peak of about 450 meters elevation. Physiographic habitats include
beaches, sea cliffs, canyons, rocky slopes and ridges. Hanna (1926:73)
mentions various canyons and a water hole in the next canyon west
of the one in which they were camped, near the center of the north
side of the island. They were there in May, when the dry season is
well advanced, so that the water must be nearly or actually perma-
nent. Concerning the geology he wrote (1926:72) “Maria Magdalena
has had an entirely different history from Maria Madre. Basement
rocks are volcanic and are overlain by a great series of cherts, sand-
stones, and mud shales. These we took to be Cretaceous in age but
definite paleontologic proof was not found. Miocene appeared to be
absent and Pliocene was not positively identified. Pleistocene, however,
is exposed near the sea and on the beach at the creek mouth and the flat
eastern end of the island is probably an elevated terrace of this age. ‘The
dangerous reefs projecting from the north side of the island are com-
posed of resistant layers of the supposed Cretaceous rocks, the softer
shale layers having been eroded away. Many of these resistant layers
weather out as huge flagstones. The high western end of the island, the
Pacific side, with its enormous sea cliffs, is composed of highly altered
78 ALLAN HANCOCK PACIFIC EXPEDITIONS voL. 13
cherts with volcanic rocks in many places. No evidence of granite, such
as compose the central core of Maria Madre Island was found.”
In 1865-67 Grayson found Maria Madre “unoccupied and covered
with a grand forest of fine timber” (1871:264). Nelson in 1897 found
the vegetation similar to that on Maria Madre. He stated that most
of the Spanish cedar was gone, but that a large percentage of the origi-
nal forest remained intact. Hanna and party “‘all agreed that the fauna
and flora of Maria Madre and Maria Magdalena were almost identi-
cal.” This is what one would expect of the vegetation, but not of the
flora, if Hanna’s supposition regarding the geology of the two islands
is correct. If Miocene and Pliocene rocks are absent on Magdalena and
present on Madre, one would infer that the former is the older, larger
area and its flora with a consequent difference in speciation of related
groups, which might in part be represented on the younger Maria Madre.
The known flora of Maria Magdalena consists of only 31 species
of vascular plants collected principally by Nelson in 1897 and Mason
(35 numbers) in 1925. Francis H. Elmore made a small collection in
May of 1939 during the Allan Hancock Pacific voyage. They are
enumerated below, Jacquinea aurantiaca being a new addition to the
island flora.
CATALOGUE OF COLLECTIONS
POLYGONACEAE
CoccoLosA SCHIEDEANA Lindau, Bot. Jahrb. Engler 13:187. 1890.
Magdalena Island, May 9, Elmore 1B3, a few plants in boulders
and sand along a dry stream at 15 feet elev.
Apparently along both coasts of Mexico from Sinaloa and Vera Cruz
south to Guatemala; type from Papantla, Vera Cruz.
‘T HEOPHRASTACEAE
JACQUINEA AURANTIACA Ait., Hort. Kew. ed. 2, 2:6. 1811.
Magdalena Island, May 9, Elmore 1B1, dry rocky partially shaded
stream bank, elev. 15 feet.
From Sinaloa to southern Mexico, Central America, and the West
Indies; also on Maria Madre Island.
VERBENACEAE
AVICENNIA NITIDA Jacq., Enum. Pl. Carib. 25. 1760.
Magdalena Island, May 9, Elmore 1B2, dry sandy soil of the upper
beach. Widespread along the coasts of tropical America.
No. 2 GENTRY: LAND PLANTS 79
Maria Cleofa Island. The last and southern-most of the group is
“Maria Cleofa. In dimensions this island is approximately 6 kilometers
long, 5 kilometers wide with an area of about 25 square kilometers. The
one central peak is given as 402 meters in elevation.
Except for the brief remarks of Grayson and Nelson, the only
naturalists who have visited the island, there is little known of the
island. Nelson noted that canyons descend from the central peak in all
directions. At least one of them carries an intermittent stream, which
sinks in its bed before reaching the sea during the dry season. In com-
parison to the other islands Nelson states (1899:12), “Maria Cleofa
is more rocky and sterile, and the trees are bushy and stunted.”
‘The total known flora of land plants consists of Nelson’s collection
of these four species: Zamia loddigesii (?), Arundo donax, Cyperus
ligularis, and Trixis Wrightit.
TABLE 4
Year Spring Summer Fall Winter
Maria Madre Island
1897 E. W. Nelson 95
1925 H. L. Mason 128
1925 R. S. Ferris 221
Maria Magdalena Island
1897 E. W. Nelson 14
1925 H. L. Mason 35
1939 F. H. Elmore 3
Maria Cleofa Island
1897 E. W. Nelson 4
Totals 279 221
Table 4. Plant collectors and their respective numbers collected on the Tres Marias
Islands.
80 ALLAN HANCOCK PACIFIC EXPEDITIONS VoL. 13
LITERATURE CITED
ATLAS CLIMATOLOGICO DE MEXICO
1939. Secr. Agr. y Fom., Mexico, D. F.
DAMPIER, WILLIAM
1703. A new voyage around the world. 5th ed.
Eastwoop, ALICE
1929. Studies in the flora of Lower California and adjacent islands. Proc.
Calif. Acad. Sci. IV, 18 :442-468.
FERRIS, ROXANA S.
1925. Preliminary report on the flora of the Tres Marias Islands. Contr. Dud.
Herb. Stanford Univ. 1:65-90.
Grayson, A. J.
1871. On the physical geography and natural history of the islands of Tres
Marias, etc. Proc. Boston Soc. Nat. Hist. 14:261-302.
Hanna, G. DALLAS
1926. Expedition to the Revillagigedo Islands, Mexico, in 1925. Proc. Calif.
Acad. Sci. IV, 15:66-76.
NE Lson, E. W.
1899. General description of Tres Marias Islands. No. Am. Fauna 14:7-13.
Rose, J. N.
1899. Plants of the Tres Marias Islands. No. Am. Fauna 14:77-91.
ZEUNER, F. E.
1945. The Pleistocene period. Ray Society, Pub., pp. 1-322.
NO. 2 GENTRY: LAND PLANTS 81
CALIFORNIA GULF REGION
GENERAL PHYSIOGRAPHY
The California Gulf Region possesses considerable physiographic
unity, although its boundaries are not fast. For the purpose of this study
it includes, besides the great gulf nucleus itself and its chromosomic
islands, the surrounding coastal plains, mostly narrow and in part lack-
ing, the coastal mountains, and the Cape District of the peninsula. It
forms a long narrow area nearly 1000 miles long containing about
150,000-175,000 square miles. It is nearly co-extensive with the Sonoran
Desert, the latter comprising additional area in northern Sonora, south-
eastern California, southwestern Arizona, and on the peninsula except
in the Cape District. The western middle portion of the peninsula is
being considered in another study.
Nearly half the area is occupied by the sea. Its western shores are
generally precipitous and without rivers, while its eastern are mostly
low coastal shores with several intermittent rivers. From the mouth
of the Colorado River in the apex, the gulf gradually deepens to 2600
meters under its 225 kilometer-wide mouth. The upper part of the
gulf is generally less than 300 meters in depth with low gradients on
the eastern and northern margins. South of Angel de la Guardia and
Tiburon Islands it rapidly deepens to over 1000 meters and the 1500
meter contour comes well up into the gulf. In this water are 25 to 30
larger islands and many smaller ones, some of which are no more than
jagged rocks set upon by the tides and wind-driven waves. The topo-
graphy of the northern half is terrestrial in type rather than marine.
It is the water relations, both of the sea and of the air, that give
the country its distinctive quality. The gulf water is changeful. It can
be as quiet as a forest pool at dawn or as choppy as Lake Erie. High
seas often run under the strong and recurrent winds. In the late sum-
mer of the convectional storm cycle, hard squalls suddenly appear and
have upset many a light ship, and in the early colonial days made the
passage of the gulf and the colonization of the peninsula a hazardous
undertaking. The waters teem with life; fish, shrimp, whale, and many
other animals run in and out in their seasons, as also do a vast assem-
blage of birds over the surface; others, from plankton and crabs to
sharks and turtles, are permanent residents. The sublittoral zone is
covered with an abundance of varied algae. Under the brilliant sun-
light, the ever mobile waters, blue or green or vermilion or gray, are
set sharp against the rocky, uneven, and disconsolate shores.
The water of the air is rare, because it seldom falls as rain, although
8? ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 13
actually the hot air contains more moisture than usually exists over
temperate regions. Hence, in contrast to the dense biota in the sea, the
land is relatively barren. The land biota, though seemingly dead, is
nevertheless there, and with many special adaptations for survival of
drought. When rains fall, the plant life suddenly becomes intensely
active and the land becomes green and flower-colored. To the man who
may be there the desolate then becomes a garden of well-spaced forms.
And it, too, in brilliant sunshine is set sharp against the inanimate rocks
beside the waters of the gulf. Such is the impression of the gulf region
on the senses today. Geologically, the perception has quite a different
quality, because the eye and mind are removed from the object by many
milleniums.
In spite of changeful orogeny, the California Gulf Region has had
a persistent character since the early Mesozoic. The gulf itself is a de-
pressed block, which Schuchert (1935), has discussed as a part of the
southern Pacific geosyncline. ‘This sea-invaded trough has had a strik-
ing physiographic evolution, the remarkable events and character of
which are geologically revealed at every great turn. The biota of the
lands has had a restless place and has endured displacements, inunda-
tions, extinctions, and has been forced into migrations with the coming
and going of the sea, with the submergence or emergence of mountains,
and with the concomitant changes of local climate. Close study of the
plant and animal life, when directed by a correlating intelligence, should
reveal a course of evolution, expressed jointly by plant and rock, hardly
equaled in plant geography. There is some lack of agreement among
geologists regarding the history of the gulf region, primarily because
investigations are still in preliminary stages. From the reconnaissance
work that has been done, however, the general history can be outlined.
Schuchert has been foremost in synthesizing available knowledge and
I have drawn heavily upon his great work in the following paragraphs.
Judging from the world-wide deposits of fossil plants, the modern
angiosperms had their inception in the Upper Mesozoic, following the
biota dominated by such groups as the seed ferns, the cycads, and the
saurians. When the Tertiary opened, the majority of the modern plant
families and genera were pretty well established. Hence, in seeking the
origin of the desert flora of the gulf region we are concerned with
events in the Cretaceous and onward. Of all the major floral elements,
the desert floras are the most obscure in origin. They are almost un-
represented in the fossil record. We must seek other sources of evidence
for determining their origin, their migrations, and their growth. A
NO. 2 GENTRY: LAND PLANTS 83
knowledge of the evolution of land forms is primary.
The withdrawal of the Mesozoic seas from the Mexican continent
was accompanied by widespread uplift. Large areas became land. They
included not only what is now the Gulf of California, but also a margi-
nal area. During the Cretaceous and early Tertiary the shore lines of
Baja California and northwestern Mexico reached 50 or more miles
westward of present limits, including some of the islands. This land
mass might even have included the Channel Islands on the northwest,
Guadelupe on the west, and the Revilla Gigedos to the southwest, al-
though there is no real geologic evidence to support such a presumption
(cf. Jtn. 1931). However, irrespective of the exact boundaries, it is
evident that during the Cretaceous and early Tertiary, Baja California
and its gulf were a part of a land mass areally different than exists
today. The progenitors of our modern flora had a broad base for develop-
ment in arid latitudes; arid because the land lay in a rain shadow of
the Mexican continent, barred from the trade winds, and because the
weak westerlies blowing onshore are warmed and dried by the radia-
tion of these latitudes.
The climate of the Eocene appears to have been somewhat wetter
than the late Mesozoic, which, because of the extensive sandstone and
gypsiferous deposits, is judged to have been relatively arid. However,
the granite batholithic and pyroclastic intrusions of the late Cretaceous
and Eocene must have raised some mountains, which in turn localized
climate abetting drought on the one side and decreasing it on the
other, according to the mountain orientation to air flow. However, the
interiors of the western land areas have apparently been relatively arid
since the middle Mesozoic. Since then, if not before, there have been
deserts, though the boundaries of them have been modified or shifted
according to climatic cycles and to the raising and lowering of land
masses. So, at the beginning of the Tertiary in the California Gulf
Region, the environment was already diversified and the evolution of
modern seed plants well begun.
In the Oligocene the sea began to invade the old downwarped block
of the Southern Pacific Geosyncline for the first time since the Triassic.
As the bend deepened the sea invaded the gulf and by the middle Mio-
cene reached half way up the present gulf to about Angel de la Guardia
Island and Tiburon Island. By middle or late Miocene it was maximal
and covered all of the present gulf, the Colorado Desert, and a section
of adjacent Arizona and northwestern Sonora besides. Some of the gulf
islands apparently date from that time and still persist as the tops of
84 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 13
submerged mountains, i.e., Angel de la Guardia, San Lorenzo and
Ceralbo. Others, as Tortuga may not have appeared until the marked
diastrophism of the Upper Pliocene and Pleistocene, when the peninsula
gained its present elevation and general outline. San Jose, Carmen, San
Marcos, and other islands close along the peninsular shore, may be fault
splinters, and their developments intimately related to the dynamics of
this compensatory zone. Too little is known geologically to time events
in detail.
It was not until the Pleistocene that the modern peninsula arrived.
During the late Miocene and the early Pliocene most of the modern
southern half of the peninsula was covered by sea, judging from the
sedimentary beds. The marine formation described by Darton as “the
yellow beds” (Jour. Geol. 24:720-748. 1921), is particularly significant.
The beds appear to have covered all but the several old central igneous
masses along the Sierra Giganta axis south of San Ignacio and a couple
of western outposts. Hence it would appear that for a portion of the
Upper Tertiary, the peninsula south of Sierra Calmalli was represented
only by a series of islands, where Tertiary pediments crested the invad-
ing sea, and which are still represented by locally exposed schists and
granites about the bases of modern mountains (Darton l.c. fig. 3).
The more important of such postinsular and prepeninsular masses
appear to be represented by the Sierra Vizcaino, the Magdalena Island
area, Sierra Zacatecas, a segment of the Sierra Giganta about Cerro
Giganta east of Comondu, and the Cape District. A shallow portal
across the mid-peninsula about the latitude of San Ignacio appears to
be clearly defined and to have been contemporaneous with the yellow
beds. As the Giganta fault subsequently became active, the modern pen-
insula grew southward by anticlinal uplift and accompanying pyroclas-
tics, which now form the greater part of the higher land. “foday we see
that the whole eastern side of the peninsula from San Ignacio south
was tilted upward, the great Giganta scarp reared, the Pliocene waters
retreated from the southern and western borders and from the trans-
peninsular portals. The mountains of the Cape District and the Sierra
Vizcaino complex were tied onto the peninsula. This was not accom-
plished as one gradual sea recession, but according to local orogeny and
to the eustatic periods of the Pleistocene. Hence such lowlands as the
Vizcaino Depression were alternately opened and closed. ‘The expanse
of sand in remotely serried dunes appears to have been formed by suc-
cessive beaches. In summary, there is little or nothing in the stratigraphy
to indicate that the southern half of the peninsula was anything more
NO. 2 GENTRY: LAND PLANTS 85
than an archipelago during a considerable portion of the Upper Ter-
tiary. The evolution of the biota, the distributions and speciations, are
linked with the physiography.
It was inevitable that the evolution of the fauna and flora developed
synchronously with the radical physiographic stages, but even though we
have both spacial and temporal yardsticks, we have yet to measure these
events in terms of plant development and to make specific correlations
between organic and inorganic evolution. Plant populations were re-
peatedly restricted or provided with new areas and divergent habitats.
This effected lines of descent with swamping, with infrequent crossing
opportunities, with new placements for variants and chance natural selec-
tions, and also with entire eliminations. However, it appears that plant
evolution can be evaluated in accordance with rates of divergence in
many groups, in so far as isolation has fostered it, or as migration has
interrupted it, and as speciation has expressed it.
The California Gulf Region was split by the sea invasion, creating
disjunct populations on the peninsula, the mainland, and the islands.
Specific divergence due to isolation should be greatest about the mouth
of the gulf because the sea invaded that end first and the distances sepa-
rating mainland and peninsula populations are greatest. Ihe Cape Dis-
trict appears to have been isolated, except for its Quaternary union
with the peninsula, since early Tertiary times and its high ratio of en-
demism is to be expected and correlates nicely with a tempo-spacial
yardstick. Endemism in the disjunct segments of the upper part of the
gulf dates generally from the Upper Miocene or Lower Pliocene. Cor-
respondingly speciation is not so clearly developed and we encounter
difficulties in separating the entities to our taxonomic satisfaction. ‘Che
Pleistocene disjuncts are even less mature and here we often engage the
aggravating problem of choosing between species, subspecies, or varieties.
Nevertheless we have to deal with them, since they represent stages
in a natural rate of evolution. Were it not for the irrepressible tendency
of life to vary, the units of life would be fixed and we would be denied
many fascinating problems. By a study of the events that demark the
periods of California Gulf history in relation to the evolving organisms,
the origins of our desert flora should be less obscure.
THE PosTINSULAR LOCALITIES
The Cape District, consisting primarily of a granitic batholithic
block and volcanic intrusives, was not until recently a continuous part
of the peninsula, as has been stated above. Westward and southward
of La Paz are a series of fossiliferous beach deposits underlaid by marine
86 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 13
deposited arkose. In this locality also, trending north and south, may
be seen a southern segment of the Sierra Giganta fault, which itself
appears to be a continuation of the San Leandro fault zone, so well
known in ‘Alta California.”” The sediments of this locality show that
this low section of the peninsula did not arrive above the sea until the
Pleistocene. The adjacent part of the peninsula, the Sierra Giganta
anticline, is composed largely of Pliocene marine sediments. This all
indicates that the block of igneous rock in the Cape District had a long
existence in the Tertiary as an island. This is significant in the con-
sideration of the biota and especially the flora. Many plants are known
only from the Cape District and the adjacent peninsula, to which latter
area they have migrated in Quaternary times. I propose to call such land
bodies as the Cape District, postinsular.
Besides the Cape District there are many coastal “‘cerros’” (a word
which the Mexicans apply to their craggy hills), whose positions and
the adjacent landward strata indicate are also postinsular mountains.
It is not within the scope of this paper to present detailed evidence for
this interpretation of the physiography, but the facts: that post-Pliocene
detrital and alluvial materials from the Sierra Madre Occidental have
built up the coastal plains from 100 to 500 feet; that the Pacific coast
is rising; that higher sea levels existed universally in the interglacial
periods; and that several Quaternary estuarine deposits and sea caves
exist several miles inland, all provide excellent grounds for this theory.
More detailed evidence accumulated during my several years of paleon-
tological reconnaissance in the area, will, I hope, appear in a later study.
The larger coastal mountains which may be considered postinsular are;
in Sonora, Sierra Coloral, Sierra Seri, the monadnock north and west
of Guaymas, probably Sierra Bacatete, Sierra Bojihuaqueme, and in
Sinaloa, Sierra Navachiste, Sierra Tecomate, and possibly Sierra ‘T’a-
cuichamona.
The floras of these postinsular localities have not been individually
studied. On most of them few if any collections have been made. More
collections have been made on the Guaymas monadnock than on any of
the others, but they are widely scattered in herbaria and not available
for detailed study. Nor do they represent all of the postinsular land
body lying northwest of Guaymas. Beginning with the collections of
Thomas Coulter in 1829-30, the plants taken at Guaymas and vicinity
have disclosed a surprising number of novelties, some of which presum-
ably had their specific origin on the Guaymas monadnock. The post-
insular Sierra Coloral has not been studied by botanists. McDougal,
NO. 2 GENTRY : LAND PLANTS 87
Shreve, Gentry, and perhaps a few others have made some fleeting col-
lections on the north end. No collections are known from Sierra Seri;
except a few Mammillaria, there are none from Sierra Bacatete and
Sierra Bojihuaqueme; none from Sierra de Navachiste except Edward
Palmer’s collections at the harbor of ‘Topolobampo; from Cerro Teco-
mate, Gentry 100 numbers; from Sierra Tacuichamona, Gentry 192
numbers. ;
These postinsular floras should show differences from that of the
mainland, more or less correlated with the ages of the respective cerros
or with the duration of their islandic isolations. Some of them may show
considerable endemism, if not of species rank, then of lesser degree. The
rare plants that are known from only one or two restricted areas along
the Mexican west coast may be postinsular endemics that have persisted
or migrated locally since their original habitats joined the mainland.
Some of the cases that attract the attention at this point are the fol-
lowing:
Adelia obovata Wiggins & Rollins
Jatropha purpurea Rose
Desmodium Wiggins Schubert
Lippia Palmeri Wats.
Phrygilanthus sonorae (Wats.) Standl.
Caesalpinia gracilis Benth.
Karwinshkia latifolia Rose
Indigofera laevis Rydb.
Ruellia leucantha postinsularis Gentry
Physalis purpurea Wiggins
Sesbania sonorae Rydb.
Physalis sonorensis Standl.
Prosopis reticulata Wats.
Aloysia nahuire Gentry & Mold.
Holographis pallida Leonard & Gentry
Porophyllum pausodynum Rob. & Greenm.
Each of these postinsular localities possesses its own floristic problems
in relation to the land flora. A detailed knowledge of their floras would
provide considerable evidence regarding their geologic histories and the
rate of evolution, in so far as species divergence can be chronologized
with physiographic developments. While it may be possible to determine
which plants have insular origin, it will be harder in many cases to
ascertain what species are of mainland origin and whose distributions
now represent migrations upon postinsular mountains. All such problems
88 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 13
offer a fascinating invitation to the student of plant evolution and
geography and their solution would contribute to the great latent story
of the California Gulf Region.
CLIMATE
The California Gulf Region in spite of its large water surface, is
extremely arid around its upper portion. In so far as the continental air
circulation dominates, its climate is continental in type. Theoretically,
the prevailing air currents are those of (1) the western Pacific anti-
cyclone, the maritime character of which is eliminated by its passage
over the west coast land surface northwest of the gulf region; (2) the
continental anticyclone, dry, and with marked annual and daily tem-
perature extremes; (3) the mild Pacific westerlies prevailing through
the spring as on-shore breezes are consistently dry because of the warmer
land surface. The conspicuous fog desert along the outer coast of the
peninsula is lacking in the gulf region proper. Near the mouth of the
gulf epiphytes occur locally on the mainland, as at Cerro ‘Tecomate.
(4) A maritime air current appears to swing in from the near south
Pacific as a western limb of the Caribbean anticyclone. In the fall,
storms develop along this track (Schiafino, 1939) and may reach into
the gulf.
However, unstable humid air masses are of two sources and two
seasons; the winter rains from the northwest Pacific storms which are
uncertain and do not fall every year; the summer rains of the tropical
convections, which occur regularly in the southern portion of the region,
but lighten materially in the interior of the gulf. Averages of yearly
rainfalls, as far as regional records are available and vegetative growth
indicate, range from 20 to 30 inches for the mountains on either side
of the mouth of the gulf to about 3 inches for the lowlands in the upper
portion of the gulf. Data are carried in the accompanying table (‘Table
5). Average winter rainfall is similar for all stations except the high of
Alamos in southern Sonora, which is explained by the proximity of that
station to Sierra de Alamos (height 1800 m) and its obvious precipitative
effect on humid air masses. Ihe same phenomenon is operative through-
out the region on other mountains having comparable mass and height.
Average summer rainfall generally decreases from south to north.
The average for the five southern stations (Muleje, La Paz, Guaymas,
Alamos, Topolobampo) is 9.5 inches, while for the northern stations of
Brawley, Lechuguilla, Ttule Tank, Cirio Point, and Libertad, it is only
1.6 inches. This greater summer rainfall in the southern part of the
NO. 2 GENTRY: LAND PLANTS 89
California Gulf Region is most responsible among the climatic factors
for the tropical elements in the southern flora. It fosters the existence
of many plants requiring or responding only to summer rains, when
higher temperatures, longer daylight periods, periods of shortening day-
light (fall), higher humidities, etc., prevail. The lack of synchrony of
these factors in the northern area excludes many subtropical plants.
TABLE 5
Pics Length Average Average Average
Station fe °° (o£ record summer winter annual
: (years) rainfall rainfall rainfall
Brawley; California..<..:... -100 29 0.63 2.01 2.64
Mexicali, Baja California...... 3 15 1.0 2.0 3.0
Muleje, Baja California.......... 110 15 EPS | 13 4.0
La Paz, Baja California.......... 60 15 4.4 27 7.0
Lechuguilla, Arizona.............- 700 5 1.7 2.6 4.3
‘Tole tank, “Arizona... 1100 y 2.2 iS 4.1
Cirio Point (Sierra Coloral),
OC) A CE eae See ae er oe 180 10 Zed. Ls 3.6
Libertad, Sonora..-:........2..-..... 100 10 2.4 1.8 3.2
Hermosillo, Sonora.................... 700 15 10.1 zal 12.2
Guaymas, sonora..2... £2. 13 15 7.6 25a 10.1
Alamos, Sonora..2. 2. 1200 15 22:1 6.2 28.3
Topolobampo, Sinaloa.............. 10 15 11.0 She 14.2
Table 5: Average rainfall in inches for some representative stations in the Cali-
fornia Gulf Region. Data extracted from Turnage and Mallery (1941) and Atlas
Climatologico de Mexico (1939).
COLLECTION LOCALITIES
The Cape District since its beginnings in the Cretaceous (cf. Schu-
chert 1935:132-133), apparently has had a relatively long and stable
geologic history as an island. Due to its age, its high elevations, and
its tropical and wetter climate, it has the best developed vegetation and
the richest flora of any other part of the gulf region of comparable size.
The complex physiography and variety of rock also contribute to its
floral richness by providing a wide range of habitats. Present are val-
leys, hillsides, cliffs, mountain tops, sandy beaches, detrital slopes, springs,
short intermittent streams, and on top of Sierra Laguna a small meadow-
like basin holds shallow water during the summer rains. The arroyo
beds, although with steep gradients, carry deep lenses of granitic sands
and support a rich assemblage of mesophytic trees and shrubs.
The principal vegetation formations are: Desert Shrub, Thorn
Forest, Short-tree Forest (a subtropical, mixed, drought-deciduous for-
90 ALLAN HANCOCK PACIFIC EXPEDITIONS Vou. vs
est), and Pine-oak Forest. Grasslands are lacking except for a few
small mountain meadow-lands, as ‘“La Laguna” on Sierra Laguna and
an obvious increase in grasses in the Pine-oak Forest generally. ‘Thorn
Forest is not as well developed as it is on the adjacent mainland, being
but a brief transitional element between Desert Shrub and the more
prevalent Short-tree Forest of the slopes and canyons which comprise
the greater part of the area. Except for the minor role of Thorn Forest
and the lack of a well defined Oak Grassland, the vegetations show a
comparable alignment to that of southern Sonora. The variance may be
attributable to the islandic origin. Views of Cape District vegetation
are shown in Plate 6.
The flora of the Cape District is more tropical than temperate.
Brandegee’s floristic survey of the eighteen nineties (1891, 1892, 1894,
1901), listed 104 species of Leguminosae, 103 species of Compositae,
and 52 species of Gramineae. While this is incomplete, he did collect
generally through all elevations and his collections appear fairly repre-
sentative of these three major groups of angiosperms. The respective
ratios of these groups per given area are often instructive about floristic
relations. The light showing of grasses is comparable to that found in
Thorn Forest and Short-tree Forest on the adjacent mainland. Generally,
the Compositae are more numerous through temperate regions, while
Leguminosae dominate the floras of tropical regions. The fact that le-
gumes equal or exceed the composites in numbers of species in the Cape
District attests its tropical affinities. ‘The number of genera common to
the cape and the adjacent mainland is far greater than those common
to the cape and the northern part of the gulf region, as may be expected.
In North America the following genera of the Leguminosae in the Cape
District have their centers of area in southern Mexico and Central
America. Acacia, Mimosa, Pithecolobium, Lysiloma, Desmanthus, Albiz-
zia, Caesalpinia, Cassia, Bauhinia, Indigofera, Tephrosia, Coursetia,
Benthamantha, Sesbania, Nissolia, Aeschynomene, Erythrina, Galactia,
Phaseolus, Haematoxylon, and Leucaena. This list is incomplete, but
much longer than we would cite for those having northern centers of
areas, as Astragalus, Lupinus, Lotus, and Trifolium, and which are
not strongly represented in species in the Cape District. Three endemic
genera (Coulterella, Clevelandia, and Faxonia) are known from the
Cape District, and over 100 endemic species and varieties have been
described (interpreting their occurrences along the Sierra Giganta as
postinsular migrations ).
Actually, except for the flora of the Desert Shrub formation, the
NO. 2 GENTRY: LAND PLANTS 91
flora of the Cape District is still in isolation. The climatic and edaphic
conditions of the peninsula, particularly north of the Sierra Giganta,
are not tolerable to the majority of the cape plants. Comparable habitats
on the mainland are still over 100 miles of water and coast away.
Equally significant to differences in the make-up of the cape flora and
the adjacent mainland are the numbers of species the two areas have
in common. Considering the long tenure of isolation for the cape flora
and the vicissitudes besetting diaspores across salt water, a higher endem-
ism could reasonably be predicted. It may be that the Cape District
was bridged to the peninsula during the middle Tertiary, allowing in-
gress of the aggresive Sinaloa element, which displaced some of the
insular population. However, whether cape isolation dates from early
or late Tertiary, it is clear that genera have generally been conserva-
tive in species generation. The genesis of species does not appear to have
progressed nearly as rapidly in land plants as it has in land mammals
(cf. Zeuner, 1945 :253-269, and 1946).
In April of 1937 and in February of 1938 the Velero III made
stops in the Cape District. P. J. Rempel and E. Yale Dawson made
collections of land plants at San Jose del Cabo, and at Punta Frailes
and vicinity (Tables 1, 6). Their collections are enumerated below in
the catalogue of species for the California Gulf Region.
Punta Frailes is among the least known of the localities visited
by the Velero III, the collections from there being the first. Punta
Frailes is a granite cerro that juts out into the mouth of the gulf on
the southeastern tip of the peninsula (Plate 5, fig. 13; pl. 6, figs. 14, 15).
Southwestward of the cerro is a sandy beach, where members of the
expedition landed and made collections. For causes which are still ob-
scure, this southeastern tip of the peninsula is the driest portion of the
Cape District. North of Punta Frailes is a mountain, known by the
natives as Sierra Victoria. This has been confounded by cartographers
(who have followed an early error) with Sierra Laguna which is the
main central mountain mass of the Cape District. There are no known
collections from Sierra Victoria. ‘This mountain and the adjacent area
around Punta Frailes form a locality in need of detailed field work.
Puerto Escondido is a small harbor with a neighboring rancho
lying at the foot of the precipitous Sierra Giganta scarp. Here the mas-
sive sedimentary formation is exposed and variously over-lapped by
volcanic lavas and breccias. A narrow plain bounds part of the shore,
in part the scarp rises high and spectacular out of the water (Plate 7,
figs. 16, 17). The climate is hot and arid, being on the lee side of the
92 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL..13
Sierra Giganta, which blocks the westerlies that cool the opposite side
of the peninsula. The vegetation is dominated by a dispersed, succulent,
microphyllous Desert Shrub with scattered small trees which increase
in stature and in number of species up in the steep canyon. Among
these latter are Bursera sp., Lemaireocereus Thurberi, Cercidium molle,
and the palm Erythea Brandegeei.
Four collections have been made from Puerto Escondido and vicinity,
mainly in the canyons cutting steeply back into the mountains of Sierra
Giganta.
I. M. Johnston May, June 1921 50 numbers
P. J. Rempel March 1937 30 numbers
H. S. Gentry April 1938 50 numbers
E. Y. Dawson February 1940 25 numbers
It should be noted that all collections were made in the spring and
that the late summer flora fostered by the summer rains has not been
collected. Due to the precipitous slopes, the arid climate, and the tor-
rential type of rains, the soils are rankly immature. ‘The humic soils
are confined to pockets in rocks, or to riparian embayments, and in
them are commonly found the small succulents (e.g. Mammillaria)
and mesophytes of erratic dispersion. In the high, narrow, and rocky
canyons, where shade and run-off conserve and augment soil moisture,
there are found many subtropical species of the wetter Cape District.
Pachycormus discolor here forms one of the largest trees with erect
straight trunks 30 feet high or more, presenting quite a different habit
from the dwarf contorted members of the species found in more arid
habitats on the peninsula. Quercus idonea occurs in the mesic saddles
and slopes near the tops of the Sierra Giganta.
In the sierran area about Puerto Escondido, including the collect-
ing localities of Agua Verde Bay 25 miles to the south and Comondu
on the other side of the mountains, there are several plants having local
distributions. These include Verbesina oligocephala, Polygala apopetala,
Ruellia cordata, Cercidium molle, Dalea vetula, Mimulus sp., Perityle
aurea, Agave sobria, and Vallesia laciniata. Their limited distributions
corroborate the little geologic evidence gathered to date that indicates
insular periods during the Tertiary for the Sierra Giganta area.
Angel de la Guardia Island, lying close along the peninsula, is
the second largest of the gulf islands. It has an approximate area of
975 square kilometers and the highest peak is 1315 meters above sea
level. As indicated in Plate 8, figs. 18-20, the island is rugged, “barren,”
with precipitous slopes, and canyons shortly discharging into the sea.
NO. 2 GENTRY: LAND PLANTS 93
No permanent source of fresh water is known. Physiographically it is
young and the arid climate tends to perpetuate the youthful appearance.
Sedimentary rocks appear to overlie basic igneous and are in part over-
lapped by extensive lavas. Very little appears to be on record describ-
ing the island. W. H. Burt of the University of Michigan in his notes
generously loaned to me described the island as follows: “A range of
mountains, attaining a height of 4315 feet in the northern part, traverses
the entire length of the island. This mountain range is highest at the
two ends and there is a low pass near the center of the island. The west
shore is for the most part precipitous but there are several landing places
on the east shore and at the north and south ends. The mammalian
fauna which is represented by three species, a pocket mouse (Perog-
nathus), rock mouse (Peromyscus), and a wood rat (Neotoma), seems
very small for an island of this size which is only eight miles from the
mainland shore at its nearest point.”
Vegetation is sparse, particularly at the northern end of the island.
Both Slevin (1923:69) and Johnston (1924) state that they found
more vegetation at the southern end. It is densest on the low gentle
slopes in the valleys, and along washes. Judging from the flora (Table 7
and Plate 8), it appears to be a microphyllous, succulent tree and suf-
frutescent shrub desert, not essentially different from that common to
the low and middle elevations of the adjacent mid-peninsula. The suc-
culent or sarcophytic tree forms consist of Pachycereus Pringlei, Le-
maireocereus Thurberi, Pachycormus discolor pubescens, Bursera micro-
phylla, and are accompanied, at least in the washes and valleys, by such
nonsucculent microphyllous trees and shrubs as Prosopis juliflora, Acacia
Greggii, Cercidium microphyllum, and Olneya tesota. A similar mixture
of succulent and microphyllous species occurs in the shrub populations
also. Low shrubby suffrutescents are well represented in Dalea, Erra-
zurizia, Frankenia, Atriplex, Petalonyx, Franseria, and Encelia.
The flora also shows a strong relationship to the central peninsula,
although some of the more striking peninsular species are apparently
lacking, e.g., Idria, palms and yuccas. Many of the plants of the upper
gulf region are here near their southern limits. The 96 species known
to the island are enumerated in Table 7. The known endemics are only
6, surprisingly few for the extent and nature of the area. But here again
only the spring flora is known. Additional field work is necessary before
we can be satisfied of an adequate showing of the flora and before prob-
lems of distribution and speciation can be evaluated. The Rempel and
Dawson collections are enumerated below in the general catalogue of
94 ALLAN HANCOCK PACIFIC EXPEDITIONS VOLUN
species. ‘hey collected on the north end of the island, chiefly at Puerto
Refugio. Dawson has 4 numbers from Pond Island, a small rocky body
connected with the east side of the Angel de la Guardia at low tide.
Their collections add 6 species to the known flora of Angel de la Guardia
Island, one of which is new to science, Lyrocarpa linearifolia.
Tiburon Island is the largest in the gulf. It is separated from the
Sonoran mainland by a shallow narrow channel, ‘‘el infiernillo,”’ two
to five kilometers wide and only three to four meters deep. Roughly
quadrangular in shape, the island contains about 1170 square kilometers.
Although mountainous, there are extensive valleys and several “‘aguajes,”
where fresh water is available for indeterminate periods following rains.
On the north end, where Bahia Agua Dulce roundly indents the shore
line, there is a permanent fresh water spring. In former times it was
regularly used as a base settlement for the seminomadic Seri Indians,
who still occasionally roam over the island hunting, fishing, and forag-
ing upon the native wild plants and animals. There are two igneous
ranges of mountains trending north and south and paralleling the ad-
jacent ranges of Sonora. The western is Sierra Menor, the eastern and
higher is Sierra Kunkaak (the Seri name for it) with a middle peak
elevation of 1218 meters.
A porphyritic granite occupies the southeast part of the island, ac-
cording to Jones (1910), who explored the island. He traversed the
island north to south along the east side, east to west across the south
end, and went into the interior around the highest peak. The greater
area of parent rock is volcanic. ““[he types are profuse and belong to
the effusive class.”” Also present are andesite, rhyolite, ‘the latter pass-
ing into the extreme phases of obsidian and pumice.’’ No limestone or
other sedimentaries were observed by him and his party. The volcanics
may be a part of the Upper Miocene pyroclastics (Comondu formation),
which predominate much of the California gulf area, although Jones
took them to be much younger.
The vegetation and the flora, so far as known, appear closely re-
lated to that of the adjacent mainland (Plate 9, fig. 21). This is to be
expected, since the shallow infiernillo channel was emerged repeatedly
during the low sea levels of the glacial periods. The land bridge would
then have allowed plant migration to or from the island, excepting those
plants restricted to the rocky slopes and which find the sandy lowlands
intolerable. The dry rocky slopes support a dispersed Desert Shrub for-
mation, while the bottomlands and aggrading surfaces are thinly forested
NO. 2 GENTRY: LAND PLANTS 95
with the wide spread mesquite, Olneya tesota, Cercidium, and several
of the cactus trees.
The known flora consists of only 77 species, which is considerably
less than one would expect on the basis of area and elevation of the
island. Obviously, Tiburon Island has been little collected and like other
islands in the California gulf, the summer-fall flora is unknown. When
the floras of ‘Tiburon and adjacent Sierra Seri are better known, a com-
mon origin will probably become apparent that may show some degree
of independence from the surrounding region. Both Dawson and Rempel
visited Tiburon Island on the voyages of the Velero III. Their collec-
tions, consisting of 36 numbers were obtained on the southeast corner
of the island and add 11 plants to the recorded flora of Tiburon Island.
Tiburon Island has the richest insular vertebrate fauna known in
the gulf. The following mammals are represented: coyote (Canis), rock
squirrel (Citellus), two species of pocket mice (Perognathus), kangaroo
rat (Dipodomys), rock mouse (Peromyscus), wood rat (Neotoma), jack
rabbit (Lepus), and the burro deer (Odocoileus). Bird life is well rep-
resented and the following varieties appear to be endemic to the island:
Tiburon quail (Lophortyx gambeli pembertoni), ‘Tiburon woodpecker
(Centurus uropygialis tiburonensis), Tiburon gnatcatcher (Polioptila
melanura curtata), Viburon cardinal (Richmondena cardinalis town-
sendi), Tiburon towhee (Pipilo fuscus jamesi).
San Esteban Island lies in mid-channel in the middle of the gulf
region off Tiburon Island. Quadrangular in shape, it embraces about
35 square kilometers of rugged land with a top elevation of 540 meters
at the south end. Volcanic in origin, it has “scoriae-covered slopes and
much breccia’ (Johnston 1924:954). It is shored mostly with high
vertical cliffs, but on the southeast is a pebble beach and a broad valley
above the beach provides ready ingress. No source of fresh water has
been reported.
The ubiquitous Desert Shrub forms a fairly close cover over the
gentle valley gradients, where growth is fostered by run-off, and a widely
dispersed cover upon the open rocky slopes. The flora is very similar to
that of adjacent islands and there are no known endemics other than
the small number of plants it shares with neighboring islands, as Echino-
cereus grandis which is common to San Pedro Nolasco, San Lorenzo,
and San Esteban Islands. The mammal fauna consists of one endemic
species of Peromyscus and a cclony of introduced rats, Rattus.
The Velero III land plant collections from San Esteban Island,
Rempel 6 numbers, Dawson 6 numbers, consist mainly of cactus. The
96 ALLAN HANCOCK PACIFIC EXPEDITIONS VoL. 13
early springs 1937 and 1940, when their collections were made, appar-
ently were too dry for general floral response. The summer-fall flora
of San Esteban Island is not known, all collections having been made in
the spring, Table 6. The known flora consists of 48 species. The Rempel
and Dawson collections are annotated in the following catalogue of
species.
San Pedro Nolasco is a rocky island 8 to 10 miles off the Sonoran
coast along the latitude of Guaymas (N 28°). About 3.5 kilometers
long and 1 kilometer wide, it is approximately 3.5 square kilometers in
area, and reaches a height of 315 meters. Like most of the gulf islands,
it rises sharply with steep rocky slopes out of the restless sea. Landings
have been made on the southeast side, where a narrow rocky defile leads
up into the interior. No source of fresh water has been reported. It is
reported as both volcanic and granitic (Fraser 1943:137, 149). Judging
from its stage of weathering (Plate 9, fig. 22), it is a youthful island,
but its age is unknown.
In accordance with the rocky slopes there is a heavy succulent ele-
ment in the vegetation represented by Pachycereus Pringlei, Lemaireo-
cereus Thurberi, Fouquieria peninsularis, Agave chrysoglossa, Pedilan-
thus macrocarpus, and several smaller inconspicuous cacti (Plates 10, 11,
figs. 23-26). In addition to the tree cactus listed above there are Bursera
microphylla, the peninsular Ficus Palmeri, and the Sonoran Acacia Wil-
lardiana. Unique also is the extensive growth of a bunch grass, Seéaria
macrostachya, which Johnston reports (1924:987), “extremely abun-
dant on north-facing slopes on San Pedro Nolasco Island (4397) where
it makes some hillsides appear like hay fields.” This odd assortment of
flora is dominantly composed of rock-inhabiting species and suggests for-
tuitous occupancy characteristic of an infant island. The island appears
too young for soils and maturely balanced plant communities to have
developed. Comparable pioneer societies have been noted on the recent
volcanics of the adjacent mainland, as on the southwestern out-lyers of
the Bacatete range along the Sonoran coast.
The known flora (Table 7) consists of 27 species, of which 8 have
been added by the Velero III collections, represented by 15 numbers
collected by Rempel and Dawson as annotated below. The iguana
(Ctenosaura hemilopha) is a conspicuous resident.
The Guaymas monadnock consists of a discontinuous range of cer-
ros with intervening and bordering valleys and plains. ‘The area has a
certain physiographic unity and comprises about 3000 square kilometers
with a peak elevation of 1316 meters. Cliff and rocky slopes form an
No. 2 GENTRY: LAND PLANTS 97
extensive habitat, which show considerable variance according to the
degree of sun and wind exposure. Such rare plants as Perityle Palmeri,
Asclepias leptopus, and Desmodium Wigginsii have been found along
the cliffs, as well as many cacti, Agave, and Ficus Palmeri. Conglomer-
ates are apparent and the Recent alluvial deposition of clay and silt has
tended to lap upon the mountain sides. The present cycle of degrada-
tion at work in the area, however, exposes and sorts the coarse and fine
gravels along the shallow arroyo channels, or hurries the coarse frac-
tured rocks down the mountain slopes and canyons.
Plants that attain true tree stature are limited to the run-off chan-
nels or the margins thereof. Saline littoral flats are extensive and an
unusually rich assortment of halophytes make up a complex association,
and among which are commonly found the following genera: Atriplex,
Lycium, Atamisquaea, Zizyphus, Wislizenia, Salicornia, Prosopis, Steg-
nospermum, Rhizophora, and many others. The sandy beach lines are
widely and intricately interrupted by the steep rocky slopes and cliffs
that are hammered by the palpitating sea. On the landward side of the
area, alluvial materials have been banked high upon the mountain pedi-
ments forming broad plains of Pleistocene aggradation.
The strata are dominated by volcanics which have intruded and
overlaid sedimentaries and are in turn partly overlaid by Quaternary
beach and littoral deposits. The process of deposition on the bajadas and
a structural uplift have raised the area above the confines of the sea.
“The hills about Guaymas and for about 80 kilometers to the north
are volcanic, consisting of basalt, tufa, and agglomerate. In the hills
behind Guaymas a number of old sea caves were noted which, though
now over 50 meters above the ocean, contained unconsolidated sands
and modern shells. This indicates recent movement at least in one sec-
tion of the coast” (Johnston 1924:953). The implications of the area
being postinsular have been noted above, and while we are not yet cer-
tain of this, it is obvious that it has grown in area during the recent
period.
The predominating plant formation of the Guaymas locality is Desert
Shrub. However, because it is near the southern limits of the Sonoran
Desert (see map in Shreve, Mallery, and Turnage 1936:215) and per-
haps because of conditions imposed by insulation, there are atypical ele-
ments in the floral composition. The Sonoran Desert Region is bounded
on the south by the Sinaloan Thorn Forest and species from this latter
formation find their northern limits in or near Guaymas. This com-
ponent includes such prominent Thorn Forest species as Acacia cymbi-
98 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 13
spina, Lysiloma divaricatum, Melochia tomentosa, Bursera laxiflora,
Pithecolobium sonorae, Zizyphus sonoriensis, and Hintonia pterosperma,
which here are either reduced in stature and incidence, or confined to
the more favorable situations of soil moisture, as along valley drainways.
Certain shrubs achieve local dominance in the Guaymas area that are
quite secondary in vegetational weight elsewhere. Among these are
Cordia parvifolia and Lippia Palmeri. With low to medium shrub stat-
ure they act a strong part locally in the dispersed shrub formation.
There is present also an arborescent element typical of the Sonoran
Desert, including species of Prosopis and Cercidium, which have normal
growth in the valleys but are stunted on the dry rocky slopes. Pachy-
cereus Pringlei is abundant upon the rocky slopes and like Ficus Palmeri
presents a special problem in distribution. These two plants are found
widely over the peninsula and on the adjacent islands. Why is their
incidence on the Sonoran coast so restricted ?
The Guaymas flora was referred by Axelrod (1939) to the Sierra
Madre element of the American flora. Chaney’s (1944) inclusion of it
in the “Southwest American Element” is more appropriate, since the
relation of the Guaymas flora to that of the Sierra Madre is remote and
at best but general. It is, however, an integral part of the great floral
complex that has a long but obscure Tertiary history and a large spacial
occupancy in the arid and semiarid southwest of North America. As sug-
gested above, the Guaymas flora has as yet an indeterminate uniqueness
in so far as insular isolation may have effected local evolution. Another
striking feature of the flora is the number of apparent natural erratics.
Some of the species whose occurrences at Guaymas and vicinity appear
extralimital are Ficus Palmeri, Pachycereus Pringleit, Hermannia pauct-
flora, Lysiloma candida, Indigofera mucronata, Acacia cymbispina, Vin-
cetoxicum petiolare, Colubrina glabra, Boerhaavia X antit, Lobelia splen-
dens, Bouchea dissecta, and Vitex mollis. There is, of course, always
the possibility that early man made such local displacements, but in any
case they now belong to the native flora.
Guaymas and San Carlos Bays are well known collection localities.
Edward Palmer in 1877 was the first to do detailed botanizing in their
vicinities. According to Watson’s report (1888:36-87), the only paper
that has itemized the Guaymas flora, Palmer collected 299 species of
flowering plants during the summer months from mid-June to mid-
November. Dawson’s collections (43 numbers) from there and Rempel’s
8 numbers from neighboring Ensenada de San Francisco represent the
land plant samplings of the Velero III, catalogued below.
NO. 2
GENTRY: LAND PLANTS 99
SUMMARY OF THE INSULAR FLoRAS
Table 6 is a summary of plant collections that have been made on
the islands in the California Gulf Region. They represent species or
varieties collected, rather than numbers of each collector. In most cases,
species collected equals numbers collected, the only notable exception
TABLE 6
S
z & P ES g = =
Islands = Bae Ze ga
Sve Oh =
Northern Gulf
SoTL Gy eae a a ee 9
(1 EST es PPE eles) eo eee 9
Angel de la Guardia...... 78
1 EST 1h: EWES |S oo Re ORE 1
ae eaer a nd Daal pets i1 7
Sal isi puedes... 1... 6
Beas: PAS os ek 3
San I erenzorc: 30... 19
REGS a esr a en ts octe 5
PPEFEDEG EE 425 rs B oe (oe dnt 40 60
Mouenee si) 0) oie Ek 8
Sai Ste WAM. cece ans-cok a,
SanvPedro Martir.. =. 23 1 14
San Pedro Nolasco........... 13
1 Gry ce A ee a 19
Southern Gulf
Salt Nlarcos. 2s. i
sinita Inez ee +
PUMEEOHSO tsetse E09 Doda: ‘ 11
Coronddes ss. io 5 ej 10
S97 1S) | a or ro 70 32 = 49
PAN ANE sees 2
Monserrate..220c2 3. 4
atalenas 2 ie ee 10 5
Santa Crug Set - fi
San Diepo. foe - 9
S21 (0 | A 9
San Francisco... 12
Pairtidd Sur. 9
Espiritu, Sante!................. 22 19 48
Sa oe) 1 oe Se aR RG Zz 42
Total Coll.
1934
Rempel
1937
1940
summer winter
fall spring
Ferris
Dawson
20 16 114
—_
ON
21 LZ,
31 62
70 81
12 2
20 109
Table 6: Collections of plants from the California Gulf Islands, according to
collector and to island.
100 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 13
being I. M. Johnston, who frequently made more than one collection
of a species at one locality or on one island. The list of collectors is not
complete, but as far as I have been able to determine from literature,
it includes all of the important ones. Others that may have collected on
the islands, as Diguet and George Lindsay who had special interests in
the Cactaceae, have provided few, if any, cited records.
From the table it is clear that botanical exploration has been fleet-
ing. On all except San Pedro Martir and Carmen Islands the summer
flora has not been collected and is therefore imperfectly known. While
many of the xerophytes produce leaf and bloom following both winter
and summer rains, there are also many which respond only in the sum-
mer-fall period. These latter are abundant in the southern portion of
the region, where summer rains are heavier. Except for Johnston’s pub-
lished notes of a general nature, the ecology of the islands has been given
only the most cursory attention. The development of the vegetation, the
nature of plant communities, the amount of endemism, and the many
diverse problems facing the phytogeographer cannot be determined until
further careful and less nomadic field work has been systematically done.
In Table 7 are listed all the plants that have been recorded from the
larger California gulf islands. A few of the smaller islands have been
omitted from the table for reasons of space, smallness of flora, or because
their floras are unknown.
Among the numerous small islands, the floras of which have not been
collected, are Consag Rock, Smith, Tassne, and Montague Islands. ‘The
known plants on Mejia and Granite Islands are included in the list of
Angel de la Guardia Island. Omitted are some small islands found in
the bays of Guaymas, Concepcion, and La Paz (Pichilinque). Islands
having small lists of spring flora are the following:
Georges Island
Chenopodium murale L.
Patos Island*
Bouteloua barbata Lag. Atriplex Barclayana typica H. &
Gc:
Amaranthus fimbriatus (Torr.) | Atriplex Barclayana Palmeri
Benth. (Wats) TC.
Carnegiea gigantea (Engelm.) Machaereocereus gummosus (En-
Britt. & Rose gelm.) Brit. & Rose
Opuntia sp. Encelia farinosa phenicodonta
(Blake) Jtn.
* In 1945 all the sporophytes were stripped off Patos Island by a Mexican guano
company and the guano producing Peruvian cormorant was introduced.
No. 2
San Luis Island
Eriogonum galioides Jtn. (type
loc. )
Hoffmanseggia microphylla Torr.
Lotus tomentellus Greene
Larrea divaricata Cav.
Euphorbia polycarpa hirtella
Boiss.
Cryptantha maritima pilosa Jtn.
Pond Island
Mammillaria angelensis Craig
Aster frutescens Wats.
Raza Island
Monanothocloe littoralis Engelm.
Batis maritima L.
Sesuvium sessile Pers.
Lemaireocereus Thurberi (En-
gelm.) Brit. & Rose
Opuntia tunicata Lehm.
Lycium brevipes Benth.
Turner’s Island
Mentzelia adhaerens Benth.
Santa Inez Island
Atriplex Barclayana Palmeri
(Wats. )
Atriplex Barclayana sonorae
(Stand. )
Lophocereus Schottii (Engelm.)
Brit. & Rose
Isla Partida**
Antigonon leptopus H. & A.
GENTRY: LAND PLANTS
101
Atriplex Barclayana typica H. &
S
Atriplex Barclayana Palmeri
(Wats.) H. & C.
Dalea mollis Benth. (0)
Bursera Hindsiana ( Benth.)
Engl.
Eucnide cordata Kell.
Vaseyanthus insularis Rose
Atriplex Barclayana typica H. &
Cc.
Atriplex Barclayana Palmeri
(Wats.) H. & C.
Fouquieria peninsularis Nash
Pachycereus Pringlei ( Wats.)
Brit. & Rose
Cressa truxillensis HBK.
Opuntia Bigelovii Engelm.
Amaranthus Watsoni Standl.
Lemaireocereus Thurberi (En-
gelm.) Brit. & Rose
Cressa truxillensis HBK.
Atriplex Barclayana typica H. &
C.
** There are two Isla Partidas in the Gulf of California; one in the northern
area between Isla Raza and Isla Angel de la Guardia, the other in southern waters
on the northern tip of Espiritu Santo Island. It is here suggested that these should
be designated respectively as Isla Partida del Norte and Isla Partida del Sur. From
the accounts of the California Academy of Sciences Expedition to the Gulf of
California (Slevin 1923, Johnston 1924), it is not possible to determine whether the
plants listed from “Isla Partida” belong to the north or to the south island.
102 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 13
Amaranthus Watsoni Standl. Atriplex Barclayana Palmeri
(Wats.) H. & C.
Lemaireocereus Thurberi (En- Cuscuta corymbosa stylosa (Choi-
gelm.) Brit. & Rose sey) Engelm.
Datura discolor Bernh. Lycium brevipes Benth.
Nicotiana trigonophylla Dunal Hofmeisteria fasciculata ( Benth.)
Walp.
Bebbia juncea (Benth.) Greene
Las Animas Island
Ficus Palmeri Wats. Atriplex Barclayana sonorae
(Stand?) Hoc:
Amaranthus Watsoni Standl. Echinocereus grandis Brit &
Rose
Solanum Hindsianum Benth. Vaseyanthus insularis Rose
Some synonomy in names of the California gulf islands are:
Las Animas=North San Lorenzo (Proc. Calif. Acad. Sci. IV, 12.
1923-24)
Pichilinque=San Juan Nepomucens (according to Leon Diguet)
San Jose—San Josef (Proc. Calif. Acad. Sci. IV, 12. 1923-24)
San Pedro Martir—San Pedro Martin (Rose, C.N.H. 1:78-79. 1890)
San Pedro Martir—San Pedro Martin (Rose, C.N.H. 1:78-79.
1890)
‘Tassne= Pelican
Turner’s=E] Datil (local idiom)
103
LAND PLANTS
GENTRY
No. 2
ae
Weralbo..2 ok
a
a
Espiritu Santo.......
San Francisco........
Se (0 (| en
San Diego..............
Sanita Crug:2..:..
Catalina 2)
Moneserrate.............
Danzante:...<......:..
Goa Gimeno se ik
Coroniados............
Ildefonso......--.-......
San Marcos..........-
Wortuca. 36.
L
mm
at on
S a =I
(ss} ~ is°]
© |e "oe
eae
PB lA og
‘ 5 a
DM dp) DMD
ATEVL
Eiburon 2h!
San Lorenzo...........
Sal si puedes.........
Angel de Guardia.
ES Sa Bsa a ore, ya oe ea i ANCIAG ESOJIS EITEJIO
oreo eae Sean oe "SAH eAyorjsoioeu BIIe}IS
“"UqIIOg ® Asse A wnyyueUYyoe] wnorueg
veined UqIIIG 2 AaseA WIn}e[NIOseyZ wuNotueg
Re SSG UIT], B[[aue} eIsiaqualynyy
Se eae hg oe ae ae ea a ‘yun y
(Od) vunadsororm veissaqualynypy
stnaencnennnaneseenaeeney UILT, SI]Iqap vis1aqualyqnyy
menenaontansencae WSSU Si]v410}T] aoIoyULUOY
sneccennsennennncnns ‘uqIIOg (‘[sa1g) vsojid vaanof
wn eneenenenne Anvag (7) $N}.10}U09 u0s0d019}2 FT
Pacnnnee ‘OWIFY (AaseA) lasapuevrg erumoy
necennenannenenncaneenenennnnes "MG BIBSILA SIIO[YO
seceeneeeecnnnnene nnn nnenne AIsevA Wowy]eg sniqouay
ae nen wenn nnn nana nn een nne ‘Se'T vsowdord BNOloNOT
sonnecenesnneeneecnnees ‘I10 J, eAYOuysAjod enojajnog
Lee ee Se een mands ‘qiIny T, Sopatjstie enojanog
SO Re emcee ange” ween Te ‘UII T, esiadsip eposiy
AVANINVAD
ho ke ee aera “T euyieu erddny
HVAOVNOLYDOWV.LOd
Vimeo ciara ch a wyjasuq eviodse vipaydy
AVaAOVLAND
pairs eataccnamrareiny ose AqiayyVa AA
TTUOXB JA] SIIV[NSuLIIy eUUIeIZOIAI
necennenanenncocnnnne Uo}JeY VIIUIOFI[VD VUIB[OYION,
AVAOVIGOdATOd
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Aypeoo] add},
y1odar ystue}0q Aq ps0da1 O
uo1j}99][09 Aq p1ova1 X
o)
voL. 13
ALLAN HANCOCK PACIFIC EXPEDITIONS
Ceralbo:. 2...
Espiritu Santo.......
San Francisco.......
104
pce wif wojyeyep wNjyeyur wnuosoug
pte ee Cogan oigg wif saploljes wnuodso11g
Bre eg eee 1ioy, Wnxepep wnuosomg7
Pc coreiera wer meres V ¥°H sndojda] uouosnuy
AVAOVNOOATOd
“Ysoly, UeA WNURNaNsIq uUoIpuapes0yg
epee HAN WNIIUJoOfI]ed uoIpuspesoyg
REE DRERr ESAS SRT Soper ht pt eee gate y amok eee a sees NN
(Od) wnyoejskyovig uorpuapes0yg
AVAOVHINVYOT
cae th Se aie oes SUA Wowyed sno
AVAOVUOW
ie ace uif (‘]e1],) BuBasor Bligos aarsy
Se Sine a a ean a asig Bligos aaesy
SO, ae ie ee wjasuq YJesap aarsy
Rp ene ts Opens uf essojsosAiyo aaesy
ae Sine = Se eae Sete es es Je, SUatuap aaesy
AVAOVACITIAYV NV
ee eee
AVAOVINITAWNOO
gueene ea ers snding lasapuerig eayjArq
cts Se ee oy
Saree aNe[G (‘quoy) voeqiivo steyooa|q
sasecteeteetecteneneneaesnenensnneresnene "I sueSaja sniadéa
NET TKS ee age Ine is es ujf snororp sniadAég
has Dc a ag i quoy snjestie sniadAy
AVAOVAAdAO
Rs aie amt tas MH Pyeyojnd erpory,
eaeeiens oer aee one qWUNyY snjynsie snjoqo1ods
yoda sty} ‘plo0de1 IsIY y
ydeisojoyd Aq pi0oa1 d
Aytpeoo] adA} CY,
J1odai ystuvjoq Aq piooa1 O
u01}9a]]09 Aq plover X
San Lorenzo..........
Sal si puedes...
Angel de Guardia.
San Esteban..........
Piburone
Monserrate.............
Coronados....34
Ildefonso:..
San Marcos...........-
S: PB: Nolasco...
SP Martins... <2.
Santa Cruz 06
Watalinanc: 2k.
9
bp
om
a
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op)
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(auaeIn) vyUalIOvIS sesr90A} ed auOWIAS.IY
AVAOVAAAVdVd
i (Filme mee a teal ts a aa I 0 Sak eect eer SUISSI AA
(asoy) esnyrp eAyorjsdAjod vrivwAiq
ne eee ee a SS i Re Sy | Be terse SUISSIAA Iuo\suYyof erivurdIg
oe, > te A We All| aes qjueg saptoajysojoy evriieuAId
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HAVAOVNIOV.LOAN
peieacerdia nee bow (°J) eB3dnasrajUT eryorpaol
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AVAOV LNVAVINV
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105
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LAND PLANTS
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VOL. 13
ALLAN HANCOCK PACIFIC EXPEDITIONS
106
Ceraihat: 35 2..%
Oo O*
Espiritu Santo.......
San Francisco........
9
of
om
2
S
cd
D
Santa (rugs! S- 1
Catalina
Monserrate........----.
Danzante...:=........:
Carnien... ns
mn)
a
Coronados....-:--------
Ildefonso............---.
San Marcos.........--
Moria ssn
S. P. Nolasco........
SP Marr:
San Esteban..........
mM
Tiburon oe
San Lorenzo.........-
Sal si puedes..........
Angel de Guardia.
Hoy, vjjAydosoiwm eissasuewyoyzy
ee asig VIVILIVUI VISSosueWYOTPT
sunlayT (‘d 8 “Y) xooavad winiprosay
aa eee eae asoy a1e[nsuruad wnipros1ag
ae gen sat qisem gee ep a se a SS uf x
asoy (“0 7,) wunyAydosoru winprosag
ieee te ake ag audaIQ) SIUYUOD BISseD
AVAOVNIDTVSAVO
el ee ah eee ‘Od evsoyiynf srdosorg
Or) crea a ‘[pueIg esuyUuOD WiNnIgo[oDayI Gg
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SOY CULIPILTI[IAA vlIovoy
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AVAOVSOWIN
ABIL) SUIDSAULD LIIOWIRIST
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asoy vioyiqye eAa;png
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~~
10
LAND PLANTS
GENTRY
No. 2
Pe dala ore eas ep ae a *PaIN
(a8sag 2% ‘I0J,) B1odoIDvUL BIUSeOSe Ay
apaccieoglabr steer fete AvIgy syploeis visnuel
eens yuag BOTULOFITVO vIsnuef
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AVAOV TIAHdAODAZ
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hae ABIQH Y ‘IIOT, (ABI) Aiieg valeq
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secennqenancnnnceencnnccaennnnne asig eWIIeW ealed
> ABI) VIIBUID LJLOTIVAIP vale
x Pa sacar a Aviny AoW valed
5 ENE or tr ea ‘|[2 3] Slie[Nsur snjesesy
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VoL. 13
a
ALLAN HANCOCK PACIFIC EXPEDITIONS
Ceszibn.. oe)
Espiritu Santo-.....
San Francisco........
108
5 Bad - Suaosaqnd Jojoostp snuodA youd
Se I ee ee Re RR Aesiaenesonia "|puBig (‘odag?) sipnpa edavs0dy
a at UVAOVIGUVOVNV
X x Ro a waren paruyog (yury) sisuourys eIspuowUts
Ber! alia: Bae Seay avaovxad
pais. ina X¥q (‘SIVAA) tL[NdO]Iq WUNIdEg
oe he ‘“juog sndivosos19vW snyyUe]Ipog
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ts era be ‘SIEAA vuUltjod eiqioydny
asap ‘sslog, vppayary vdavodjod eiqaoydny
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i net at og ee ee uf (dsyp tA)
vyNpOAUT vasaftpNorpad viqaoydny
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csi acs Nae pa ‘Yiuog viostu viqsoydnsgy
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‘yusg eypAydoonsy eiqioydnsy
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109
LAND PLANTS
GENTRY
No. 2
eign urea ‘wWyesuy Suapualds vlamnbnoy
fae aRN SMA AN SEDI ysenN stavypnsuruod visaimbnogy
idelanidaiaa beet aban dea: asoy lesesing viiainbnoy
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a aes ABIL) VIPOFIIUND LIIaYIVYyoS
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AVUOVULS V THO
ALLAN HANCOCK PACIFIC EXPEDITIONS
110
B
Peraipe. of «2.
Espiritu Santo.......
San Francisco........
Wn ee oe
San Diese.)
Santa Cr.
Cataimia = =
Monserrate...........-
hi, ==. ReneS MS EP ge oa dSOY ® ‘VUIG
(‘ujaduq) snsowuns snasad.0108Y IR
(I cana sere ao a ET asoy
RB WAg (‘wyasuq) m30Y9g snars.0ydoT
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Q Wag (‘wyaduyq) ruoziystAq snjyovo0.1a9y
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AVAOVLOVO
Pre (ast Aelgy (‘[[teg) stysadni vrayajaduidg
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or pees ‘uf ey[Aydouays vuissiynsary BIyazjUITA]
eae ae he ‘Hueg suatavype vijazjUay
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AVAOVSVOT
xX ae nen soy Maw[eVd voyisseg
mais seria dif[ry vsoonnaz vlopyisseg
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AVAOVAOTAISSVd
x x
yoda sry} ‘p10991 JSIY y
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Sal si puedes...
Angel de Guardia.
San Lorenzo..........
San Esteban..........
(Muir tre, : Mee eee
S. P. Nolasco...
Sb: Marie:
San Marcos............
Wertaca (2)
Corenados..
Edefonse...-...
Carr 5 | ee eee
pOanzante
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Pace soy BY ‘Wig vuvaseiing enundgo
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No. 2
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VoL. 13
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ame ade erase wif voryasue evyjuridAig
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AVAOVTNATOANOO
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AVAOVLOdVS
ALLAN HANCOCK PACIFIC EXPEDITIONS
San Diese...
Santa Cruz.
@ataima.2. 5:
Monserrate.......-...
Danzante.22 2
San Francisco........
San’ Jose.
Ceramne. 2.
Espiritu Santo.......
112
yoda sty} ‘p10da1 JsIY y
ydeasojoyd Aq psooa1 d
Ayrpesoy] adAq TF,
y1odai ystuejoqg Aq p10oa1 O
u01}99{[09 Aq p1ooa1 X
San Lorenzo..........
Sal si puedes..........
Angel de Guardia.
San Esteban..........
apron. oe eS.
Ildefonso..............-
San Marcos............
S. Po Nolasco...
S: PJ Morar.
n
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Lol
9
O
113
LAND PLANTS
GENTRY
No. 2
L
X
x
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uf epryyed eorus0yijeo eNnYystiMojied
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oe pepeens ywueg wnsazigyeAD WNUIYIInUYy
AVAOVIEV TOHdOWOS
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VoL. 13
ALLAN HANCOCK PACIFIC EXPEDITIONS
114
Ceraihe 22504
mx
Espiritu Santo.......
3 x —=9yeT_ eyuopootuayd vsouriey vrpsouq
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ded eae tack omne Se, e ore arore ecg ‘sdaf
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Sal si puedes..........
Angel de Guardia.
San Lorenzo..........
San Esteban..........
4S) ETc 0): ee
Coronados:.:.\=...
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LAND PLANTS
GENTRY
116 ALLAN HANCOCK PACIFIC EXPEDITIONS VOLS
Table 8 compares the number of known species with the approxi-
mate areas and peak elevations for each island. According to other
studies made of island floras (Cain, 1944:215-220), we could expect the
islands with more numerous species to be correlated with (1) greater
island area, (2) islands with higher elevations, (3) complex physiogra-
TABLE 8
Islands Area in Elevation Number of
sq. km meters plants known
Ve gd BAU Ce ey ee a ee ee Re 5.0 11
| ICI ener Soa Se OMe Seema Stef ee ene nL 3.0 8
Anveltde la Guardia 27. e 975.0 1315 97
| ELOvT (OPER ce aS ne SMA Oe ye Re 1.0 4
SFT HOT C0 nee en ae BZN NERA PAN ae aD 10.0
i 22 ce (ile «OR CE a: FD eee 155 11
Sal Si PUCR CS nee ee 3.0 7
De au ss 0 tee ees ee RSM A a 7.0 6
SAM COTE M ZO iu ctte sot cc aan ese ee 60.0 22
PCOS Ae Stee eee eke eee oe Saat yk i eo 2.0 8
AAS EEOEN eee noe ae ree eee ne a A 1170.0 1218 80
ISR RCT Si oe eS ae ee ete ae eae 2.0 172 3
PGaASSING Yee sent che eee ee Oe okt 5.0
RETO AN SS EL Oe | aks ey aA a OE i gt 35.0 540 48
Samm TOV EATER cc er nO eS) 2.0 21
San Pedro INOlaseO a= ge 3.5 330 29
GORE ise uses oe ee ae 7.0 312 48
Sal VEARCOS. cere iat A eed a 43.0 274 36
SITIO 1a 0, 2 lg ESS Rea Onan RR Bee 6
HG ch fat 7 Ss 0 Te RRR a Bi. INO ae St ak SP Ne 1.5 14
@anana dog ccs 2. ei eo aoe ee a 6.0 224 23
ENT gc 1a) 0 veil od eae ie ENON Ie CO EOE 135.0 483 100
AMI ZAMGE Wetter eee ee cee 4.0 138 23
IVE OnSER ta Gel ei sew och ae et oe 20.0 226 ; 25
CAtaliniae ste ee ee eee Noe eee ee 44.0 475 14
Santas Crug, ok Ph ak es eee 14.0 461 28
SAN Nes Or st 8 sth acd, Se EM oe et 1.0 222 24
SAN JOSEs 203... toch eae ee ee Be eee 210.0 583 31
DAM ORANG ISCO ested oc ese 4.5 212 30
| ee Fg 0: Ry. Sap Eee eS Aa Soe eo YN 30.0 11
Espirit Santowicto er ee ee 90.0 600 78
Pichilnque) va a a ae 16
eral bo: 2.225 ete se ERE 162 Tis 55
Table 8: The number of known species and varieties of plants compared with area
and elevation of the respective gulf islands. Areas have been computeed on the
basis of approximate measurements and can only be considered relatively.
NO. 2 GENTRY : LAND PLANTS 117
phy, (4) wetter latitudes, and degree of endemism to be heightened with
these same factors plus greater duration of isolation. However, the
available figures show us scarcely no such correlations. For example, al-
though Tiburon Island is the largest and one of the highest, it has fewer
species (80) than the much smaller island of Carmen (100). Catalina
with an area of 44 square km has only 14 species, while San Francisco
with an area of 4.5 square km has 30 species of plants. Such figures are
meaningless for phytogeographic analysis, because the islands have been
so incompletely collected. There is no published meteorological data for
any of the islands.
The most striking aspect of the island floras is the apparent lack of
divergent evolution. Endemism is at an all space low. This may be ex-
plainable on the basis of island youthfulness, or the types of migrules
and the agencies that bear them. Or it may be that lack of endemism
is in large part apparent rather than actual, since the summer-fall flora
is unknown. Can we expect more endemism to have evolved out of the
sub-tropical element than has appeared already in the temperate one?
The most certain deduction that can be made at present is that all
analysis will be tenuous until the island floras are individually and com-
pletely known and the physiography of the gulf well dated. The tables
are presented at this time not for a complete reference, but rather as a
summing up of our present knowledge and to accentuate the need for
additional field work. Our ignorance regarding the island floras is nearly
enormous.
CATALOGUE OF COLLECTIONS
POLYPODIACEAE
ADIANTUM CAPILLUS-VENERIS L., Sp. Pl. 1096. 1753.
Puerto Escondido, February 11, Dawson 1090.
Cosmopolitan in warm temperate regions. In western North America
it is known from southern California south to the Sierra Giganta in
southern Baja California and central Sinaloa, Mexico.
| GRAMINEAE
ANTHEPHORA HERMAPHRODITA (L.) Kuntze, Rev. Gen. Pl. 2:759.
1891.
- Punta Frailes, Cape District, February 16, Dawson 1122.
Widely distributed in tropical and subtropical America; type from
Jamaica.
118 ALLAN HANCOCK PACIFIC EXPEDITIONS VoL. 13
ARISTIDA PuRPUSIANA Hitche., C.N.H. 17:276. 1913.
San Jose del Cabo, February 17, Dawson 1211.
Known only from southern Baja California; the type from San Jose
del Cabo.
BoUTELOUA BARBATA Lag., Cienc. 24:141. 1805.
San Jose del Cabo, February 17, Dawson 1182. Punta Frailes, Cape
Frailes, February 16, Dawson 1119.
Southwestern United States and northern Mexico; type from Mexi-
co. It is most abundant through the middle and low elevations of the
Grama Grasslands, where it often takes its place as one of the codomi-
nants. The cape specimens show no significant differences from main-
land material and the population from which they come may be a recent
or post-Pleistocene development.
BOUTELOUA CURTIPENDULA (Michx.) Torr. in Emory, Notes Mil.
Reconn. 154. 1848.
San Jose del Cabo, February 17, Dawson, 1207. Agua Verde Bay,
March 10, Rempel 136.
Widely distributed in North America from Canada to Central
America. It is most abundant in the Grama Grasslands of the semiarid
southwestern United States and northern Mexico, where it is one of the
codominating gramas. It is also in South America, occupying similar
habitats. The type locality is the Limpio Mountains, Texas. The Feb-
ruary collection is in anthesis, that of March already seeded. The species
is apparently capable of flowering twice a year.
CENCHRUS PALMERI Vasey in Brge., Proc. Calif. Acad. Sci. II,
22211. 1889.
San Jose del Cabo, February 17, Dawson 1181.
This strongly spined burr grass is endemic to the California Gulf
Region where it is known from the southern half of the peninsula, on
the adjacent islands, and around Guaymas, Sonora, the latter being the
type locality. It forms extensive stands along the stationary dunes of the
outer peninsular coast and is obnoxious because of the strong sharp spines
on the large fruits.
ERAGROSTIS VISCcOSA (Retz.) Trin., Mem. Acad. Petersb. Ser. VI,
Math. Phys. Nat. 1:397. 1830.
San Jose del Cabo, February 17, Dawson 1160.
The Cape District of Baja California and India; the type from
Malabar Beach. Obviously an introduction, perhaps in ballast.
No. 2 GENTRY : LAND PLANTS 119
HETEROPOGON CONTORTUS (L.) Beauv. Roem. & Schult., Syst. Veg.
2 :836. 1817.
San Jose del Cabo, February 17, Dawson 1151.
Widely distributed in the warmer parts of both the Old and New
Worlds; type from India. An aggressive persistent, harsh, scarcely palat-
able grass and a nuisance in many areas of Mexico. It may be successive
on burnt areas.
JouvEA PILosaA (Presl.) Scribn., Bull. Torr. Bot. Club 23:143.
1913.
Punta Frailes, February 16, Dawson 1122.
Coastal from Baja California to Nicaragua. In the California Gulf
Region it is known from the Cape District and on the adjacent islands
as far north as Carmen Island (Johnston 3835).
MUHLENBERGIA Porrteri Scribn. in Beal, Grasses N. Am. 2:259.
1896.
San Jose del Cabo, February 17, Dawson 1203.
Southwestern United States and northern Mexico.
SETARIA MACROSTACHYA H.B.K., Nov. Gen. & Sp. 1:110. 1851.
San Pedro Nolasco Island, February 6, Dawson 10335.
Texas to Colorado, Arizona, and Mexico; type from Guanajuato,
Mexico. On San Pedro Nolasco Island it forms extensive stands, being
the dominant vegetation over some of the open hill slopes.
CYPERACEAE
CYPERUS ELEGANS L., Sp. Pl. 45. 1753.
San Pedro Nolasco Island, February 6, Dawson 1036.
Apparently native to northern Mexico. This is the first record of the
species on San Pedro Nolasco Island.
CYPERUS PERENNIS (Jones) O’Neill, in Morton C.N.H. 29:93.
1945.
San Jose del Cabo, February 18, Dawson 1164.
Known only from the Cape Region. Apparently rare and seldom col-
lected.
PALMAE
ERYTHEA BRANDEGEI! Purpus, Gartenflora 52:11, f. 1-2. 1903.
Canyon above Puerto Escondido, March 13, Rempel 146, 146a.
Described originally from the mountains back of San Jose del Cabo,
Baja California, the species is common to the canyons where intermit-
120 ALLAN HANCOCK PACIFIC EXPEDITIONS VoL. 13
tent streams have regular perennial flows through their steep rocky
channels in the canyons of the Sierra Laguna and to the north along the
east face of the Sierra Giganta. It has not been collected north of Puerto
Escondido, but may occur as far north as the sierras west of Muleje.
The leaves are small and more lucid than glaucous. Typical specimens
appear in Plate 10, fig. 23.
COMMELINACEAE |
COMMELINA ELEGANS H.B.K., Nov. Gen. & Sp. 1:259. 1851.
San Jose del Cabo, February 17, Dawson 1225.
Widespread in the region of summer rainfall from northern Mexico
to Central America; type from ‘“‘ad:ripas fluvii Juanambu, alt. 760
hexap.,” central Mexico. A low polypodial perennial herb with bright
blue frosty flowers and thick fibrous roots.
AMARYLLIDACEAE
AGAVE CHRYSOGLOSSA Jtn., Proc. Calif. Acad. Sci. IV, 12 :998. 1924.
San Pedro Nolasco Island, March 29, Rempel 300.
This distinctive Agave of the subgenus Littaea is characterized by
the unarmed leaf margins, geminate flowers, and small capsules (2 cm
long) and is known certainly only from San Pedro Nolasco Island. The
above collection, with missing fruit and flowers, is apparently the second
collection. The species apparently flowers through March and April.
AGAVE DENTIENS Trel., Rep. Mo. Bot. Gard. 22:51, pl. 38-40. 1911
South end of San Esteban Island, March 27, Rempel 295.
Described from San Esteban Island, the extent of its range is un-
certain, but it most likely occurs on adjacent islands. I cannot agree with
Johnston (Proc. Calif. Acad. Sci. IV, 12:996-997) in assigning the San
Esteban plants to Agave deserti. In comparing them with the popula-
tions on Angel de la Guardia Island, he apparently was misled by inter-
grading or hybrid plants. The above specimen with its linear-lanceolate
leaves and its distinctive deciduous or ‘‘friable’’ mammilloid marginal
prickles shows no close relation to plants of 4. deserti at the type locality,
San Felipe, California and which I have observed. Until more material
and evidence is obtained, it appears appropriate to maintain the San Es-
teban plants as specifically distinct.
AGAVE OwENI Jtn., Proc. Calif. Acad. Sci. IV, 12:999. 1924.
Ensenada de San Francisco, Sonora, March 30, Rempel 311.
Apparently endemic to the mountains about Guaymas; the type from
an islet in Guaymas Harbor. Except for the smaller marginal prickles
NO. 2 GENTRY: LAND PLANTS 121
and the dark brown color of the terminal spine, probable ecologic varia-
tions, the above collection agrees well with Johnston’s description. The
present collection as well as his description, however, hardly bear out his
surmise that the plant is related to 4. yaguiana Trel. The short conical
terminal spine, the grooved or striate perianth, and the ovoid capsule,
rather, express a relationship to 4. datylio Simon of the Cape District of
the peninsula.
AGAVE SOBRIA Brge., Proc. Calif. Acad. Sci. II, 2:207. 1889.
A gave carminis Trel., Rep. Mo. Bot. Gard. 22:55. 1912.
A gave affinis Trel., 1. c. p. 56.
Canyons above Puerto Escondido, Baja California, March 13, Rem-
pel 143.
Ranges through the mountains south of San Ignacio to and along
the Sierra Giganta, its southern limits are not exactly known. Brande-
gee collected the type on the mesas above Comondu. Dispersed colonies
or stands of this 4gave were commonly observed by the author on the
rocky slepes and rocky summits of the long mesas running out westward
from the Sierra Giganta towards the Magdalena Plains. The rather
small panicles of greenish-yellow flowers are conspicuous through the
spring months.
MORACEAE
Ficus PALMERI Wats., Proc. Am. Acad. Sci. 24:77. 1889.
Canyon above Puerto Escondido, Baja California, March 13, Rem-
pel 168.
Endemic to the California Gulf Region, where it occurs on many
of the gulf islands and the southern two-thirds of the peninsula from
Yubay southward. Except for Guaymas and vicinity it is lacking on the
mainland. Type locality is San Pedro Martir Island, where Palmer
first collected it. It is found principally along rocky canyons, cliffs, and
rocky slopes on the mountains where run-off augments the precipitation
in increasing soil moisture. The leaves are rather variable, but the most
typical form appears to be regularly cordate and during the rainy season
they form a dense shade.
LORANTHACEAE
PHORADENDRON CALIFORNICUM Nutt., Jour. Acad. Phil. II, 1:185.
1848.
Tiburon Island, January 25, Dawson 1016. Agua Verde Bay, Baja
California, March 10, Rempel 131.
Known from southern Utah, Arizona, southern California, and
122 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 13
northern Mexico; type from California. It appears partial to legumin-
ous trees. Rempel collected it on Prosopis. Both specimens are in flower
indicating a considerable latitude for seasonal flower.
PHORADENDRON DIGUETIANUM Van ‘ieghem, Bull. Mus. Hist.
Nat. Paris 1:31. 1895.
Escondido Bay, February 10, Dawson 1106. San Gabriel Bay, Es-
piritu Santo Island, March 7, Rempel 90, 91, on Bursera.
Known from the southern half of Baja California and the islands
in the California gulf; sensu latus of the species as defined by Johnston
(1924:1008). ,
OLACACEAE
SCHOEPFIA CALIFORNICA Brge., Proc. Calif. Acad. Sci. II, 2:139.
1889.
San Jose del Cabo, February 17, Dawson 1179. Puerto Escondido,
February 11, Dawson 1090.
It forms a shrub or small tree. The leaves are sclerophyllous, ovate,
sessile, thickish, mostly 1.5 to 2.0 cm long, and fall away on the herb-
arium sheets. It is known from near Miller’s Landing and Santo Do-
mingo at the north end of the Vizcaino Desert (Goldman, C.N.H. 16:
324. 1916) to the cape.
POLYGONACEAE
ANTIGONON LEPTOPUS Hook. & Arn., Bot. Beech. 308, t. 69. 1840.
San Jose del Cabo, February 17, Dawson 1174. Punta Frailes, Feb-
ruary 16, Dawson 1127. Cabeza Ballena, Cape District, March 3, Rem-
pel 68.
Mostly in the Thorn Forest along the west coast of Mexico from
southern Baja California and southern Sonora to Oaxaca; type from
Tepic, Nayarit. It is a showy summer vine with bright pink sprays of
inflorescence; cultivated in Mexico and southwestern United States as
an ornamental.
ERIOGONUM DEFLEXUM ‘Torr., Bot. Ives Rep. 24. 1860.
Angel de la Guardia Island, Puerto Refugio, January 26, Dawson
1027:
Known from around the upper gulf in California, Arizona, and
Baja California; type from Three Point Bend, Colorado River.
ERIOGONUM INFLATUM DEFLATUM Jtn., Proc. Calif. Acad. Sci. IV,
b2-1013.. 1924.
Puerto Refugio, Angel de la Guardia Island, January 26, Dawson
NO. 2 GENTRY: LAND PLANTS 123
1030; March 20, Rempel 274. Tortuga Island, March 17, Rempel 228.
Known only from the Colorado Desert, northern Baja California,
and the adjacent islands of San Marcos, Angel de la Guardia, and Tor-
tuga; type from the Colorado Desert, California. This variety differs
from the species in the tendency to produce more numerous and nonin-
flated stems. Ihe March specimen from Tortuga is less advanced than
the January one of a later year, indicating a broad seasonal tolerance in
harmony with the irregularity of winter rain in the region.
CHENOPODIACEAE
ALLENROLFIA OCCIDENTALIS (Wats.) Kuntze, Rev. Gen. Pl. 1:546.
1891.
Agua Verde Bay, Baja California, March 10, Rempel 116, forms
mounds on the crescentic dunes. San Francisco Island, March 9, Rempel
111, (both sterile).
In moist saline soils of arid southwestern United States and north-
western Mexico from Oregon and Utah south to the Cape District;
type from about Great Salt Lake, Utah. A low succulent shrub with
brittle short branches and caducous leaves common to the halophytic
associations around the lagoons and estuaries of the gulf and western
peninsular shores.
ATRIPLEX BARCLAYANA (Benth.) Dietr., Synop. 5:537. 1852.
Puerto Refugio, Angel de la Guardia Island, January 26, Dawson
1031. Guaymas, Sonora, January 23, Dawson 1007. Tortuga Island,
March 17, Rempel 219, 220.
A common and widespread bush on salty or nonsalty soils through-
out the gulf area in Baja California and western Sonora; type from
Magdalena Bay, Baja California. Goldman (C.N.H. 16:326. 1916)
reports it as an abundant low shrub 90 to 120 cm high between Calmalli
and San Ignacio. In its several varieties it is an abundant and wide-
spread plant, either as low decumbent perennial herbs or more erect
bushes which may become woody.
ATRIPLEX POLYCARPA (Torr.) Wats., Proc. Am. Acad. Sci. 9:117.
1874.
Puerto Refugio, Angel del la Guardia Island, March 20, Rempel
271. Los Angeles Bay, Baja California, March 19, 20, Rempel 2406.
_ Widely distributed in the arid southwest from southern Utah and
central California south to Sonora and southern Baja California; type
from the Gila River Valley, Arizona. While abundant around the
124 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 13
shores of the gulf, there are relatively few collections of the plant from
the outer coast of the peninsula. The narrower leaves, shrubby branches,
and multituberculate fruits are a combination of characters conveni-
ently separating this species from A. Barclayana.
AMARANTACEAE
AMARANTHUS CAUDATUS L., Sp. Pl. 990. 1753.
Tortuga Island, March 17, Rempel 213.
Pansubtropical; type locality unknown, described from cultivated
plants. It is apparently one of the weeds that was early and widely dis-
seminated in ballast and baggage. It has not previously been reported
for the California gulf area.
AMARANTHUS Wartsonl Standl., Bull. Torr. Bot. Club 41:505.
1914.
Tiburon Island, January 25, Dawson 1014. Agua Verde Bay, Baja
California, March 10, Rempel 135, reef.
Rather frequent in bottomland and saline soils in the southern part
of the gulf region from about Calmalli south on the peninsula; type from
vicinity of Guaymas, Sonora. It is also known from several of the gulf
islands. (See Table 7.)
CELOSIA FLORIBUNDA Gray, Proc. Am. Acad. Sci. 5:167. 1861.
Cabeza Ballena, Cape District, March 3, Rempel 64.
Southern part of Baja California along the rocky slopes and canyons
of the mountains; type from Cape San Lucas. A shrub or small tree
with rather variable leaves, varying from ovate to ovate-acuminate and
from crenate to serrate. ‘Those of Rempel 64 are unusual in being
broadly lobed near the base. ‘he specimen is fruiting.
FROELICHIA INTERRUPTA (L.) Mog. in DC., Prodr. 132 :421. 1849.
San Jose del Cabo, February 17, Dawson 1206.
Widely distributed in warmer America. It is a slender erect peren-
nial herb about 1 m high with tomentose pallid leaves all basal and
several terminal or nodal, brownish yellow, dense spikes 1.5 to 5 cm long,
the lower flowers caducous leaving a whitish naked rachis.
IRESINE ANGUSTIFOLIA Euphrasen, Beskr. St. Barthel. 165. 1795.
Puerto Escondido, February 11, Dawson 1940. Punta Frailes, Feb-
ruary 16, Dawson 1116.
From Baja California to Vera Cruz south through Central America
to Brazil and the West Indies; type from St. Barthelomew Island, West
Indies.
No. 2 GENTRY: LAND PLANTS 125
NycTAGINACEAE
ABRONIA MARITIMA Nutt. in Wats., Bot. Calif. 2:4. 1880.
San Francisco Island, March 9, Rempel 103, on beach dunes. San
Juanico Bay, March 2, Rempel 46.
Widely distributed in the California Gulf Region where it has been
collected or reported along the shores and on many of the islands. Type
locality is San Pedro, California.
CoMMICARPUS BRANDEGEI Standl., C.N.H. 12:374. 1909.
Puerto Escondido, February 11, Dawson 1099. Punta Frailes, Feb-
ruary 16, Dawson 1123. San Jose del Cabo, February 17, Dawson 1204.
Endemic to southern Baja California; type from San Pablo. Insular
in origin, it appears to have migrated in Quarternary times northward
along the Sierra Giganta. It is a scandent shrub similar in habit to C.
scandens, but distinguished by larger leaves and the annular arrange-
ment of glands on the fruits.
BATIDACEAE
BATIS MARITIMA L., Syst. Nat. ed. 10:1289. 1759.
San Francisco Island, March 9, Rempel 102, around playa.
Littoral in the warmer parts of the New World from Hawaiian
Islands to Florida and Brazil; type locality unknown.
PHYTOLACCACEAE
STEGNOSPERMA HALIMIFOLIUM Benth., Bot. Voy. Sulph. 17. 1844.
San Jose del Cabo, February 17, Dawson 1202. Sonora, near Guay-
mas, February 9, Dawson 1083. San Carlos Bay, February 8, Dawson
1058. Puerto Refugio, Angel de la Guardia Island, March 20, Rempel
278. Tortuga Island, Rempel 230. Island in Concepcion Bay, Rempel
192.
Widely distributed through the littoral of middle America; type from
Cape San Lucas, Baja California. It forms a dense symmetrical bush
1-2 x 1-3 m and has a long inflorescence period through the spring.
AIZOACEAE
MOLLUvUGO VERTICILLATA L., Sp. Pl. 89. 1753.
San Jose del Cabo, February 17, Dawson 1205.
Widely distributed in North America and the Old World. A low
prostrate or ascendant-stemmed annual herb with radiating stems, verti-
cellately branched, lanceolate to linear leaves, and cymose inflorescence.
The minute apetalous flowers having tripartite stigmas distinguished it
from the Drymarias, which it greatly resembles in appearance. The seeds
are reniform, shiny brown, and distinctly ribbed.
126 ALLAN HANCOCK PACIFIC EXPEDITIONS VoL. 13
SESUVIUM PORTULACASTRUM L., Syst. Nat. ed. 10:1058. 1759.
Cabeza Ballena, Cape District, March 3, Rempel 54. West cove in
Concepcién Bay, March 15, Rempel 171. Agua Verde Bay, March 10,
Rempel 114. Lagoon Head Anchorage, Vizcaino Desert, March 1, Rem-
pel 21.
Common along the shores of the tropics and subtropics of the Old
and New Worlds; type from Curacao, Dutch West Indies. ‘The above
collections established the plant as general in distribution along the
saline littoral of the southern half of the California peninsula.
CARYOPHYLLACEAE
DrYMARIA HOLOSTEOIDES Benth., Bot. Voy. Sulph. 16. 1844.
San Francisco Island, March 9, Rempel 108, edge of playa. San
Gabriel Bay, Espiritu Santo Island, March 7, Rempel 100, transition
between beach dunes and alluvial flats. Los Angeles Bay, March 19, 20,
Rempel 260, north end.
Sandy soils from central Baja California to the Cape District and
the surrounding islands. It is one of the most common low winter an-
nuals in the middle peninsula where it affects the arid gravelly soils as
well as the sands of alluvial fills and dunes. The type locality was er-
roneously given as Cape San Lucas, but it is most likely Magdalena Bay,
where Barclay and Hinds collected it (Wiggins, Proc. Calif. Acad. Sci.
IV, 25:194. 1944).
DRrYMARIA PENINSULARIS Blake, Jour. Wash. Acad. Sci. 14:285.
1924.
San Jose del Cabo, February 17, Dawson 1189.
Endemic to the postinsular Cape District. A diffuse stipitate-glandu-
lar annual 15 to 18 cm tall with thickish linear leaves. A close examina-
tion of the petals shows the appendages in the sinuses to be variable.
They may consist of one forked ligulate appendage, or 2. to 3 lobes of
varying width, some of which are nearly subulate, and which, according
to Wiggins (1. c. p. 203, pl. 22), separates the peninsular species from
the mainland D. arenarioides. Hence, in the Dawson specimens, this
floral character separating the two species is not consistent, and suggests
that typical D. arenarioides may exist on the peninsula, although it has
never been collected there, and the Dawson specimen is an intergrading
or hybrid form. If this should prove to be the case, then D. peninsularis
had better be regarded as a variety of D. arenarioides.
DrRYMARIA POLYSTACHYA DIFFUSA (Rose) Wiggins, Proc. Calif.
Acad. Sci. IV, 25:198. 1944.
No. 2 GENTRY : LAND PLANTS 127
Puerto Escondido, February 9, Dawson 1095.
Known only from Carmen Island and the adjacent peninsula; type
from Carmen Island. Annual diffuse herb with sparsely puberulant
stems and small broadly cordate leaves 6 to 8 mm long, 6 to 9 mm wide.
The Dawson collection disagrees with Wiggins’ description in having
the sepals acute rather than retuse to rounded and the claw is unusually
long. Otherwise it agrees and the clawed long-lobed petals are particu-
larly diagnostic of the species.
PAPAVERACEAE
ARGEMONE MEXICANA L., Sp. Pl. 508. 1753.
San Jose del Cabo, February 17, Dawson 1223.
Widely adventive in the tropics of both hemispheres, especially in
waste lands; type from Mexico. This specimen is typical of the pale
yellow-flowered annual commonly aggressive in the fallowing fields of
western Mexico; flowers, spring.
ESCHSCHOLTZIA MINUTIFLORA Wats., Proc. Am. Acad. Sci. 11:122.
1876.
Puerto Refugio, Angel de la Guardia Island, March 20, Rempel 269.
The species is widely distributed in the southewestern deserts, reach-
ing its southern limits in central Sonora and middle Baja California.
The above collection is the first reported from the California Gulf
Islands. It is a small slender annual 20 cm tall with reddish root, sca-
pose, the dried petals only 4 mm long.
CRUCIFERAE
DrYOPETALON PALMERI (Wats.) O. E. Schultz in Notizbl. Bot.
Gart. Berlin 10:561. 1929.
Puerto Escondido, February 11, Dawson 1089. Agua Verde Bay,
Baja California, March 10, Rempel 140a (fruiting).
Winter annual of southern Baja California.
Lyrocarpa linearifolia Rollins sp. nov.
Herba perennis suffruticosa; caulis ramosis stramineis pubescentibus ;
foliis linearis sparse lobatis vel integris pubescentibus 1-4 cm longis, 1-3
mm latis; siliquis obcordatis pubescentibus 4-10 mm longis, 5-12 mm
latis ; stigmatibus sessilibus.
Suffrutescent perennial; older stems ash gray, glabrate, striate, bark
exfoliating in longitudinal strips, young stems densely pubescent, terete,
reddish-purple beneath the white trichomes; leaves persistent, subfascicu-
late, densely pubescent with white substellate trichomes, sparingly lobed
with 1 to 3 pairs of small lobes or sometimes entire, linear, scarcely dif-
128 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 13
ferentiated into petiole and blade, 1-4 cm long, 1-3 mm wide, lobes 1-3
mm long, ca. 1 mm wide; flowers unknown; siliques clustered at the
apex of a nearly leafless peduncle, the infrutescence approaching a sub-
umbellate condition, siliques broadly obcordate with a very shallow sinus
above, densely pubescent throughout, strongly flattened contrary to the
replum, 4-10 mm long, 5-12 mm wide; stigma sessile and not lobed.
Known only from the type no. 6913 in the herbarium at the Allan
Hancock Foundation, University of Southern California, collected at
Puerto Refugio, Angel de la Guardia Island, Gulf of California, March
20, 1937, Rempel 280.
Lyrocarpa linearifolia is unmistakably related to L. Coulteri, var.
Palmeri. It differs strikingly from var. Palmeri in having narrowly
linear, relatively undifferentiated leaves, smaller siliques and sessile un-
divided stigmas. In some plants of var. Palmeri, the leaves show a strong
trend toward reduction of the blade, but in no case do they approach
the narrowness and small lobes of L. linearifolia. ‘The leaves of the latter
species are subfasciculate but never so in var. Palmeri. ‘The stigmas of
var. Palmeri terminate in a definite short style and are conspicuously
lobed, whereas those of L. linearifolia are sessile and undivided. Another
difference is notable in the infructescence which is subumbellate in L.
linearifolia and racemose in var. Palmeri. The material of L. lineari-
folia is insufficient to permit speculation as to the natural variation
found in the species. The type specimen lacks roots, and the stems ap-
pear to have been broken off somewhat above the root-crowns. For this
reason it is not possible to form any notion as to the height of the plants
from which the specimens were taken.
LyrocaRPA XANTII Brge., Proc. Calif. Acad. Sci. II, 2:127. 1890.
San Jose del Cabo, February 17, Dawson 1199.
Stony canyon slopes and coarse alluvium along the mountains from
the Vizcaino Desert to the Cape District.
RESEDACEAE
OLIGOMERIS LINIFOLIA (Vahl) McBr., Cont. Gray Herb. II, 53:13.
1918.
North end of Los Angeles Bay, March 19, 20, Rempel 258.
Widely scattered in the deserts of the southwest from Texas and
California south throughout Baja California; also in Asia and Africa.
MorRINGACEAE
MorInGA OLEIFERA (L.) Lam., Encycl. 1:39. 1783.
Guilandina Moringa L., Sp. Pl. 381. 1753.
No. 2 GENTRY : LAND PLANTS 129
Punta Frailes, Cape District, February 16, Dawson 1139.
Native of eastern Africa and perhaps of the East Indies. It is culti-
vated in the tropical latitudes for the ‘‘ben” oil of commerce obtained
from the seeds. In India the young leaves, pods, and flowers are cooked
and eaten. It is cultivated in parts of the American tropics and has be-
come naturalized locally. The collector reports that the above cited
number was found growing spontaneously with native vegetation, far
from any appreciable settlement.
The plant forms a small tree or shrub and the pinnate leaves,
5-merous and slightly irregular corolla on jointed pedicles, and long
legume-like capsules strongly suggests some of the Caesalpiniaceae. The
author narrowly averted erecting a new genus to receive it. It is dis-
tinguished from members of the Caesalpiniaceae by its tripinnate leaves
and the 3 parietal placentae (or 2 plus 1 double placentae) of the ovary.
The pod in Dawson’s collection is quite terete, somewhat longitudinally
ribbed, not perceptibly 3-angled as described by authors, and the anthers
are basally affixed rather than dorsifixed as described. The seeds appear
to be imbedded in a pulpy aril, rather than winged. The specimen is
illustrated in Plates 1 and 2.
KRAMERIACEAE
KRAMERIA PARVIFOLIA Benth., Bot. Voy. Sulph. 6, pl. 2. 1844.
San Jose del Cabo, February 19, Dawson 1201.
Arid rocky situations of the gulf region and throughout the Sonoran
Desert. This species shows considerable variation in leaf form and in
the presence or absence of glandular hairs. Through the northern part
of its range in northern Baja California and southwestern United
States a wider-leaved glandular variety occurs, K. parvifolia glandulosa
(Rose & Painter) McBr. Gentry (Carn. Inst. Wash. Publ. 527:120.
1942) reports the species also from southern Sonora and western Chi-
huahua. A close study of collections should reveal geographic segregates
of historical significance.
KRAMERIA PAUCIFOLIA Rose, C.N.H. 10:108. 1906.
Island in Concepcién Bay, Baja California, March 16, Rempel 198,
on alluvial fan. North end of Los Angeles Bay, March 19, 20, Rempel
254.
A low stiff spreading shrub with canescent twigs and foliage common
130 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 13
on the rocky arid slopes of central and southern Baja California; type
from La Paz, Cape District.
MIMOSACEAE
AcACcIA FARNESIANA (L.) Willd., Sp. Pl. 4:1083. 1806.
Near Guaymas, February 9, Dawson 1079. Agua Verde Bay, Baja
California, March 10, Rempel 126, floor of valley.
Widely distributed in the tropics and subtropics of both hemispheres.
A low thorny tree. In the Old World the flowers are employed in mak-
ing perfume.
Acacia GoLpMANII (Brit. & Rose) Wiggins, Cont. Dud. Herb.
3:68. 1940.
Acaciella Goldmanii, Brit & Rose, N. Am. FI. 23:99. 1928.
San Jose del Cabo, February 17, Dawson 1173. Cabeza Ballena,
March 3, Rempel 67.
A slender tree, rare in herbaria, known only from southern Baja
California; the type from between San Pedro and Tres Pachilas, Lower
California Desert, Nelson and Goldman 7336.
Calliandra Brandegeei (Brit. & Rose) Gentry new comb.
Anneslia Brandegeei Brit. & Rose, N. Am. FI. 23:62. 1928.
San Jose del Cabo, February 17, Dawson 1165.
Known only from the Cape District; type from Sierra San Fran-
cisco, Baja California. This is a low, stiff, tortuously twigged shrub,
the old branches gray, the new reddish brown. The reddish-yellow
flowers are described as glabrous, but the above specimen shows a few
whitish hairs on both the calyx and corolla.
CALLIANDRA CALIFORNICA Benth., Bot. Voy. Sulph. 14. 1844.
San Juanico Bay, Baja California, March 2, Rempel 31.
Scattered through middle Baja California from the latitudes of Ro-
sario south along the outer coast to Magdalena Bay, the type locality.
Goldman (C.N.H. 16:332) cites it also from the Cape District, but
the cape population is referrable rather to C’. peninsularis Rose. It forms
a low stiff bush broadly spreading, its specific ecologic niche being the
rocky arroyos. When in bloom through the spring the bright red flowers
make it one of the most attractive of the Calliandra.
LysILOMA CANDIDA Brge., Proc. Calif. Acad. Sci. II, 2:153. 1889.
San Jose del Cabo, February 17, Dawson 1171. Agua Verde Bay,
NO. 2 GENTRY : LAND PLANTS 131
March 10, Rempel 132 (sterile).
Southern half of Baja California; type from La Purissima. The
northern limits appear to be in the mountains just north of San Ignacio
about Lat. 27°30’. It is a small tree with conspicuously white bark,
white flowers, and rather sparse open foliage.
PITHECOLOBIUM CONFINE Standl., C.N.H. 20:191.1919.
Cabeza Ballena, Cape District, March 3, Rempel 61.
A low branching, broad, spreading shrub with thick spiny branches
and very heavy, wide, dark brown pods, usually constricted in the mid-
dle, common to the river valleys and arroyos of the southern half of the
peninsula; the type from Cabo San Lucas.
PROSOPIS JULIFLORA (Swartz) DC., Prodr. 2:447. 1825.
San Gabriel Bay, Espiritu Santo Island, March 7, Rempel 84 (ster-
ile). Agua Verde Bay, March 10, Rempel 124 (flowering).
Widely scattered in the deserts of North America, the mesquite
shows many local variants which are hard to define, but which are in
need of close taxonomic study.
CAESALPINIACEAE
CAESALPINIA ARENOSA Wiggins, Cont. Dud. Herb. 3:68, figs. 1-3.
1940.
San Juanico Bay, March 2, Rempel 41.
Sandy coastal plains in the southern part of the peninsula from Lo-
reto and San Juanico south nearly to La Paz; type from Guadelupe,
Baja California. A rather openly branched shrub up to 2 m tall related
to C. pannosa and C. placida, both of which are apparently cape endem-
ics. C. arenosa differs from the others in having tortulose branchlets,
puberulent, glandular leaflets, eglandular calyces, and the outer surfaces
of the petals glandular almost to the tip.
CAESALPINIA CALIFORNICA (Gray) Standl., C.N.H. 23 :426. 1922.
Punta Frailes, February 16, Dawson 1125.
Known only from the Cape District. An open shrub with very long
peduncles 18 to 24 cm long, pods puberulent, eglandular, straw-colored ;
pedicles, calyces, petals, and filaments long puberulent. First collected
by Xantus, this shrub has rarely been taken since.
CAESALPINIA PALMERI Wats., Proc. Am. Acad. Sci. 24:47. 1889.
San Carlos Bay, Sonora, February 8, Dawson 1053, 1061.
132 ALLAN HANCOCK PACIFIC EXPEDITIONS VoL. 13
Northern Sonora along the coast and foothills to central Sinaloa;
type from Guaymas, Sonora. A small tree with irregular divaricate
branching, the bark brown and spotted with lenticels. he foliage is
sparse, especially in the arid spring when the small leaflets are reduced
in size and number. It is distinguished from other members of the genus
by its glabrous leaves, eglandular calyces, and small flowers usually not
more than 1 cm long.
CASSIA CONFINIS Greene, Pittonia 3:225. 1897.
West cove in Concepcién Bay, March 15, Rempel 184. North end
of Los Angeles Bay, March 19, 20, Rempel 251.
It has been collected only along the east side of the peninsula and
adjacent islands from the vicinity of Los Angeles Bay to Santa Rosalia;
the type from Los Angeles Bay. It is distinguished from its near Sonoran
relative, C. Covesii, by its larger leaves, thicker fruits, and generally
shorter pubescence.
CERCIDIUM MICROPHYLLUM (‘Torr.) Rose & Jtn., Cont. Gray Herb.
II, 70:66. 1924.
West cove in Concepcién Bay, March 15, Rempel 186, rocky hill-
side (sterile).
This is one of the most common of the palo verde trees so charac-
teristic of the Sonoran Desert. On the mainland it reaches into southern
Sonora and well into middle Baja California. It forms a low spreading
tree with a round crown of foliage and while scatteringly common on
the open slopes, it attains its best development along arroyos and allu-
vial fans.
CERCIDIUM PENINSULARE Rose, C.N.H. 8:301. 1905.
Agua Verde Bay, Baja California, March 10, Rempel 125 (sterile).
Southern part of the peninsula and on Carmen and Ceralbo Islands;
type from La Paz, Cape District. A small symmetrical tree with rela-
tively dense foliage. Goldman (C.N.H. 16:336) provided a photograph
of the tree and states, ‘““Ihe type of this species was taken by the present
writer on the open plain near La Paz April 16, 1899, then in flower.
It is abundant throughout the Cape District south of La Paz except on
the upper slopes of the mountains and reaches northward to an unde-
termined limit, its range overlapping or so continuous with that of tor-
reyanum that we did not distinguish between them.”
NO. 2 GENTRY: LAND PLANTS 133
HoFFMANSEGGIA INTRICATA Brge.?, Proc. Calif. Acad. Sci. II, 2:
151. 1889.
Tiburon Island, January 25, Dawson 1017.
Northern Baja California; type from El] Campo Aleman. This al-
most sterile leafless specimen is not certainly identifiable. It contains two
or three sordid flowers 4 to 5 mm long, regularly stipitate glandular on
bracts, pedicels, sepals, and petals. The filaments are barbate below and
with a few stipitate glands above the hairs midway along the filaments.
The ovary is 4 to 5 ovulate and bears 2 or 3 irregular rows of sessile
or subsessile glands. It is apparently a low shrub with slender numerous
purple to glaucous branches forming a broom-like crown.
FABACEAE
AESCHYNOMENE NIVEA Brge., Proc. Calif. Acad. Sci. II, 2:150.
1889. |
San Gabriel Bay, Espiritu Santo Island, March 7, Rempel 94.
A virgate subshrub, striking because of its silvery pubescence. The
above collection is sterile indicating no spring flowering. Known from
the southern half of the peninsula and the adjacent islands; type from
La Purissima.
COURSETIA GLANDULOSA Gray, Proc. Am. Acad. Sci. 5:156. 1862.
Sonora: San Carlos Bay, February 8, Dawson 1067. Baja Cali-
fornia: San Jose del Cabo, February 17, Dawson 1180. Cabeza Ballena,
Cape District, March 3, Rempel 60.
Cape District of Baja California, southern Sonora to central Sina-
loa; type locality, vicinity of Cape San Lucas. A slender polypodial shrub
characteristic of the arid rocky soils along washes in the Sonoran Desert
and in washes and on slopes in the Thorn Forest. It is host to a lac
insect. It flowers in the spring with depauperate foliage. Its real period
of vegetative growth is during summer and fall concomitant with the
summer rains.
Da.LeaA Emory Gray, Mem. Am. Acad. Sci. II, 5:315. 1854.
Los Angeles Bay, March 19, 20, Rempel 245.
Found nearly throughout the Sonoran Desert, lacking apparently
only in southern Sonora and tending to be replaced on the outer pen-
insular coast by D. tinctoria, its close relative. Type locality: Table-
lands of the Gila, Arizona.
DALEA MARITIMA Brge., Proc. Calif. Acad. Sci. II, 3:125. 1891.
San Gabriel Bay, Espiritu Santo Island, March 7, Rempel 98, in
134 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 13
more or less alkaline soil at west end of pass.
A decumbent suffrutescent with canescent, purplish, and glandular-
pustulate stems. Known hitherto only from the Cape District; the type
from Todos Santos.
DALEA MOLLIS Benth., Pl. Hartw. 306. 1848.
San Juanico Bay, Baja California, March 2, Rempel 45,
A prostrate or decumbent or somewhate ascending herb in sandy and
coarse gravelly soils nearly throughout the Sonoran Desert.
DaLeA Parry (Gray) Torr. & Gray, in Gray, Proc. Am. Acad.
Sa. 7239/7. 1868.
Tortuga Island, March 17, Rempel 227. Los Angeles Bay, March
19, 20, Rempel 240. Island in Concepcién Bay, March 16, Rempel 200,
on alluvial fan.
Low, erect, slender, suffrutescent herb with divergent branches widely
scattered in sandy and gravelly soils, slopes and washes throughout the
California Gulf Region; type from Fort Mojave, California.
Dalea variegata (Rydb.) Gentry new comb.
Parosela variegata Rydb., N. Am. Fl. 24:55. 1919.
Cabeza Ballena, Cape District, March 3, Rempel 71.
A low slender subshrub described originally from San Jose del Cabo.
It appears to be a postinsular endemic and to have migrated little north
of its original confines. It is closely related to D. divaricata, which ranges
northward along the gulf side of the peninsula.
OLNEYA TESOTA Gray, Mem. Am. Acad. Sci. II, 5:328. 1855.
Los Angeles Bay, March 19, 20, Rempel 247. West cove in Con-
cepcién Bay, March 15, Rempel 182, rocky hillside of east exposure.
Widely but intermittently distributed throughout the Sonoran Desert
’ in washes and on alluvial fans up to 2500 feet elevation; type from the
tablelands along the lower part of the Gila River, Arizona. A densely
branched tree, armed or thornless, with rather persistent leaves, and
characteristic of the open washes of the deserts. Ihe Rempel collections
are sterile. The tree normally flowers from latter April to June.
PHASEOLUS ATROPURPUREUS DC., Prodr. 2:395. 1825.
San Jose del Cabo, February 17, Dawson 1214.
Widely distributed in North America from Arizona and Texas to
Central America. This lacks the sericeus pubescence of typical material
from the Cape District, which Gray described as variety sericeus.
No. 2 GENTRY: LAND PLANTS 135
PHASEOLUS FILIFORMIS Benth., Bot. Voy. Sulph. 13. 1844.
Punta Frailes, February 16, Dawson 1145. San Jose del Cabo, Feb-
ruary 17, Dawson 1213. Puerto Escondido, February 10, Dawson 1085.
March 13, Rempel 156. Tortuga Island, March 17, Rempel 223.
A common small vine throughout Baja California below the chapar-
ral and on adjacent islands; type from Magdalena Bay, Baja California.
The leaves are dimorphic; flowers pink.
STYLOSANTHES VISCOSA Sw., Prod. Veg. Ind. Occ. 108. 1788 vel aff.
San Jose del Cabo, February 17, Dawson 1154.
Swartz’ species is widely distributed through tropical America. The
genus is in need of revision and Dawson’s collection is tentatively as-
signed.
Tephrosia hamata (Rydb.) Gentry new comb.
Tephrosia Palmeri Brge., Proc. Calif. Acad. Sci. II, 3:126. 1891.
Not JT. Palmeri Wats. 1889.
Cracca hamata Rydb., N. Am. FI. 24:177. 1923.
Tephrosia hamata Brge. ex. Rydb., N. Am. Fl. 24:177. 1924, a MS
name in synonomy only.
San Jose del Cabo, February 17, Dawson 1153.
Endemic to the postinsular Cape District; type from San Jose del
Cabo. It is a low silvery sericeus perennial with sagging stems.
TEPHROSIA TENELLA Gray, Pl. Wright. 2:36. 1853.
Near Guaymas, Sonora, February 9, Dawson 1076. Punta Frailes,
February 16, Dawson 1144. Tortuga Island, March 17, Rempel 206,
in wash.
Coarse arid soils from Texas to Baja California and Sinaloa; type
from San Pedro, Sonora. A low bushy perennial herb with slender
branches from near the base, and purple flowers. Apparently long flower-
ing following favorable rains, from October to March. The Cape Dis-
trict specimen has longer stipules, larger and more pubescent flowers.
ZYGOPHYLLACEAE
FAGONIA CALIFORNICA BARCLAYANA Benth., Bot. Voy. Sulph. 10.
1844.
San Juanico Bay, Baja California, March 2, Rempel 42, wash.
West side of the peninsula from San Juanico Bay south to the Cape
District ; type from Magdalena Bay.
FAGONIA CALIFORNICA GLANDULOSA Vail, Bull. Torr. Bot. Club
22 :229. 1895.
136 ALLAN HANCOCK PACIFIC EXPEDITIONS VoL. 13
Puerto Escondido, February 11, Dawson 1102. Los Angeles Bay,
March 19, 20, Rempel 237. Island in Concepcion Bay, March 16,
Rempel 203, on fan.
Arid desert slopes around the Gulf of California on the peninsula
and on the mainland.
LARREA TRIDENTATA (DC.) Cov., C.N.H. 4:75. 1893.
Los Angeles Bay, March 19, 20, Rempel 242.
Found in nearly all the hot American deserts.
VISCAINOA GENICULATA (Kell.) Greene, Pittonia 1:163. 1888.
Los Angeles Bay, March 19, 20, Rempel 241. Puerto Refugio, Angel
de la Guardia Island, March 20, Rempel 277.
An irregular branching shrub along rocky arroyos of the southern
two-thirds of the peninsula, along the mid-Sonoran coast, and known
also from Tiburon Island. Rempel 277 appears to represent the first
record from Angel de la Guardia Island.
SIMARUBACEAE
CASTELA PENINSULARIS Rose, C.N.H. 12:278. 1909.
San Gabriel Bay, Espiritu Santo Island, March, Rempel 85 (sterile)
A low stiff spiny shrub with sclerophyllous drought-deciduous and
rather ephemeral leaves, the branches varying from yellowish green to
reddish purple, the whole pubescent except the spines. It is known from
the southern part of the peninsula from Magdalena Bay and near Mu-
leje southward ; the type from San Jose del Cabo. Johnston (Proc. Calif.
Acad. Sci. IV, 12:1056) collected it on several of the adjacent gulf
islands from Catalina south.
BURSERACEAE
BursErA HInpsIANA (Benth.) Engl. in DC., Monogr. 4:58. 1883.
Bursera rhoifolia (Benth.) Jtn., Proc. Calif. Acad. Sei. IV, 12:1058.
1924.
West cove in Concepcién Bay, March 15, Rempel 181, low shrub or
tree on rocky slopes. Puerto Refugio, Angel de la Guardia Island, March
20, Rempel 267a. Los Angeles Bay, March 19, 20, Rempel 234a. Tor-
tuga Island, March 17, Rempel 229.
A thick-butted and usually dwarf tree with thick reddish or gray
branches and spur branchlets. ‘The leaves are quite variable; simple, or
partially trifoliate, or distinctly trifoliate, as on the Tortuga specimen
(up to 7 cm long) or small, as on the Concepcién Bay sheet (10 to 15
mm long). As Bullock (Kew Bull. 1936:366) has pointed out, the
NO. 2 GENTRY: LAND PLANTS 137
name 8. Hindsiana takes precedence over B. rhoifolia, because Art. 56
of the International Rules makes binding the first selection of a name
out of two or more applicable to the same species under the same date.
In this case the rule invalidates later combinations made apparently on
the basis of page priority. B. Hindsiana appears to be common to the
rocky slopes and washes from Los Angeles Bay south through the penin-
sula and has also been collected on the north central Sonoran coast
(Pringle, sine no. in 1884).
BURSERA MICROPHYLLA Gray, Proc. Am. Acad. Sci. 5:155. 1861.
San Gabriel Bay, Espiritu Santo Island, March 7, Rempel 93. Ca-
beza Ballena, Cape District, March 3, Rempel 57.
On rocky slopes and draws it is scattered through the Sonoran
Desert. A closely related plant, B. morelensis from the state of Morelos,
Mexico, has doubtfully been referred to synonomy under this species
(Bullock ep. 371).
MALPIGHIACEAE
‘THRYALIS ANGUSTIFOLIA (Benth.) Kuntze, Rev. Gen. PI. 1:89.
1891.
San Jose del Cabo, February 17, Dawson 1209.
Widely distributed in northwestern Mexico; the type from Cape
San Lucas, Baja California. A suffrutescent plant, in the above speci-
men 2 to 3 dm tall, the ovary glabrous except for a few minute hairs on
the apex and angles.
EUPHORBIACEAE
ADELIA VIRGATA Brge., Zoe 4:406. 1894.
Cabeza Ballena, Cape District, March 3, Rempel 63. Agua Verde
Bay, Baja California, March 10, Rempel 137, in wash.
Arroyos along the mountains of the Cape District and the Sierra
Giganta as far north as Comondu, and reported by Johnston on the
adjacent gulf islands of San Jose, Espiritu Santo, and Ceralvo; type
from the Sierra Laguna, Cape District. It is an erect slender shrub with
several branches bearing fascicles of obovate leaves. “The Rempel collec-
tions are sterile.
Diraxis BRANDEGEI ( Millsp.) Rose & Standl., C.N.H. 16:13. 1912.
Puerto Escondido, February 11, Dawson 1108. Agua Verde Bay,
Baja California, March 10, Rempel 123.
Widely but infrequently scattered in the California Gulf Region;
type from San Gregorio, Baja California. A rather succulent polypodial
138 ALLAN HANCOCK PACIFIC EXPEDITIONS VoL. 13
subshrub with purplish stems 1 to 2 m tall with regularly lanceolate,
remote, finely serrate leaves.
DiTAXIS LANCEOLATA (Benth.) Pax & Hoffm. in Pflanzenr. IV,
147 :64. 1912.
Puerto Refugio, Angel de la Guardia Island, January 26, Dawson
1032. San Jose del Cabo, February 17, Dawson 1215.
Open situations in the California Gulf Region, Sonora and. Baja
California; type from Magdalena Bay, Baja California. A low suffru-
tescent plant with pale, linear-lanceolate, cinereus leaves. Also related to,
but not conspecific, is Dawson 1150, from San Jose del Cabo.
DITAXIS NEOMEXICANA (Muell. Arg.) Heller, Cat. N. Am. Pl. 5.
1898.
North end of Los Angeles Bay, March 19, 20, Rempel 257, washes
and. sandy benches.
Arid and semi-arid climates from Texas to southern Arizona, Sonora,
and middle Baja California.
EUPHORBIA CALIFORNICA Benth., Bot. Voy. Sulph. 49, pl. 23B.
1844.
San Jose del Cabo, February 17, Dawson 1170.
Southern part of the gulf region in Baja California, Sonora, and
Sinaloa; type from Magdalena Bay, Baja California.
‘The specimen is unusually robust, reflecting better soil moisture con-
ditions than commonly obtained in other parts of its range. Questionably
referred here also is Rempel 70 from Cabeza Ballena, Cape District, a
shrub having unusually thin, long petiolate, obcordate leaves, and exfoli-
ating bark.
EUPHORBIA ERIANTHA Benth., Bot. Voy. Sulph. 51. 1844.
Los Angeles Bay, March 19, 20, Rempel 248. San Juanico Bay,
outer coast, March 2, Rempel 34. San Jose del Cabo, February 17, Daw-
son 1221.
Throughout the deserts of the California Gulf Region in sandy soils,
east to Texas; type from Magdalena Bay, Baja California.
An erect winter annual with single stem and ascending branches,
long linear leaves, and terminal capitate inflorescences, the erect gray-
green fruits usually conspicuous. Commonly scattered in dispersed colo-
nies over sandy areas.
EUPHORBIA LEUCOPHYLLA Benth., Bot. Voy. Sulph. 50. 1844.
Punta Frailes, February 16, Dawson 1127.
NO. 2 GENTRY: LAND PLANTS 139
Known from the southern part of Baja California and the adjacent
islands of Tiburon and Ceralbo; type from Cape San Lucas.
EUPHORBIA MAGDALENAE Benth., Bot. Voy. Sulph. 50. 1844.
San Gabriel Bay, Espiritu Santo Island, March 7, Rempel 97, west
end of pass on shell and coral. San Francisco Island, March 9, Rempel
107, shrub 2 feet high on south-facing hill slope.
On both coasts and adjacent islands of the southern part of the
peninsula; type from Magdalena Bay, Baja California. Johnston ob-
served what he took to be this plant at San Pedro Bay on the coast
above Guaymas, but apparently failed to collect it. It is a low slender-
stemmed, densely and intricately branched shrub 4 to 10 dm tall, form-
ing low globose bushes with minute flowers in the spring.
EUPHORBIA PEDICULIFERA Engelm. in Torr., U.S. & Mex. Bound.
Bot. 186. 1859.
Tortuga Island, March 17, Rempel 222. North end of Los Angeles
Bay, March 19, 20, Rempel 259. Island in Concepcién Bay, March 16,
Rempel 199, in wash. San Gabriel Bay, Espiritu Santo Island, March 7,
Rempel 83, on beach dunes.
Widely scattered on the deserts of southwestern United States and
northern Mexico and throughout most of the California Gulf Region.
EUPHORBIA PEDICULIFERA LINEARIFOLIA Wats., Proc. Am. Acad.
Sci. 24:76. 1889.
Guaymas, Sonora, January 23, Dawson 1005 (topotype).
Southern Sonora; type from Guaymas. It is distinguished from the
typical in the species by its erect habit and linear leaves. Both are winter
annuals flowering in the early spring or late winter.
EUPHORBIA PETRINA Wats., Proc. Am. Acad. Sci. 24:75. 1889.
Puerto Refugio, Angel de la Guardia Island, January 26, Dawson
1022.
Known from southern Sonora, Angel de la Guardia and San Pedro
Martir Islands, the type from the latter. Perennial prostrate herb form-
ing dense mats; spring flowering.
EUPHORBIA POLYCARPA Benth. ?, Bot. Voy. Sulph. 50. 1844.
Tortuga Island, March 17, Rempel 204a.
Widely scattered apparently throughout the California Gulf Region;
type from Magdalena Bay, Baja California. A perennial, spring-flower-
140 ALLAN HANCOCK PACIFIC EXPEDITIONS VoL. 13
ing, prostrate herb. Since the inflorescence of the Rempel collection has
been modified by galls, Wheeler has questionably referred the collection
to this species.
EUPHORBIA TOMENTULOSA Wats., Proc. Am. Acad. Sci. 22:476.
1887.
Near Guaymas, Sonora, February 9, Dawson 1080. San Carlos Bay,
February 8, Dawson 1057.
Common on coarse rocky dry soils nearly throughout the gulf region
as far south as southern Sonora and the Cape District. It is a low suf-
frutescent, bushy, flat-topped herb.
EUPHORBIA XANTI Engelm. in Boiss., DC., Prodr. 152:62. 1862.
Puerto Escondido, February 11, Dawson 1092, 1099. Canyon above
Puerto Escondido, March 13, Rempel 149.
Southern Baja California and northern coastal Sinaloa; type from
Cape San Lucas. It forms a slender, erect, flat-crowned shrub 1 to 2 m
tall with dichotomous virgate branching; the leaves are ephemeral fol-
lowing the summer rains. The plant may bloom in a leafless condition
in the spring. It has the largest flowers, 6 to 9 m in diameter, of any of
the gulf region euphorbs and is attractive in bloom. It was cultivated
successfully in the greenhouse of the Carnegie Desert Laboratory in
Tucson for many years.
JATROPHA CINEREA (Ort.) Muell. Arg. in DC., Prodr. 152:1078.
1866.
Questionably referred here is Rempel 119 from Agua Verde Bay
collected March 10, 1937. The specimen consists of a sterile and what
was once a turgescent shoot, bearing large cordate, ternately lobed, long-
petiolate leaves, 9 to 14 cm broad, the emarginate sinuses very narrow
and deep. Other collections seen have been referred to either this species
or to J. canescens of Bentham, but neither name seems satisfactorily ap-
plicable. Flower and fruiting material are needed for taxonomic place-
ment of the plant. It occurs in the deep canyons of the Sierra Giganta.
JATROPHA CUNEATA Wiggins & Rollins ?, Cont. Dud. Herb. 3 :272.
1943.
San Gabriel Bay, Espiritu Santo Island, March 7, Rempel 92, small
thick-trunked tree throughout pass except on alkali.
‘The succulent woody branches with numerous short spur-branchlets
of the sterile Rempel collection are doubtfully referred here. ‘The species
is widely distributed in the California Gulf Region; type from near
Kino Bay, Sonora.
NO. 2 GENTRY: LAND PLANTS 141
BUXACEAE
SIMMONDSIA CHINENSIS (Link) Schneid., Handb. Laubholzk. 2:
141. 1907.
San Carlos Bay, Sonora, February 8, Dawson 1056. San Gabriel
Bay, Espiritu Santo Island, March 7, Rempel 95.
Southern Sonora, southern California, Sonora, and Baja California.
It is a characteristic shrub of the arid rocky slopes in the California Gulf
Region, occurring usually in widely scattered stands. It is not known
south of the Rio Yaqui and the above collection from Sonora is near the
southern limits of the species on the mainland.
ANACARDIACEAE
CyYRTOCARPA EDULIS (Brge.) Standl., C.N.H. 23 :659. 1923.
Tapirira edulis Brge., Zoe 5:78. 1900.
Cabeza Ballena, March 3, Rempel 56. San Gabriel Bay, Espiritu
Santo Island, March 7, Rempel 89, up to 12 feet high in Cactus scrub.
Known only from the Cape District and adjacent islands. This is a
thick-stemmed Bursera-like tree with smooth yellowish bark that peels
off perennially in thin sheets. The above cited specimens are sterile and
the leaves are the small drought-pauperized ones of the arid spring.
It is widely and naturally spread in the Cape District and also occasion-
ally planted by the inhabitants for its edible plum-like fruits. It appears
to be a postinsular endemic, since it is quite distinct from its only near
relative, C. procera of the Mexican mainland. However, little is known
of the ecology of the plant. There is the possibility that it was intro-
duced to the peninsula by early man.
Pachycormus discolor var. pubescens (Wats.) Gentry new comb.
Schinus discolor Benth., Bot. Voy. Sulph. 11, pl. 9. 1844.
Pachycormus discolor (Benth.) Cov., Cent. Dict. rev. ed. 6708.
191M
Bursera pubescens Wats., Proc. Am. Acad Sci. 24:44. 1889.
V eatchia discolor Brge., Proc. Calif. Acad. Sci. II, 2:140. 1889.
V eatchia discolor pubescens (Wats.) Jtn., Proc. Calif. Acad. Sci. IV,
12:1079. 1924.
Puerto Refugio, Angel de la Guardia Island, January 26, Dawson
1025 (sterile). March 20, Rempel 273.
_ A low, sprawling, openly crowned, sarcophytic tree with massive
trunk and branches, endemic to and characteristic of the arid peninsula
about Los Angeles Bay and the adjacent Angel de la Guardia Island,
the type locality. The above cited specimens are sterile, but the smal]
142 ALLAN HANCOCK PACIFIC EXPEDITIONS VoL. 13
pubescent leaves differ materially from leaves of other varietal popula-
tions of the species studied on the peninsula. According to Johnston,
this variety is characterized by “‘its very loose deltoid inflorescence, by its
rather small leaves, and perhaps also by its brownish sap.”
CELASTRACEAE
MaAyYTENUS PHYLLANTHOIDES Benth., Bot. Voy. Sulph. 54. 1844.
Puerto Escondido, February 11, Dawson 1088. Cabeza Ballena, Cape
District, March 3, Rempel 74 (sterile). San Gabriel Bay, Espiritu Santo
Island, March 7, Rempel 87 (sterile). Island in Concepcion Bay, March
16, Rempel 188 (mature fruit).
Coastal from Baja California to Cuba and Florida; type from Mag-
dalena Bay, Baja California.
SCHAEFFERIA CUNEIFOLIA Gray, Pl. Wright. 1:35. 1852.
San Gabriel Bay, Espiritu Santo Island, March 7, Rempel 86, shrub
3-4 feet high scattered in nonalkaline soil.
Semiarid localities of northern Mexico and western Texas; type from
“high prairies of the San Felipe and on the San Pedro.” In Baja Cali-
fornia it has been collected previously only on the slopes of Tres Virgines
in middle peninsula, at Muleje, and in the Cape District. It is a short stiff
Condalia-like shrub with spinescent branchlets and small, obovate, thick-
ish, drought-deciduous, caducous leaves.
SAPINDACEAE
CARDIOSPERMUM HALICACABUM L., Sp. PI. 366. 1753.
Guaymas, January 23, Dawson 1000. San Carlos Bay, Sonora, Feb-
ruary 8, Dawson 1069. San Jose del Cabo, February 17, Dawson 1198.
San Gabriel Bay, Espiritu Santo Island, March 7, Rempel 96. Agua
Verde Bay, March 10, Rempel 128.
A scandent diffuse shrub or self-supporting subshrub forming a low
bush with interlocking stems and recurved branches. ‘The common Mexi-
can name is “‘bolsilla,” aptly referring to the inflated papery fruits, hang-
ing showily like unlit jack-o-lanterns through the fruiting season of late
fall and again perhaps in the spring. The species in the larger sense is
variable and subspecific names have been assigned.
RHAMNACEAE
CONDALIA GLOBOSA Jtn., Proc. Calif. Acad. Sci. IV, 12:1086. 1924.
Los Angeles Bay, March 19, 20, Rempel 234c (sterile).
Known in middle and southern Baja California, on adjacent islands
in the gulf, and near Guaymas, Sonora; type from La Paz. Though not
important in the aggregate of vegetation, this stiff low shrub with spine-
tipped branchlets appears to be widely scattered through the desert of
the California Gulf Region.
No. 2 GENTRY : LAND PLANTS 143
KARWINSKIA HUMBOLTIANA (Zucc.) R. & S., Abh. Akad. Wiss.
Miichen 2:351. 1832.
Cabeza Ballena, Cape District, March 3, Rempel 69.
The species as now known includes several variants which range
over Mexico and southwestern Texas. The peninsular population exists
in the Cape District and along the Sierra Giganta scarp, mainly in the
wetter canyons and northern slopes, and is not readily separable from
some of the populations of northwestern Mexico.
MALVACEAE
ABUTILON CALIFORNICUM Benth., Bot. Voy. Sulph. 8. 1844.
Puerto Escondido, February 11, Dawson 1086.
West coast of Mexico from Baja California and Sonora south to
Oaxaca; type from Magdalena Bay, Baja California.
ABUTILON CRISPUM (L.) Sweet, Hort. Brit. 53. 1827.
San Jose del Cabo, February 17, Dawson 1226.
In open situations from southern Arizona south to Central America.
A decumbent perennial herb with inflated fruits; the present specimen
with remote, cordate, acuminate, and characteristically gray canescent
leaves, the pale petals marked with bright carmine in the base.
ABUTILON INCANUM (Link) Sweet, Hort. Brit. 53. 1827.
San Jose del Cabo, February 17, Dawson 1210. San Carlos Bay,
Sonora, February 8, Dawson 10606.
Widely distributed as a wayside and fallow-land weed in north-
western Mexico; also reported in Hawaii. It is a bushy perennial 1 to
2 m high with rather strictly ascending branches. The yellow petals are
Carmine spotted within and reflexed at anthesis, closing at night.
Gossypium Davipsonu Kell., Proc. Calif. Acad. Sci. I, 5:82. 1873.
San Jose del Cabo, February 17, Dawson 1197.
Southern Baja California; type from San Jose del Cabo. Rarely col-
lected.
Higiscus DENUDATUS Benth., Bot. Voy. Sulph. 7, pl. 3. 1844.
West Cove in Concepcién Bay, March 15, Rempel 176, hill slope of
west exposure. Guaymas, Sonora, January 23, Dawson 1006.
The more arid situations in northwestern Mexico and western Texas
to southern Arizona in the United States. It appears to be quite generally
scattered through the California Gulf Region. At best it forms a low
open suffrutescent bush, the young branches are densely yellowish tomen-
144 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 1S
tose, the old glabrous. The flowers are lavender and with only light
winter rains the plant will persist in flowering from late winter months
through the spring.
HorsForDIA ALATA (Wats.) Gray, Proc. Am. Acad. Sci. 22:297.
1887.
Puerto Escondido, February 11, Dawson 1086.
California Gulf Region on both the peninsula and the mainland;
type from northwestern Sonora, Mexico. he genus is distinguished by
its winged carpels; this species is distinguished from H. Newberryi, the
only other Sonoran Desert species, by its relatively large, thickish, ovate
leaves and pink petals drying purplish or blue.
HorsrorpiA NEwBERRYI (Wats.) Gray, Proc. Am. Acad. Sci. 22:
297. 1887.
West Cove in Concepcién Bay, March 15, Rempel 179, foot of
rocky slope. Island in Concepcién Bay, March 16, Rempel 191, in wash.
Rather infrequently scattered in the lower elevations of the Cali-
fornia Gulf Region. It is uncommon or lacking along the outer coast
of the peninsula and has a smaller range than H. alata.
Sipa XANTI Gray, Proc. Am. Acad. Sci. 22:296. 1887.
San Jose del Cabo, February 17, Dawson 1190.
Known in Baja California and listed also by Standley (C.N.H. 23:
765. 1920-26) as occurring in Sinaloa. The type locality is from Cape
San Lucas, Baja California. The pale flowers are unusually large for
the genus, the petals may be as much as 1.5 to 2 cm long.
SPHAERALCEA COULTERI (Wats.) Gray, Proc. Am. Acad. Sci. 22:
291. 1887.
San Carlos Bay, Sonora, February 8, Dawson 1050.
In sandy and coarse detrital soils of the Sonoran Desert from the
Colorado Desert, California south and in the Sinaloa Thorn Forest
south to Mazatlan; type apparently from southwestern Arizona or ad-
jacent Sonora. It is a leafy annual, single-stemmed or polypodial, rather
showy with salmon-colored flowers through the arid spring.
SPHAERALCEA COULTERI CALIFORNICA (Rose) Kearney, U. C. Publ.
Bot. 19:32..1935.
Puerto Escondido, February 11, Dawson 1091.
Southern half of Baja California; type from La Paz.
NO. 2 GENTRY: LAND PLANTS 145
SPHAERALCEA HaInesil Brge., Proc. Calif. Acad. Sci. II, 2:136.
1889.
Tortuga Island, March 17, Rempel 224. Los Angeles Bay, Baja Cali-
fornia, March 19, 20, Rempel 244.
Middle part of the California Gulf Region along the eastern coast
of the peninsula and the islands of San Pedro Martir, San Marcos, Tor-
tuga; type from Jesus Maria, Baja California. On the peninsula it fre-
quents waste lands like a weed, but Johnston reported “it is the most
abundant herbaceous perennial on the island” of San Pedro Martir.
STERCULIACEAE
HERMANNIA PALMERI Rose, C.N.H. 1:67. 1890.
San Jose del Cabo, February 17, Dawson 1220.
Apparently endemic to southern Baja California; type from La Paz.
This plant is rare in collections. ‘The above cited specimen is in flower
only, the characteristic Solanum-like stamens conspicuous. The cordate-
triangular crenate leaves are unusually ample, the blades up to 4 cm
wide and 4 cm long, indicating good moisture conditions or shade during
the weeks preceding collection.
MELOCHIA TOMENTOSA L., Syst. Nat. ed. 10:1140. 1759.
San Carlos Bay, Sonora, February 8, Dawson 1062. San Jose del
Cabo, February 17, Dawson 1191.
Lower elevations nearly throughout Mexico and south into Central
America. It is a common shrub in the environs of Guaymas, where, in
the fall after the summer rains, it forms a rather showy slender shrub
with light purplish flowers.
WALTHERIA AMERICANA L., Sp. Pl. 673. 1753.
San Jose del Cabo, February 17, Dawson 1158.
Widely distributed through the American tropics and subtropics ;
type from the Bahama Islands.
FRANKENIACEAE
FRANKENIA PALMERI Wats., Proc. Am. Acad. Sci. 11:124. 1876.
Los Angeles Bay, March 19, 20, Rempel 262, 238.
Littoral flats of the upper gulf region, where it forms low rounded
brittle-stemmed bushes. It is one of the common halophytes of the region.
but Johnston (Proc. Calif. Acad. Sci. IV, 12:1097) attributes its appar-
ent halotropism to the salt air father than to saline soils. It is also found
on nonalkaline soils and locally occurs in extended stands making a low
suffrutescent vegetation with or without associates.
146 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 13
FOU QUIERIACEAE
FOUQUIERIA PENINSULARIS Nash, Bull. Torr. Bot. Club 30:454.
1903.
Near Guaymas, Sonora, February 9, Dawson 1079. Baja California:
Punto Frailes, February 16, Dawson 1136; San Jose del Cabo, Feb-
ruary 17, Dawson 1219; Puerto Escondido, March 13, Rempel 167, on
alluvial fan; Frailes Bay, April 4, Rempel 328.
Mainly coastal in the southern part of the California Gulf Region
in southern Baja California, Sonora, and northern Sinaloa; type from
La Paz, Baja California. These collections all show the thickish pedicels
and narrow panicles typical of the species.
FOUQUIERIA SPLENDENS Engelm. in Wisliz., Mem. Tour. Mex.,
30th Cong. Ist Sess. misc. rep. No. 26:98. 1848.
Los Angeles Bay, March 19, 20, Rempel 249.
Northern part of the California Gulf Region in Sonora, on the pen-
insula, on Tiburon Island, north into the deserts of California, Arizona,
and Nevada, and eastward in northern Mexico.
‘TURNERACEAE
TURNERA DIFFUSA Willd., Schult. Syst. Veg. 6:679. 1820.
San Jose del Cabo, February 17, Dawson 1152.
Widely distributed in Mexico, Central America, and South America,
mainly in arid soils on hill slopes.
PASSIFLORACEAE
PASSIFLORA ARIDA (Mast. & Rose) Killip, Jour. Wash. Acad. Sci.
12-256. 1922.
Island in Concepcién Bay, March 16, Rempel 190, on fan.
Widely scattered along the coasts in the California Gulf Region as
far south as Mazatlan, Sinaloa; type from Guaymas, Sonora. It is par-
ticularly abundant along the inner shore of the mid-peninsula, infrequent
on the outer peninsular coast and the Sinaloa coast. It is a densely pu-
bescent vine flowering and fruiting in the spring and related to P. Pal-
meri and P. fruticosa, but distinguished from those two species by the
lack of oily stipitate glands.
PASSIFLORA PALMERI Rose, C.N.H. 1:131, pl. 14. 1892.
West Cove in Concepcién Bay, March 15, Rempel 175, on hillside.
Island in Concepcién Bay, March 16, Rempel 195, generally distributed
on fans and lower hillsides.
On the gulf side of the peninsula and adjacent islands in the gulf
NO. 2 GENTRY : LAND PLANTS 147
from Angel de la Guardia south to San Jose del Cabo; type from Car-
men Island. A low spreading flat-topped viscous shrub with showy
flowers in the spring.
LOASACEAE
EUCNIDE CORDATA Kell. in Curran, Bull. Calif. Acad. Sci. 1:137.
1885.
San Gabriel Bay, Espiritu Santo Island, March 7, Rempel 99, in
alkaline flats not far from beach dunes. Agua Verde Bay, Baja Cali-
fornia, March 10, Rempel 121, wash. Tortuga Island, March 17, Rem-
pel 215.
Common to the cliffs, rocky slopes, and occasional in washes through
the mid-section of the peninsula and the adjacent islands; type from
Cedros Island. It is a coarse rather succulent or turgescent perennial
herb with bright green, cordate, crenate, lobate leaves, and creamy white
tubular flowers. |
MENTZELIA ADHAERENS Benth., Bot. Voy. Sulph. 15. 1844.
Turner’s Island, January 25, Dawson 1012. Near Guaymas, Feb-
ruary 9, Dawson 1096. Tortuga Island, March 17, Rempel 226.
Sonora and Baja California; type from Magdalena Bay, Baja Cali-
fornia. Johnston also reports it from Tortuga and Tiburon Islands. The
Dawson numbers show the pauperate foliage of a dry winter season, the
blades being mostly less than 2 cm long. It is a brittle herb sometimes
found clambering among the low branches of shrubs. The Mexicans have
been heard to call it “pega pega.”
PETALONYX LINEARIS Greene, Bull. Calif. Acad. Sci. 1:188. 1885.
Tortuga Island, March 17, Rempel 214.
A low bushy subshrub with rough scabrous leaves, large floral bracts,
and small white flowers. Widely scattered over the northern half of the
peninsula and the adjacent islands; into southern California and Ari-
zona. | ype from Cedros Island.
SYMPETALEIA RUPESTRIS ( Baill.) Gray in Wats., Proc. Am. Acad.
Sci. 24:50. 1889.
Tiburon Island, January 25, Dawson 1013. Puerto Escondido, March
13, Rempel 162. Island in Concepcion Bay, March 16, Rempel 202.
~ On cliffs and dry rocky situations in the mid-gulf region in Sonora,
Baja California, and the gulf islands of Sal si puedes, Tiburon, and
Tortuga. A low sticky herb forming rounded clumps; spring flowering.
148 ALLAN HANCOCK PACIFIC EXPEDITIONS VoL. 13
CACTACEAE
CocHEMIEA POSELGERI (Hildm.) Brit. & Rose, Cactaceae 4:22.
1923.
Punta Frailes, Cape District, February 16, Dawson 1111. Agua
Verde Bay, Baja California, March 10, Rempel 115, in wash. Frailes
Bay, Cape District, April 4, Rempel 327.
Cape District of Baja California and northward along the Sierra
Giganta scarp; exact locality of type collection unknown.
ECHINOCEREUS GRANDIS Brit. & Rose, Cactaceae 3:18. 1922.
San Pedro Nolasco Island, February 6, Dawson 1037; San Esteban
Island, February, Dawson 1042. South end of San Esteban Island,
March 27, Rempel 294.
Known only from San Pedro Nolasco, Las Animas, San Lorenzo,
and San Esteban Islands in the Gulf of Baja California; the type from
San Esteban. Flowers March and April.
ECHINOCEREUS MAMILLATUS (Engelm.) Brit. & Rose, Cactaceae
3:41. 1922.
West Cove in Concepciédn Bay, March 15, Rempel 172 (sterile),
hillside of east exposure. Frailes Bay, April 4, Rempel 323a (sterile).
A short-bodied, long-spined species, the stems tapered at the base.
Ranges along the Sierra Giganta scarp and through the mountains of
the Cape District; type from “mountain sides south of Muleje, Lower
California.”
ECHINOCEREUS SCIURUS (K. Brge.) Purpus, Monatsschr. Kakteenk.
14:130. 1904.
San Jose del Cabo, February 17, Dawson 1222.
Known only from the Cape District of the peninsula. The type
locality is the hills near San Jose del Cabo, Dawson 1222 being a topo-
type.
ECHINOCEREUS SCOPULORUM Brit. & Rose, Cactaceae 3:31. 1922.
Ensenada de San Francisco, Sonora, March 30, Rempel 315. Guay-
mas, January 23, Dawson 1008.
Native of the coastal mountains of southern Sonora and northern
Sinaloa; type from near Guaymas, Sonora.
ECHINOCEREUS WEBSTERIANUS G. Lindsay, Cact. Succ. Jour. 19:
153. 1947.
San Pedro Nolasco Island, March 29, Rempel 301, 303; February
6, Dawson 1040.
NO. 2 GENTRY : LAND PLANTS 149
Known only from San Pedro Nolasco Island where it commonly
grows in close association with Mammillaria multidigitata. Lindsay
(1.c.) has written that “its large golden clumps [contrast] pleasantly
with the white masses of the latter.”’
FEROCACTUS ACANTHODES (Lem.) Brit. & Rose, Cactaceae 3:129.
1922.
North of Point Lobos, Sonora, March 26, Rempel 287 (sterile).
This is the common Ferocactus or bisnaga on the arid slopes and
mesas in the northern part of the gulf region; type locality, “California.”
FerocactTus CoviL_el Brit. & Rose, Cactaceae 3:133. 1922.
Guaymas, Sonora, January 23, Dawson 1009 (in part).
From southern Arizona to southern Sonora; the type from near
Altar, northern Sonora. Guaymas is near the southern limit of the
species.
FEROCACTUS TOWNSENDIANUS Brit. & Rose, Cactaceae 3:127. 1922.
Frailes Bay, April 4, Rempel 318, hillside.
A poorly known species from the southern part of the peninsula and
adjacent islands; the type from Isla San Jose. Continuation of this name
is questionable, since it appears applicable to the species described earlier
by Weber as Echinocactus peninsulae, Bull. Mus. Nat. Paris 1:320.
1895. Britton and Rose failed to resolve the question, apparently be-
cause they did not have access to Weber’s material collected by Leon
Diguet in 1894 near Santa Rosalia, and based their concepts of the
species on a fragmentary collection of Gabb. This they state to be with-
out radial spines, the main character segregating F. Townsendianus from
F. peninsulae (Weber) Brit. & Rose, Cactaceae 3 :133. 1922, but Weber
describes ‘‘Aiguillons rougeatres, a pointe jaune; exterieurs 11, Ao
Taxonomically the question can be cleared by field work and ample
herbarium material, and more solidly by access to Diguet’s original notes
and photos. Britton and Rose’s name is retained here solely because it is
the one in common use for the southern peninsular plexus.
FEROCACTUS SP.
Tetas de Cabra near Guaymas, Sonora, January 23, Dawson 1009a.
- Referred here is a specimen strongly suggestive of Ferocactus ala-
mosanus platygonus G. Lindsay, Cact. Succ. Jour. 14:139. 1942, but
differing materially in the strongly ascending 7-8 lateral spines and as
reported by the collector in the large size; up to 1.5 m. This is the plant
150 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 13
which Johnston referred to F. alamosanus, apparently, Proc. Calif. Acad.
Sci. 13:1110. 1924. Although the present collection, the species, and its
variety appear to be related, further field work and study may reveal
that we are dealing with three specific entities.
LEMAIREOCEREUS THURBERI (Engelm.) Brit. & Rose, C.N.H. 12:
426. 1909.
South end of Tiburon Island, March 27, Rempel 297. San Pedro
Nolasco Island, March 29, Rempel 305. Ensenada de San Francisco,
Sonora, Rempel 312a. Frailes Bay, Rempel 322.
The pitaya (traditionally spelled: pitahaya, but poorly so from the
phonetic standpoint) is widely distributed in the central and southern
part of the California Gulf Region; from southern Arizona to central
Sinaloa. In central Baja California it favors the rocky slopes where run-
off increases soil moisture. In southern Sonora, the area of greatest
abundance, it is found both on rocky slopes and alluvial plains, as on the
plain south of Navojoa, where it abounds in dense nearly pure stands
over many square miles. Flowers in late spring, fruits ripen in late May
and June. All the above collections are sterile.
LEMAIREOCEREUS ‘THURBERI LITTORALIS (K. Brge.) G. Lindsay,
Desert Pl. Life 12:186. 1940.
Cereus Thurberi Engelm. var. littoralis K. Brge., Zoe 5:191. 1904.
Canyon above Puerto Escondido, March 13, Rempel 145 (imma-
ture). Fraile Bay, April 4, Rempel 326.
Cape District and north along the Sierra Giganta scarp to Con-
cepcién Bay; type from ‘“‘on steep seacoast bluffs between San Jose del
Cabo and Cabo San Lucas, Baja California.” This low slender plant
appears to be a good variety. The collections show only 6 to 7 ribs and
weaker spines than is typical of the species. Rempel 209 from an island
in Concepcién Bay is probably also referrable here. All specimens are
sterile.
LopHOCEREUS SCHOTTII (Engelm.) Brit. & Rose, C.N.H. 12:427.
1919.
Los Angeles Bay, Baja California, March 19, 20, Rempel 232, in,
wash and on fan. Fraile Bay, April 4, Rempel 324.
Widely distributed in the gulf area; type from Magdalena, Sonora.
A widely spreading plant commonly 2 to 3 m tall with many stems from
the decumbently spreading base, recognizable by the sordid “beard” of
long bristles of the terminal 1 to 3 feet of the flowering branches.
No. 2 GENTRY : LAND PLANTS 151
MACHAEROCEREUS GUMMOSUS (Engelm.) Brit. & Rose, Cactaceae
22116, 1920.
Puerto Escondido, Dawson 1109, abundant over all brush-land.
Fraile Bay, Rempel 323. Tortuga Island, Rempel 210.
Common and widespread through Baja California south of Ensen-
ada and on the adjacent islands; type from northwestern Baja Cali-
fornia. In places it is abundant and is a codominant with other desert
shrubs.
MAMMILLARIA ALBICANS (Brit. & Rose) Berger, Kakteen, 308.
1929.
San Pedro Nolasco Island, February 6, 1940, Dawson 1039.
Recorded only from Santa Cruz, San Jose, and San Pedro Nolasco
Islands, the above cited specimen being new to the known flora of the
latter island. Referred here doubtfully is Rempel 302 also from San
Pedro Nolasco Island. It is a smaller, slenderer plant with an evident
tendency to be cespitose.
MAMMILLARIA ANGELENSIS Craig, Mam. Handb. 165. 1945.
Angel de la Guardia Island (probably Puerto Refugio), January 26,
Dawson sine no. Pond Island, February 5, Dawson sine no. Punta
Frailes, February 16, Dawson 1112.
Known previously only from Angel de la Guardia Island, the species
is now certainly known from Pond Island, but Punta Frailes collection
(sterile) is doubtfully referred to this species. ‘The long reflexed petals
are singularly characteristic of this species.
MAmMMILLARIA bDIoIcaA K. Brge., Erythea 5:115. 1897.
Tiburon Island, January 25, Dawson 1018.
Apparently ranges throughout Baja California, but hitherto not re-
ported for any of the California Gulf Islands.
MAMMILLARIA EVERMANNIANA (Brit. & Rose) Orcutt, Cactogra-
phy 7. 1926.
Canyon above Puerto Escondido, Sierra Giganta scarp, Rempel 144,
sides of canyon.
Along the Sierra Giganta scarp in southern Baja California and
adjacent islands; type from Ceralbo Island. Craig (Mam. Handb. 82.
1945) states, but without citation, that it is also reported from San Pedro
Nolasco Island. It is a small globose plant 6 to 10 cm high preferring
humic soils in the detrital pockets of rocky terrain. It is rare in both
living and herbarium collections.
152 ALLAN HANCOCK PACIFIC EXPEDITIONS VoL. 13
MAMMILLARIA FRAILIANA (Brit. & Rose) Boedeker, Mammil. Vergl.
Schluss. 30. 1933.
South end of San Esteban Island, Rempel 293 (sterile).
It is also known from Ceralbo, Catalina, and Pichilinque Islands,
the latter being the type locality. It will probably be found also on the
adjacent part of the peninsula. A closely related species is M. V erhaerti-
ana Boedeker, reported from Los Angeles Bay.
MAMMILLARIA INSULARIS Gates, Cact. Succ. Jour. 10:25. 1938.
Ildefonso Island, March 15, Rempel 1708, on rocky ridge. Ensenada
de San Francisco, Sonora, March 10, Rempel 316.
Central part of the Gulf of California; type from easternmost islet
of Smith Island, Los Angeles Bay, Baja California. A low cespitose
plant with purplish hooked spines. Doubtfully referred here also is
Rempel 325 (in part). All of his collections, made in March, are sterile.
MAaAMMILLARIA MULTIDIGITATA G. Lindsay, Cact. Succ. Jour. 19:
152. 1947.
San Pedro Nolasco Island, March 29, Rempel 302; February 6,
Dawson 1038.
Apparently endemic to San Pedro Nolasco Island, this plant is re-
lated to M. albicans, but differs in its cespitose habit, its slender cylindri-
cal stems (not globose), and the appressed fine white radial spines.
Lindsay reports it as being abundant on the steep slopes of the island.
MAMMILLARIA SLEVINII (Brit. & Rose) Boedeker, Mammil. Vergl.
Schluss. 44. 1933.
San Francisco Island, March 9, Remfel 101 (sterile).
A rare and little known species related to M. albicans and may be as
Craig (l.c. p. 262) surmised, conspecific with it. Known only from San
Francisco and San Jose Islands in the Gulf of California, Rose having
collected the type on the latter island.
OpuntTIA BiceLtovit Engelm., Proc. Am. Acad. Sci. 3:307. 1856.
Angel de la Guardia Island, Puerto Refugio, January 26, Dawson
sine no. Turner’s Island, Dawson sine no. Tiburon Island, January 25,
Dawson 1019. Tortuga Island, Rempel 210a. South end of San Esteban
Island, March 27, Rempel 292.
A common cactus shrub of the northern part of the California Gulf
Region in Mexico and the United States; type from Bill Williams
River, Arizona. The Tortuga Island collection is the southernmost
record. All the above collections are sterile.
NO. 2 GENTRY: LAND PLANTS 153
OPUNTIA BuRRAGEANA Brit. & Rose, Cactaceae 1:70. 1919.
San Gabriel Bay, Espiritu Santo Island, March 7, Rempel 80,
round-jointed Opuntia in cactus-scrub. Fraile Bay, April 4, Rempel 319
(flowering). Puerto Escondido, March 13 (flowering), Rempel 142,
alluvial fan; February 11, Dawson sine no. (sterile).
The collections from Puerto Escondido are doubtfully referred here.
‘They are atypical of the species in the elongate slender joints and with
more prominent tubercles. he ovaries have numerous, acicular, yellow-
ish spines about 1 cm long that deciduate soon after anthesis on the
growing ovary. Ihe specimens also suggest O. ciribe, but are scarcely
consepecific. Typical O. Burrageana is recognized as ranging through-
out the Cape District and on the adjacent islands as far north as Car-
men. It may be a postinsular endemic of the Cape District. O. ciribe
distribution is thought to be only in the central part of the peninsula
from the vicinity of Santa Rosalia south to the vicinity of Comondu.
It is apparent that there is a complex of cylindropuntia species in the
central part of the peninsula in marked need of field work and taxonomic
study.
OPUNTIA AFF. CLAVELLINA Engelm., in Coulter, C.N.H. 3:444.
1896.
Patos Island, March 26, Rempel 290. San Pedro Nolasco Island,
March 29, Rempel 304. South end of Tiburon Island, March 27, Rem-
pel 292, All specimens sterile.
Typical O. clavellina is known only along the outer peninsula coast;
type from near Purissima (see Map 2). The rather short thickish joints
with prominent papery-sheathed spines of the above collections indicate a
close but scarcely specific relationship.
OPUNTIA COMONDUENSIS (Coult.) Brit. & Rose, Smith. Misc. Coll.
50:519. 1908.
San Gabriel Bay, Espiritu Santo Island, March 7, Rempel 82
(sterile). Fraile Bay, Baja California, April 4, Rempel 320 (sterile).
Southern Baja California and the adjacent island of Espiritu Santo
and probably others; type from Comondu, Baja California. Little is
known of the actual habitat and range of this platyopuntia and the above
collections extend the known range southward and to Espiritu Santo
Island. Johnston (Proc. Calif. Acad. Sci. IV, 12:1116. 1924) reported
observing it on all of the southern gulf islands except Catalina, stating
that it was the only platyopuntia observed on these islands. The small
oval joints, the remote prominent areoles, and the 1 or 2 long porrect
154 ALLAN HANCOCK PACIFIC EXPEDITIONS voL. 13
spines, either whitish or yellow, characterize this species among the
platyopuntia of the peninsula.
OPUNTIA AFF. FULGIDA Engelm., Proc. Am. Acad. Sci. 3:306. 1856.
San Pedro Nolasco Island, March 29, Rempel 304a.
Doubtfully referred here, the specimen also shows relationship to O.
ciribe Engelm., a peninsular species (see Maps 1 and 2).
OPUNTIA GOSSELINIANA Weber, Bull. Soc. Acclim. France 49:83.
1902.
Ensenada de San Francisco, Sonora, March 30, Rempel 313.
Reported by Britton and Rose from “Sonora and Lower California,
Mexico ;” type locality, “Coast of Sonora on the Gulf of California.”
Rempel’s collection is flowering and typical except that the joints are
suborbicular being broader than long.
OPUNTIA“INVICTA Bree), Proc. Calif. Acad. Sci. 1f,'2:163-. 1869;
Los Angeles Bay, March 19, 20, Rempel 233 (fruiting), in wash
on fan.
Central part of the peninsula, the type from San Juanico Bay. A low
plant with trailing stems, short thick joints with high tubercles, large,
3-cornered, whitish, sheathless spines, and bristly fruits.
OPUNTIA LEPTOCAULIS DC., Mem. Mus. Hist. Nat. Paris 17:118.
1828.
Tiburon Island, January 25, Dawson 1020.
Widely distributed in both the high and low deserts of the south-
western United States and Mexico; type locality in Mexico.
OPUNTIA RAMOSISSIMA Engelm., Am. Jour. Sci. II, 14:339. 1852.
Los Angeles Bay, March 19, 20, Rempel 231 (flowering), in wash.
Widely distributed in the southwestern United States and adjacent
Mexico west of the continental divide; type from near the Colorado
River in California. This appears to be the first cited collection from
Baja California, although the species has long been known to occur there.
OPUNTIA VERSICOLOR Engelm. in Coulter, C.N.H. 3:452. 1896.
Ensenada de San Francisco, Sonora, March 30, Rempel 312. South
end of San Esteban Island, Rempel 291.
Widely distributed in the northern part of the gulf region on the
mainland from southern Arizona to southern Sonora; type from ‘Tucson,
Arizona. I have seen no specimens nor records referrable to the peninsula
and the above citation from San Esteban Island is the first for the gulf
islands ; fruiting, it compares favorably with mainland material.
NO. 2 GENTRY: LAND PLANTS 155
MAP 1
CYLINDROPUNTIA IN CALIFORNIA GULF AREA
1. O. versicolor Engelm. >
molesta Brge.
fulgida Engelm.
spinosior (Engelm.) Toumey
prolifera Engelm.
alcahes Weber
Burrageana B. & R.
invicta Brge.
cineracea Wiggins
reflexispina Wig. & Rollins
rosarica G. Lindsay
PODMNAMNPYN
156 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 13
MAP 2
CYLINDROPUNTIA IN CALIFORNIA GULF AREA
1. O. mortolensis B. & R. »
Poa: SO Oe ae OFS
leptocaulis DC.
Thurberi Engelm.
echinocarpa Engelm.
serpentina Engelm.
Parryi Engelm.
Bigelovii Engelm.
ciribe Engelm.
cholla Weber
calmalliana Coulter
clavellina Engelm.
NO. 2
GENTRY: LAND PLANTS 157
MAP 3
se oe
-—
: = —_
——
——
— ont ome ee cee ous ene oe .
_ —
¥
PLATYOPUNTIA IN CALIFORNIA GULF AREA
1. O. basilaris Engelm.
pycnantha Engelm. \
OveorenanPpwnd
comonduensis (Coult.) B. & R.
Gosseliniana Weber
occidentalis Engelm.
discata Griffiths
chlorotica Engelm.
tapona Engelm.
Wilcoxii B. & R.
species undescribed
Bravoana Baxter
158 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 13
OPUNTIA AFF. WILCoxI Brit. & Rose, Cactaceae 1 :172. 1919.
San Pedro Nolasco Island, March 29, Rempel 306.
West coast of Mexico in southern Sonora and northern Sinaloa;
type from Fuerte in northern Sinaloa. This first insular collection ap-
pears to be in good character with the species. It was just coming into
flower when collected. Unusual are the areoles around the edge of the
joints; they are larger and with longer glochids than those on the flat
faces.
OPUNTIA SP.
Dawson 1091 from Puerto Escondido, Baja California, collected in
a sterile condition February 11, 1940, is a flat-jointed Opuntia resemb-
ling O. tardispina Griffiths from eastern Texas, as illustrated in Brit. &
Rose (l.c. p. 141). Doubtless, this is one of the unknown Ofuntiae men-
tioned by Johnston (Proc. Calif. Acad. Sci. IV, 12:1117).
PACHYCEREUS PRINGLEI (Wats.) Brit. & Rose, C.N.H. 12:422.
1909.
South end of Tiburon Island, March 27, Rempel 298 (sterile).
Abundant over wide areas through middle and southern Baja Cali-
fornia, on the gulf islands, on the cerros southwest of Altar in north-
western Sonora, and in the hills about Guaymas, Sonora; type from the
Altar River, Sonora. Its western limit is Cedros Island, where it was
recently discovered by Howell (Leafl. West. Bot. 3:183. 1942).
Sterile nubbins represented by Rempel 211, 307, 317, from Tortuga
Island, San Pedro Nolasco Island, and Fraile Bay respectively, are either
referrable to this plant or to Pachycereus pecten-aboriginum, the other
giant cactus abundant through the southern part of the gulf region.
RATHBUNIA ALAMOSENSIS (Coult.) Brit. & Rose, C.N.H. 12:415.
1909. :
Ensenada de San Francisco, Sonora, March 30, Rempel 314. Near
Guaymas, Sonora, January 23, Dawson 1074.
Coastal lowlands from southern Sonora to Nayarit; type from
Alamos, Sonora. It commonly forms colonies several yards in diameter,
spreading by declining or broken stems taking root. It is also employed
locally and effectively for making fences, the cuttings taking root readily
and eventually forming a dense hedge row.
RHIZOPHORA MANGLE L., Sp. Pl. 443. 1753.
West Cove in Concepcién Bay, March 15, Rempel 174.
NO. 2 GENTRY: LAND PLANTS 159
The above cited locality is about the northern limit of this wide-
spread littoral plant on the east side of the peninsula. On the Mexican
mainland it reaches Tiburon Island.
ONAGRACEAE
OENOTHERA ANGELORUM Wats., Proc. Am. Acad. Sci. 24:29. 1889.
Los Angeles Bay, March 19, 20, Rempel 236a.
Known only from the eastern shore of the peninsula near the type
locality, Los Angeles Bay.
OENOTHERA CARDIOPHYLLA Torr., Pacif. R.R. Rep. 5:360. 1856.
North end of Los Angeles Bay, March 19, 20, Rempel 253a.
Widely distributed around the north and west sides of the Gulf of
California, south to central Baja California, and known from the gulf
islands of San Luis, Angel de la Guardia, San Pedro Martir, and San
Marcos, Type locality, near Fort Yuma, Arizona. A winter annual or
possibly a short-lived perennial, it blooms in the early spring months.
SAPOTACEAE
BUMELIA OCCIDENTALIS Hemsl., Biol. Cent. Am. Bot. 2: 298. 1881.
Canyon above Puerto Escondido, March 13, Rempel 153. Los En-
cinos, Sierra Giganta, Gentry 4264.
Usually a small rather bushy tree scattered in the canyons of the
southern part of the peninsula and northern Sonora on the lower moun-
tain slopes; type locality, ‘Sonora alta.” it flowers and fruits in the
spring.
APOCYNACEAE
VALLESIA GLABRA (Cav.) Link, Enum. Pl. 1:207. 1821.
Island in Concepciédn Bay, March 16, Rempel 196.
An evergreen shrub with white flowers and small pyriform trans-
lucent fruits adapted to the mesophytic bottomlands, particularly the
river margins from southern Baja California and southern Sonora south
along the coastal tierra caliente to South America and the West Indies.
ASCLEPIADACEAE
ASCLEPIAS ALBICANS Wats., Proc. Am. Acad. Sci. 24:59. 1889.
Puerto Escondido, February 11, Dawson 1107. Island in Concepcion
Bay, March 16, Remfel 194, on fan and low on north exposure. Puerto
Refugio, Angel de la Guardia Island, March 20, Rempel 268.
Nearly throughout and confined to the Sonoran Desert; type from
ravine near Los Angeles Bay, Baja California.
160 ALLAN HANCOCK PACIFIC EXPEDITIONS voL. 13
ASCLEPIAS CURASSAVICA L., Sp. Pl. 215. 1753.
Puerto Escondido, February 11, Dawson 1087.
Widely distributed in the tropics and subtropics of America. It is a
mesophyte found only along stream banks or wastelands of irrigated
fields in Baja California. It is an erect perennial herb or strictly branched
bush with showy heads of reddish orange flowers.
ASCLEPIAS SUBULATA Decne. in DC., Prodr. 8:571. 1844.
Guaymas, January 23, Dawson 1101. San Jose del Cabo, February
17, Dawson 1156. Found throughout the desert of the California Gulf
Region, mostly along arroyos and canyon bottoms in sandy or gravelly
soil; type from ‘‘Nova Hispania.” This and J. albicans are perennial
herbs with several to many rush-like stems 1 to 2 m tall, bearing remote
filiform leaves for short periods in the rainy seasons, the terminal pani-
culate white and yellowish flowers often outlasting the ephemeral leaves.
The flowers are greedily visited by many species of wasps and flies.
CONVOLVULACEAE
EVOLVULUS LINIFOLIA L., Sp. Pl. ed. II :392.
San Jose del Cabo, Baja California, February 17, Dawson 1188.
Sonora and Baja California. Distinguished from the more widely
spread E. alsinoides by the narrower leaves and smaller flowers.
JACQUEMONTIA ABUTILOIDES Benth., Bot. Voy. Sulph. 34. 1844.
Puerto Escondido, February 11, Dawson 1093; March 13, Rempel
148. Punta Frailes, February 16, Dawson 1126. San Jose del Cabo,
February 17, Dawson 1162, 1186.
Southern Sonora and middle and southern Baja California; type
from Magdalena Bay, Baja California.
HyDROPHYLLACEAE
PHACELIA SCARIOSA Brge., Proc. Calif. Acad. Sci. II, 2:185. 1889.
Puerto Escondido, February 11, Dawson 1103; March 13, Rempel
150. Tortuga Island, March 17, Rempel 205.
Southern Baja California and adjacent islands including Tortuga
and Carmen in the gulf; type from Magdalena Island on the outer coast.
BORAGINACEAE
BouRRERIA SONORAE S. Wats., Proc. Am. Acad. Sci. 24:62. 1889.
San Jose del Cabo, February 17, Dawson 1208.
Baja California and Sonora, type from Guaymas, Sonora. It is a
shrub 1 to 2 m tall scattered in the coarse soils of the less arid localities.
NO. 2 GENTRY: LAND PLANTS 161
COoLDENIA PALMERI Gray, Proc. Am. Acad. Sci. 8:292. 1870.
Los Angeles Bay, March 19, 20, Rempel 235, 255.
In sandy soils through the northern part of the gulf region, where
it forms a low suffrutescent mat or mound with parts of the older stems
exfoliating a white cortical layer.
HELIOTROPIUM CURASSAVICUM L., Sp. Pl. 130. 1753.
Punta Frailes, Cape District, February 16, Dawson 1138.
Coastal lowlands throughout most of tropical and subtropical America.
HELIOTROPIUM HINTONII Jtn., Jour. Arn. Arb. 21:50. 1940.
Punta Frailes, February 16, Dawson 1120, 1176. San Jose del Cabo,
February 17, Dawson 1185, 1216.
Known from the mountains of west central Mexico and from the
Cape District of Baja California. It is a low suffrutscent 3 to 4 dm
high with elongating racemes of small white flowers, the stems leafy with
strongly pubescent linear-lanceolate leaves 15 to 25 mm long.
LABIATAE
Hyptis Emoryi Torr. in Ives, Rep. Col. River 20. 1861.
Puerto Refugio, Angel de la Guardia Island, March 20, Rempel
276. Near Guaymas, Sonora, February 9, Dawson 1081.
Found throughout the California Gulf Region; type from the Colo-
rado River country. It is one of the regular opportunists among the
shrubs along rocky arroyos and is able to withstand, or at least to endure
as a species, the grinding flash floods that arise with torrential desert
rains. Guaymas appears to be about its southern limit on the Mexican
mainland. A variant of the species occurs about Guaymas and was des-
cribed by Watson as a species, H. Palmeri, but later was reduced to a
variety by Johnston, H. Emoryi Palmeri. It may well be a postinsular
endemic. Standley (C.N.H. 23:1276. 1924) lists Hyptis Emoryi from
Tepic, but his statement is in part based on the related H. albida Kunth.,
which is known to range through Nayarit.
Hyptis LANIFLORA Benth., Bot. Voy. Sulph. 42, pl. 20. 1844.
Punta Frailes, February 16, Dawson 1124. San Jose del Cabo, Feb-
ruary 17, Dawson 1183.
Southern Baja California and adjacent islands; type from Cape San
Lucas.
The material from Punta Frailes has calyx lobes shorter than usual,
scarcely half as long as the tube, and the lanate pubescence of the calyx
is much denser than on the San Jose del Cabo specimen.
162 ALLAN HANCOCK PACIFIC EXPEDITIONS VoL. 13
STACHYS COCCINEA Jacq., Pl. Hort. Schoenbr. 3:18. 1798.
Canyon above Puerto Escondido in the Sierra Giganta, March 13,
Rempel 170, canyon bottom.
Widely distributed in the warmer mountains of southwestern United
States and northwestern Mexico.
VERBENACEAE
AVICENNIA NITIDA Jacq., Enum. Pl. Carib. 25. 1760.
West cove in Concepcion Bay, March 15, Rempel 173.
As a regular associate of the mangrove marshes, it is common along
the coasts of tropical and subtropical America. Concepcion Bay is near
its northwestern limit. As residue of sea mist, salt crystals are commonly
apparent on its leaves.
SOLANACEAE
DaTuRA DIscoLoR Bernh., Prommed. N. Jour. Pharm. 26:149.
1838.
North end of Los Angeles Bay, March 19, 20, Rempel 251a. Ti-
buron Island, January 25, Dawson 1010. San Jose del Cabo, February
17, Dawson 1224.
From southeastern California and southern Arizona south through
the California Gulf Region to Central America; type from the West
Indies. A relatively small Datura with small leaves and narrow flowers
with a purple flush in the throat. The Tiburon material has smaller
flowers and heavier fruiting spines than the typical peninsular material.
LycIuM AFF. ANDERSONI Gray, Proc. Am. Acad Sci. 7:388. 1868.
Puerto Refugio, Angel de la Guardia Island, March 20, Rempel
27 6a.
Common through the deserts from southern Utah and southern Ne-
vada south throughout the California Gulf Region, more common along
the coasts than inland in the latter area.
LyYCIUM BREVIPES Benth., Bot. Voy. Sulph. 40. 1844.
Lycium Richiit Gray, Proc. Am. Acad. Sci. 8:292. 1870.
Island in Concepcién Bay, March 16, Rempel 189. Agua Verde Bay,
March 10, Rempel 118.
Sandy slopes, washes, and alluvial and saline soils along the coast
throughout the gulf region and south into Sinaloa. It is one of the
larger-leaved, bushy Lyciums, making dense plants and dense thickets
locally.
NO. 2 GENTRY : LAND PLANTS 163
NICOTIANA GREENEANUM Rose, C.N.H. 1:18. 1890.
Agua Verde Bay, March 10, Rempel 127, wash.
Known previously only from Cedros Island and the adjacent western
part of the peninsula, this appears to be the first record of the plant from
the gulf side of the peninsula. The annual habit, nonclasping and non-
auriculate leaves with ovate to lanceolate blades, the small corolla with
very narrow limb (3 mm wide in the dried specimen), and the dull
light brown muriculate seeds relate it pretty definitely to Rose’s plant.
NICOTIANA TRIGONOPHYLLA Dunal in DC., Prodr. 131:562. 1852.
San Carlos Bay, Sonora, February 8, Dawson 1023, 1059. Near
Guaymas, February 9, Dawson 1078. Tortuga Island, March 17,
Rempel 217.
Mostly in the coarse alluvial soils in arroyos and valleys in Desert
Shrub and Thorn Forest from Texas to California and south to Nayarit.
This is a common member of the tobacco genus in the arid gulf region.
It appears to be perennial in the lower latitudes of its range, as shown
by the woody base of Dawson 1023. Another sheet, Dawson 1078, repre-
sents a young plant in its first season of spring flower, indicating it as
having germinated during the preceding early fall or late summer rains.
PETUNIA PARVIFLORA Juss., Ann. Mus. Hist. Nat. Paris 2:216.
1803.
San Jose del Cabo, February 17, Dawson 1159.
Southern Florida to California and south into tropical America.
Through the deserts it is chiefly confined to the moist sands of perma-
nent or intermittent streams. Low herb with minute lavender flowers.
PHYSALIS CRASSIFOLIA Benth., Bot. Voy. Sulph. 40. 1844.
Willard Point, Gonzaga Bay, Baja California, March 23, Rempel
283, wash.
Wide-spread in the southwestern United States and adjacent Mexico
in arid climates on sandy and rocky soils. Type locality, Magdalena Bay,
Baja California.
PHYSALIS CRASSIFOLIA INFUNDIBULARIS Jtn., Proc. Calif. Acad.
Ser ive I2sttog., 1924.
_ Puerto Refugio, Angel de la Guardia Island, January 26, Dawson
1026.
Known only from San Esteban Island, Angel de la Guardia Island,
and the adjacent coast of the peninsula; type from Angel de la Guardia
164 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL.4S3
Island. It differs from typical P. crassifolia in having a funnelform co-
rolla as long as or longer than wide, rather than a rotate corolla.
PHYSALIS GLABRA Benth., Bot. Voy. Sulph. 39. 1844.
Punta Frailes, February 16, Dawson 1128.
Known only from the Cape District of Baja California.
PHYSALIS PUBESCENS L., Sp. Pl. 183. 1753.
Canyon above Puerto Escondido, March 13, Rempel 157; April 22,
Gentry 3764, riparian in canyon bottom.
A mesophytic to hydrophytic annual with pale yellow flowers, purple
stamens, and pubescent viscid herbage, widely distributed across southern
United States and southward in Mexico; Galapagos Islands.
PHYSALIS PURPUREA Wiggins, Cont. Dud. Herb. 3:74. 1940.
San Carlos Bay, Sonora, February 8, Dawson 1063.
Known only from the vicinity of Guaymas, Sonora. This perennial
Physalis with its bright purple corolla and rather open habit with remote
leaves is not easily confused with any other members of the genus in the
gulf area. Its apparent very limited distribution, which kept it from
being discovered so long, probably marks it as an endemic of the coastal
mountains near Guaymas, and which for a period in the Tertiary may
have been insular.
SOLANUM HINpsIANuM Benth., Bot. Voy. Sulph. 39. 1844.
Tiburon Island, January 25, Dawson 1011. San Carlos Bay, Sonora,
February 8, Dawson 1052. Punta Frailes, Baja California, February 16,
Dawson 1142. San Jose del Cabo, February 17, Dawson 1192.
Baja California and Sonora; type from Magdalena Bay. This plant
is a low openly branched shrub rather closely related to S. elaeagnifolium,
but in the field is at once distinguished by its larger size and larger
corollas. It becomes abundant locally in the southern part of the gulf
region, but is infrequent in the northern part.
SCROPH ULARIACEAE
ANTIRRHINUM CYATHIFERUM Benth., Bot. Voy. Sulph. 40. 1844.
Near Guaymas, Sonora, February 9, Dawson 1084.
Southwestern Arizona, Sonora, and Baja California; type from Mag-
dalena Bay. Guaymas appears to be about the southern Hime for the
species on the mainland.
MIMULUS SP.
Canyon above Puerto Escondido, February 11, Dawson 1104, seep-
NO. 2 GENTRY : LAND PLANTS 165
age in palm canyon. Canyon above Puerto Escondido, March 13, Rempel
161, on damp rocks.
‘These collections represent two species, neither of which I can place
satisfactorily. Dawson 1104 is an erect herb about 15 cm high with rela-
tively large orbicular coarsely dentate leaves, strongly 3-veined from the
base, the calyces prominently red-spotted, but the spots fading on the
fruiting calyces.
The plant represented by the Rempel 161 is a diminutive, procum-
bent, finely cut herb with yellow flowers forming mats in wet or moist
sand or on rocks by seeps and pools in the canyon bottom. It is to be
expected in other localities of the Sierra Giganta. It has also been col-
lected in the same locality; Gentry 3772 and Johnston 4113. The latter
collection was referred by Grant (Ann. Mo. Bot. Gard. 11:186. 1924)
to Mimulus dentilobus, described from Nacari, Sonora by Robinson and
Fernald. While I have not seen Johnston’s collection, those of both
Rempel and Gentry fail to show the laciniately-lobed corollas character-
istic of M. dentilobus. ‘Though the Puerto Escondido plants are clearly
related to M. dentilobus, they appear worthy of taxonomic recognition.
Unfortunately, none of the material at hand is worthy of type designa-
tion. Future collectors should make it a point to secure a large series of
good material of both of these rare Mimulus, not otherwise known.
MOoHAVEA CONFERTIFLORA (Benth.) Heller, Muhl. 4:48. 1912.
Puerto Refugio, Angel de la Guardia Island, March 20, Rempel 270.
Widely but infrequently scattered through the deserts from southern
Nevada south to Angel de la Guardia Island; not known from Sonora.
The type locality is uncertain. A diminutive winter annual with large
showy flowers.
STEMODIA ARIZONICA Penn., Notul. Nat. Acad. Sci. Phil. 43:1-10.
1940.
Canyon above Puerto Escondido in the Sierra Giganta, March 13,
Rempel 158, in canyon bottom.
Hydrophytic herb, often with the older branches decumbent. Along
the perennial streams from low to middle elevations in the mountains
and foothills of northwestern Mexico and adjacent United States.
MARTYNIACEAE
MarTYNIA ALTHEAEFOLIA Benth., Bot. Voy. Sulph. 37. 1844.
Punta Frailes, February 16, Dawson 1134.
Widely scattered in the sandy deserts from Texas to California,
166 ALLAN HANCOCK PACIFIC EXPEDITIONS voL. 13
Sonora and Baja California; type from Magdalena Bay, Baja California.
A procumbent spreading viscid herb 1 m or more in diameter and locally
forming extensive dispersed colonies; the sticky stem often with adher-
ing sand particles, the long petiolate leaves cordate to oricular. The
Papago Indians still use the tough fibers of the fruits in weaving baskets.
BIGNONIACEAE
TECOMA sTANS (L.) HBK., Nov. Gen. & Sp. 3:144. 1789.
Canyon above Puerto Escondido, Sierra Giganta, March 13, Rempel
166, hillside.
Widely distributed in tropical and subtropical America. It is often
cultivated locally for its showy yellow blossoms and one of its most
common names is “Iluvia de oro.” In the Cape District it is commonly
found in the rocky swales where run-off adds to the precipitated soil
moisture.
ACANTHACEAE
BELOPERONE CALIFORNICA Benth., Bot. Voy. Sulph. 38. 1844.
Puerto Refugio, Angel de la Guardia Island, March 20, Rempel
275 (sterile) ; January 27, Dawson 1029. Puerto Escondido, March 13,
Rempel 165. Punta Frailes, February 16, Dawson 1141. San Jose del
Cabo, February 17, Dawson 1217. Cabeza Ballena, Rempel 65. San
Carlos Bay, Sonora, February 8, Dawson 1070.
A subshrub with long flowering branches bearing orange-red flowers
in the spring through the California Gulf Region and adjacent areas,
and south to central Sinaloa along the sandy coast (Isla ‘Tachechilte,
January 20, Gentry 7127).
BELOPERONE Purpuslil Brge., Zoe 5:172. 1903.
San Jose del Cabo, February 17, Dawson 1175.
Known only from the Cape District of Baja California; type from
San Felipe. The lower anther only is mucronate, the upper lip is bicus-
pidate. It is suffrutescent or grows to a small shrub. Rarely collected.
BERGINIA PALMERI Rose, C.N.H. 1:86. 1890.
Island in Concepcion Bay, March 16, Rempel 197, 208. Puerto Es-
condido, February 11, Dawson 1098.
Known only from the southern part of the peninsula and adjacent
Carmen Island; type from Santa Rosalia.
This is a small usually nondescript shrub with brittle shiny branches,
sparse foliage, and lavender or pink flowers. It is rare in collections and
has often been confused with B. virgata. ‘Though very similar in appear-
ance to the latter it is distinguished by the stalked glands of the inflor-
NO. 2)? GENTRY: LAND PLANTS 167
escence, and by the cordate bases of the uppermost leaves. Standley’s key
(C.N.H. 23:1337. 1926) does not make use of the important gland
character and the foliage feature he uses is applicable only to the reduced
leaves of the inflorescence; the stems and leaves of both species being
narrowly lanceolate and acute at the base. Although he reports B. vir-
gata as occurring in Baja California, it is doubtful if it actually occurs
there. Others in following his key have also assigned Baja California to
B. virgata, as Johnston (l.c. p. 1168) who attributed his collections
from San Nicolas Bay and Carmen Island to B. virgata, but states that
they have glandular calyces, which identifies them as B. Palmeri.
Though these two species are closely related they appear to be geo-
graphically distinct and no intergrading forms have been seen by the
author. For the time being they should be kept distinct, or until such
time as adequate collections can be brought together for study.
BERGINIA VIRGATA Harv. in Benth. & Hook, Rev. Gen. Pl. 2:1097.
1873.
Guaymas, Sonora, January 23, Dawson 1004; February 9, Dawson
L073:
Coastal and foothill regions in Desert Shrub and Thorn Forest of
Sonora from Puerto Libertad to the Rio Mayo country. A small slender
strictly or openly branched shrub about 1 m tall with lavender flowers.
CARLOWRIGHTIA CALIFORNICA Brge., Zoe 5:172. 1903.
Punta Frailes, February 16, Dawson 1146. San Jose del Cabo, Feb-
ruary 17, Dawson 1196.
Baja California, Sonora, and Sinaloa; type locality, southern Baja
California. Doubtfully distinct from C. cordifolia Gray, described from
southwestern Chihuahua and with a similar range on the mainland.
DICLIPTERA RESUPINATA (Vahl) Juss., Ann. Mus. Hist. Nat. Paris
9:268. 1807.
San Carlos Bay, Sonora, February 8, Dawson 1071.
Southern part of the California Gulf Region and south to tropical
America.
JACOBINIA CANDICANS (Nees) Benth. & Hook. in Hook. & Jacks.,
Ind. Kew. 1:1246. 1893.
San Carlos Bay, Sonora, February 8, Dawson 10065.
Common through the Thorn Forest of southern Sonora and Sinaloa,
thence southeast along the Pacific coast to southern Mexico; type from
168 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 23
the mountains of Oaxaca. It forms a low irregularly branched shrub
with rather thin ovate to lanceolate acuminate leaves and short racemes
of bilabiate red flowers in the spring. Closely related to J. mexicana,
which occurs in the same region, but distinguished from it by the floral
bracts which equal or exceed the calyx, while in J. mexicana they are
shorter than the calyx. Both plants belong with the Thorn Forest rather
than with the desert, and their occurrence in the latter is marginal and
restricted to bottomlands of overflow or the more moist canyon slopes.
Justicia HIANS Brge., U. C. Publ. Bot. 6:194. 1915 and Proc.
Calif. Acad. Sci. II, 2:194. 1889.
San Jose del Cabo, February 17, Dawson 1200.
Low suffrutescent herb rarely collected and apparently a postinsular
endemic of the Cape District of Baja California.
RUELLIA CALIFORNICA (Rose) Jtn., Proc. Calif. Acad. Sci. IV,
12:1171. 1924.
Guaymas, January 23, Dawson 1002. San Carlos Bay, February 8,
Dawson 1073a. Agua Verde Bay, Baja California, March 10, Rempel
133, 138, rocky hillside. Island in Concepcién Bay, March 16, Rempel
193.
Southern part of the gulf region, mainly on the rocky slopes of the
coastal cerros; type from Santa Rosalia, Baja California. It forms a low
shrub with twiggy branches often in dispersed small colonies with showy,
lavender, campanulate, caducous flowers about 3 cm long. ‘The foliage
is vernicose or glutinous with dull, sparse, blunt or capitate hairs, erect
or impacted in the surface excretion.
The species is closely related to R. peninsularis, from which it is dis-
tinguished by the longer, more attenuate, calyx lobes bearing clavate
glandular “hairs.” The indument on R. peninsularis although glandular
is not clavate. Johnston’s attempt to separate these two species on foliage
characters alone is not altogether satisfactory (Proc. Calif. Acad. Sci. IV,
12:1172), since both species are glandular and glutinous, nor is the
foliage of R. peninsularis glabrate. ‘The varnish tends to accumulate on
the leaf surface with age and in time may submerge the “hairs” in a
glutinous film, a condition apparently mistaken by Johnston for glabrate.
It is common to both species. R. peninsularis appears to be limited to the
peninsula, since all the collections I have reviewed from the mainland
are referrable to R. californica.
Johnston assigned some Guaymas collections to R. peninsularis, but
in view of the criteria used in separating the two species, I believe he
NO. 2 GENTRY: LAND PLANTS 169
was in error, although I have not seen the specimens he cites. ‘This is not
surprising since Rose’s original descriptions are inadequate. Leonard of
the United States National Herbarium, who has access to the type col-
lections, has kindly determined Dawson’s Guaymas collections. With his
assistance I believe I am correct in restricting R. peninsularis from the
Sonora flora until such time as it may be found in typical form.
RUELLIA LEUCANTHA Brge., Zoe 5:109. 1901.
Punta Frailes, February 16, Dawson 1135.
Endemic to the postinsular Cape District. It is a suffrutescent peren-
nial with white flowers and densely tomentose leaves. It is rare in col-
lections.
RUELLIA PENINSULARIS (Rose) Jtn., Proc. Calif. Acad. Sci. IV,
125: bis2.. 1924.
San Jose del Cabo, February 17, Dawson 1163.
Southern part of Baja California; the type from mesas about La Paz.
PLANTAGINACEAE
PLANTAGO INSULARIS FASTIGIATA (Morris) Jeps., Man. FI. PI.
Calif. 956., 1925.
Puerto Refugio, Angel de la Guardia Island, March 20, Rempel 269.
A low villous annual common to the deserts of the California Gulf
Region.
RUBIACEAE
HousTONIA ASPERULOIDES (Benth.) Gray, Proc. Am. Acad. Sci.
5:158. 1860.
Houstonia Brandegeana Rose, C.N.H. 1:70. 1890.
Punta Frailes, February 16, Dawson 1113, 1132. San Jose del Cabo,
February 17, Dawson 1187.
Apparently limited to southern Baja California. A finely cut annual
with purple flowers. Although the flowers on the specimens from Punta
Frailes are smaller than those described for the species (3 to 4 mm high),
the calyx is sparsely strigose and the lobes acute, two characters agreeing
with H. asperuloides, and there are no other significant differences.
HovusTONIA MUCRONATA (Benth.) Rob., Proc. Am. Acad. Sci. 45:
401. 1910.
San Francisco Island, March 9, Rempel 110, beach dunes.
Southern Baja California and the adjacent islands; type from Mag-
dalena Bay. It forms a low shrubby bush 2 to 9 dm high with white
corollas which turn black on drying. Reported by Johnston to be abun-
dant on some of the islands in the southern part of the gulf.
170 ALLAN HANCOCK PACIFIC EXPEDITIONS voL. 13
MiTRACARPUS PORTORICENSIS Urb., Symb. Antill. 4:609. 1911.
Doubtfully referred to this Caribbean species is Dawson 1184 from
San Jose de! Cabo, February 17 (flowering). Standley, who determined
the collection, reported that he had not been able to place the specimen
satisfactorily.
CUCURBITACEAE
CucuMIS DIPSACEUS Ehrenb. in Sprach, Hist. Veg. Phan. 6:211.
1838.
San Jose del Cabo, February 17, Dawson 1194.
Apparently originally from the north African highlands, it is now
widely but discontinuously dispersed in both the Old and New Worlds.
In North America it has been collected from such widely separated
regions as Oregon, Baja California, and the West Indies.
ECHINOPEPON MINIMUS (Kell.) Wats., Proc. Am. Acad. Sci. 24:
52. 1889.
Marah minima Kell., Proc. Calif. Acad. Sci. 2:18.
Canyon above Puerto Escondido, Sierra Giganta, March 13, Rempel
152; April 20-22, 1938, Gentry 3747 (fruiting).
Rather widely scattered in central and southern Baja California and
the adjacent islands on the outer coast ; type from Cedros Island. Appar-
ently annual, it has very slender and rather short stems, about the
smallest of the cucurbit vines in the region, with densely echinate fruits,
dehiscing irregularly, the prickles rather short and somewhat flattened.
Echinopepon peninsularis Gentry sp. nov.
Herba annua; caulis ramique graciles, striati, ad nodos pilis longis
albis praediti; petioli 2-3 cm longi; folia membranacea, 4-6 cm longa,
6-8 cm lata, lobis 5, late lanceolatis, serrulatis, aristatis, sparse scabro-
pubescentibus; cirrhi graciles 1-2-fidi; @ pedunculi glabri, 10-15 mm
longi; pedecelli glandulo-hispidi; corolla 12-15 mm lata, segmentis ovatis,
ciliolatis; 2 pedunculi 5-8 cm longi; corolla ca. 10 mm lata; fructus
solitarius, 2 cm longus, sparse glandulo-pubescens, echinatus; aculei 8-
12 mm longi.
Typus: Dawson 1193, “San Jose del Cabo, Cape District, Baja
California, Mexico, February 17, 1940,” in hb. Allan Hancock Founda-
tion, University of Southern California. Duplum in hb. Univ. Mich.
Annual scandent herb; stems 1-2 m long, slender, sulcate, glabrous
except for rings of white hyaline hairs 4-6 mm long at the nodes; pet-
ioles 2-3 cm long, slender, glabrous; leaf blades 4-6 cm long, 6-8 cm
wide, deeply 5-lobed nearly to the base, rarely 7-lobed, the lobes mostly
No. 2 GENTRY: LAND PLANTS 171
ovate-lanceolate, the lower often broadly ovate, obtuse to acuminate, ser-
rulate, ciliolate, aristate, glabrous except for sparse scabrous conic scales
or hairs below, thinly membraneous, greener above than below; tendrils
1—2-fid; & inflorescence racemose; peduncles 10-15 cm long, glabrous
below the pedicles; pedicles filiform, mostly 1-2 cm long at anthesis,
glandular hispid; corolla shallowly campanulate, spreading, glabrous
without, 12-15 mm broad, the lobes subequal, ovate, obtuse, ciliolate;
2 flowers solitary from same axials as male; peduncles 5-8 cm long; ovary
echinate, glandular-pubescent; corolla like the o, but smaller, about
1 cm broad; fruit oblong, 2 cm or more long, glabrate, glandular pubes-
cent, echinate throughout with slender prickles 8-12 mm long, narrowly
beaked, 1 cm long.
‘Taxonomists have assigned earlier collections of this well marked
species to either E. toguata D.C., an uncertain species from the Mexi-
can mainland (Rose, C.N.H. 5:118 ) or to E. minimus, well known on
the peninsula. ‘The proposed new species is distinguished from the latter
by the deeply lobed leaves, the hyalinely tufted nodes, the long & pedun-
cles, the larger flowers, and the larger, longer-prickled fruits. The range
of the species appears to be restricted to the southern part of the peninsula,
and is perhaps a postinsular endemic of the Cape District. Besides the
type collection, the following specimens have been reviewed in the Uni-
versity of California Herbarium: San Jose del Cabo, Brandegee sine no.
in October 1902; Brandegee 231, September 27, 1890; Brandegee sine
no., september 18, 1893; La Mesa, Brandegee sine no., October 24, 1893.
VASEYANTHUS BRANDEGEI (Cogn.) Rose, C.N.H. 5:119. 1897.
Echinocystis Brandegeit Cogn., Proc. Calif. Acad. Sci. II, 3:59. 1890.
Ensenada de los Muertos, Cape District, March 5, Rempel 78, hill-
side.
This vine is rare in herbaria. It is known only from the Cape Dis-
trict; type from La Paz. It is the basis of Cogniaux’s section, Pseudo-
Echinopepon, (1. c.), characterized by the globose, 1-2 seeded, echinate,
long-beaked fruits, features embodied in the genus Vaseyanthus.
Vaseyanthus Palmeri (Wats.) Gentry new comb.
Echinopepon Palmeri Wats., Proc. Am. Acad. Sci. 24:52. 1889.
Brandegea Palmeri (Wats.) Rose, C.N.H. 5:120. 1897.
San Carlos Bay, February 8, Dawson 1073.
~ Known only from Guaymas and vicinity where it has been but rarely
collected. It is probably to be grouped with those plants having insular
origin in the cerros northwest of Guaymas. It is related to V. insularis,
172 ALLAN HANCOCK PACIFIC EXPEDITIONS VoL. 13
but distinguished by its shorter prickles, more acuminate leaf lobes, and
in having but 3-4 stamens, rather than the normal 5.
VASEYANTHUS INSULARIS INERMIS Jtn., Proc. Calif. Acad. Sci. IV,
12:1182. 1924.
Puerto Refugio, Angel de la Guardia Island, January 26, Dawson
1024.
Johnston lists it from the following islands in the Gulf of California:
San Pedro Nolasco, Tortuga, South San Lorenzo, San Esteban, Angel
de la Guardia, Mexia, San Pedro Martir, and Partida, the type from
the latter.
A slender twining herb, stems strongly 4-5-angled, sparsely hispid in
the deep broad grooves, commonly ovate-pustulate on the angles; petioles
7-12 mm long, appressed hispid, ribbed ; leaf blades orbicular, palmately
5-10-lobed, 1.5-3 cm broad, the lobes rounded to biangulate, aristate,
strongly scabrous on both sides with scale-like trichomes, 10-nerved;
tendrils bifid; inflorescence racemose, hispid; peduncle 1-1.5 cm long;
corollas minute, 3 mm broad; fruit globose, acuminte-rostrate, glabrous,
unarmed, 6-10 mm long, 4-7 mm in diameter, dehiscing transversely
around the middle.
LOBELIACEAE
LoBELIA LAXIFLORA ANGUSTIFOLIA A. DC. in DC., Prodr. 7 :383.
1839.
Puerto Escondido, February 16, Dawson 1105.
Mainly along canyon bottoms and stream banks in the lower eleva-
tions of the mountains from Baja California and Chihuahua south to
Oaxaca.
CoMPOSITAE
AMAURIA ROTUNDIFOLIA Benth., Bot. Voy. Sulph. 31. 1844.
West cove in Concepcién Bay, March 15, Rempel 180, foot of rocky
slope.
Infrequent along the coasts of Baja California; type from San Quen-
tin. A perennial herb, like Perityle, but distinguished by the linear, 4-
angled, epappose achenes.
ALVORDIA FRUTICOSA Brge., Erythea 7:5. 1889.
Punta Frailes, February 16, Dawson 1114. San Jose del Cabo, Feb-
ruary 17, Dawson 1172 (topotype).
Known only from the Cape District. ‘The genus, consisting of three
species, is limited to the southern half of the peninsula. ‘Chey are shrubs
NO. 2 GENTRY : LAND PLANTS 173
with slender peduncles having capitate clusters of few-flowered, small,
strongly graduated involucres.
ASTER SPINOSUS Benth., Pl. Hartw. 20. 1839.
Canyon above Puerto Escondido, Sierra Giganta, March 13, Rempel
154; April 21, Gentry 3770.
Widely distributed in western North America from Texas and Cali-
fornia south to Costa Rica; type from Aguascalientes, Mexico. A
broom-like, bushy, gray-green perennial with reduced, remote, linear
leaves, the branchlets often spine-tipped. It commonly forms bushy
clumps along the canyon bottoms of the Sierra Giganta escarpment.
BACCHARIS SARATHROIDES Gray, Proc. Am. Acad. Sci. 17:211.
1882.
San Gabriel Bay, Espiritu Santo Island, March 7, Rempel 88, west
end of pass.
Widely scattered along the washes of the California Gulf Region
and into adjacent deserts of the southwestern United States; type from
near Old Mission Station, San Diego County, California. It is a rather
dense broom-like shrub ordinarily 1-2 m tall. The Rempel collection is
a low suffrutescent 1-2 dm tall, quite sterile, and doubtfully referred to
this species.
CoREOCARPUS DISSECTUS LONGILOBUS Blake, Proc. Am. Acad. Sci.
49 :345. 1913.
Leptosyne dissecta Gray, N. Am. Fl. 1:301. 1884.
Canyon above Puerto Escondido, Sierra Giganta, March 13, Rempel
163, canyon bottom. Isla San Pedro Nolasco, February 6, Dawson 1034.
Middle Baja California and adjacent islands in the gulf; type from
Carmen Island. Distinguished from the typical form of the species by the
long filiform leaf lobes and the crenate margins of the achenes.
CoREOCARPUS SHREVEI Sherff, Bot. Gaz. 97:185. 1935.
Tiburon Island, January 25, Dawson 1015.
Middle and southern Baja California, islands in the gulf, and middle
coast of Sonora. The above citation is the first record for Tiburon Island.
It is a widely distributed species for one that remained so long unde-
scribed. A winter annual flowering in the early spring; the rays rosaceous
or yellow, the achenes biaristate, pectinately winged.
COULTERELLA CAPITATA Vasey & Rose, C.N.H. 1:71. 1890.
San Francisco Island, March 9, Rempel 112, hillside facing south.
174 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL./15
On San Francisco and Espiritu Santo Islands and probably on the
adjacent peninsula. Originally described from near La Paz, but the type
colony is reported to have been washed out by a storm. Johnston (l.c.
p. 1199) makes some interesting observations concerning this rare, mono-
typic, and endemic plant.
DysopiA sPpEcIOSA Gray, Proc. Am. Acad. Sci. 5:163. 1861.
Punta Frailes, Baja California, February 16, Dawson 1131.
Apparently endemic to the postinsular Cape District and the adja-
cent islands; type from Cape San Lucas. It is a slender-stemmed sub-
shrub with showy orange-colored rays and a pungent aromatic odor.
ENCELIA FARINOSA Gray in Emory, Mil. Reconn. 143. 1848.
Near Guaymas, February 9, Dawson 1082.
Mostly on the arid rocky foothill slopes in southern Nevada, Cali-
fornia, Arizona, Sonora, and south to central Sinaloa; type from Cali-
fornia.
ENCELIA FARINOSA PHENICODONTA Blake, Proc. Am. Acad. Sci.
49 :362. 1913.
Ensenada de los Muertos, Cape District, March 5, Rempel 76. Tor-
tuga Island, March 17, Rempel 218.
Irregularly through the gulf region from southern Arizona south to
Guaymas, Sonora on the mainland, on the islands Patos, ‘Tiburon, or-
tuga, and probably others, on the deserts of the peninsula, and in the
Cape District ; type from near San Quentin, Baja California. This form
is distinguished from the typical species by the purple disk flowers in
generally smaller heads. Johnston (Proc. Calif. Acad. Sci. IV, 12:1198.
1924) raised Blake’s form to a variety. It appears to be more widely
distributed than the species.
ERICAMERIA DIFFUSA Benth., Bot. Voy. Sulph. 23. 1844.
San Francisco Island, March 9, Rempel 106, shrub 2 feet tall on
hillside facing south. Agua Verde Bay, Baja California, March 10,
Rempel 117, in draw on mesa about 2 miles inland; Rempel 122, wash.
Los Angeles Bay, March 19, 20, Rempel 243.
Along the coasts of southern Sonora and southern Baja California
as far as La Paz and on adjacent islands; type from Magdalena Bay.
It forms a bushy shrub 1-2 m tall, common and even abundant in some
localities. Besides San Francisco Island it has also been collected on San
Marcos and Ildefonso Islands. ‘The Rempel collections are either sterile
or in the last stages of seeding.
NO. 2 GENTRY : LAND PLANTS 175
EUPATORIUM Purpusi Brge., Erythea 7:3. 1899.
Canyon above Puerto Escondido, Sierra Giganta, March 13, Rempel
160, canyon bottom.
Southern Baja California in the mountains of the Cape District and
along the Sierra Giganta; type from San Pablo. A low polypodial her-
baceous perennial with stems 3-6 dm long, often forming colonial bushes
in the damp shady recesses of the mountains. The triangular serrate
leaves are large, 5-8 cm long, shallowly emarginate, the lower long petio-
late (4-7 cm long), the stems commonly purplish. Rarely collected.
FRANSERIA ARBORESCENS Brge., Zoe 5:162. 1903.
Canyon above Puerto Escondido, Sierra Giganta, March 13, Rempel
151 (sterile), canyon bottom.
Southern Baja California; type from Ascension. A large-leaved per-
ennial, which may form large woody-stemmed shrubs up to 3 m tall,
and which is one of the least xerophytic of the genus, apparently limited
to the canyons and arroyos, drawing upon subsurface run-off.
FRANSERIA DUMOSA Gray in Frem. 2nd Rep. 316. 1845.
Los Angeles Bay, March 19, 20, Rempel 250 (sterile).
Widely distributed in the drier areas of the Sonoran Desert from
central Sonora and middle Baja California north to the Mojave Desert
of southeastern California and southern Nevada, also in southern Ari-
zona; type from the sandy uplands of the Mojave River. It is lacking
or scarce in the arboreal desert of middle Sonora and the wetter areas
of the peninsula. It commonly forms a low, densely intricated, pallid,
and rather brittle bush with ephemeral leaves, pinnately dissected. ‘he
burr-like fruits mature quickly and are easily detached from the rachis.
It normally flowers in March; the Rempel collection is indicative of a
dry season.
FRANSERIA ILICIFOLIA Gray, Proc. Am. Acad. Sci. 11:77. 1876.
North end of Los Angeles Bay, March 19, 20, Rempel 253. Puerto
Refugio, Angel de la Guardia Island, March 20, Rempel 279.
Around the shores of the northern part of the gulf region including
nora; type from the “Great Canyon of the Tantillas Mountains, near
the border of Lower California,’ Baja California. A low, spreading
polypodial bush with harsh leaves having spiny marginal aristations. In
the gulf it is known from San Lorenzo, Angel de la Guardia, and San
southeastern California and adjacent Arizona, but not known from So-
Esteban Islands.
176 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 13
HAPLOPAPPUS JUNCEUS Greene, Bull. Calif. Acad Sci. 1:190. 1885.
Puerto Refugio, Angel de la Guardia Island, March 20, Rempel 265.
A low glandular-pubescent suffrutescent with slender ascending
branches, the spinulose leaves reduced upward, bearing 1 to a few heads
of involucres 6-8 mm high. Known from northern Baja California and
adjoining states, Pinacate Mountain in Sonora; the type from San Diego
County, California.
HELIOPSIS PARVIFOLIA Gray, Pl. Wright. 2:86. 1853.
Puerto Escondido, Sierra Giganta, February 11, Dawson 1100. San
Carlos Bay, Sonora, February 8, Dawson 1051.
Known from southwestern Texas to Arizona and northern Mexico.
The appearance of this plant at low elevations near Guaymas is of in-
terest, since it is more commonly found in the middle elevations of
mountains. A related plant, H. longipes (Gray) Blake, of central Mexi-
co has recently been found to contain active ingredients in the roots,
which give promise of value as an insecticide.
HETEROSPERMA XANTII Gray, Proc. Am. Acad. Sci. 5:162. 1861.
San Jose del Cabo, February 17, Dawson 1176, 1168.
Cape District. Annual, yellow-flowered in spring.
HOFMEISTERIA FASCICULATA PUBESCENS (Wats.) Rob., Proc. Am.
Acad. Sci. 47:192. 1911.
Puerto Escondido, February 11, Dawson 1105. West cove in Con-
cepcién Bay, March 15, Rempel 178, foot of rocky slopes. Agua Verde
Bay, Baja California, March 10, Rempel 120. Punta Frailes, February
16, Dawson 1143.
Gulf side of the southern part of the peninsula; type from Muleje,
Baja California. Flowers February to April or May.
LAGASCEA DECIPIENS Hemsl., Diag. Pl. Mex. 33. 1879.
San Carlos Bay, Sonora, February 8, Dawson 1064.
Sonora and Chihuahua to Jalisco; type from Sierra Madre Occiden-
tal of northern Mexico. It is common along the coast and in the foot-
hills, rarely or not at all penetrating the Sierra Madre itself, and may
be frequently seen along the washes where it occasionally rambles over
other shrubs.
MALACOTHRIX XANTI Gray, Proc. Am. Acad. Sci. 9:213. 1874.
Puerto Escondido, February 11, Dawson 1101. Agua Verde Bay,
March 10, Rempel 139, foot of rocky arroyo wall.
NO. 2 GENTRY: LAND PLANTS 177
Southern Baja California; type from Cape San Lucas. Annual with
the leaves all basal, the scape 2-2.5 dm tall, bearing several, narrow,
irregularly fimbriate bracts and terminating in an open panicle, minutely
bracteate. The involucre bracts are pale, with irregular rather large
glands, the ray flowers pale pink, erose. The above collections are near
the northern limit for the species.
MALPERIA TENUIS Wats., Proc. Am. Acad. Sci. 24:54. 1889.
Puerto Refugio, Angel de la Guardia Island, March 20, Rempel
270a.
Coarse arid soils of the rocky slopes through the deserts of northern
and middle Baja California; type from stony ridges near Los Angeles
Bay. It is a diminutive winter annual, corymbosely branching, the seeds
maturing in March and early April.
NICOLLETIA TRIFIDA Rydb., N. Am. Fl. 34:180. 1915.
Los Angeles Bay, March 19, 20, Rempel 236, on fan and in washes.
Sandy soils of middle Baja California; the type from Los Angeles
Bay. A distinctive perennial herb with linear dissected leaves, a Dysodia-
like odor and appearance. The flowers are made striking by the con-
spicuous white rays striped medially with reddish purple.
PALAFOXIA LINEARIS (Cav.) Lag., Gen. & Sp. Pl. 26. 1816.
Los Angeles Bay, March 19, 20, Rempel 239.
From southern Utah and southern Nevada south through the deserts
into northern and northwestern Mexico, chiefly in sandy soils. It is ag-
gressive in colonizing disturbed soils, as along roads and trails. The
woody section of old stem and the strigose leaves of the Rempel collec-
tion Indicate it should be more closely assigned to the variety leucophylla
(Gray) Jtn.
PECTIS MULTISETA Benth., Bot. Voy. Sulph. 20. 1844.
Punta Frailes, February 16, Dawson 1121. San Jose del Cabo, Feb-
ruary 17, Dawson 1155.
Southern Baja California; type from Cape San Lucas. The ray
flowers are about 8 mm long or 3 mm longer than described for the
species by Rydberg (N. Am. FI. 34:214. 1916).
_ PERITYLE AUREA Rose, C.N.H. 1:84. 1890.
Tortuga Island, March 17, Rempel 225. Agua Verde Bay, Baja
California, March 10, Rempel 140, foot of rocky side of arroyo. Canyon
above Puerto Escondido, March 13, Rempel 141.
178 ALLAN HANCOCK PACIFIC EXPEDITIONS voL. 13
Middle Baja California and the adjacent islands of San Marcos and
Tortuga; type from Santa Rosalia, Baja California. The plant has a
limited distribution, has been little collected, and may be a postinsular
relic from the mountains south of Santa Rosalia, now migratory upon
Quaternary lands. The Tortuga Island collection shows a plant signifi-
cantly different in its more robust and diffusive growth, the leaves larger,
coarser, and more deeply lobed, and in bearing 20 to 50 rather than only
2 to 10 heads as typical of the mainland forms.
PERITYLE CUNEATA Brge., Zoe 1:54. 1890.
Punta Frailes, February 16, Dawson 1118.
Southern Baja California; type from Sierra Laguna, Cape District.
Apparently a postinsular endemic.
PeriTyLE Emoryi Torr. in Emory, Mil. Reconn. 142. 1848.
San Carlos Bay, February 8, Dawson 1068, 1073b. Canyon above
Puerto Escondido, Sierra Giganta, March 13, Rempel 147, canyon bot-
tom.
Southern California, Baja California, Arizona, and Sonora; type
from “‘Cordilleras of California.’’ A common winter-spring annual, abun-
dant in many localities of the Sonoran Deserts.
PERITYLE INCOMPTA Brge., U. C. Publ. Bot. 6:503. 1919.
Agua Verde Bay, Baja California, March 10, Rempel 134, beach
dunes; Rempel 130, wash. Ensenada de los Muertos, Cape District,
March 5, Rempel 77, among rocks close to shore.
Southern part of the peninsula from San Ignacio south mostly along
outer coast; on Santa Magdalena and Santa Margarita Island; type
from Los Dolores, Baja California, probably in the Cape District.
Resembles P. crassifolia somewhat, but lacks the dense glandular pub-
escence of that species and the leaves of P. incompta are more intricately
dissected.
PERITYLE PALMERI Wats., Proc. Am. Acad. Sci. 24:57. 1889.
Guaymas, January 23, Dawson 1003.
Coastal cerros in southern Sonora; type from Guaymas. Low cespi-
tose pilose perennial herb with relatively large radiate heads with yellow
rays.
POROPHYLLUM CRASSIFOLIUM Wats., Proc. Am. Acad. Sci. 24:57.
1889.
West cove in Concepcion Bay, March 15, Rempel 183.
No. 2 GENTRY: LAND PLANTS 179
Southern Baja California mainly along the gulf coast and adjacent
islands; type from Carmen Island. Suffrutescent with linear succulent
leaves having a large gland at the apex below the claw-like tip; the in-
volucre bracts are 5 or 6, rounded, with a single large gland above the
middle. Related to P. tridentatum and, as Johnston suggests (l.c. p.
1211), may be only a variety of it.
POROPHYLLUM GRACILE Benth., Bot. Voy. Sulph. 29. 1844.
Punta Frailes, Cape District, February 16, Dawson 1115. San Jose
del Cabo, February 17, Dawson 1218. Puerto Refugio, Angel de la
Guardia Island, March 20, Rempel 266.
Widely distributed in the California Gulf Region and adjacent area
in southeastern California and Arizona as far north as the Grand Can-
yon, south into Sinaloa; type from Magdalena Bay, Baja California.
A shrubby herb with purplish, slender stems, small linear leaves,
rather colorless or purplish flowering heads, and a pleasant pungent odor
when crushed. It is not infrequent through southern Sonora, where it
often grows up under shrubbery.
POROPHYLLUM PORFYREUM Rose & Standl., N. Am. Fl. 34:191.
1916.
San Jose del Cabo, February 17, Dawson 1166, 1153a.
Known only from the Cape District; type from San Jose del Cabo. |
Another linear-leaved species, but characterized by its short, thick,
purplish flowering heads.
SENECIO MOHAVENSIS Gray, Syn. Fl. 12:446. 1884.
North end of Los Angeles Bay, March 19, 20, Rempel 261.
General through the Sonoran Desert. A diminutive winter annual
2-3 dm tall, the leaves auriculately clasping, coarsely dentate, both leaves
and stems purplish. Sometimes found on shady talus slopes.
TRIXIS CALIFORNICA Kell., Proc. Calif. Acad. Sci. I, 2:182, f. 53.
1863.
San Carlos Bay, Sonora, February 8, Dawson 1072. Guaymas, Feb-
ruary 9, Dawson 1077. San Jose del Cabo, Cape District, February 17,
Dawson 1161. Tortuga Island, March 17, Rempel 216. Puerto Refugio,
Angel de la Guardia Island, March 20, Rempel 264.
A low spreading shrubby bush, long flowering through the spring
with numerous heads on short erect branchlets. It is common in arroyos
and also on slopes throughout the gulf region and adjacent territory,
southern California, southern Sonora; type from Cedros Island.
180 ALLAN HANCOCK PACIFIC EXPEDITIONS VoL. 13
VERBESINA OLIGOCEPHALA Jtn., Proc. Calif. Acad. Sci. IV, 12:
1200. 1924.
Canyon above Puerto Escondido, Sierra Giganta, March 13, Rempel
164, canyon bottom.
Known only from the canyons of the Sierra Giganta, southern Baja
California; type from mountains back of Agua Verde Bay. Rempel’s col-
lection is the second. The plant may well be a relic endemic of a Sierra
Giganta postinsular locality. Johnston reports it as an erect growing
little-branched shrub about 1 m tall. It is distinguished by its rather
large triangular, coarsely irregularly serrate to undulate leaves, the to-
mentose stem, and the long-pedunculate (2-4 cm) heads with a double
series of unlike involucre bracts, the outer of which are broader than
the inner and markedly reflexed.
VIGUIERA DELTOIDEA CHENOPODINA (Greene) Blake, C.N.H. 54:
91. 1918.
San Pedro Nolasco Island, February 6, Dawson 1033. Island in Con-
cepcién Bay, March 16, Rempel 201.
Middle Baja California and adjacent islands; type from between
Santo Domingo and Matancita.
Although Johnston (1.c. p. 1201) referred his Nolascan collection
(3127) to typical Viguiera deltoidea Gray, the present collection with
its small, deltoid, entire, strigillose leaves appears to relate the plant to
the variety, chenopodina. ‘The flowers and achenes, however, are con-
siderably smaller and the leaves larger than Rempel’s Concepcion Bay
number, which appears typical of the variety.
VIGUIERA TOMENTOSA Gray, Proc. Am. Acad. Sci. 5:161. 1861.
Punta Frailes, February 16, Dawson 1117, 1129. San Jose del Cabo,
February 17, Dawson 1169. Cabeza Ballena, Cape District, March 3,
Rempel 58.
Known only from the Cape District of Baja California; the type
from Cape San Lucas. A large-leaved and large-flowered shrub.
No. 2 GENTRY: LAND PLANTS 181
LITERATURE CITED
ATLAS CLIMATOLOGICO DE MEXICO
1939. Secr. Agri. y Fom., Mexico, D. F.
AXELROD, DANIEL
1939. A Miocene flora from the western border of the Mojave Desert. Carn.
Inst. Wash. Publ. 516, pp. 1-129, pl. 12.
BRANDEGEE, T. S.
1891. Flora of the cape region of Baja California. Proc. Calif. Acad. Sci. II,
3 :108-182.
1892. Additions to the flora of the cape region of Baja California. Proc. Calif.
Acad. Sci. II, 3:218-227.
1892. Distribution of the flora of the cape region of Baja California. Zoe
3 :223-231.
1894. Additions to the flora of the cape region of Baja California II. Zoe
4 :398-408.
1901. New species of plants mainly from Baja California. Zoe 5:104-108.
CAIN, STANLEY A.
1944. Foundations of plant geography. 556 pages, illus. Harper & Brothers.
CHANEY, RALPH
1944. Pliocene floras of California and Oregon. Im Chaney, Condit, Axelrod.
Carnegie Inst. Wash. Publ. 553, pp. 1-19, 1 fig.
Darton, N. H.
1921. Geologic reconnaissance in Baja California. Journ. Geol. 29 :720-748.
FRASER, C. MCLEAN
1943. General account of the scientific work of the Velero III in the Eastern
Pacific, 1931-41, Part I, Historical introduction, Velero III, Personnel.
Allan Hancock Pacific Exped., 1 (1) :1-48, pls. 1-16.
1943b. General account. Part II. Geographical and biological associations.
Tbid., 1(2) :49-258, pls. 17-128.
1943c. General account. Part III. A ten-year list of the Velero III collecting
stations. [bid., 1(3) :259-432, charts 1-115.
GENTRY, H. S.
1948. Additions to the flora of Sinaloa and Nuevo Leon. Brittonia 6 :309-331.
JouNsTON, I. M.
1924. The Botany; Expedition of the Calif. Acad. Sci. to the Gulf of Cali-
fornia in 1921. Proc. Calif. Acad. Sci. IV, 12:952-1218.
1931. Flora of the Revillagigedo Islands, Mexico. 1925. Proc. Calif. Acad.
Sci. IV, 1521-113.
Jones, F. A.
1910. Jones Expedition to Tiburon Island. Mining World 32:269-270.
SCHUCHERT, CHARLES
1935. Historical geology of the Antillean-Caribbean region. 811 pp. John
Wiley & Sons, Inc. New York.
SHREVE, ForREST, T. D. MALLERY AND W. V. 'TURNAGE
1936. Desert investigations. Carn. Inst. Wash. Annual Report, pp. 214-221.
SLEVIN, JOSEPH R.
1923. General account. Expedition of the Calif. Acad. of Sci. to the Gulf of
California in 1921. Proc. Calif. Acad. Sci. IV, 12:55-72.
TuRNAGE, W. V. AND T. D. MALLERY
1941. An analysis of rainfall in the Sonoran Desert and adjacent territory.
Carn. Inst. Wash. Publ. 529, pp. 1-45, maps.
WATSON, SERENO
1888. Upon a collection of plants made by Dr. E. Palmer in 1887 about
Guaymas, etc. Proc. Am. Acad. 24:36-87.
ZEUNER, F. E.
1945. The Pleistocene period. Ray Society Publ., pp. 1-322.
182 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 13
JALISCO AND OAXACA
‘Tenacatita Bay is a rather broad bay in the southernmost part of the
Mexican state of Jalisco not far from the Colima border, plate 13. So
far as I am aware, the collection of plants, made there by the Allan
Hancock Expedition in the Velero IIT in 1939, is the first. Jalisco, like
other Mexican states has been incompletely and intermittently collected.
One of the first botanists to collect in the state was Jose Mariano Mo-
cifio, who traveled through the state in the latter part of the eighteenth
century. About 100 years later in the 1890’s, Cyrus Guernsey Pringle
made what are probably the largest Jaliscan collections. “Iwo of his
more important localities were a barranca near Guadalajara and the
hills about Etzatlan. Rose, Standley, and others have since collected
along the railroad through the interior highland. The most important
collection in this century to date is that of Inez Mexia, made during the
last decade in the western mountains, where she discovered many new
plants. Except for Edward Palmer’s important collections about the port
of Manzanillo, the coast flora has not been sampled, and the slopes of
the mountains facing the sea are quite untouched.
The plants collected at T’enacatita Bay are therefore of interest for
the records they provide in the distribution of subtropical and tropical
American plants. A few of the species collected have not previously been
known in Jalisco. ‘Taken in the tierra caliente zone, they are typical repre-
sentatives of the tropical drought-deciduous heterogeneous forest that ex-
tends along the Pacific Coast from Sinaloa to Costa Rica. It is unfor-
tunate that the expedition happened to visit this little known locality in
the month of May, because the dry season is then at its height and very
few of the plants are in a collectable or even recognizable condition.
Except for the riparian communities, the innumerable members of the
natural flora covering the hills and mountains are leafless and either rest-
ing or dormant. A few only fruit and flower during this period. ‘The
whole great biota is in a kind of waiting for the summer rains, which
normally start in June.
Chacagua Bay, Oaxaca, plate 13, is in southernmost Mexico and
although it is not a wet climate except for the summer months, it is
within the American tropics. Unlike Jalisco, the state of Oaxaca has had
the attentions of a resident botanist. Professor C. Conzatti of Ciudad
Oaxaca has long given the state special study. He classifies the region
around the littoral of Chacagua Bay as the “Subregion de la Costa y
Cafiada de Cuicatlan.”* Although less accessible than Jalisco, Oaxaca
*Las Regiones Botanico-Geograficas del Estado de Oaxaca. Presented at the
IV International Botanical Congress, Ithaca, New York. Printed by the eee Cc:
Conzatti, 1926, Oaxaca, Oaxaca.
NO. 2 GENTRY: LAND PLANTS 183
seems to have had more attention from botanists and several have made
extended collections through portions of the state. Ihe Velero III visited
Chacagua Bay on March 21, 1939. Francis H. Elmore went ashore and
made a small collection of plants, consisting of 27 numbers representing
26 species. These together with the 25 numbers, representing 22 species,
from Tenacatita Bay, Jalisco are catalogued below.
CATALOGUE OF COLLECTIONS
POLYPODIACEAE
LYGODIUM VENUSTUM Sw. in Schrad., Jour. 1801 2:303. 1803.
Tenacatita Bay, May 8, Elmore 1412, along dry stream bank.
Southern Mexico through Central America to Brazil and the West
Indies.
BROMELIACEAE
TILLANDSIA FASCICULATA Sw., Prodr. 56. 1788.
Tenacatita Bay, Jalisco, May 8, Elmore 1417, epiphytic on Cono-
carpus erectus.
Widely distributed in tropical America from Florida and the West
Indies to Mexico and Central America to Colombia and Guiana. It is
a highly polymorphic species and has been divided into many varieties.
PIPERACEAE
PIPER AFF. MISANTLENSE C.DC. in DC., Prodr. 161 :286. 1869.
Tenacatita Bay, Jalisco, May 8, Elmore 1420.
Vera Cruz and perhaps elsewhere.
The above collection with pubescent branchlets is doubtfully referred
to this species, which is described as having glabrous branchlets. It agrees
fairly well with herbarium material labeled P. misanilense.
PIPER TUBERCULATUM Jacq., Icon. Pl. Rar. 2:2. 1786.
Tenacatita Bay, Jalisco, May 8, Elmore 1422.
From Vera Cruz and Nayarit south through tropical America. It is
one of the few species of Piper having a wide distribution.
MorACEAE
Ficus MEXICANA Miquel, Ann. Mus. Bot. Lugd. Bat. 3:300. 1867.
Tenacatita Bay, Jalisco, May 8, Elmore 1410, rocky sandy soil of
hot dry forest along a dry stream bank of 15 feet elevation.
In Mexico from southern Sonora south to Oaxaca; reported also to
be in Yucatan.
The trees along the west coast of Mexico which taxonomists have
assigned to Miquel’s name are among the largest in the genus. They
affect the open streamways, as the intermittent arroyos, which though
184 ALLAN HANCOCK PACIFIC EXPEDITIONS VoL. 13
dry on the surface for much of the year, carry a charge of water in their
sandy beds. The trees spread with ponderous limbs into a great mound
of relatively open foliage. The leaves are uniformly ellyptic, acute at
both ends, with strong scalleriform lateral veins, the blade commonly
14 to 18 cm long. The fruit is 1 to 1.5 cm in diameter, quite round,
dryish, and little suited to human taste and consumption.
AMARANTACEAE
PHILOXERUS VERMICULARIS (L.) R. Br., Prodr. 416. 1910.
Gomphrena vermicularis L., Sp. Pl. 224. 1753.
Chacagua Bay, Oaxaca, March 21, Elmore D26.
Florida through the West Indies and Central America to northern
South America.
NYCTAGINACEAE
PISONIA ACULEATA L., Sp. Pl. 1026. 1753.
Chacagua Bay, Oaxaca, March 21, Elmore D18, shaded in dry
sandy soil, a vine with yellow flowers.
Widely distributed along beaches in tropical and subtropical Ameri-
ca. Also in southern Asia.
A large, spiny, intricately branched shrub with sweet-scented flowers.
It occasionally takes a scandent form and runs over large trees.
SALIPIANTHUS ARENARIUS H. & B., PI. Aequin. 1:139. 1807.
Chacagua Bay, Oaxaca, March 21, Elmore D4, dry shaded sandy
soil.
Jalisco to Oaxaca; type from near Acapulco, Guerrero.
An herbaceous shrub common to sandy and alluvial soils. Elmore re-
ports it as having ‘“‘a very strong pleasant odor.” A closely related species,
S. macrodontus, is known to have a large tuberous edible root (Gentry,
Carn. Inst. Publ. 527:111. 1942), and it would be of interest to know
if the present species has a similar organ.
PAPAVERACEAE
ARGEMONE MEXICANA L., Sp. Pl. 508. 1753.
Tenacatita Bay, Jalisco, May 8, Elmore 1A11, dry alluvial soil of
a stream bank.
Common in wastelands and fallow fields of low and middle eleva-
tions throughout Mexico and into Central America.
CAPPARIDACEAE
CAPPARIS BADUCA L., Sp. PI. 504. 1753.
Tenacatita Bay, Jalisco, May 8, Elmore 1A21.
No. 2 GENTRY: LAND PLANTS 185
On both coasts of Mexico south through tropical America. The col-
lection represents a new plant for the flora of Jalisco and extends the
known range northward.
This Capparis is distinguished from other members of the genus by
the combination of long petioles below and short petioles (some leaves
subsessile) above towards the apex of the branchlets.
AMYGDALACEAE
CHRYSOBALANUS IcAco L., Sp. Pl. 513. 1753.
Chacagua Bay, Oaxaca, March 21, Elmore D15, few plants in dry
sandy soil at 10 feet elevation, flowers white.
Widely distributed along the coasts of tropical America and in west
Africa; type from Jamaica. The cocoa-plum tree is widely known for its
edible fruits, eaten raw or cooked.
CoUEPIA POLYANDRA (HBK.) Rose, C.N.H. 5:196. 1899.
Chacagua Bay, Oaxaca, March 21, Elmore D14, many plants in dry
sandy soil at 10 feet elevation, flowers white.
Sinaloa to Oaxaca in the tierra caliente; type from Acapulco Guer-
rero.
LEGUMINOSAE
Acacta Hinpstana Benth., Lond. Jour. Bot. 1:504. 1842.
Tenacatita Bay, Jalisco, May 8, Elmore 1413, in dry open forest at
10 feet elevation. Chacagua Bay, Oaxaca, March 21, Elmore D1/1.
Along the Pacific coast from Sinaloa to San Salvador.
It is a shrub or small tree belonging to that group of trees known as
the Bull Horn Acacias, so-called from the large hollow spines with flar-
ing bases along the branches, and in which ants live. These animals are
pugnacious with a strong sense of proprietorship and rush forth from
their spine retreats to attack anything that disturbs their arboreal world,
botanists included. This species is found in the more open forests and
along stream banks and is tolerant to a wide range of soils.
CANAVALIA MARITIMA (Aubl.) Thouars, Jour. de Bot. Desv. 1:80.
1813.
Chacagua Bay, Oaxaca, March 21, Elmore D1, growing on small
sand dunes.
Littoral of tropical America; commonly associated with Ipomoea
pes-caprae.
186 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 13
This collection may be referable to C. apiculata Piper (C.N.H. 20:
566. 1925), but the leaves are broadly ovate and retuse, not acute, which
latter character Piper used to separate his northwest Mexican maritime
species. He does not cite C’. maritima from the Mexican west coast,
hence Elmore’s Oaxaca collection with the characters of C. maritima
makes Piper’s C. apiculata a dubious species, since the small differences
apparently are not correlated with geographic segregation.
DESMODIUM SCORPIURUS (Sw.) Desv., Jour. de Bot. 1:122. 1813.
Chacagua Bay, Oaxaca, March 21, Elmore D9, on dry, shaded,
sandy soil under cocoanut trees. |
Littoral from central Sinaloa south through Central America. A
procumbent herb characteristic of the sandy littoral.
PHASEOLUS ADENANTHUS Meyer, Prim. Fl. Esseq. 239. 1818.
Chacagua Bay, Oaxaca, March 21, Elmore D2, growing on and
among sand dunes on the upper beach.
Widely distributed through lowlands of tropical America.
A glabrous or puberulent vine with lanceolate leaflets, very unequal
calyx lobes (upper broad and rounded, lower lanceolate, acute), bracts
strongly 9-10-nerved, pale flowers, and rather straight pods 7-8 x 100
mm.
PROSOPIS AFF. JULIFLORA (Sw.) DC., Prodr. 2:447. 1825.
Tenacatita Bay, Jalisco, May 8, Elmore 1424.
This form of the species is common along the west coast of Mexico
from Sinaloa south, chiefly below 2000 feet elevation.
EUPHORBIACEAE
EUPHORBIA HIRTA TYPICA Wh., Cont. Gray Herb. 127:68. 1939.
Tenacatita Bay, Jalisco, May 8, Elmore 1413, dry clay soil in forest
clearing.
Widely dispersed through tropical and subtropical America.
HipPpOMANE MancIineELta L., Sp. Pl. 1191. 1753.
‘Tenacatita Bay, Jalisco, May 8, Elmore 1418, in dry open forest.
From southern Mexico south through Central America to South
America and the West Indies.
SAPINDACEAE
PAULLINIA FUSCESCENS HBK., Nov. Gen. & Sp. 5:93. 1821.
Chacagua Bay, Oaxaca, March 21, Elmore D5, growing as a vine
over a tree in sandy soil in dry forest at 10 feet elevation.
NO. 2 GENTRY : LAND PLANTS 187
Widely distributed in the tierra caliente from central Sinaloa, Mexi-
co to Brazil; type from the Rio Amazon.
During the arid spring when many plants are leafless through the
Pacific lowlands, this vine is conspicuous by its clusters of reddish fruits
and dissected, strongly crenate, lobed leaves.
STERCULIACEAE
GUASUMA ULMIFOLIA Lam., Encycl. 3:52. 1789.
Tenacatita Bay, Jalisco, May 8, Elmore 148, in dry open forest.
Widely distributed in tropical and subtropical America from central
Sonora and Tamaulipas, Mexico to South America.
The guazima tree is primarily a riparian dweller along the Pacific
tierra caliente from sea level up to 2500 to 3000 feet. It appears to re-
quire ground water either at high or low levels, at least in the more arid
climates as in Sonora, and grows readily in a wide variety of soils, coarse
or fine. In contrast to the trees of the slope forests, it carries its leaves
through most of the year, dropping them only at the height of the spring
dry season. Its apparent absence from the Cape District of Baja Cali-
fornia is rather puzzling, when so many of its mainland associates are
found there.
WALTHERIA AMERICANA L., Sp. Pl. 673. 1753.
Chacagua Bay, Oaxaca, March 21, Elmore D7, in dry, shaded,
sandy soil.
Widely distributed in the warmer parts of both hemispheres.
WaALTHERIA Prestu Walp., Report. Bot. 1:340. 1842.
Chacagua Bay, Oaxaca, March 21, Elmore D10, in dry sandy soil
at 10 feet elevation, flowers yellow.
Oaxaca to Guerrero along the southwest coast of Mexico; type from
Acapulco, Guerrero.
This plant has been collected rarely and the above collection is the
first cited from Oaxaca.
‘TURNERACEAE
‘TURNERA ULMIFOLIA. L., ‘Sp! Pl 271.) 1753:
Chacagua Bay, Oaxaca, March 21, Elmore D8, a few plants in dry
sandy soil at 10 feet elevation, flowers yellow.
Widely distributed in tropical America; naturalized in the Old
World.
188 ALLAN HANCOCK PACIFIC EXPEDITIONS voL. 13
PASSIFLORACEAE
PASSIFLORA HOLOSERICEA L., Sp. Pl. 958. 1753.
Chacagua Bay, Oaxaca, March 21, Elmore D20, vine with white and
purple flowers climbing on Chrysobalanus icaco in dry, hot, shaded jungle
with sandy soil.
Tierra caliente from southern Mexico to Honduras, Cuba, Vene-
zuela, and northern Colombia; type locality, Vera Cruz, Mexico.
Vine with flexuous stems and coriaceous, pubescent, 3-lobed leaves,
the lobes aristate, bidentate on the broadly rounded base. It is common
in the southern low country of Mexico and is known from collections at
Mazatlan, Sinaloa, the most northern records, and the Tres Marias
Islands.
RHIZOPHORACEAE
RHIZOPHORA MANGLE L., Sp. PI. 443. 1753.
Chacagua Bay, Oaxaca, March 21, Elmore D24, edge of lagoon.
From Tiburon Island south throughout the tropics of the Americas;
type from the Caribbean Sea.
CoMBRETACEAE
COMBRETUM MEXICANUM H. & B., Pl. Aequin. 2:159, pl. 132.
1809.
Tenacatita Bay, Jalisco, May 8, Elmore 141, vine growing on trees
from dry clay soil in the forest, elevation 10 feet.
Tierra caliente, Jalisco to Oaxaca, Mexico; type from Acapulco,
Guerrero. This collection apparently is the first from Jalisco and con-
stitutes a northern record for the species.
CONOCARPUS ERECTUS L., Sp. Pl. 176. 1753.
Tenacatita Bay, Jalisco, May 8, Elmore 1416, in sand on upper
beach. Chacagua Bay, Oaxaca, March 21, Elmore D25, on edge of
lagoon. :
On the shores throughout tropical America and in western Africa.
CONOCARPUS ERECTUS SERICEUS DC., Prodr. 3:16. 1828.
Chacagua Bay, Oaxaca, March 21, Elmore D21, in moist sandy soil
by a lagoon.
Widely distributed in the American tropics from southern Mexico
through Central America to South America and the West Indies along
the shores.
LAGUNCULARIA RACEMOSA (L.) Gaertn., f. Fruct. & Sem. 3 :209.
1807.
Chacagua Bay, Oaxaca, March 21, Elmore D27.
NO. 2 GENTRY: LAND PLANTS 189
Littoral of the tropics and subtropics in North and South America
and in western Africa.
The inflorescence is very young, indicating the start of the flowering
period for the Oaxaca population.
PLUMBAGINACEAE
PLUMBAGO SCANDENS L., Sp. PI. ed. 2, 215. 1762.
Chacagua Bay, Oaxaca, March 21, Elmore D6, sandy soil in the
shade of dry hot forest, 10 feet elevation.
Widely distributed in the tierra caliente of tropical America from
‘Tamaulipas and Sonora south along both coasts.
ASCLEPIADACEAE
ASCLEPIAS CURASSAVICA L., Sp. Pl. 215. 1753.
Tenacatita Bay, Jalisco, May 8, Elmore 1419.
Widely distributed in tropical and subtropical America from south-
ern Sonora and central Baja California southward.
FUNASTRUM CLAUSUM (Jacq.) Schlechter, Rep. Sp. Nov. Fedde
13 :283. 1914.
Tenacatita Bay, Jalisco, May 8, Elmore 1423, climbing on shrubs
on stream bank around pools of a dry stream, flowers white.
Widely known through tropical and subtropical America and nearly
throughout Mexico.
CONVOLVULACEAE
IPOMOEA PES-CAPRAE (L.) Roth., Nov. Sp. PI. 109. 1821.
Chacagua Bay, Oaxaca, March 21, Elmore D23, among and on the
small sand dunes of the beach.
Along the beaches of the tropics and subtropics of both hemispheres ;
type from India.
HyYDROPHYLLACEAE
WIGANDIA CARACASANA HBK., Nov. Gen. & Sp. 3:127. 1819.
Tenacatita Bay, Jalisco, May 8, Elmore 1415, sandy rocky alluvium
on dry stream bank at 10 feet elevation, flowers blue.
From northern Sinaloa, Mexico south through Central America to
northern South America.
BORAGINACEAE
CorpiA SELERIANA Fern., Proc. Am. Acad. Sci. 36:498. 1901.
Tenacatita Bay, Jalisco, May 8, Elmore 144, in dry open forest at
15 feet elevation, flowers white.
Southwestern Mexico from Jalisco to Oaxaca; type from Huilotepec,
190 ALLAN HANCOCK PACIFIC EXPEDITIONS VoL. 13
Oaxaca.
Not previously known from Jalisco, the collection of this shrub
marks a northern extension of range. Like many other spring blooming
shrubs of the semiarid tropical Pacific tierra caliente, it is nearly leafless
at flowering time, as faithfully reflected by Elmore’s specimens.
TOURNEFORTIA HIRSUTISSIMA L., Sp. Pl. 140. 1753.
Tenacatita Bay, Jalisco, May 8, Elmore 145, in dry open forest at
15 feet elevation, flowers white.
Widely distributed in tropical and subtropical America, from Sinaloa
to South America and the West Indies.
VERBENACEAE
AVICENNIA NITIDA Jacq., Enum. Pl. Carib. 25. 1760.
Chacagua Bay, Oaxaca, March 21, Elmore D21a.
Littoral from Baja California and Tamaulipas south through tropi-
cal America.
LANTANA HORRIDA HBK., Nov. Gen. & Sp. 2:261. 1817.
Chacagua Bay, Oaxaca, March 21, Elmore D13, a few plants in dry
sandy soil climbing on Cowepia polyandra, flowers red and yellow.
Widely distributed in the warmer parts of America; from southern
Sonora south along the Mexican west coast.
PHYLLA NODIFLORA (L.) Greene, Pittonia 4:48. 1899.
Chacagua Bay, Oaxaca, March 21, Elmore D3, dry sandy soil near
sea level.
Widely distributed in the tropical lowlands of both hemispheres.
This is a common strand plant along the beaches and bottomlands
of western Mexico. On the sand dunes it forms only sparse covering of
loosely branched, prostrate, dispersed plants, while on the moister clay
soils back of the beach dunes and inland it may form a compact turf-
like covering.
SOLANACEAE
SOLANUM DIVERSIFOLIUM Schlecht., Linnaea 19:297. 1846.
Tenacatita Bay, Jalisco, May 8, Elmore 149, a few shrubs with
white flowers growing in dry open exposed clay soil.
Apparently along both Mexican coasts from Baja California, Sina-
loa, and Tamaulipas south to Central America.
SOLANUM NuUDUM HBK., Nov. Gen. & Sp. 3:33. 1818.
Chacagua Bay, Oaxaca, March 21, Elmore D17, many plants,
NO. 2 GENTRY: LAND PLANTS 191
shaded in dry sandy soil under the forest, flowers white.
Tierra caliente of Mexico and Central America; type from Jalapa,
Vera Cruz.
BIGNONIACEAE
ASTIANTHUS VIMINALIS (HBK.) Bail, Hist. Pl. 10:44. 1888.
Tenacatita Bay, Jalisco, May 8, Elmore 1414, sandy rocky alluvium
along dry stream bank, elevation 10 feet.
From Jalisco southeast across southern Mexico to Guatemala; type
from between Mexcala and Estola, Guerrero. Apparently not previously
known from Jalisco. It is a tree with long linear leaves and showy yel-
low flowers. The genus consists of a single species.
‘TABEBUIA PENTAPHYLLA (L.) Hemsl., Biol. Cent. Am. Bot. 2:
495. 1882.
Chacagua Bay, Oaxaca, March 21, Elmore D19, a large tree of the
forest about 100 feet high with lavender flowers, the ground below
covered with its leaves.
Southern Mexico through Central America to Venezuela and the
West Indies.
As Elmore’s notes indicate the leaves are normally dropped in the
dry spring season, before or about the time of flowering, the time being
determined largely by the time and amount of precipitation in the last
rainfalls of the fall or winter. The tree is very showy when in bloom
and the wood has a high quality for furniture. It has often been em-
ployed for ceiling beams and other structural uses. See Standley’s ac-
count .(C.N El... 23 :1320)).
RUBIACEAE
DIODIA SARMENTOSA Sw., Prod. Veg. Ind. Occ. 30. 1788.
Chacagua Bay, Oaxaca, March 21, Elmore D12, a few plants in dry
sandy soil at 10 feet elevation, flowers lavender.
Mexico, Central America, and the West Indies.
CoMPOSITAE
EUPATORIUM CF. BREVIPES DC., Prodr. 5:168. 1836.
Tenacatita Bay, Jalisco, May 8, Elmore 146, in dry, open, level,
clay ground of grassland, flowers white.
Northwestern and southern Mexico; chiefly Sierra Madrean from
southern Sonora and Chihuahua to Oaxaca.
The above specimen apparently represents a shrub, the branchlets
smooth, white, glabrous, the prominent nodes remote, the corymbose in-
florescence deeply oval in outline; phyllaries mostly in one series, sub-
- af * ee —
: a oo No
»
j emer |
192 ALLAN HANCOCK PACIFIC EXPEDITIONS VoL. 13
tended by a few short ones, the former longer than the corollas, linear
lanceolate, acute, hispid; heads about 40-flowered. The leaves are de-
ciduated except for a few young ones subtending the inflorescence, which
are 2 to 3 cm long, lanceolate, mostly acuminate, remotely serrulate,
cuneate, hispid above and below, 3-nerved from near the base.
COSTA RICA
The best work on the fabulously rich flora of Costa Rica is that of
Standley (Flora of Costa Rica, Field. Mus. Bot. 18:1-1571. 1937-38).
Because of the author’s inimitable style, his introductory discussion of
the region and its plants is one of the most interesting to be read in any
flora. His work has been my guide in preparing the following report on
the collections of the Allan Hancock Pacific Expedition of 1939. The
expedition visited two peninsular localities which apparently had not
been botanized previously. On March 24, the collecting botanist, F. H.
Elmore, went ashore at Port Parker, Salinas Bay in northwestern Costa
Rica, where he secured 25 numbers with 1-8 duplicates. On March 26
he collected 28 numbers with duplicates on the Peninsula de Osa, Golfo
de Dulce in southwestern Costa Rica. This gulf is named Golfo de Osa
on some maps. Plates 14 and 15 are general views in these collecting
localities.
Both localities are tropical and only 8 to 11 degrees north of the
equator. hey are, however, rather arid, since the prevailing winds are
from the south Caribbean equatorial current and are deprived of most
of their precipitable moisture in rising over the central mountains.
Throughout the long spring there is little or no rainfall. Both localities
are in what is universally known in Central America as the “tierra cali-
ente,’ the warm to hot lowlands under 3000 feet elevation.
“For half the year, at least, there is less of green than of brown and
yellow. In the wet season the general hue of the landscape is not the
deep, dreary green of the rain forest, but a livelier green, brightened by
abundant sun, more like the vivid green of temperate lands.—The At-
lantic forests are evergreen, those of the Pacific, such as they are, mostly
deciduous, many of the trees and shrubs being leafless during much of
the dry season, and many of the herbs dying if annual, or remaining
dormant if perennial.” (Standley, 1. c. p. 17)
In addition to the forests and thickets there are extensive savannas,
where arborescent vegetation is scattered and the grassy herbs dominate.
In such areas agriculture takes the form of cattle ranching.
‘The strand vegetation is not notably different from that found widely
along the shores of the Caribbean or from the Mexican Pacific coast.
NO. 2 GENTRY : LAND PLANTS 193
As a whole the Pacific tierra caliente may be considered as one major
floristic unit, so uniform are its climatic and vegetative characters. But
while the strand flora is homogeneous, that of the coastal interior is not,
for several floristic elements have met and blended through the more
northern latitudes. Among these floral elements are Caribbean, the Mexi-
can Continental, and the Sinaloan. ‘The latter two appear to have been
derived largely from a Tertiary element part of which during geologic
times may have migrated southward and blended with the more tropical
one. Ihe following genera of trees and shrubs are common through the
Pacific tierra caliente from Sinaloa to Panama and are either abundant
in number of species or in individuals, exercise a dominating influence
in the vegetation, and are characteristic of the Pacific slope flora. ‘The
legumes are the most dominating family of plants.
Prosopis Anacardium Cedrela
Pithecolobium - Solanum Ficus
Acacia Coccoloba Ceiba
Mimosa Cereus Euphorbia
Lonchocarpus Eupatorium Croton
Enterlobium Fiacoel Jatropha
amelia
Cassia Ruellia Acalypha
Diphysa Hura
Gliricidia = ars Chlorophora
Inga Diospyros Guasuma
Caesalpinia Palms Psidium
Bauhinia Piper Byrsonima
Platymiscium Bursera Cochlospermum
Spondias Cordia Tabebuia
The Costa Rican Pacific tierra caliente has apparently had little
botanical exploration. Men have preferred to visit the more varied and
interesting, as well as the healthier, highland. “Certainly it is the least
agreeable in which to work, for the climate is hot, the forests and thick-
ets particularly so, and full of tangled vines and spiny branches, not to
mention the ticks that thrive better than elsewhere. On this account,
and for lack of good means of transportation, partly also because of the
sparsely settled country, the Pacific tierra caliente has been relatively
little investigated by botanists. Its exploration involves long rides on
horseback on obscure trails, where there are few and often uncomfortable
lodging places. It must not be forgotten that some localities on the Pa-
cific coast are noted for a virulent type of malaria” (Standley 1. c. p. 21).
The following enumerations of the Allan Hancock Pacific collections,
194 ALLAN HANCOCK PACIFIC EXPEDITIONS | VOLS
therefore, are of interest for the additional records they provide in plant
distribution.
CATALOGUE OF COLLECTIONS
POLYPODIACEAE
Bo.sitis (LEPTOCHILUS) CLADORRHIZANS (Spreng.) Ching, in C.
Chr. Ind. Suppl. 3:47. 1934.
Golfo de Dulce, March 26, Elmore F23, rocky walls of a moist
shaded stream at 20 feet elevation.
West Indies to Mexico and Colombia.
DRYOPTERIS SUBTETRAGONA (Link) Maxon, Pter. Porto Rica 473.
1926.
Golfo de Dulce, March 26, Elmore F10, in humus of moist shaded
jungle at 10 feet elevation.
West Indies and Central America.
NEPHROLEPIS PENDULA (Raddi) J. Smith, Job. 4:197. 1841.
Golfo de Dulce, March 26, Elmore F4, growing on old coconut
palm stump.
Central America.
GRAMINEAE
GYNERIUM SAGITTATUM (Aubl.) Beauv., Ess. Agrost. 138. 1812.
Golfo de Dulce, March 26, Elmore F3, shaded in moist humus of the
forest at 10 feet elevation.
From southern Mexico to Paraguay and the West Indies; type ap-
parently from Peru. This giant grass is abundant along the tropical
coasts and widely used by the native peoples in their buildings and for
many miscellaneous uses.
CYPERACEAE . ;
Cyperus Hayesu (Clarke) Standl., Jour. Wash. Acad. Sci. 15:
451.1925,
Golfo de Dulce, March 26, Elmore F11, in sandy soil of clearing in
jungle at 15 feet elevation.
Panama and Costa Rica. It has previously been known only from the
canal zone, so Elmore’s collection supplies an extension of range for the
species and an addition to the flora of Costa Rica.
RHYNCHOSPORA CEPHALOTES (L.) Vahl, Enum. 2:237. 1806.
Southwest island of the Secas group, March 27, Elmore G1, shaded
in moist peat humus of the jungle at 50 feet elevation.
No. 2 GENTRY: LAND PLANTS 195
Found generally in forests and thickets of the tierra caliente in tropi-
cal America. Elmore reports seeing only a few plants on a 30° slope;
the inflorescences green.
BROMELIACEAE
BROMELIA PiNGUIN L., Sp. Pl. 285. 1753.
Port Parker, Salinas Bay, March 24, Elmore E3, sandy soil of the
upper beach, fruits orange-colored. |
Common along the Pacific slope where it forms spiny colonies.
AMARYLLIDACEAE
Agave costaricana Gentry sp. nov.
Folia glauca, lineari-lanceolata, tenuia, 6-10 cm lata, 70-80 cm longa;
spina terminali conica, ferruginea, 4-5 cm longa, 3-4 mm diam. ad basim,
decurrenti 8-12 cm; spinis lateralibus minutis papillatis 0.5-2 mm altis,
8-10 mm distantibus; marginibus foliorum directis ; inflorescentia panicu-
lata; perianthio pallide flavo, brevi-campanulato, 2.5 cm longo, segmini-
bus 2 cm longis, 4-5 mm latis, lineariis, obtusis, involutis; staminibus
longi-exsertis ; ovario juvenali, 20-25 mm longo, lineari-oblongo; semina
non vidi.
Typus: Elmore E18, “a few plants growing along the rocky bank of
a dry stream bed, at or near Port Parker, Salinas Bay, Costa Rica,
March 18, 1939,” in hb. Allan Hancock Foundation, University of
Southern California. Duplum in hb. Univ. Mich.
Leaves glaucus, linear-lanceolate, rather thin, at least 6-10 cm wide,
70-80 cm long, gradually tapering below; terminal spine straight, reddish
brown, conical, 4-5 cm long, 3-4 mm in diam. at base, with or without
a narrow basal groove, decurrent as a narrow horny margin along the
blade for 2 to 3 times the length of the spine; marginal spines minute,
papilloid, brownish, 0.5-2 mm high, more prominent towards the termi-
nus of the blade, mostly 8-10 mm apart; margin of the blade straight,
lightly and narrowly calloused ; inflorescence a terminal compound pani-
cle; perianth yellowish, rotate or shallowly campanulate, constricted be-
low, 2.5 cm long, the segments 2 cm long, 4-5 mm wide, linear obtuse,
involute; filaments inserted a little above the middle of the short corolla
tube, long exserted; stamens large, attached below the middle; style
about 4 cm long, long exserted; stigma triquetrous, truncate; ovary 20-
25 cm long, linear-oblong, constricted above; seeds not seen.
This is only the second species of Agave reported for the flora of
Costa Rica, the other being Agave Werklei Weber (C.N.H. 23:132.
1920). The proposed new species is distinguished by its narrow linear-
lanceolate leaves with minute marginal prickles along a straight margin,
196 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 13
and by the small flowers with relatively wide linear perianth segments.
These characters together with the open paniculate inflorescence place
it in the section Sisalanae of ‘Trelease or Rigidae of Berger. It is ap-
parently related to Agave nivea Trel., from which it differs by its flat
and shorter leaves, the unraised bases of the prickles, and the straight de-
current terminal spines. 4 gave Seemanniana Jacobi, known from Guate-
mala and Nicaragua, is to be expected in Costa Rica also.
ORCHIDACEAE
BRASSAVOLA NODOSA Lindl., Gen. & Sp. Orch. 114.
Golfo de Dulce, March 26, Elmore F26, on trees in jungle.
Widely distributed in the American tropics from southern Mexico to
South America and the West Indies. It blooms in the spring dry season,
having relatively inconspicuous greenish flowers tinged with purple.
LAELIA TIBICINIS (Batem) L. O. Wms.
Port Parker, Salinas Bay, March 24, Elmore E19, a shaded epiphyte
high on a tree, elev. 175 feet. Petals pale lavender to a dark lavender
red with yellow markings on the upper petal.
This is a first record of the species from Costa Rica.
LORANTHACEAE
PHORADENDRON QUADRANGULARE (HBK.) Krug. & Urb., Bot. Jahrb.
24:35. 1818.
Port Parker, Salinas Bay, March 24, Elmore E17, growing on Byr-
sonima crassifolia.
Widely distributed from southern Mexico to South America and the
West Indies, growing mostly on broad-leaved trees in middle and lower
elevations. Trelease recognized six or eight closely related species that
Standley and Steyermark (FI. Guata., Fieldiana Botany 24:73. 1946)
relegated to synonomy under the above name.
AMARANTHACEAE
ALTERNANTHERA LAGUROIDES Standl. in Standl. & Cald., Lista Pl.
Salvador 74. 1925.
Golfo de Dulce, March 26, Elmore F13, sandy soil of clearing in
jungle near sea level. Vine with white flowers.
Clearings and thickets of the Pacific slope from Guatemala to Pana-
ma.
CYATHULA ACHYRANTHOIDES (HBK.) Mog. in DC., Prodr. 13 pt.
2:326. 1849.
Golfo de Dulce, March 26, Elmore F14.
NO. 2 GENTRY: LAND PLANTS 197
From southern Mexico to northern South America and the West
Indies; type from Magdalena River, near Mompos, Colombia.
MENISPERMACEAE
HypPERBAENA LEPTOBOTRYOSA (D. Sm.) Standl., Field Mus. Bot.
18:618. 1937.
Golfo de Dulce, March 26, Elmore F2, shaded in moist humus at 10
feet elev.
Type from Santo Domingo de Golfo Dulce, Prov. Puntarenas, Costa
Rica. Known only from the vicinity of the type locality.
LAURACEAE
OcOTEA VERAGUENSIS (Meisn.) Jahrb. Bot. Gart. Berlin 5:240.
1889.
Port Parker, Salinas Bay, March 24, Elmore E13, shaded in moist
soil on rocky stream bank. Flowers white.
Common in the forests of the Pacific tierra caliente from southern
Mexico (Chiapas) to Panama. A common tree along stream banks.
CAPPARIDACEAE
CRATAEVA TAPIA L., Sp. Pl. 444. 1753.
Golfo de Dulce, March 26, Elmore F22, shaded in moist humus soil
in jungle at 15 feet elev.
A tree widely distributed in the thickets and forests of tropical
America from southern Mexico to South America and the West Indies.
LEGUMINOSAE
Acacia Hinpsu Benth., Lond. Jour. Bot. 1:504. 1842.
Port Parker, Salinas Bay, March 24, Elmore E8, dry sandy soil of a
dry stream bank. Infested with ants.
Rather common in the tierra caliente of the Pacific coast from south-
ern Sinaloa, Mexico to San Salvador.
DIPpHYSA HUMILIs Oerst. ? in Benth. & Oerst. Vid. Meddel. 1853:
12.
Port Parker, Salinas Bay, March 24, 25, Elmore E20, upper beach
in moist hot exposed rocky soil. “Small tree with yellow flowers.”
The collection is doubtfully referred to the only known Costa Rican
species, apparently represented by only one collection from the Volcan
Rincon in Guanacaste province. The collection is fragmentary ; in flower,
but leafless.
GLIRICIDIA SEPIUM ( Jacq.) Steud., nom. Bot. ed. 2, 1:688. 1841.
Port Parker, Salinas Bay, March 24, Elmore E7, moist rocky sand
198 ALLAN HANCOCK PACIFIC EXPEDITIONS VOR. tS
of the upper beach, elev. 5 feet. Flowers pink with a yellow spot on
banner.
Common in the tierra caliente from Mexico to South America and
the West Indies. This tree is often planted for shade in the cacao plan-
tations.
OXALIDACEAE
Oxatis NEAEI DC., Prodr. 1:690. 1824.
Port Parker, Salinas Bay, March 26, Elmore E12.
In moist soils from southern Mexico to tropical South America. It is
frequent as a weed in cultivated ground.
MELIACEAE
CEDRELA MEXICANA Roem., Fam. Nat. Syn. 1:137. 1846.
Golfo de Dulce, March 26, Elmore F6, in moist shaded humus of
the jungle, elev. 10 feet.
In the tierra caliente from central Sinaloa south through southern
and eastern Mexico and south through Central America to Brazil. In
groves this tree forms long straight boles of commercial timber of soft
wood; one of the species that supplies the Spanish Cedar of commerce.
MALPIGHIACEAE
BYRSONIMA CRASSIFOLIA (L.) DC., Prodr. 1:579. 1824.
Port Parker, Salinas Bay, March 24, Elmore E16, dry sandy soil on
a dry stream bank, elev. 50 feet. Flowers yellow and orange.
Widely distributed and common in many areas on coastal hill slopes
and with higher grasslands from central Sinaloa through southern Mexi-
co, Central America, the West Indies, and northern South America.
STIGMAPHYLLON LINDENIANUM Juss., Arch. Mus. Paris 3:362.
1843.
Golfo de Dulce, March 28, Elmore F19, shaded in dry forest humus.
Common in the tierra caliente from southern Mexico to Panama.
The leaves of this woody vine vary from deeply 3-lobate to nearly ovate
entire. In the field it can be distinguished from most other species by the
dentate leaf margins. In the above collection the dentations are remote.
POLYGALACEAE
SECURIDACA DIVERSIFOLIA (L.) Blake, C.N.H. 23 :594. 1923.
Polygala diversifolia L., Sp. Pl. 703. 1753.
Port Parker, Salinas Bay, March 24, Elmore E9, moist sandy soil
on a dry stream bank, flowers dark lavender.
From Jalisco and Tamaulipas, Mexico south through Central Ameri-
NO. 2 GENTRY: LAND PLANTS 199
ca to Ecuador and the West Indies. A scandent shrub with shiny thick-
ish leaves. ‘The genus is distinctive in the Polygalaceae because of the
samaroid fruits.
EUPHORBIACEAE
ACALYPHA VILLOSA Jacq.,. Enum. Pl. Carib. 32.
Golfo de Dulce, March 26, Elmore F9.
Widely dispersed in tropical America. The determination by Croizat
is based on vegetative characters, female flowers being absent, and it is
therefore tentative.
HIpPOMANE MANCINELLA L., Sp. Pl. 1191. 1753.
Port Parker, Salinas Bay, March 24, Elmore E4, shaded in moist
sand of the upper beach.
This small tree, with poisonous apple-like fruits, is common along
the Pacific beaches and is found nearly throughout the tropical Americas.
ANACARDIACEAE
ANACARDIUM OCCIDENTALE L., Sp. Pl. 383. 1753.
Golfo de Dulce, March 26, Elmore F20.
Widely distributed in the New World tropics, naturalized in the
Old World tropics. This is the Cashew Tree. Both the fruit, borne on
the fleshy receptacle, and the receptacle itself are edible.
HIPPOCRATEACEAE
HippocraTEA OBOVATA Pittier, C.N.H. 12:176. 1909.
Port Parker, Salinas Bay, March 24, Elmore E14, shaded on moist
sandy rocky stream bank at 20 feet elev.
Endemic to Costa Rica where it occupies the forests and thickets of
the Pacific tierra caliente. The flowers are reported by Elmore to be
greenish white.
MALVACEAE
Hipiscus TILIACEuS L., Sp. Pl. 694. 1753.
Golfo de Dulce, March 26, Elmore F18, shaded in moist sandy soil
of the upper beach; flowers yellow turning dark orange or reddish on
withering. Port Parker, Salinas Bay, Elmore E5.
Widely distributed as a littoral plant in tropical regions. On the
west coast it is known as far north as central Sinaloa (Altata, Gentry
5427), Mexico. The pressed flowers on the herbarium sheet are a dark
purple or brown.
BOMBACACEAE
BoMBACOPSIS SESSILIS (Benth.) Pittier, C.N.H. 18:162. 1916.
Southwest Island of the Secas group, off Costa Rica, March 27,
200 ALLAN HANCOCK PACIFIC EXPEDITIONS VoL. 13
Elmore G2, steep rocky slopes of the upper beach.
From Costa Rica and Panama. Also reported at Buenos Aires,
South America.
CLUSIACEAE
CLUSIA ROSEA Jacq., Enum. Pl. Carib. 34. 1760.
Golfo de Dulce, March 26, Elmore F27, in humus and shade of hot
moist level jungle at 100 feet elev.
Widely distributed in the American tropics from Yucatan south
through Central America to northern South America and the West
Indies. It forms a small tree, beginning as an epiphyte on other trees;
characterized by the thick obovate leaves, almost as wide as long, with
a heavy midvein and numerous ascending parallel secondaries, and pulpy
gummy fruits up to 2 inches in diameter.
PASSIFLORACEAE
PASSIFLORA FOETIDA SALVADORENSIS Killip, Carn. Inst. Wash. Publ.
461 :327. 1936.
Port Parker, Salinas Bay, March 25, Elmore E10, in moist rocky
bank of dry stream bed. Flowers lavender, fruit red.
Known only from San Salvador and Costa Rica, type from Nahu-
lingo, Sonsonate, Salvador. Elmore’s collection is an extension of range,
adding another plant to the flora of Costa Rica.
RHIZOPHORACEAE
RHIZOPHORA MANGLE L., Sp. Pl. 443. 1753.
Port Parker, Salinas Bay, March 24, Elmore E6, sandy upper beach.
Widely distributed in tropical America.
CoMBRETACEAE
CoMBRETUM ERIANTHUM Benth., Pl. Hartw. 73. 1840.
Port Parker, Salinas Bay, March 24, Elmore E15, dry sandy soil on
a dry stream bank, flowers red. Elev. 50 feet.
From Costa Rica to southern Mexico in the tierra S catienne type
from Retalhuleu, Guatemala.
CONOCARPUS ERECTUS L., Sp. Pl. 176. 1753.
Port Parker, Salinas Bay, March 24, Elmore E2, sandy lower beach
on tidal land.
Littoral of tropical and subtropical America, also in western Africa.
It often forms borders around lagoons above the mangroves.
MELASTOMACEAE
MICONEA ARGENTEA (Sw.) DC., Prodr. 3:182. 1828.
Golfo de Dulce, March 26, Elmore F17, a few plants in peaty or
NO. 2 GENTRY: LAND PLANTS 201
humus soil in the jungle, flowers white.
Known in Central America from southern Mexico to Panama;
type from the Mosquito Coast.
UMBELLIFERAE
ERYNGIUM FOETIDUM L., Sp. Pl. 232. 1753.
Golfo de Dulce, March 26, Elmore F12, dry sandy soil in forest
clearing.
Widely distributed as a weed in tropical America. The plant has a
strong offensive odor, but in spite of it, is used with good results as a
seasoning for foods, the offensive quality being dispelled by heating.
BORAGINACEAE
TOURNEFORTIA HIRSUTISSIMA L., Sp. Pl. 140. 1753.
Golfo de Dulce, March 26, Elmore F16, dry sandy soil of a forest
clearing, flowers white.
From Sinaloa and Tamaulipas south through Central America to
South America and the West Indies. In Costa Rica it has been reported
from Region of Dota and San Ramon. It is a scandent shrub with irri-
tant hairs along the stem.
VERBENACEAE
AVICENNIA NITIDA Jacq., Enum. Pl. Carib. 25. 1760.
Port Parker, Salinas Bay, March 24, Elmore E1, on sandy beach in
tidal land.
Widely distributed along the shores of tropical and subtropical
America where it is associated with mangrove.
SCROPH ULARIACEAE
RUSSELLIA VERTICILLATA HBK., Nov. Gen. & Sp. 2:360. 1817.
Port Parker, Salinas Bay, March 24, Elmore E11, dry sandy soil of
a dry stream bank, elev. 10 feet.
From northern Mexico to Panama along the Pacific coast mainly
below 3000 feet elev.; type from Puente de la Madre de Dios.
ACANTHACEAE
APHELANDRA DeEpPpEANA Schlecht. & Cham. Linnaea 5:96. 1830.
Golfo de Dulce, March 26, Elmore F21, shaded in moist humus soil
at the edge of a jungle clearing, elev. 15 feet.
From southern Mexico to northern South America and the West
Indies; type from Hacienda de la Laguna, Vera Cruz.
RUELLIA AFF. BIOLueyY! Lind. in Pittier, Prim. 2:301. 1900.
Golfo de Dulce, March 26, Elmore F7, in moist soil of the forest at
10 feet elev.
Wet forests of Costa Rica and Panama.
202 ALLAN HANCOCK PACIFIC EXPEDITIONS VO. 15
RUBIACEAE
HAMELIA MAGNIFOLIA Wernham, Jour. Bot. 49:210. 1911.
Golfo de Dulce, March 26, Elmore F8, shaded in dry humus at the
edge of a clearing, flowers yellow and red.
Costa Rica and Panama.
204 ALLAN HANCOCK PACIFIC EXPEDITIONS
PLATE 1
Moringa oletfera Lam.
Fig. 1. Section of branchlet with leaf x).
Fig. 2. Pod x™%.
VOL. 13
i
rE
GENTRY : LAND PLANTS
NO.
ALLAN HANCOCK PACIFIC EXPEDITIONS
PLATE 2
Moringa oleifera Lam.
Fig. 3. Flower at anthesis x3.3.
Fig. 4. Stamen x11.
Pic, 5s bud x5.
Fig. 6. Sepal x6.7.
VO
WO GENTRY : LAND PLANTS Pee
208
Fig.
Fig.
Fig.
Fi
is
ALLAN HANCOCK PACIFIC EXPEDITIONS
PASE 3
Echinopepon peninsularis Gentry
7. Wabit x.
8. Node x4.
9. Fruit prickle x6.5 to compare with.
10. Fruit prickle x6.5 of Echinopepon minimus.
VOE-
ils
PL.
LAND PLANTS
GENTRY :
NO.
210 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 13
PEATE 4
Fig. 11. View on the north end of Santa Rosa Island. Grassland covers
the more level slopes, while bushy perennials are spotted on
the bluff. (Photo from the Los Angeles Museum Channel
Island Survey).
Fig. 12. Braithwaite Bay, Socorro Island on a calm cloudy day in
March.
GENTRY : LAND PLANTS PL. 4
1S)
—
iS)
PEALE
Fig. 13. Punta Frailes, Cape District, Baja California. The arborescent
growth is widely dispersed on the steep rocky slopes, dense on
the outwash fans.
ALLAN HANCOCK PACIFIC EXPEDITIONS VOL.
PL.
LAND PLANTS
GENTRY
o
NO.
ALLAN HANCOCK PACIFIC EXPEDITIONS VOLS
LO
oN)
bo
PEALE 6
Fig. 14. Vegetation above Frailes Bay, Cape District. On the basic rock
slope the vegetation is sparse and stunted.
Fig. 15. Dense Thorn Forest vegetation in a broad wash near Frailes
Bay, Cape District, Baja California.
No. 2 GENTRY : LAND PLANTS PL. 6
Fig. 16.
Figs Ti:
ALLAN HANCOCK PACIFIC EXPEDITIONS VO IS
PEACE 7
View southward near Puerto Escondido, Baja California, over-
looking a narrow coastal plain with the scarp of the Sierra
Giganta in the background. The foreground shows a xerophytic
grass ground cover with scattered trees of Bursera microphylla
and Lemaireocereus Thurbert.
Canyon above Escondido, Baja California. The steep slopes
are brecciated lavas; the palm, Erythea Brandeget.
~I
NO. 2 GENTRY : LAND PLANTS 124 Ue
nes
Fig. 18.
Bis. 9:
Fig. 20.
ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 13
PAE 38
Angel de la Guardia Island. Typically sparse desert vegetation
on washes and fans with a scattered grove of Pachycereus
Pringlet.
Angel de la Guardia Island. The effect of wind on the
sarcophytic tree, Pachycormus discolor pubescens, along a rocky
crest.
Angel de la Guardia Jsland. Sparse Desert Shrub on an east
exposure with Pachycereus Pringlei on the lower gentler slopes.
No. 2 GENTRY : LAND PLANTS PL. 8
220) ALLAN HANCOCK PACIFIC EXPEDITIONS VOR tS
PLALE
Fig. 21. Tiburon Island. Low Desert Shrub on the granitic terrain of
the southeast coast.
Fig. 22. San Pedro Nolasco Island, showing the ‘raw’ rock surfaces,
almost no soil, and adventive or pioneering perennials.
PL. 9
GENTRY : LAND PLANTS
NO. 2
227 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL.
PLATE 10
Fig. 23. San Pedro Nolasco Island. A clump of Echinocereus grandis.
Fig. 24. San Pedro Nolasco Island. A succulent vegetation of Agave,
Opuntia, and Pachycereus on very rocky terrain.
13
GENTRY : LAND PLANTS
2
é
:
is
3
2
Fi
ee ee
Pik
Cl
224 ALLAN HANCOCK PACIFIC EXPEDITIONS VO
[ENCED La
Fig. 25. San Pedro Nolasco Island. Agave chrysoglossa and Lematreo-
cereus Thurbert in foreground.
Fig. 26. San Pedro Nolasco Island. A dense colony of the succulent low
shrub, Pedilanthus macrocar pus.
122 bee Il
GENTRY: LAND PLANTS
a
NO. 4
226
ALLAN HANCOCK PACIFIC EXPEDITIONS VOL.
PEATE a2
. Espiritu. Santo Island. A dispersed shrub formation with
scattered trees of Pachycereus :Pringlet.
. Espiritu Santo Island. Detail of branch and fruit of Opuntia
Cholla.
13
No. 2 GENTRY: LAND PLANTS Pree
228 ALLAN HANCOCK PACIFIC EXPEDITIONS ViOnenls>
PIB AGI ans
Fig. 29. Tenacatita Bay, Jalisco. The subtropical forest is close upon
the beach.
Fig. 30. Chacagua Bay, Oaxaca. The scrubby vegetation on the hill in
the background shows evidence of having been cut over.
Woes GENTRY: LAND PLANTS Pre
230) ALLAN HANCOCK PACIFIC EXPEDITIONS Ole Is
PEAT E14
Fig. 31. Lowland coastal vegetation of the tierra caliente in Costa
Rica near Puerto Culebro.
Fig. 32. Close lowland forest of Costa Rica with a dense tangle of
trunks, limbs, and clambering stems, crooked to semi-straight.
Py. 14
GENTRY: LAND PLANTS
NO. Z
IO
iS)
ALLAN HANCOCK PACIFIC EXPEDITIONS VO bs
PEARS
Fig. 33. Forest of the tierra caliente in the Golfo de Dulce, Costa Rica.
The varied tree forms indicate the richness of the flora.
NWO. 2 GENTRY: LAND PLANTS PEt
i
—
\
- 2
=)
Poe
-
t
'
y
= |
Ow
.
;
4”
:
S
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)
INDEX
INDEX TO GENERA, LOCALITIES FEATURED, AND TO COLLECTORS*
Abronia alba, 24
maritima, 24, 105, 125
Abutilon aurantiacum, 109
californicum, 143
crispum, 143
Dugesii, 109
incanum, 143
Lemmoni, 109
Nuttallii, 109
Palmeri, 109
Acacia cymbispina, 97, 98
Farnesiana, 130
filicioides, 106
Goldmanii, 130
Greggii, 93, 106
Hindsiana, 185
Hindsii, 197
sp., 106
Willardiana, 96, 106
Acaciella Goldmanii, 130
Acalypha californica, 108
villosa, 199
Acanthambrosia Bryantii, 114
Achillea millefolium lanulosa, 36
Achyronychia Cooperi, 105
Adelia obovata, 87
virgata, 108, 137
Adiantum Capillus-veneris, 117
Aeschynomene nivea, 107, 133
Agave affinis, 121
carminis, 121
chrysoglossa, 96, 104, 120
costaricana, 13, 195
dentiens, 104, 120
deserti, 104, 120
nivea, 196
Oweni, 120
sebastiana, 49
Seemaniana, 196
Shawii, 49
Shawii sebastiana, 13, 50
Shawii var. sebastiana, #9
sobria, 104, 121
sobria roseana, 104
Werklei, 195
Alfordia fruticosa, 172
Allenrolfia occidentalis, 105, 123
Allionia incarnata, 105
Aloysia nahuire, 87
Alternanthera laguroides, 196
Alvordia glomerata, 114
Amaranthus caudatus, 105, 124
fimbriatus, 100
Watsoni, 101, 102, 105, 124
Amauria rotundifolia, 172
Amsinckia intermedia, 32
Anacardium occidentale, 199
Anagallis arvensis, 32
Anneslia Brandegeei, 130
Anthephora hermaphrodita, 117
Antigonon leptopus, 101, 104, 122
Antirrhinum cyathiferum, 113, 164
Aphelandra Deppeana, 201
Argemone mexicana, 127, 184
platyceras gracilenta, 105
platyceras hispida, 106
Aristida adscensionis, 49, 103
californica, 103
dispersa, 103
Purpusiana, 118
Artemesia californica, 36
Asclepias albicans, 112, 159, 160
curassavica, 160, 189
leptopus, 97
subulata, 160
Aster frutescens, 101, 114
spinosus, 173
Astianthus viminalis, 191
Astragalus insularis, 107
leucopsis, 28
Nevinii, 28
Atamisquaea, 97
emarginata, 106
Atriplex Barclayana, 51,123
Barclayana Palmeri, 100, 101, 102,
105
Barclayana typica, 100, 101, 105
Barclayana sonorae, 101, 102, 105
dilatata, 50
leucophylla, 23
pacifica, 51
polycarpa, 105, 123
Avicennia nitida, 78, 113, 162, 190, 201
Ayenia filiformis, 109
Baccharis Douglasii, 36
pilularis consanguinea, 37
Plummerae, 37
sarathroides, 59, 114, 173
Baeria chrysostoma gracilis, 37
Batis martima, 101, 105, 125
Bebbia juncea, 59, 102, 114
atriplicifolia, 114
*Page numbers in bold face indicate a new combination; page numbers in Italics
indicate synonyms.
[ 237 ]
238 INDEX
Beloperone californica, 113, 166
Purpusii, 166
Berginia Palmeri, 113, 166, 167
virgata, 166, 167
Boerhaavia caribea, 69, 105
Bolbitis (Leptochilus) cladorrhizans,
194
Bombacopsis sessilis, 199
Bourreria sonorae, 112, 160
Bouteloua aristiedes, 103
barbata, 100, 118
curtipendula, 118
polystachya, 103
racemosa, 103
Brandegea Palmeri, 171
Brassavola nodosa, 196
Brickellia brachiata glabra, 114
Brandegei, 114
peninsularis amphithalassa, 72
Brodiaea capitata, 22
Bromelia Pinguin, 195
Bumelia occidentalis, 159
Bursera Hindsiana, 101, 107, 136,137
laxiflora, 98
microphylla, 93, 96, 107, 137
morelensis, 137
pubescens, 141
rhoifolia, 137
Byrsonima crassifolia, 196, 198
Caesalpinia, 90
arenosa, 131
californica, 131
gracilis, 87
Palmeri, 131
pannosa, 131
placida, 131
Calandrinia martima, 52
Calliandra Brandegeei, 13, 130
californica, 130
peninsularis, 130
Canavalia apiculata, 186
maritima, 185, 186
Capparis baduca, 184
Cardiospermum halicacabum, 109, 142
Carlowrightia californica, 113, 167
californica pallida, 113
cordifolia, 167
Carnegiea gigantea, 100, 110
Cassia confinis, 106, 132
Castela peninsularis, 107, 136
Castilleja anacapensis, 34
hololeuca, 34
latifolia, 35
mollis, 35
sp., 35
Caulanthus inflatus, 27
Cedrela mexicana, 198
voL. 13
Celosia floribunda, 105, 124
Cenchrus mysuroides, 68
Palmeri, 103, 118
Centaurium venustum, 32
Cercidium microphyllum, 93, 106, 132
peninsulare, 106, 132
praecox, 106
Cereus Thurberi var. littoralis, 150
Cheilanthes peninsularis insularis, 68
Chenopodium murale, 24, 100, 105
Chloris virgata, 103
Chrysobalanus icaco, 185, 188
Citharexylum flabelliformis, 113
Clusia rosea, 200
Cnidosculus Palmeri, 108
Coccoloba Schiedeana, 78
Cochemiea Pondii, 57
Poselgeri, 110, 148
Coldenia canescens subnuda, 112
cuspidata, 112
Palmeri, 112, 161
Colubrina glabra, 109
Combretum erianthum, 200
mexicanum, 188
Commelina elegans, 120
Commicarpus Brandegei, 125
Condalia globosa, 109, 142
globosa pubescens, 109
lycioides canescens, 109
Conobea intermedia, 113
Conocarpus erectus, 188, 200
erectus sericeris, 188
Convolvulus occidentalis cyclostegius, 32
Cordia brevispicata, 112
parvifolia, 98
Seleriana, 189
Coreocarpus arizonicus, 114
dissectus, 114
dissectus longilobus, 114, 173
Shrevei, 114, 173
Coreopsis gigantea, 37
Corethrogyne filaginifolia robusta, 37
Couepia polyandra, 185
Coulterella capitata, 114, 173
Coursetia glandulosa, 133
Cracca hamata, 135
Crataeva tapia, 197
Cressa truxillensis, 101, 112
Crossosoma californicum, 27
Croton californica, 108
magdalenae, 108
Cryptantha angelica, 112
angustifolia, 112
Clevelandii, 33
Grayi nesiotica, 112
maritima, 58, 112
maritima pillosa, 101
racemosa, 113
voL. 13
Cucumis dipsaceus, 170
Cuscuta corymbosa stylosa, 102, 112
umbellata, 112
Cyathula achyranthoides, 196
Cynanchium Palmeri, 112
Cyperus aristatus, 104
dioicus, 104
elegans, 104, 119
Hayesii, 194
perennis, 119
Cyrtocarpa edulis, 108, 141
procera, 141
Dalea Benthami, 53
divicata cinerea, 107
Emoryi, 107, 133
maritima, 107, 133
megacarpa, 53
mollis, 101, 107, 134
Parryi, 107, 134
spinosa, 107
variegata, 13, 133
Datura discolor, 102, 113, 162
Desmanthus fruticosus, 106
Desmodium scorpiurus, 186
Wigginsii, 87, 97
Dicliptera resupinata, 167
Diodia sarmentosa, 191
Diphysa humilis, 197
Diplacus longiflorus, 35
parviflorus, 35
Distichlis spicata, 21
Ditaxis Brandegei, 108, 137
lanceolata, 108, 137
neomexicana, 138
serrata, 108
Drymaria holosteoides, 105, 126
Johnstonii, 105
peninsularis, 126
polystachya diffusa, 105, 126
Dryopetalon Palmeri, 127
Dryopteris subtetragona, 194
Dudleya albiflora, 106
farinosa, 27
Greenei, 27
Dysodia speciosa, 114, 174
Echinocereus Brandegei, 110
grandis, 95, 102, 110, 148
mamillatus, 148
maritimus, 57
sciurus, 148
scopulorum, 148
Websterianus, 110, 148
Echinocystis Brandegei, 114, 171
Echinopepon minimus, 59, 170, 171, 209
Palmeri, 171
peninsularis, 13, 770, 207
toquata, 171
Eleocharis caribaea, 104
INDEX 239
Elymus triticoides, 21
Encelia californica, 38
californica asperifolia, 59
farinosa, 174
farinosa phenicodonta, 100,
114, 174
stenophylla, 60
Ephedra aspera, 49, 103
peninsularis, 49
Eragrostris viscosa, 118
Eremocarpus setigerus, 30
Ericameria diffusa, 60, 115, 174
Erigeron foliosus, 38
glaucus, 38
Eriogonum arborescens, 22
deflexum, 104, 122
fasciculatum, 50
fasciculatum var. flavoridi, 50
galioides, 101, 104
giganteum, 22
grande, 23
inflatum deflatum, 104, 122
intricatum, 50
Pondii, 50
rubescens, 23
Eriophyllum Nevinii, 38
Eryngium foetidum, 201
Erythea Brandegei, 104, 119
Errazurizia Benthami, 53
megacarpa, 107
Eschscholtzia californica, 26
californica martima, 26
minutiflora, 52, 106, 127
Esenbeckia flava, 107
Eucnide cordata, 101, 110, 147
Eupatorium brevipes, 191
Purpusii, 175
Euphorbia Anthonyi, 70
bartolomaei, 54
Benedicta, 54
californica, 70, 138
carmenensis, 108
clarionensis, 70
eriantha, 108, 138
hirta typica, 186
incerta, 108
leucophylla, 108, 138
magdalenae, 108, 139
misera, 54, 108
pediculifera, 108, 139
pediculifera involuta, 108
pediculifera involuta linearifolia,
139
petrina, 108, 139
polycarpa, 108, 139
polycarpa hirtella, 101, 108
tomentulosa, 108, 140
Xantii, 108, 140
240
Evolvulus linifolia, 160
Fagonia californica, 107
californica Barclayana, 135
californica glandulosa, 135
densa, 107
insularis, 107
laevis, 53
pachycantha, 107
Palmeri, 107
Rosei, 107
Ferocactus acanthodes, 149
alamosanus, 150
alamosanus platygonus, 149
chrysanthus, 57
Covillei, 149
Diguetii, 110
Johnstonianus, 110
sp., 149
‘Townsendianus, 149
Wislizeni, 110
Festuca megalura, 21
pacifica, 21
Ficus cotinifolia, 68, 69
mexicana, 183
Palmeri, 96, 98, 102, 104, 121
Foeniculum vulgare, 31
Forchammeria Watsoni, 106
Fouquieria burragei, 109
peninsularis, 96, 101, 109, 146
splendens, 109, 146
Frankenia grandifolia, 31
Palmeri, 56, 109, 145
Franseria arborescens, 175
chenopodifolia, 60
dumosa, 115, 175
ilicifolia, 115, 175
Froelichia interrupta, 105, 124
Funastrum clausum, 189
Galvezia juncea, 58
juncea foliosa, 113
juncea pubescens, 113
Gilia multicaulis, 32
Gliricidia sepium, 197
Gnaphalium beneolens, 38
bicolor, 38
palustre, 39
Gochnatia arborescens, 115
Gomphrema vermicularis, 184
Gossypium Davidsonii, 109, 143
Harknessii, 109
Gouinia Brandegei, 103
Guasuma ulmifolia, 187
Guilandina Moringa, 128
Gynerium sagittatum, 194
Hamelia magnifolia, 202
Haplopappus arenarius, 115
arenarius incisifolius, 115
INDEX
arenarius Rossii, 115
junceus, 115, 176
sonoriensis, 60
spinulosus, 115
spinulosus scabrellus, 115
tridentatus, 60
venetus vernonioidides, 39
Helianthus niveus, 115
Heliopsis longipes, 176
parvifolia, 176
Heliotropium curassavicum, 33, 71, 113,
161
Hemizonia clementina, 39
fasciculata, 39, 60
Streetsii, 61
Hermannia Palmeri, 145
Hesperonia cedrosensis, 51
laevis, 25
tenuiloba, 105
Heteropogon contortus, 103, 119
Heterosperma Xantii, 176
Hibiscus denudatus, 109, 143
tiliaceus, 199
Hintonia pterosperma, 98
Hippocratea obovata, 199
Hippomane Mancinella, 186, 199
Hoffmanseggia intricata, 106, 133
microphylla, 101, 106
Hofmeisteria crassifolia, 115
fasciculata, 102, 115
fasciculata pubescens, 115, 176
filifolia, 115
laphamioides, 115
pluriseta pauciseta, 115
Holographis pallida, 87
Horsfordia alata, 109, 144
Newberryi, 109, 144
Houstonia asperuloides, 169
brevipes, 114
Brandegeana, 169
gracilenta, 114
mucronata, 114, 169
Hymenoclea pentalipes, 115
Hyperbaena leptobotryosa, 197
Hyptis albida, 161 :
Emoryi, 113, 161
Emoryi Palmeri, 113, 161
laniflora, 161
laniflora insularis, 113
Palmeri, 161
Indigofera argentata, 107
laevis, 87
Ipomoea aurea, 112
cathartica, 71
pes-caprae, 185, 189
Iresine angustifolia, 105, 124
Isomeris arborea, 52
voL. 13
voL. 13
Jacobinia candicans, 167
Jacquemontia abutiloides, 160
Eastwoodiana, 112
linifolia, 160
Jacquinea aurantiaca, 78
pungens, 111
Janusia californica, 107
gracilis, 107
Jatropha cinerea, 140
cuneata, 140
purpurea, 87
spathulata, 108
Jouvea pilosa, 68, 103, 119
Justicia hians, 168
Karwinskia Humboltiana, 109, 143
latifolia, 87
Krameria canescens, 106
parvifolia, 129
parvifolia glanduiosa, 129
paucifolia, 129
Laelia tibicenis, 196
Lagascea decipiens, 176
Laguncularia racemosa, 111, 188
Lantana horrida, 190
Larrea divaricata, 101, 107
tridentata, 136
Lavatera assurgentiflora, 30
venosa, 56
Layia platyglossa, 39
Lemaireocereus Thurberi, 93, 96, 101,
102, 110, 150
Thurberi littoralis, 150
Lepidium lasiocarpum, 26
Leptosyne dissecta, 173
Linaria canadensis texana, 36
Lippia Palmeri, 87, 98, 113
Lobelia laxiflora angustifolia, 172
Lophocereus Schottii, 101, 110, 150
Lotus dendroideus, 28
humilis, 53
niveus, 29
ornithopus, 29
tomentellus, 101, 107
Lupinus arizonicus barbatus, 107
Pondii, 53
sparsiflorus, 29
Lycium Andersoni, 162
brevipes, 101, 102, 113, 162
californicum, 33
Richii, 162
Lygodium venustum, 183
Lyonothamnus floribundus aspenifolius,
27
Lyrocarpa Coulteri, var. Palmeri, 128
linearifolia, 13, 106, 727, 128
Xantii, 128
Lysiloma candida, 106, 130
divaricatum, 98
INDEX
241
Maba intricata, 112
Machaerocereus gummosus, 100, 110,
151
Macrosiphonia hesperia, 112
Malacothrix Clevelandii, 40
foliosa, 40
incana, 40
saxatilis implicata, 40
Xantii, 176
Malperia tenuis, 115, 177
Mammillaria albicans, 111, 151
angelensis, 101, 111, 151
cerralboa, 111
dioica, 111, 151
Evermanniana, 111, 151
frailiana, 111, 152
Goodridgei, 57
insularis, 111, 152
multidigitata, 111, 149, 152
phitauiana, 111
Slevinii, 111, 152
Marah fabacea, 36
minima, 59, 170
Marrubium vulgare, 33
Martynia altheaefolia, 113, 165
Mascagnia macroptera, 107
Maximowiczia sonorae brevicaulis, 114
sonorae peninsularis, 114
Maytenus phyllanthoides, 109, 142
Melochia tomentosa, 98, 109, 145
Mentzelia adhaerens, i101, 110, 147
hirsutissima, 56, 110
hirsutissima stenophylla, 110
Mesembryanthemum chilense, 25
crystallinum, 51
nodifilorum, 25, 51
Miconea argentea, 200
Mimulus dentilobus, 165
guttatus depauperatus, 35
sp., 164
Mitracarpus linearis, 114
portoricensis, 170
Mohavea confertiflora, 113, 165
Mollugo verticillata, 125
Monanthocloe littoralis, 21, 101, 103
Montia perfoliata, 25
Moringa oleifera, 128, 203, 205, 207
Muhlenbergia debilis, 103
microsperma, 103
Porteri, 119
tenella, 103
Nephrolepis pendula, 194
Nicolletia trifida, 177
Nicotiana Greeneanum, 163
nesophila, 72
chinensis, 54, 108, 141
pabulosa, 54
trigonophylla, 102, 113, 163
242
Notholaena californica, 103
Ocotea veraguensis, 197
Oenothera angelorum, 159
cardiophylla, 111, 159
chieranthifolia, 31
Oligomeris linifolia, 128
Olneya tesota, 93, 107, 134
Opuntia alcahes, 155
basilaris, 157
Bigelovii, 101, 111, 152, 156
Bravoana, 157
Burrageana, 111, 153, 155
calmalliana, 57, 156
chlorotica, 157
cholla, 111, 156
cineracea, 155
ciribe, 153, 156
clavellina, 111, 153, 156
comonduensis, 111, 153, 157
discata, 157
echinocarpa, 156
fulgida, 154, 155
Gosseliniana, 154, 157
invicta, 154, 155
leptocaulis, 111, 154, 156
littoralis, 18, 31
molesta, 155
mortolensis, 156
occidentalis, 71, 157
Parryi, 156
prolifera, 57, 155
pycnantha, 157
ramosissima, 154
reflexispina, 155
rosarica, 155
serpentina, 156
sp.,'57, 100,157,158
spinosior, 155
tapona, 157
tardispina, 158
tesselata, 57
Thurberi, 156
tunicata, 101
versicolor, 111, 154, 155
Wilcoxii, 111, 157, 158
Orthocarpus purpurascens, 36
Oxalis cernua, 29
Neaei, 198
Pachycereus pecten-aboriginum, 111,
158
Pringlei, 93, 96, 98, 101, 111, 158
Pachycormus discolor, 141
discolor pubescens, 13, 93, 108
discolor var. pubescens, 141
discolor Veatchiana, 13, 55
Palafoxia linearis leucophylla, 115, 177
Panicum fasciculatum, 103
lachmanthum, 103
INDEX
voL. 13
Parasela variegata, 134
Passiflora arida, 110, 146
cerralbensis, 110
foetida salvadorensis, 200
fruticosa, 110
holosericea, 188
Paullinia fuscescens, 186
Palmeri, 110, 146
tortuosa, 109
Pectis multiseta, 177
Pectocarya linearis ferocula, 33
Pedilanthus macrocarpus, 108
Pellaea andromedaefolia, 20
Peluchia trifida, 115
Peniocereus Johnstonii, 111
Penstemon Clevelandii angelicus, 112
Perityle aurea, 115, 177
cuneata, 178
Emoryi, 41, 115, 178
Grayi, 61
incompta, 178
Palmeri, 97, 178
robusta, 115
socorrosensis, 72
Petalonyx linearis, 110, 147
Petunia parvifolia, 34, 163
Peucephyllum Schottii latisetum, 115
Phacelia ixodes, 58
scariosa, 112, 160°
Phaseolus adenanthus, 186
atropurpureus, 134
atropurpureus sericeus, 69
filiformis, 107, 135
Philoxerus vermicularis, 184
Phoradendron brachystachum, 104
californicum, 104, 121
Diguetianum, 104, 122
quadrangulare, 196
Photinia arbutifolia, 27
arbutifolia macrocarpa, 28
Phrygilanthus sonorae, 87
Phylla nodiflora, 190
Physalis crassifolia, 113, 163
crassifolia infundibularis, 113, 163
glabra, 164
pubescens, 164
purpurea, 87, 164
sonorensis, 87
versicolor microphylla, 113
Pinus radiata, 20
radiata binnata, 20
remorata, 20
Piper misantlense, 183
tuberculatum, 183
Pisonia aculeata, 184
Pithecolobrium confine, 106, 131
sonorae, 98
Pityrogrammatriangularis Maxonii, 103
VoL. 13
Plantago insularis fastigiata, 114, 169
Platystemon californicus, 26
Pluchea odorata, 115
Plumbago scandens, 189
Polygala diversifolia, 198
Polyogonum aviculare, 23
Polypogon monspeliensis, 21
Porophyllum confertum, 115
crassifolium, 115, 178
gracile, 61, 115, 179
leptophyllum, 115
pausodynum, 87
porfyreum, 179
tridentatum, 179
Portulaca pilosa, 105
Prosopis juliflora, 93, 106, 131, 186
reticulata, 87
Prunus Lyoni, 28
Quercus agrifolia, 22
dumosa, 22
Randia megacarpa, 114
Rathbunia alamosensis, 158
Rhizophora mangle, 111, 158, 188, 200
Rhus integrifolia, 30
Lentii, 56
Veatchiana, 55
Rhynchospora cephalotes, 194
Rosa gratissima, 28
Ruellia Biolleyi, 201
californica, 113, 168
leucantha, 169
leucantha postinsularis, 87
peninsularis, 168, 169
Ruppia maritima, 103
Russelia verticellata, 113, 201
Salicornia europea, 105
subterminalis, 24
Salipianthus arenarius, 184
macrodontus, 184
Salvia Brandegei, 33
cedrosensis, 58
platycheila, 113
Samolus ebracteatus, 111
Sanicula arguta, 32
Sapium biloculare, 108
Schaefferia cuneifolia, 109, 142
Schoepfia californica, 122
Schinus discolor, 141
Scripus californicus, 22
Securidaca diversifolia, 198
Selaginella Bigelovii, 20
Senecio Lyonii, 41
mohavensis, 179
Sesbania sonorae, 87
Sesuvium portulacastrum, 69, 126
sessile, 101
Setaria macrostachya, 96, 103, 119
setosa, 103
INDEX 243
Sibara pectinata, 52
Sidalcea malvaeflora, 30
Sida Xantii, 144
Sideroylon leucophyllum, 112
Silene gallica, 25
laciniata, 25
Silybum Marianum, 41
Simmondsia californica, 54
chinensis, 54, 108, 141
pabulosa, 54
Solanum Clokeyi, 34
diversifolium, 190
Douglasii, 34
elaeagnifolium, 164
Hindsianum, 102, 113, 164
nudum, 190
villosum, 34
Sonchus oleraceus, 41
Sophora tomentosa, 70
Spergularia macrotheca, 26
Sphaeralcea ambigua versicolor, 109
axillaris, 109
Coulteri, 144
Coulteri californica, 144
fulva, 56
Hainesii, 109, 145
Sporobolus argutus, 68, 104
Stachys coccinea, 162
Stegnosperma halimifolium, 105, 125
Stemodia arizonica, 165
Stigmaphyllon Lindenianum, 198
Stylosanthes viscosa, 135
Suaeda californica, 24
taxifolia, 24
sp., 51
Sympeteleia aurea, 110
rupestris, 110, 147
Tabebuia pentaphylla, 191
Tapirira edulis, 141
Tecoma stans, 166
Tephrosia hamata, 13, 135
Palmeri, 107, 135
tenella, 107, 135
Teucrium glandulosum, 58
Townsendii, 72
Thryalis angustifolia, 137
Tillandsia fasciculata, 183
Tournefortia hirsutissima, 190, 201
Toxicodendron diversifolium, 30
Tradescantia heterophylla, 104
Trianthema portulacastrum, 105
Tribulus cistoides, 70
Trifolium microcephalum, 29
tridentatum aciculare, 29
Triodia pulchella, 104
Trixis californica, 115, 179
Turnera diffusa, 146
ulmifolia, 187
244
Urtica holosericea, 22
Vallesia glabra, 112, 159
Vaseyanthus Brandegei, 171
insularis, 101, 102, 114, 171
insularis inermis, 172
Palmeri, 13, 771
Veatichia discolor, 141
discolor pubescens, 141
discolor Veatchiana, 55
Verbena robusta, 33
Verbesina oligocephala, 180
Viguiera deltoidea, 115, 180
INDEX
voL. 13
deltoidea chenopodina, 115, 180
deltoidea var. chenopodina, 180
deltoidea Townsendii, 72
lanata, 61
tomentosa, 180
Viscainoa geniculata, 107, 136
Waltheria americana, 71, 145, 187
Preslii, 187
Wigandia caracasana, 189
Wilcoxia striata, 111
Zauschneria californica villosa, 31
Ziziphus sonoriensis, 98
GEOGRAPHICAL INDEX
Anacapa Island, 14, 17
Angel de la Guardia Island, 14, 15,
84, 92, 99, 103, 116
California Gulf Region, $1, 82, 83, 85,
98
Carmen Island, 99, 103, 116
Cape District, 11, 14, 81, 85, 86, 89, 90
Cedros Island, 14, 15, 43, 47
Ceralbo Island, 84, 99, 103, 116
Chacagua Bay, 15, 184, 185, 186, 187,
188, 189, 190, 191
Channel Islands, 11, 17
Clarion Island, 15, 63, 64
Coronados Islands (Gulf), 99, 103, 116
Costa Rica, 12:15, 192
Danzante Island, 99, 103, 116
El Datil Island, 102
Espiritu Santo Island, 14, 99, 103, 116
Guaymas, 86, 96
Ildefonso Island, 14, 99, 103, 116
Isla Partida, 116
Las Animas Island, 99, 102, 116
Maria Cleofa Island, 79
Maria Madre Island, 75, 76, 79
Maria Magdalena Island, 74, 75, 77, 78,
79
Mejia, 99, 116
Monserrate Island, 99, 103, 116
North San Lorenzo Island, 102
Partida Sur, 99
Patos Island, 14, 99, 116
Pelican Island, 102
Pichilinque Island, 102, 116
Pond Island, 15, 99, 110
Puerto Escondido, 15, 91
Punta Frailes, 15, 91
Raza Island, 99
Revilla Gigedo Islands, 15, 63
Sal si puedes Island, 99, 103
San Benedicto Island, 63, 64
San Benito Islands, 14, 47
San Clemente Island, 14, 15, 17
San Diego Island, 99, 103, 116
San Esteban Island, 14, 15, 95, 99, 103,
116
San Francisco Island, 14, 99, 103, 116
San Josef Island, 102
San Jose del Cabo, 15, 102, 103
San Jose Island, 99, 116
San Juanito Island, 76
San Juan Nepomucens Island, 102
San Lorenzo Island, 84, 99, 103, 116
San Luis Island, 99, 116
San Marcos Island, 99, 103, 116
San Miguel Island, 14, 17
San Nicolas Island, 17
San Pedro Martin Island, 102
San Pedro Martir Island, 99, 100, 102,
103, 116
San Pedro Nolasco Island, 14, 15, 96, 99,
103, 116
Santa Barbara Island, 14, 17
Santa Catalina Island, 14, 15, 17, 99,
103, 116
Santa Cruz Island (Channel), 15, 17
Santa Cruz Island (Gulf), 99, 103,
116
Santa Inez Island, 99, 116
Santa Rosa Island, 14, 17
Secas Islands, 15
Smith Island, 116
Socorro Island, 15, 63, 64
Sonora, 15
Tassne Island, 102, 116
Tenacatita Bay, 15, 182, 183
Tiburon Island, 14, 15, 94, 95, 99, 103,
116
Tres Marias Islands, 15, 74
Turners Island, 99, 102, 116
VOL...13 INDEX 245
COLLECTORS’ INDEX
Barkelew, F. E., 64, 67 McDougal, D. T., 86
Belding, L., 47 Mocifio, J. M., 182
Brandegee, I. S., 44, 47, 48 Nelson, E. W., 78, 79
Coulter, T., 86 Nelson & Goldman, 99
Conzatti, C., 182 Palmer, E., 47, 48, 98, 99, 182
Dawson, E. Y., 92, 95, 96, 98,99 Pond, 44, 46, 47, 48
Elmore, F. H., 19, 46, 47, 64, 66, 68, 78, Pringle, C. G., 182
79, 182, 192 Rempel, P. J., 46, 47, 48, 92, 95, 96, 98,
Ferris, R.. S., 74, 79, 99 99
Gentry, H. S., 87, 92 Rose, J. N., 47, 75, 99, 182
Greene, 45, 47, 48 Shreve, 87
Hale & Haines, 45, 47 Standley, P. C., 182
Hanna, G. D., 43, 47, 65, 67 Steward, 47
Hinds, 44 Stockton, 64
Howell, J. T., 47 Streets, 47, 48
Johnston, I. M., 55, 66, 92, 99 Townsend, 64
Mason, H. L., 47, 64, 67, 78, 79 Veatch, 47
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REPORTS OF THE COLLECTIONS OBTAINED BY ALLAN HANCOCK PACIFIC EXPEDITIONS OF
VELERO III OFF THE COAST OF MEXICO, CENTRAL AMERICA, SOUTH AMERICA, AND
GALAPAGOS ISLANDS IN 1932, IN 1933, IN 1934, IN 1935, IN 1936, IN 1937, IN 1938,
IN 1939, IN 1940, IN 1941, AND VELERO IV IN 1949.
PLANT ECOLOGY OF THE CHANNEL
ISLANDS OF CALIFORNIA
(Ficures 1-12, Piates 1-6)
By MERYL BYRON DUNKLE
UNIVERSITY OF SOUTHERN CALIFORNIA PUBLICATIONS
ALLAN HANcockK PAcIFIC EXPEDITIONS
VoLUME 13, NUMBER 3
Issu—ED NOVEMBER 30, 1950
Price $2.50
Tue UNIVERSITY OF SOUTHERN CALIFORNIA PRESS
Los ANGELES, CALIFORNIA
PLANT ECOLOGY OF THE CHANNEL ISLANDS
OF CALIFORNIA
By Meryt Byron DUNKLE
I INTRODUCTION
Off the coast of populous southern California lie a number of islands,
uninhabited for the most part. They are far enough out from shore to
have a distinctive climate and a noteworthy endemic plant and animal
life. While these islands have been known for over four centuries they
have been the object of scientific study for only about one century.
The study of the island plant life was begun in 1847 when Dr.
William Gambel of the Philadelphia Academy of Sciences collected
a few plants on Santa Catalina Island (Nuttall, 1848). In 1874 Dr.
Albert Kellogg and W. G. G. Harford made a small plant collection
on Santa Cruz Island (Eastwood, 1941). Yet not until 1884 were
any extensive collections made. In that year T. S. and Katherine
Brandegee (1890), and W. S. Lyon made collections on Santa Catalina
Island, and continued their work for several years, while Dr. E. L.
Greene began his extensive work on the island flora in 1886 with an
extended visit to Santa Cruz Island.
Lorenzo G. Yates (1889, 1890) in connection with his geological
reconnaissances of the Channel Islands devoted considerable study to
the island plants. In 1895 Mrs. Blanche Trask went to Santa Catalina
Island and during the ensuing twelve years as a resident botanist col-
lected indefatigably there and on the three other southern islands
(Trask, 1897, 1898, 1899, and 1904).
C. F. Millspaugh and L. W. Nuttall of the Chicago Field Museum
of Natural History started their collections on Santa Catalina Island
in 1919 and 1920 respectively, and published their splendid volume
on the “Flora of Santa Catalina Island” in 1923. They give a complete
account of the botanical work on this island. Ralph Hoffman (1932)
made extensive studies of the flora of the four northern islands, but
his sudden death in 1932, while collecting on San Miguel Island left
his work incomplete.
AQ "
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247 f %, em teat
aie be fe" B®)
248 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 13
The Los Angeles County Museum Channel Islands Biological
Survey, begun in 1939, was the first attempt to study the complete
biota of the individual islands and to integrate the information thus
obtained for the island group as a whole. The author, acting as field
botanist for the Survey, made extensive collections on all the Channel
Islands. "The problems arising in this work led to ecological studies
under the direction of the late Dr. Howard de Forest of the University
of Southern California.
While incidental mention has been made of the general ecological
conditions, in the various taxonomic reports of the island flora, there
had been previously, no detailed or objective study. No descriptive
account of the vegetation as such had been given in either general or
specific terms. For instance it was not possible to know, from written
accounts, what types of plant associations were to be found on the
different parts of each of the several islands.
At intervals geologic, topographic, and oceanographic surveys and
reconnaissances had been conducted in the insular area and several
reports have been made upon its geologic evolution. Nevertheless,
little attempt has been made to trace the effect of these physiographic
changes upon the development of the present flora of the islands, and
there has been also insufficient study of the affinities of the island flora
with the floras of adjacent regions. Accordingly this investigation was
undertaken to study the island vegetation, to investigate the distribution
and the affinities of the island plants, and to make inquiry into the
effects of the ecological agencies upon the island plant life and its com-
munities. The study of the environmental factors of these insular habitats
led the writer to select Santa Barbara Island as the most central for
quantitative and instrumental analysis. The period of study extended
from March 17, 1940 to April 22, 1942.
Meteorological stations have been maintained, by different agencies,
for various periods during the past forty five years. However, there
had been previously, little or no attempt to correlate the results of
climatological studies with the characteristics of the present vegetation.
Ten instrument stations were set up on Santa Barbara. The instru-
ments used were: standardized, spherical, Livingston porous black-cup
and white-cup atmometers for measuring evaporation and insolation,
anemometers, rain gauges, and maximum and minimum registering
thermometers. At two stations recording hygrographs and thermo-
graphs were used for obtaining a continuous record of humidity and
temperature. All of these instruments were modified or rebuilt to serve
No. 3 DUNKLE: PLANT ECOLOGY, CHANNEL ISLANDS 249
for long-period intervals between observations. ‘This was necessitated
by the difficulties encountered in arranging for frequent trips to this
isolated island. Soil samples were taken at each of the instrument-
stations for mechanical analysis and hydrogen ion determination.
While these investigations are necessarily incomplete because of
weather hazards, distance, and war-time restrictions, and some of the
conclusions hypothetical, it is hoped that the methods used and the
problems discussed may be of value to other students of insular condi-
tions and to the administrators of the various islands.
The scope of this ecological study has involved the cooperation of
specialists in many fields. Meteorologists, oceanographers, geologists,
climatologists, and zoologists have contributed to the solution of the
ecological problems. Because of the diversity of the separate fields in-
volved in this study a glossary of technical terms is given. See p. 332.
The field of this investigation has covered such a large area, so difficult
of access, that it has made other assistance essential. Merely to name
all who have contributed in some measure to the success of the under-
taking would be impossible. However, this account would be incomplete
without mention of those whose assistance has been indispensable.
First among these has been Dr. John A. Comstock, Curator of
science in the Los Angeles County Museum, whose leadership in the
organization of the expeditions of the Los Angeles County Museum
Biological Survey of the Channel Islands has made them possible.
Don C. Meadows, the field executive of the island expeditions, assisted
in the field work and in the organization of the material.
The scientific interest of Captain Allan Hancock and his generosity
with the Velero III provided transportation for many of the voyages.
The use of the sedimentation laboratory of the Allan Hancock Founda-
tion facilitated the detailed study of the soils and marine sediments of
the island area. The patrol boats of the California Fish and Game
Commission also assisted in the matter of transportation.
II INsuLAR ENVIRONMENT
The continental shelf of the western coast of North America is
very narrow when compared with that of the eastern coast. Off central
California the edge of the shelf roughly parallels the coast, trending
30 degrees east of south. At Point Conception the coast turns abruptly
eastward and then swings southward to regain its original trend only
along the coast of San Diego County. As the edge of the shelf does not
250 ALLAN HANCOCK PACIFIC EXPEDITIONS voL. 13
change its trend through these latitudes it comes to lie, along southern
California, about one hundred and twenty miles farther out than it
did at Point Conception.
Thus, within this wide, sweeping arc of the southern California
coast lies a great embayment of the sea. The continental shelf is wider
here than the entire width of the Coast Ranges of central California
and the submerged area is in general alignment with these ranges. This
section of the continental shelf thus represents a submerged part of
the continent; a mountainous section with peaks rising eight thousand
feet above the deeply submerged basins. Only the higher portions of
these mountains ranges rise above sea level, and form an archipelago of
scattered islands extending over an area of some five thousand square
miles. As this archipelago roughly parallels the coast, along which
coastwise vessels ply, the island group is called the Channel Islands
of California. These islands extend from 23.3 miles south of Point
Conception to 62.4 miles west of Point Loma.
‘THE GEOLOGIC SETTING
The area now occupied by the Channel Islands was in past ages the
scene of great epeirogenic activity. Reed (1933) states that this area
was a large island which he calls “Catalinia.” This land mass, which
apparently existed from the Cretaceous to the early part of the Tremblor
formation of the Middle Micoene, extended west and south from the
present islands, probably including the Cortez and Tanner Banks, and
possibly also Guadalupe Island, two hundred and fifty miles to the
south of San Clemente Island. Intermittent periods of submergence
and uplift differentiate areas of this ancient land mass. Only occasionally
has it been connected with the mainland. Many plant endemics, many
of which are only distantly related to present mainland plants, and
some endemic animals are to be found on the islands.
Figure 1 shows the relationship of the Channel Islands to each other
and to the southern California coast, as well as to the general contours
of the continental shelf.
The northern four islands form the summits of a partly submerged
ridge extending westward from the Santa Monica Mountains. San
Miguel Island lies the farthest west, nearly due south of Point Con-
ception. The relative positions of the islands can best be visualized by
reference to Figure 1. During at least the latter part of the Cenozoic
the area about the four northern islands is thought by Reed (1936) to
have been a separate geological province, which he calls ‘“Anacapia.”
NO. 3 DUNKLE: PLANT ECOLOGY, CHANNEL ISLANDS 251
The presence of fossil elephants on Santa Rosa and Santa Cruz (Stock,
1935) indicates that there must have been a land connection with the
mainland in the early or middle Pleistocene. ‘Chis evidence is further
substantiated by the presence of many plants with northern affinities
on the northern islands. This invasion of northern plants is thought to
have occurred during the glacial stages of the Pleistocene (Leconte,
1893).
The four southern islands are much more widely scattered and
form the high points of submerged northwest and southeast ridges.
Santa Catalina, the largest of the southern islands, lies only twenty-two
miles south of Point Vicente. The second in size, San Clemente, the
most southern of the islands, is sixty-three miles west of La Jolla, while
the third largest of the southern islands, San Nicolas, lies farthest from
the coast, sixty miles from the nearest point of the mainland. Santa
Barbara is the smallest of the islands and is situated about half way
between San Nicolas and Santa Catalina.
A fact of some interest in considering the location of the islands
is that the channels separating them from the mainland are shown by
Coast and Geodetic Survey charts to be about twice the depth of the
channels separating England from France, Asia from Alaska, and
Borneo, Java, and Sumatra from the Malay Peninsula, these latter all
being less than 100 fathoms in depth. The Catalina Channel is ap-
proximately the same depth as the arms of the north Atlantic separating
Iceland both from Greenland and from Europe. This not only shows
the deep subsidence of this portion of the continental shelf, but indicates
that there has been little possibility of any connection of the islands with
the mainland during the lower ocean levels of the Wisconsin glacial
stage of the ice age, unless diastrepic agencies have considerably altered
the levels existing at that time.
Figure 2 shows the islands in such a manner that their sizes may
easily be compared, and also shows the fifty-fathom contour which
roughly marks the lower limit of the beaches existing during the Wis-
consin stage.
Past CLIMATIC CHANGES
Another element in the geologic evolution of the islands is the long
term change which has occurred since the early Pliocene, interrupted
by the glacial stages of the Quaternary and by long term cycles since.
The overall change has been a gradual drying of the climate. In recent
time the general record of geochronological climatology has shown a
252 ALLAN HANCOCK PACIFIC EXPEDITIONS VOLS
gradual amelioration of glacial conditions for several thousand years
(Russell, 1941, p. 86). In these latitudes this change has been mani-
fested by the northward spread of desert conditions. It is illustrated by
the progressive drying of lakes Bonneville, Lahontan, Searles, and Death
Valley. The Mohave River lies directly east of the Channel Islands
and far enough south so that the gradual elevation of the Sierra Nevada
could scarcely have cast a rain shadow over this region. The drying of
the lower streams and lakes of the Mohave system is most eloquent
testimony of this increasing desiccation. ‘The study of lake varves and
tree rings (Huntington and Visher, 1922), and of ancient Syrian
civilization (Butler, 1920) all point to the same progressive desiccation
of these latitudes. |
Progressive desiccation of the island area itself is indicated, too,
by the fact that seedlings of several insular endemics, such as Lyono-
thamnus (Ironwood), Dendromecon (Tree Poppy), and Quercus
tomentella Engelm. (Island Oak), have rarely been found. A few
Dendromecon seedlings have been found in disturbed soil about mine
dumps on Santa Catalina. The lack of young plants of the above men-
tioned endemics may be due, in part, to grazing animals or to the com-
petition of exotic plants, but the evidence seems to indicate that these
plants are incapable of reproducing themselves at present under normal
climatic conditions.
The effect of long continued desiccation would be to modify the
life forms of the individual species, and to produce changes in the flor-
istic composition of the plant communities. Direct evidence of such
change will be produced later in this paper.
CLIMATE
The classification of the climates of the Channel Islands has been
an unsettled question in the past owing to the lack of adequate data.
However, the United States Navy has recently established two aero-
logical stations, one on San Nicolas in 1932, and another on San Cle-
mente in 1937, and the Coast Guard has been recording meteorological
data on Anacapa since 1934. A Weather Bureau station was established
at Avalon, Santa Catalina Island, in 1909, and its records have since
been continuous. The San Miguel Station of the Weather Bureau was
established in 1897, discontinued in 1903, reestablished in 1906, again
stopped in 1921, and resumed from 1940 to 1942. These various records,
when assembled with other observations to follow, enable reasonably
definite conclusions to be drawn.
NO. 3 DUNKLE: PLANT ECOLOGY, CHANNEL ISLANDS 253
Precipitation. ‘The summer months are generally dry with the only
effective precipitation during the winter. Light rains may start in the
latter part of September and gradually increase in intensity until early
February, after which they show a rapid decrease until the last of
April. The regime of the insular precipitation is shown in table 1.
There is slightly more rain during the summer months on the
westernmost and the higher of the islands than on the southern islands
and the lower islands to the east. Thus San Miguel, Santa Rosa, San
Nicolas, and Santa Catalina each have some light rain during the
summer, while practically no summer rain is reported from Anacapa,
Santa Barbara, and San Clemente. More rain is reported from San
Clemente, Santa Catalina, and San Nicolas for October and the latter
part of September than for November. This undoubtedly is owing to
the tropical storms that come up along the coast of Mexico in the early
fall and tend to turn eastward or die out north of latitude 30° N.
The area of precipitation from these storms may occasionally reach
the southern islands.
The hydrotherm shown in figure 6 summarizes the monthly pre-
cipitation and temperature for the Channel Islands, and is almost
identical with those of some of the islands of the Mediterranean Sea,
as shown by Raunkiaer (1934). The break in regularity of the pre-
cipitation graph for November shows the effect of the tropical storms.
The summer aridity of the islands is reflected in the abundance of
many annuals and the marked abundance of suffrutescence of the island
vegetation. The general dominance of grasslands and the presence of
chaparral in certain areas of Santa Cruz, Santa Rosa, and Santa Cata-
lina, and formerly of San Miguel, is typical of the Mediterranean
climates in similar latitudes in corresponding sections of continental
masses; i.e., the Mediterranean “maqui,” the South African “veldt,”
the Australian ‘‘bush,”’ and the South American “‘lanos.”
In addition to the records obtained from the governmental meteoro-
logical stations it was deemed desirable to obtain further information
in regard to temperature and humidity ranges, and precise measurement
of the evaporation rates in different exposures. This was done by means
of specially designed, recording instruments.
Temperature and humidity. In order to obtain records of the temper-
ature and humidity ranges, thermographs and hygrographs were estab-
lished at two stations on Santa Barbara Island. Because the weather was
such as to make visits to this island impracticable for a small boat during
the months of January, February, and March of 1942, no records are
available for that period. Consequently the records for the first week
ALLAN HANCOCK PACIFIC EXPEDITIONS voL. 13
254
‘pajonb sarjizoqyne 10F Z aqUT, {Ix
ClO eases 02 et 00s a 700 - 4b. 120" SS = LEE AVC ayuaura[ ues
er or 0 6 O- = 5t0 = 200 Bo -200 62:0 “760 “10% Se%- Mee yp BUTE) eIULS
CU rice cea acct. 000 1. 600 3 —cL0 = “06% 00 c0'e rr SUlOOIN ueg
Riemee OC aha 190 60 = 000: 000 “000 - 000. “SOT -- Soe. IE. SE ee edevovuy
ee PC ce 190-10 200 600“ ZNO: = 210. = 680 S0'S 0S 96 Bsoy PULSE
Ci ele Ste eae 0 -— 100-400 210 “S80 900... Phe 8 OS Jensry ues
‘10 T, 29qQ ‘AON po ydag ‘sny <Ajnf ounf Aepo Ady ‘se ‘qjay ‘uel
*«SANVISI TANNVHO FHL YOd NOLLVLIdI0ddd ATHLNOW
T HIaVL
No. 3 DUNKLE: PLANT ECOLOGY, CHANNEL ISLANDS 20D
of each of several consecutive months have been arbitrarily chosen as a
fair example. It is worth noting, however, that the maximum-minimum
thermometer readings showed no lower temperatures than are indicated
on figs. 5, 6. (pp. 350-2). Consequently these records do well illustrate
the remarkably small range of temperature throughout the year. The
recordings were taken from instruments at the station situated on the
main ridge about the center of the island. ‘The low range of temperature
is clearly shown especially for the fall months, as well as the uniformly
high humidity. For weeks at a time, during the summer, the relative
humidity ran at 100 per cent for from sixteen to eighteen hours of the
day. Observation has shown that this is similar to conditions on all
of the islands, with the exception of the eastern part of Santa Catalina.
Here there is less fog than on the other islands or on the adjacent main-
land coast.
The hygro-thermogram for May 4 to 11, 1941, indicates a most
remarkable deviation from the normal uniformity. Examination of
the Weather Bureau records for southern California for the period in
question shows that exceptional temperatures then prevailed on the
mainland. Periods of high pressure over the southern part of the Great
Basin cause a pressure gradient, bringing dry, hot wind to the coastal
area. The inland high pressure area is related to the extensive sub-
tropical anticyclone over the “‘horse latitudes’ of the Pacific, which
is characterized by settling air. The adiabatic warming of this air causes
extremely low relative humidity.
The extreme fluctuations of relative humidity indicated by this
May hygro-thermogram, sometimes as much as 50 per cent within a
period of minutes, could only be caused by waves of superior air alter-
nating with the horizontal movement of Pacific maritime air. Only
tropical air from the upper troposphere would be capable of producing
such exceptionally low relative humidities in an area so far removed
from the mainland shore. Dry periods similar to that of this May week
have been experienced on several of the other islands and doubtless occur
several times a year. Only rarely, however, would conditions probably
be such as to produce a relative humidity as low as 2 per cent. The
normal offshore breeze usually reaches Santa Barbara Island late at night
and persists several hours after sunrise. This normal land breeze, how-
ever, does not noticeably affect the relative humidity.
Wind. There are few records of wind velocity but these are fairly
consistent. San Miguel is the most windy of all the islands, with San
Nicolas a close second. Plate 2, p. 368, in the next sub-section shows
clearly the effect of the northwest wind on San Miguel. There it has
256 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL:.15
been necessary to construct a ten-foot stockade about the ranch house,
but even with this protection shutters must be provided for the windows
so that the window glass will not be abraded by the sand-blasting. On
Santa Barbara the intensity of the wind reaches an unknown maximum.
Twice the instrument station of the north peak was wrecked, the rain
gauge recording cylinder blown out, the wire screen protecting the
instruments torn loose and blown over onto the east terrace. I'wice the
anemometer on the ridge station was wrecked when the anemometer
cups were blown off.
At Wilson Cove on San Clemente Island the average wind velocity
for the period from April 1, to June 30, 1940, was 11.8 miles per hour.
On the terrace south of the ranch house on Santa Rosa the average
wind velocity for a period of 193 days, from October 10, 1921, to May
13, 1922 was 12.0 miles per hour. It is interesting that the average
for the night hours was almost identical with that for daylight hours.
On the eastern bluff of Santa Barbara near the cabin the wind velocity
for the two years from March 26, 1940, to April 1, 1942, averaged 7.8
miles per hour. It should be noted that the anemometer here was only
7.5 feet from the ground, whereas the Weather Bureau anemometers
are usually placed thirty feet from the ground. On each of the three
islands referred to, the recording station was on the lee side of the island
and was operating for different periods of time. The observation that
the prevailing winds show less force on the south and east tends to be
confirmed.
Observation of the more exposed sections of the islands indicates
that the winds there are much stronger, but reliable records are almost
wholly lacking. On Santa Barbara the anemometer which was twice
wrecked, situated 7.5 feet above the ground, gave a reading from Sep-
tember 11, 1940, to December 6, 1941, of 16.8 miles per hour for the
average wind velocity. The wind is the most powerful factor in the
environment of the island plant communities. Its variation is so great
from one topographical location to another that it appears to be the
most effective agent in the distribution and limitation of the communities.
This will be treated in more detail later.
The maritime climate of the islands shows also the following char-
acteristics: (1) a mean noon relative humidity of over 60 per cent, (2)
a mean July temperature of less than 22°C. (71.6° F.), (3) an aridity
coefficient of 12 per cent or less (Gorczynski, 1940, p. 5), and (4) night
or morning low stratus or fog for the greater part of the year.
The designation “foggy desert,” as defined by Russell (1926, p.
79), might appear to be applicable to some of the southern islands.
No. 3 DUNKLE: PLANT ECOLOGY, CHANNEL ISLANDS 251,
However, the low summer temperatures, the high relative humidity,
and the great amount of fog or low stratus, give an effectiveness to
the annual precipitation well above that of an eleven inch precipitation
inland. It is true that on southern slopes, with the high angle of the
sun, the shallow soil, and the high wind velocity produce xeric condi-
tions which have misled casual observers as to the true climatic status
of the islands. The general physiognomy of the vegetation, its density and
its floristic composition, do not fit the definition of a desert. Only on
the southern end of San Clemente does the physiognomy of the vegetation
approach that of a desert.
Maritime climate. Thus it is seen that the islands have the dry
summers, the humid-temperate winters, and the characteristic vegeta-
tion of the Mediterranean climate, and the incipient trade winds of
summer, supplemented by intermittent westerlies in winter, with some
modifications; i.e., uniformly low ranges of annual and diurnal tempera-
tures, high average of relative humidity, considerable low stratus or fog.
These latter features are characteristic of an oceanic climate. This
type, in contrast to the continental climate, has long been recognized by
geographers. That a sub-type of oceanic climate is typical of windward
coasts in the low latitude temperate windward coasts of the temperate
zones has also been established, and the terms ‘‘oceanic,” “littoral,” and
“coastal”? have been applied (Blair, 1941), (Salisbury, 1931). Inasmuch
as the flora of the Channel Islands is sufficiently distinctive to have led to
its classification as one of the primary divisions of the ‘“‘Nearctic’”’ region
(Leconte, 1888), its climatic distinctiveness should be adquately recog-
nized. The controlling factor of the insular climate lies in the narrow
range of annual and diurnal temperature. There is a difference of less
than 10° C. (18.0° F.) between the January and the July mean temper-
atures. Indeed, for the islands themselves no annual range of more than
6.3° C. (11.1° F.) has yet been reported.
Additional characteristics of the insular climate shows also the fol-
lowing characteristics: (1) a mean noon relative of over 60 per cent,
(2) a mean July temperature of less than 22° C. (71.6° F.), (3) an
aridity coefficient of 12 per cent or less (Gorcznsky, 1940), and (4)
night or morning low fog or stratus for the greater part of the year.
Accordingly the term “Mediterranean maritime’ is proposed, though
for the purposes of this paper the term ‘‘maritime”’ will be used to
designate the climatic type of the insular area and of the immediately
adjacent mainland coast. The data for computing the annual range
of temperature together with the average precipitation, are given in
table 2.
258 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 13
PABVE 2
PRECIPITATION AND 'TEMPERATURE RECORDS
FOR THE MARITIME CLIMATE*
Length Av. Mean Mean Mean
of Annual Annual July Annual
Record Prec. Temp. Temp. Range
Years Inches (Degrees Fahrenheit)
Islands
Sartat Iie 3k es See ae le 32 14.24 56.7 58.7 5.4
POTTS 1 2 Ste) CONF WR Cha CI AU ce Ec aeRO 11 1 koveg ANU Pees ea Ree
Ser zee sek a LO ere oe
HAT VC APA ce ee ete eae Ace eT eoe 8 A DES Sly teen ate
Sanca ran ara sss cal Ser esse kB ed 2 AW RA ieee Cee jens
Sct ie CALs see oe ec a 32 12.35 60.9 66.6 oi.3
ASE I Yigal: PLEX) be of ede OD Bae a Pe TR I 10 11.08 60.3 63.2 6.2
Same lementes.\ 2 aes oy ee he + 10.56 59.4 62.3 5.6
Mainland
| Etovti ot etal bra’ 07 be Whe eeu eae ers LT AB etre aI Git SA Aas Oe 25 11.07 60.7 67.0 12.9
rye u ibd BL STS eco COS SE ARE eee a ae a ei ee eA 59 9.67 61.2 67.4 12.7
GR lass 1stas eee ee ee 12 10.50 59.5 66.7 14.5
een sudee = Ciba Ne ok ha ey 10 1237 68.8 74.1 14.8
Ponombeadcwws ecko Ales de a gs 10 9.93 61.6 70.0 16.9
OPERA) Ee bar RAN Ree A ORR OO MRR Bene aE aD eh 11 10.66 61.3 66.8 10.9
LD o\staeva Watbea( el (10 2 SAS Une nO RE eR 53 14.95 62.7 70.4 15.3
Otane et ce eee en nee Eee es eee 8 P16 58.8 63.4 9.5
Samtarsvigmicaice co weet) ee 33 14.78 59.5 65.9 13.1
DAntaw arpa tas cles SA eee ee OU 46 18.04 59.9 65.7 1253
Sani WmisvObisposn 20 ea hea 36 20.92 58.6 64.3. «12:3
*Data obtained from the following sources: San Miguel, San Nicolas, and
Santa Catalina, U.S. Weather Bureau, Regional Office, San Francisco; San
Clemente, Aerological Office, Naval Air Station, San Diego; Anacapa, Coast
Guard Station, Anacapa; Santa Rosa, Dr. Ford Carpenter and H. M. Hall,
Los Angeles; Santa Barbara, adjusted instrumental records; Mainland cities,
Climatic Summary, U.S. Weather Bureau, Washington.
In addition to these, meteorological data, correlative studies of the
life forms, and the distribution of the island plants have been made, and
the interpretation of this evidence adds additional information bearing
upon the nature of the insular climate and its sub-divisions. This is
in accordance with Tihomirov who states (1940) that studies of vegeta-
tion may give dependable corroboration of meteorological records and
assist in delimiting boundaries in areas where no other data are available.
A seaman, cruising about the islands, is forcibly impressed by the
differences of wind and fog, even between different parts of the same
No. 3 DUNKLE: PLANT ECOLOGY, CHANNEL ISLANDS 259
island. This is significant as it has been demonstrated that the wind is
the controlling factor, with precipitation a subsidiary factor, in the
distribution of insular plant communities. While a study of meteoro-
logical records shows clearly that while there is a general climatic
similarity for the entire insular area, there are wide extremes between
the southern tip of San Clemente and the northern tier of islands. ‘These
differences are even more pronounced in the areas of maritime climate
on the adjacent mainland.
There is considerable uniformity in both precipitation and tempera-
ture in the area between Point Vicente and Cabo San Quintin in Baja
California, with a rather sharp break north of the former and south of
the latter. Accordingly, these seem logical points for a division of the
maritime climate into three types.
The northern or semi-humid maritime would be separated from
the central or arid maritime by the isohyet of thirteen inches of annual
precipitation. The division between the arid and the desert maritime
would be on the isohyet of six inches.
The northern or semi-humid maritime would be separated from the
central or arid maritime by the isohyet of thirteen inches of annual
precipitation. The division between the arid and the desert maritime
would be on the isohyet of six inches. Figure 5 shows the approximate
area of the maritime and the proposed division of this climatic type.
South of Cabo San Quintin much of the dominant growth is cacti and
other low shrubs typical of desert conditions, with the individual plants
well spaced. North of Cabo San Quintin, extending to Point Vicente
there is much grassland on the rolling slopes with typical chaparral on
the steeper slopes, with a general scarcity of trees at lower elevations
with the exception of the riparian woodlands. North of Point Vicente
trees become increasingly evident and cacti become rare, while more
mesic plants such as Myrica, Umbellularia, and Holdodiscus appear.
Among the islands, the counterparts of the sub-divisions of the
maritime climate on the mainland are recognized as follows: San Miguel,
Santa Rosa, Santa Cruz, and the western island of Anacapa! would
fall in the semi-humid maritime; Santa Catalina, Santa Barbara, San
Nicolas, and the northern two-thirds of San Clemente would be placed
1An eight-year record on the eastern island of Anacapa shows an average
annual precipitation of 12.58 inches, and this period includes two rather ex-
ceptional wet years. The middle island of Anacapa possesses much the same
aspect as the east island, and Opuntia prolifera is to be found on both islands.
The vegetation of the western island of Anacapa has a different aspect from the
two eastern islands. Due to the greater heights of Santa Cruz and the west
island of Anacapa it would appear that the two eastern lie in a rain shadow.
260 ALLAN HANCOCK PACIFIC EXPEDITIONS voL. 13
in the arid maritime; while the southern one-third of San Clemente
would be provisionally in the desert maritime. Of the three factors
which might account for this desert aspect of the vegetation at the
southern end of San Clemente Island: climate, soil, and topography;
the climate is apparently the limiting factor. ‘The soil of the entire
island is of volcanic origin, while the southern exposures of the other
islands have no similar vegetation.
Certain plants may well be used as indicators for the sub-divisions
of the maritime climate. Thus the following species are suggested for
the semi-humid region:
Pinus muricata Malvastrum Nuttallu
A bronia umbellata Oenothera cheiranthifolta
Myrica californica Mimulus longiflorus
Lupinus Chamissonis Erigeron glaucus?
IJlustrative of plants found in the area designated as arid maritime
are:
Abronia umbellata platyphylla Lycium californicum
Opuntia prolifera Mimulus puniceus
Oenothera bistorta Coreopsis maritima
The vegetation of the southern one-third of San Clemente has a
true desert aspect and resembles that of the Baja California coast south
of Cabo San Quintin. The following plants appear to be limited to this
area, or appear only sporadically on southern exposures of the arid
maritime:
Euphorbia misera Senecio Lyonit
Notholaena Newberryi Phacelia floribunda
Cereus Emoryti Lupinus argophyllus adsurgens
Cereus Emoryi and Opuntia prolifera are dominant here, showing
an abundance and luxuriance which can only be equalled south of Cabo
San Quintin. Furthermore, the aspect of the vegetation of the northern
two-thirds of San Clemente Island is distinctly different from the
succulent-suffrutescent shrub type of the southern one-third. The north-
ern uplands bear a typical grassland association with very little cactus.
Thus the marked differences in vegetation and the accompanying
variation in the precipitation, appear to justify the division of the mari-
time climate into the three sub-types.
2The nomenclature followed in this paper is that of Munz (1935) in his
Manual of Southern California, with certain changes by Dunkle (1940, a, b, ¢,
1941, and 1942, a, b.) Author’s citations for each species are provided in the
tables of sections IV, V, and in section VIII.
No. 3 DUNKLE: PLANT ECOLOGY, CHANNEL ISLANDS 261
THE INFLUENCE OF MAn
The environmental factors of wind, sun, and temperature operate
slowly in producing climatic changes and cannot be readily controlled,
whereas the activities of man can be. Man has introduced many grazing
and browsing animals as well as aggressive plant competitors with the
native plants. These agencies have been immensely destructive to the
original island vegetation. Few records have been kept of the more direct
activities of man. Disastrous fires have occurred on most, if not all, of
the islands. ‘Thus Santa Barbara Island was burned over in 1918 to
clear the small arable areas for agricultural purposes (Meadows, 1944).
Trees have been cut on Santa Rosa, Santa Cruz, San Clemente, and
Santa Catalina for fuel, and timber is said to have been used for ship
repairs in the early days. Small areas have been under cultivation on
Santa Cruz, Santa Barbara, and Santa Catalina. However, the plants
and animals introduced by man have been a major factor in changing
the aspects of the native vegetation.
DESTRUCTIVE GRAZING AND EROSION
Erosion has assumed dangerous proportions on several of the islands
Owing to a century or more of destructive overgrazing. The island of
San Miguel was used as a sheep ranch prior to 1850 (Ellison, 1937)
and has been continuously grazed since, though this has been much
restricted in recent years. Santa Rosa was stocked with sheep in 1844
and sixty thousand head of sheep were there in 1874 (Ellison, 1937).
There were two hundred sheep on Santa Cruz in 1852; in 1855 the
sale of wool from the island brought $22,000.00; in 1877 twenty
five thousand sheep were killed for tallow, glue, and hides. Sheep were
being raised on San Clemente as early as 1877 (Meadows, 1944) and on
Santa Catalina in considerable numbers for some years prior to the pur-
chase of the island by the Banning brothers in 1892. Sheep were grazed
on at least the middle island of Anacapa for several years. Goats have
been on some of the islands for even a longer period than sheep, for
they were introduced on Santa Catalina in 1827 (Bancroft, 1886),
and Farnham (1857) states that San Nicolas, San Clemente, and Santa
Barbara islands were densely populated by goats.
Large areas of both San Nicolas and San Miguel have been rendered
completely barren by a combination of wind and water erosion. The
presence of too many sheep for the available pasturage has resulted in
the killing of grasses, forbs, and shrubs. Wind and rain have thus been
262 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL;115
able to erode the soil excessively. The roots of trees and shrubs have
been exposed and the plants eventually killed. On San Miguel many
of the ancient kitchen middens of the aborigines are now perched on
ridges fifteen to twenty feet above the surrounding level. The surface
covering of shell, bone, and rock fragments has slowed the erosion of
the middens themselves. The airplane view of San Miguel Island,
plate 2, taken prior to 1933, shows the results of wind erosion. The
direction of the prevailing winds is indicated by the deep, parallel
trenches eroded in the sandstone. At the time of the writer’s visit to
the island in 1940 vegetation had already started to reclaim some of the
waste land in the east and west parts of the island. This was made
possible by the fact that, for several years, the number of sheep had been
limited to three thousand.
San Nicolas is nearly as windy as San Miguel. It has been grazed
continuously for about seventy-five years. Hence, as a result, the island
has undergone great wind and water erosion. When George Nidiver
removed an Indian woman from San Nicolas in 1853 he found Lava-
tera assurgentifiora (malva real) bushes and “a species of moss,, grow-
ing about the hut of the Indian woman (Ellison, 1937). Today the area
about the hut and, indeed, that entire end of the island is a desolate
waste of wind-driven sand. The steep slopes leading to the central mesa
have been cut into a “bad lands’ by water erosion and the gullies are
rapidly eroding back into the upland.
While Santa Rosa is somewhat less windy than either San Miguel
or San Nicolas, many areas are badly wind-eroded. However, grazing
here has been under careful management since 1893. The rule has been
to stock the island only to the extent for which the forage of the driest
year will be amply sufficient, and to rotate the pasturage so that it is
only grazed once in three years. Nevertheless even this plan failed for
the cattle had to be removed from the island during the dry seasons
of 1946-1948. Water erosion has been the principal erosion problem on
Santa Cruz, but check dams and contour cultivation indicate careful
conservation of the arable areas by the Caire family during their long
ownership of the island.
The effects of wind erosion have greatly increased the sand dune
areas on San Nicolas, San Miguel, Santa Rosa, and San Clemente. It
is probable that only small coastal dunes were present originally, and
the larger dune areas of the present were originally occupied by the
forbs and semi-shrubs reported by early travelers. There is no evidence
to show that the small salt or fresh-water lagoons on most of the islands
have been materially changed since earlier times, except as the result
of natural succession.
No. 3 DUNKLE: PLANT ECOLOGY, CHANNEL ISLANDS 263
DESTRUCTIVE GRAZING AND THE
LirE Forms OF PLANTS
Other islands have suffered severely from erosion only in limited,
exposed areas, but the vegetation has generally suffered from the selective
grazing and browsing of various introduced animals. The island vegeta-
tion had, previous to the coming of the white man, been free from
grazing or browsing animals for an indefinite period in the past, as
there is no record or trace of any such animals since the Pleistocene,
until their introduction in the past century. It is highly probable that a
type of vegetation developed under such circumstances which would
have been impossible of development in the presence of herbivorous
animals. Certain individual species: Coreopsis gigantea, Lavatera assur-
gentiflora, Malacothrix saxatilis implicata, Nemophila racemosa, Erto-
phyllum Nevinii, Eriophyllum staechadifolium depressum, and A plo-
pappus canus are examples of insular plants that are readily damaged
by grazing. This is implied by their tender, succulent nature; the lack
of ability to reproduce from adventitious buds; and by the fact that
they are now limited to inaccessible areas where grazing animals have
not been present.
The destructiveness of grazing animals cannot be as well envisioned
by the near-extinction of a few species, as by their effect upon the vegeta-
tion as a whole. This may best be seen by comparing conditions on the
much grazed islands, such as San Miguel, San Nicolas, and San Cle-
mente with the conditions of little grazed areas such as that of the west
island of Anacapa, Santa Barbara, Prince, and Sutil islands, and Bird
Rock. One or more of the plant species just mentioned are abundant or
dominant on these small islands in habitats similar to habitats on the
other islands where none or few of these species can be found at present.
Other animals than sheep or goats have been introduced on the
islands. Hogs have been on Santa Cruz for many years and on Santa
Catalina for at least ten years. A few rabbits are to be found on Santa
Barbara; and the eastern island of Anacapa is overrun with rabbits at
the present time, with consequent serious destruction of the native
vegetation. Rats have also been introduced on most of the islands. Deer
and bison have been on Santa Catalina for about fifteen years. Tule
elk, deer, and Siberian white deer have been on Santa Rosa since 1893
(Meadows, 1943). The long previous freedom from herbivorous animals
permitted the development of extensive and unique plant communities,
dominated by tender forbs and semi-succulent, suffrutescent shrubs.
264 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 13
PLANT INVADERS
A further effect of the activities of man has been the introduction
of numerous foreign plant species on each of the islands. These have
often become more abundant than the native species and grow so vigor-
ously under the existing conditions that the native plants can only rarely,
and with difficulty survive the competition. Such species as Mesembry-
anthemum crystallinum, Hordeum murinum, Avena fatua, Bromus
mollis, Atriplex semibaccata, and Medicago hispida, dominate many
extensive areas to the almost complete exclusion of the indigenous flora.
Only a few of the more vigorous, suffrutescent perennials, shrubs, or
bulb plants can withstand the competition.
No adequate attempt can be made to list all of the plant species
that have been introduced since the discovery of the islands by Juan
Rodriquez Cabrillo in 1542. Four centuries represent a period during
which many of the species arriving during the first two or three hundred
years may have become thoroughly naturalized. Many species reached
the islands from Europe by way of the United States, while others
may have come from Siberia or northwestern North America during
the days of Russian sea otter hunting, or may have been brought from
Mexico or South America by the early Spanish, English, and American
voyagers. Holder (1910) considers it highly probable that such explorers
as Drake, Woodes, Rogers, Shelvocke, and the adventurers and buc-
caneers of the latter part of the sixteenth or the early part of the seven-
teenth may have visited the islands during their journeys along the
west coast of North America. Following Vizcaino’s visit in 1602, during
the next two and one-half centuries many Spanish vessels must have
stopped at the islands. Early American mechants made the islands bases
for smuggling activities during the Mexican regime, landing their
cargoes on the islands to be transferred to smaller boats for surreptitious
landing on the mainland. As these cargoes had often been earlier landed
in Chile, it is possible that many of the plants now reported as common
to both Chile and the islands have reached them through this agency.
Most of the introduced plants have come directly or indirectly from
southern Europe or northern Africa where similar climatic conditions
prevail. Most of these plants not only come from the semi-arid regions
of the world, but come from regions where grazing has been practiced
for many centuries, and possess life forms that enable them to success-
fully withstand the activities of grazing animals.
No. 3 DUNKLE: PLANT ECOLOGY, CHANNEL ISLANDS 265
CLIMAX CHANGES
Climaxes are, in the long run, unstable, since changes are constantly
taking place in climate, in soil, and in the biotic environment. Weather-
ing, erosion, and sedimentation are unceasingly active and their rate
of activity is being affected by the mutations of the climate and the
biota, as well as by diastrophic agencies affecting the topography. Vegeta-
tion, through the accumulation of humus, and the disintegration of rock
materials, continually modifies the chemical and physical properties of
the soil. These changes, operating singly or in various combinations,
inevitably affect the floristic composition of an area. That which may
be of minor importance in a continental area, may have a powerful
influence upon the vegetation within the narrow limits of an island.
The gradual rise of the ocean level and increasing aridity have
affected the insular environment since Pleistocene time. The influence
of man has been active through only a few centuries, but this effect
has been catastrophic. The original vegetation has been affected over
wide areas by overgrazing, wind and water erosion, and fires. Yet
the most potent instrument of modification brought about by man has
been the introduction of plants from other regions of the world as
previously described. These exotics have thrived for two reasons: (1)
they have come, for the most part, from dry regions and are better
equipped to withstand the present arid or semi-humid conditions than
the indigenous plants which are relicts of a more humid time; (2) the
exotics have survived for centuries because of adaptations which have
enabled them to withstand all the destructive agencies of man, whereas
the native flora had experienced few previous contacts with either man
or herbivorous animals.
Many areas on all of the islands have been so changed that it is
now extremely difficult to envision the nature of the original climax
or the possible successional stages of the present sub-sere. hus, broad
terraces, wide interior uplands, and long gentle slopes are now dominated
by introduced grasses and forbs. These areas of fine-textured, deep soil
are those most favorable for grazing. That such parts, or even a major
portion of them, were originally grassland is open to doubt. Coarse
grasses, such as Stipa lepida, S. pulchra, and Melica imperfecta are
present among herbs and suffrutescent perennials. Grazing, erosion,
and fire must have destroyed many suffrutescents and most shrubs (cf.
ante p. 261). Many sea bluffs and canyon slopes near the sea are
now dominated by introduced Mesembryanthemum and Atriplex. In
all these areas the original nature of the vegetation may be estimated
266 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 13
only by the accounts of early explorers, by indirect evidences which
remain, or by comparison with the vegetation of similar habitats which
may have remained relatively unaffected.
The testimony of early visitors to the islands is rarely trustworthy
because their bases of comparison is unknown and their interests varied.
Their visits were short and usually localized. In many cases, observations
were made largely from boats and amplified by hearsay evidence. The
island of San Clemente furnishes an illuminating illustration of such
evidence. Farnham (1887) said it was partly covered with trees, but
that a greater portion of it was barren sand and rock, while Cronise
(1868) said: “it contains neither soil, vegetation, nor water.” ‘Trask
(1897) wrote of the luxuriant growth of clovers and other forbs on
the eastern benches, but said that the main upland was so covered with
rock as to make each step a perilous undertaking. Yet the writer, in
1941, forty-five years later, found the main upland well covered by
soil and grasses.
The extent of erosion caused by overgrazing on San Miguel and
San Nicolas has been mentioned. This combined effect of grazing and
erosion has obliterated many of the original plant communities and
caused the extinction of several species. Dall has reported of San Miguel
as follows*: “Near the shell heaps is a small grove of malva trees whose
green leaves and penciled blossoms refresh the eyes. There are no young
trees, however, as the omnipresent sheep crop every green thing within
their reach close to the ground.” In respect to San Nicolas, Schumacher4
states: ‘“The vegetation of this island is like that of San Miguel, ruined
by overstocking it with sheep . . . On the eastern end, near the house,
we found some malva-like bushes, cleared of their foliage to the reach of
a sheep, which gave them the appearance of scrub-oak trees when seen
from a distance.”
George Nidiver was one of the earlier Americans to be occupied
about the islands. He hunted sea otter, fished, and engaged in sheep
raising on the islands. Fortunately his biography has been preserved
(Ellison, 1937). Nidiver and his party had an encounter with north-
western Indians, also engaged in otter hunting, on Santa Rosa Island
in 1836. Afterwards the Nidiver party hid in the thick brush near the
beach. The scene of this encounter has been reestablished and there
is now mainly open grassland in that part of the island. Nidiver again
speaks of sagebrush and Lavatera (malva real) in a section of San
Nicolas Island which is now utterly barren, and also speaks of trees,
The lords of the isles, Overland Monthly, June, 1874.
4Some remains of a former people, Overland Monthly, October, 1875.
No. 3 DUNKLE: PLANT ECOLOGY, CHANNEL ISLANDS 267
brush, and “moss” on San Miguel Island, which now has no trees or
shrubs. Parish (1890) states that within the memory of living man
Lavatera occupied a large part of Santa Catalina, yielding only to the
overstocking with sheep and goats, and that it was also on San Miguel,
Santa Rosa, and San Clemente. These fragments are almost all of the
direct testimony that I have been able to find relative to the original
nature of the vegetation.
Natural evidence as to the previous growth on the island is also rare.
On San Miguel small tree trunks, as of arborescent chaparral, are
still standing near the west end of the island. For many years such
fragments have been gathered from all parts of the island and used for
fuel. On San Nicolas most of the wind-eroded slopes have root remains,
incased in mineral casts, projecting well above the present surface.
These may be remains of perennial herbs or of shrubs. The fire-blackened
kitchen-middens of the aborigines in all sections of all the islands, except
Santa Barbara, indicate the presence of considerable fuel in places
where little or no natural fuel is now available. While some of this
may have been driftwood, there is not much drift on the beaches today,
and it seems probable that there must have been considerably less drift
in earlier times.
Lavatera, Coreopsis, and other succulent or brittle-stemmed, her-
baceous plants have been mentioned (cf. p. 263) as occurring in somewhat
inaccessible places on nearly all of the islands. Many of these must
have been tid-bits for cattle, sheep, or goats, during the long dry season.
Moreover, their brittle stems could easily be broken by animals and
the plants destroyed. The largest island of the Anacapa group has been
little grazed and on the terraces the introduced grasses are thickly
interspersed with forbs, suffrutescent herbs, and woody shrubs (cf.
plate 5a). Here also steeper slopes are covered with a dense tangle of
herbaceous perennials and low shrubs. The eastern island of Anacapa
and Santa Barbara Island have extensive remnants of a Coreofsis associ-
ation that once covered most of the interior mesa. Bird Rock off Santa
Catalina, is covered with Lavatera. It seems extremely probable that
these plants, and others of the same life-forms, once covered extensive
areas on other islands which are now grasslands.
The steep walls of canyons and northeastern slopes are now covered
by chaparral, by a suffrutescent coastal sagebrush association, or by a
mixture of these two associations. This is particularly true of the larger
islands, although remnants of the coastal sagebrush association are to be
found on even the smaller ones. The western slopes of most of the
islands have, at present, a patchy growth of Lyctum, which, in the
268 ALLAN HANCOCK PACIFIC EXPEDITIONS VoL. 13
northern islands, is usually combined with, or replaced by Suaeda. A tri-
plex, Lotus, Opuntia, Aplopappus, Astragalus, and other low herbs
and semi-shrubs. Native annuals and geophytes are also abundant in
all of the uplands, and in the gently sloping areas where they have not
yet been displaced by exotics or destroyed by erosion. It seems probable
that this type of vegetation must formerly have extended into many
areas which are now occupied by introduced grasses and forbs.
Even if there had been no overgrazing on the islands, it is probable
that great change in the plant communities would have been brought
about by the introduction of exotic plants. Braun-Blanquet (1932)
states that geographic and climatic isolations are essential for the pre-
servation of relict plant communities, saying: “They are ill adapted
for combat with the ubiquitous immigrants brought in everywhere by
cultivation.”” While there has been little cultivation on any of the
islands, the mere occupation by modern man has inevitably brought
about this immigration.
There is little evidence to indicate any considerable changes in these
areas now occupied by woodland, by chaparral, or by coastal sagebrush.
However, it is probable that woodland may originally have extended
into some of the areas now occupied by chaparral. Since San Miguel
originally possessed considerable chaparral of the island type, which
is more susceptible to browse, it may be considered probable that certain
western upland areas of other islands, where the evidences of erosion
from destructive overgrazing are present, may once have been occupied
by chaparral. It is also possible, in this connection, that, as destructive
overgrazing was discontinued on Anacapa, Santa Cruz, and Santa
Catalina from thirty to forty years ago, badly eroded land may sub-
sequently have been reclaimed by the dense growth of introduced grasses
and forbs.
III Santa BarBARA ISLAND
Although observations of various environmental factors had already
been made on all of the Channel Islands during the course of the Los
Angeles Museum Channel Islands Biological Survey it was desirable
that detailed measurements of certain ecological factors should be made.
Extended instrumental work could not be carried out on each of the
islands because of the large area involved and the difficulties of trans-
portation. Therefore it seemed desirable to select one island for this
objective study, one so situated that conclusions reached on it might
be more or less applicable to the other islands.
No. 3 DUNKLE: PLANT ECOLOGY, CHANNEL ISLANDS 269
Santa Barbara Island was thus chosen for instrumental reasearch,
partly because it is centrally located among the Channel Islands, and
partly because of its small size. The central location of the island can
be most graphically visualized on certain clear, late afternoons, when,
from its high central ridge, a magnificent spectacle is presented by the
encircling islands. Every island of the entire group can be seen, except
San Miguel which is hidden behind Santa Rosa. It is only from this
vantage point that the true character of this widespread archipelago can
be realized. From Santa Barbara the nearest land, which is the north-
western point of Santa Catalina, is 24.0 miles directly east. San Nicolas
bears 36° east of south and is 27.5 miles distant. San Clemente lies
39.0 miles bearing 40° east of south, while Anacapa is 41.0 miles in
the opposite direction, bearing 40° west of north. Santa Barbara, more-
over, is almost equidistant from the coast near the western end of the
Santa Monica Mountains and from Point Vicente, both points lying
at an approximate distance of 40.0 miles.
The small size of Santa Barbara permitted the instrument stations
to be located on all of the principal exposures in such a manner that all
the stations could be visited within the twelve-hour period available
on a week-end trip. Although the small size of the island does not
provide a wide range of habitats, certain advantages are presented by
the fact it is uninhabited and has no large grazing animals. Further-
more, as part of the Channel Islands National Monument, it is not
liable to disturbance, and the future course of natural succession can
be followed.
‘ToPOGRAPHY
Santa Barbara Island is roughly triangular in outline with a central,
saddle-shaped ridge running approximately north and south, and wide
terraces to east and west. The area of the island is slightly less than a
square mile, 638 acres. The eastern terrace is about one and one-half
miles in length, sloping from about 139 meters (450 feet) to 47 meters
(150 feet) at the break of the eastern blufis. The western terrace is
shorter, with a slope from about 123 meters (400 feet) to 61.5 meters
(200 feet) at the western break. To the west of this terrace there is a
small terrace with an average elevation of about 47 meters (150 feet),
extending to the northwestern tip of the island.
The central ridge culminates in a peak on the southwestern coast
which has an elevation of 200 meters (635 feet), and another peak
with an elevation of 172 meters (562 feet) on the northwestern coast.
270 ALLAN HANCOCK PACIFIC EXPEDITIONS VoL. 13
From both peaks the land falls abruptly to the water’s edge in nearly
vertical cliffs. The extension of these cliffs forms the northern and
southern boundaries of the two main terraces. The eastern face of the
island presents an alternating series of abrupt cliffs and moderately
sloping bluffs. Detached segments of the main ridge form small islets
to the north and south of the island.
There are a few narrow sand beaches in shallow coves on the south-
ern and northwestern coast but as precipitous cliffs encircle these coves
the only practicable landing places are on the lee side of projecting
rocky ridges. he heavy surge from the south makes landing precarious
at best and impossible at times. There is good anchorage in most weather
off the eastern coast.
The rocky foundation of the island is volcanic in nature, consisting
mostly of alternating beds of indurated breccias and tuffs. One very
small sedimentary deposit, apparently of Pleistocene age, is located at
an approximate elevation of 148 meters (475 feet) near the southern
end of the island. Six shallow canyons cut directly across the lower
part of the eastern terrace. Only one of these, Graveyard Canyon, has
developed a steep-walled gorge. Except for a small seepage on one of
the eastern bluffs there is no permanent water on the island.
The wide marine terraces of the island and the abrupt cliffs rising
almost directly from the water play such an important role in the de-
velopment of plant communities that it may be well to consider the
origin of these features. Santa Barbara Island, in common with the
other islands, with the possible exception of Santa Catalina, appears
to have undergone considerable elevation in no very remote geological
time. This is inferred from the presence of marine terraces. San Cle-
mente Island has seventeen terraces, rising to a total height of 400
meters (1320 feet) (Lawson, 1893). These indicate intermittent periods
of uplift. Santa Barbara, owing to its lower elevation; has only two
levels of terraces. he Pleistocene deposits at a higher level than the
terraces might indicate greater uplift than that shown by the terraces,
but the sharp angles on the rocks of the highest ridge do not indicate
that the island was completely submerged prior to the uplift. The
depth of the canyons on San Clemente would place the major period of
uplift well back into the Pleistocene, and the small amount of surface
erosion on the terraces of San Clemente, San Nicolas, and Santa Barbara
would indicate no longer lapse of time.
The formidable cliffs and bluffs surrounding the island are due to
the ceaseless attack of the sea upon the shore line. This is undoubtedly
the most powerful geological agency operating upon the island during
No. 3 DUNKLE: PLANT ECOLOGY, CHANNEL ISLANDS 271
recent time. The smaller an island the greater is the amount of shore
line in proportion to surface area. The evidence of this wave attack is
strikingly evident upon all of the islands and typically so on Santa
Barbara. The height and slope angle of the bluffs have been largely
determined by their relative exposure to wave and surf action. A long,
powerful swell with recurring periods of intensification, probably caused
by distant, tropical storms, comes from the south. The prevailing west
to northwest winds cause shorter waves to pound almost continuously
upon exposed flanks of the island. An occasional northeaster sets up
violent onslaught upon the northeastern coast.
This wave erosion is particularly active because of the very narrow
beaches. Since the island is essentially a mountain ridge rising from a
submerged base, narrow beaches might well be expected. This condition
has been greatly intensified by the rising level of the ocean since the
Wisconsin stage of the Quarternary. It has been estimated that the
melting of the last glacial stage has caused, for some 25,000 years, the
gradual rise of the ocean level to a total of at least 76 meters (250
feet), (Schuchert and Dunbar, 1937). Disregarding any epeirogenic
activity, this must have meant a more or less continuous submergence
of detrital beaches, which would facilitate renewed wave attacks upon
the main land mass of the island. That such a condition has actually
existed has been shown by study of the ocean bottom about Santa Cata-
lina (Shepard and Wrath, 1937).
This condition of rapid shore erosion occasions recurrent slides
which set up xeroseres in the plant life of the bluffs. Xeroseres may be
found in various stages at different localities, being more noticeable
upon the islands with softer or more disintegrated rock layers than on
Santa Barbara. All successional stages do not normally occur, since
the bare areas are usually first invaded by xeric rock-crevice plants which
form on the sea-bluffs a community of many facies. On benches where
soil has accumulated, many shrubs, forbs, and grasses of the insular
uplands establish themselves. In this rapidly changing environment plants
might be expected to undergo considerable modification. That they do
so is indicated by the large number of insular endemics to be found in
such locations.
SOILS
The soils appear to have been derived almost entirely from the
volcanic rocks. They seem to be deepest on the upper part of the main
terraces where they have been formed from the material transported
ALLAN HANCOCK PACIFIC EXPEDITIONS VOL.. 13
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NO. 3 DUNKLE: PLANT ECOLOGY, CHANNEL ISLANDS 273
from the higher volcanics and gradually become shallower as the break
of the cliffs is approached. The soils of the terraces are relatively deep
and underlain by silty clay. At the immediate edge of the cliffs the soil
is only a few inches deep and much coarser than on the terraces. On
wind-swept headlands the soil is extremely shallow and consists mainly
of lag gravels. Soils in all parts of the island are alkaline in character,
the pH varying from 8.0 to 8.6.
Table 3 presents data on wind force, angle of slope, and mechanical
analyses of different soils.
The percentage of gravel in the soil is highest and the percentages of
silt and clay lowest where the slope is greatest or the wind velocity
highest. A clear-cut descending sequence in the percentage of particle
size is evident under either of the preceding conditions. The fine soils
of the terraces have been enriched by the decomposition of the luxuriant
vernal growth of grasses and forbs, as well as by the droppings of the
thousands of sea birds which have nested there for untold years. The
covering of grasses, forbs, and shrubs is so dense that there can be but
little run-off from the seasonal rains. This fact is evidenced by the small
amount of water erosion.
CLIMATIC AGENCIES
Because of its central location among the other islands the wind,
temperature, fog, and precipitation are intermediate in respect to these
conditions on adjacent islands. The climate is more oceanic in character
than that of the nearby mainland. The thermograph records show an
average annual temperature range of less than 3° C. (5.4° F.). This
small range is partially accounted for by the more frequent periods of
warm, east wind on the island during the late fall, winter and early
spring.
Wind must be considered the controlling factor in the climate of
the island. The direction of the wind, rather than the height of the
sun determines the temperature. The velocity of the wind determines
the areal limits of the plant communities. The prevailing direction of
the wind is from a little north of west. There is usually, however, a
weak land breeze during the early morning hours, and the seasonal
pressure gradients from September to May bring a dry, warm, east
wind over rather extensive periods. The average wind velocity recorded
on the central ridge at an elevation of 133 meters (435 feet) from
September 11, 1940, to December 6, 1941, was 16.8 miles per hour,
while that recorded on the eastern bluff at an elevation of a little less
274 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 13
than 47 meters (150 feet) from March 22, 1940, to April 2, 1942,
was 7.8 miles per hour. ‘Two storm periods were severe enough to
break off the atmometer cups at the station on the central ridge, so that
the average of 16.8 miles per hour must be well under the actual average
for that station, and is probably approximate to an average for the
island as a whole.
Variations in the wind velocity between different locations produce
a greater variation in evaporation rate than does the sun. The difference
between the evaporation rate on the windy north peak and that of the
northern exposure of Cave Canyon (cf. map, p. 359) for the same period
of seven months was 16.06 cc. per day, as measured by standardized
Livingston spherical white-cup atmometers. During the same period
the greatest difference in the evaporation rates of white-cup and similar
black-cup atmometers® was recorded at the central ridge station, where
it averaged 10.81 cc. per day. That is, the effect of wind on evaporation
was approximately 50 per cent greater than that of the sun.
Where the full force of the wind sweeps across comparatively level
areas on the headlands, the soil, as has been said, is shallow and coarse,
while on protected terraces it is deep and fine-grained. Entirely different
plant communities occupy the two areas. Exotic plants rarely invade the
windiest areas, although Mesembryanthemum grows in some windy
localities. Astragalus Traskiae, Malacothrix foliosa, Hemizonia cle-
mentina, and Baeria hirsutula are dominants of the windiest areas.
Under Russell’s modification of the Koppen international climatic
system the island would probably be described as possessing a “foggy
desert” type of climate. This classification, however, does not fit the
conditions existing on Santa Barbara Island. In view of the records
available for this island and those adjacent, and the general physiog-
nomy of the vegetation, it would seem fitting to apply the climatic
designation presented in section II1I—that of the arid maritime climate.
It was not possible to obtain accurate records of the precipitation
with the type of rain gauges available. Even with the use of oil in the
rain gauges of the type used, there was considerable evaporation. ‘Che
latter is indicated by the fact that very much larger readings were
obtained from stations sheltered from the sun than from stations ex-
posed to the full sun.® Also, the rain guage would overflow during
5Black-cup atmometers absorb much of the sun’s radiation which is re-
flected from the white-cup atmometers, and thus afford a measure of the influence
of insolation upon evaporation.
6For November, 1940, the most sheltered station B 2, on the northern ex-
posure of Cave Canyon, recorded 2.13 inches of precipitation while the station
B 1, on a sunny southern exposure only about 50 meters from station B 2, recorded
only 1.00 inch of precipitation.
No. 3 DUNKLE: PLANT ECOLOGY, CHANNEL ISLANDS 213
periods of heavy rainfall, such as occurred during the winter of 1940-
1941. While the actual record of the most sheltered rain gauge was
18.83 inches for 1940-1941 and 6.38 inches for 1941-1942, these figures,
on account of evaporation and overflow, are probably considerably less
than the actual precipitation. The average annual precipitation should
lie between that of the San Nicolas figure of 11.08 and the Santa
Catalina figure of 13.35. The recorded average of Santa Barbara for
the two wet years of 1940-1942 was 12.60 inches, and an empirical
estimate of the ten-year average precipitation might be about 12 inches.
Figure 7 shows the results of over two years of instrumentation
at the east bluff station.
In figure 7 it is noticeable that there is a fairly close correlation
between wind velocity, maximum temperature, and evaporation rate.
During the winter the wind graph shows an increase over the normal,
but follows the graph of the evaporation rate very closely during the
remainder of the year. Ihe convergence of the graphs for the black-cup
and the white-cup evaporation rates is of seasonal rather than insular
significance. Ihe rise of the evaporation rate in spring and fall is quite
in harmony with previous observations in respect to drying, east winds
during those seasons. There is normally much fog during the summer,
as hygrograph records show. Both wind and sunshine are more prevalent
during spring and fall.
Brotic INFLUENCES
Although this little island has not been inhabited continuously for
many years and is not easily accessible it has many evidences of man’s
visits. It has been used as a base for otter hunting, for lobster fishing,
and for farming operations. The writer has talked with various indivi-
duals who have built cabins there and have tried to fill in unfavorable
fishing seasons by desultory farming. It is remarkable how much human
activity has been centered about this tiny island and how quickly time
and storm have erased most of the visible handiwork. Yet the indirect
influences of man will affect the island for years to come.
Twenty species of exotic plants have been introduced and now
dominate large sections of the island. Cats and rabbits also have been
introduced. The cats have been able to keep the rabbits in check so
that they have made no serious inroads upon vegetation, as they have
on the eastern island of Anacapa. White-footed mice are the only native
land mammals. A recent effort has been made by the National Park
Service to reduce the cat population in order to protect nesting birds.
276 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL015
This effort may affect the biotic balance to the detriment of the vegeta-
tion, especially as the rabbits and mice have few other enemies.
Man’s activities have favored the establishment of the exotic plants.
In 1918 nearly the entire island was burned over and both east and
west terraces placed under cultivation. As a result the indigenous plants
are to be found mainly in the shallow soils and on the steep seaward
slopes. Rocky areas on the western terrace and about the headlands,
the section of the eastern terrace cut by canyons, and parts of the central
ridge, also harbor many native plants together with the aggressive
foreign species. Introduced grasses, with Mesembryanthemum and A tri-
plex semibaccata, have appropriated most of the area formerly under
cultivation, which was the most fertile part of the island. However, at
the present time, some of the natives, such as Coreopsis, Lycium, Suaeda,
Brodiaea, and Chenopodium californicum are at least holding their own
against the exotic competitors. —vhe smaller annual plants cannot as yet
compete successfully with the introduced Hordeum, Avena, or Mes-
embryanthemum.
As springs, streams, lagoons, or marshes are entirely absent, no
hydrophytes, except those of marine habitats, are present. Due to the
fact that the few narrow beaches are wave-washed at the periods of
spring tides, and are colonized by the California and the Stellar sea
lions and an occasional sea elephant, no plant life is to be found on them
at the present time. However, Oenothera cheiranthifolia, a typical beach
plant, has been reported from the island by Hemphill (Jepson, 1925).
PLANT COMMUNITIES
This small island does not present the varied topography of such a
larger one as Santa Cruz. No habitat on Santa Barbara is as much as
a half mile from the sea, and the highest elevation is. but 200 meters
(635 feet). Ihe limited number of species on a small island cannot
give a great floristic complexity. ‘Thus, there are no chaparral shrubs
and trees; neither are there dune or riparian communities. However, the
variations in slope, exposure, and soil are as great as on any of the
Channel Islands. The habitats which are present on Santa Barbara
can be compared later with similar ones on the other islands, even
though on Santa Barbara but few species of the normal plant com-
munity for that habitat may be present. Because of the essential simplic-
ity of the environmental pattern of Santa Barbara any differences be-
tween habitats would be less than the more sharply differentiated en-
vironments on the large islands. The general topography of Santa Bar-
bara and the distribution of its plant communties is shown in figure 8.
No. 3 DUNKLE: PLANT ECOLOGY, CHANNEL ISLANDS pa |
There are but four closed communities on Santa Barbara Island,
two with native dominants; the Coreopsis and the Lyctum-Suaeda;
and two exotic dominants: the Hordeum-Avena and the Mesembry-
anthemum. It is interesting to note that the two native associations each
appear to have a bird in such close association as to form a biome: the
Lycium-Suaeda-Larus biome on both the eastern and western terraces ;
and the Coreopsis-Melospiza biome on the lower part of the eastern
terrace.
Since Santa Barbara is essentially an elevated mesa outlined by
precipitous cliffs and steep bluffs it may logically and coveniently be
divided into two main areas. These two areas, which differ strikingly
in respect to evaporation rates, plant life, and soil, are: (1) mesa and
ridges; the central region of terraces, shallow canyons, and most of the
central ridge; (2) sea bluffs; the surrounding series of cliffs, benches,
and headlands that break off abruptly to the sea, and the upper, wind-
exposed parts of the western slope of the central ridge.
Mesa and Ridge. The mesa and ridge are occupied by several com-
munities comparable with somewhat similar ones on the other islands.
These communities include a grassland, Mesembryanthemum colonies,
the suffrutescent Lycium-Suaeda association, and the Coreopsis associa-
tion which is related to, but wholly different from, the coastal sagebrush
association.
Grassland. A grassland disclimax occupies the upper part of the
eastern terrace, much of the central ridge, and a narrow belt extending
around most of the main western terrace. Much of the grassland now
occupies areas which were burned over and subsequently placed under
cultivation. The dominant plant is Hordeum murinum except for one
rather extensive area about the head of the landing cove where Avena
fatua is dominant. Even in this last locality the Hordeum is a sub-
dominant, while Avena occurs here and there the entire length of the
eastern terrace. These grasses die early in the spring, regardless of the
amount of moisture in the soil, and form a deep, tangled mat which
persists for the remainder of the dry season.
Scattered plants and small colonies of Coreopsis gigantea, Lyctum
californicum, and Suaeda californica pubescens occur in various parts
of the grassland. Plants such as Atriplex semibaccata, Chenopodium
californicum, and Brodiaea capitata occur here and there, while small
plants such as Malva parviflora, Trifolium microdon, and Amsinckia
intermedia form an understory in many places. Amblyopappus pusillus,
Spergularia macrotheca, Erodium cicutarium, and Mesembryanthemum
nodiflorum may be found in disturbed places, as along trails.
278 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL.13
Mesembryanthemum colonies. One of the most successful of the
plant invaders of the south-western islands is Mesembryanthemum
crystallinum. It has colonized large areas on San Clemente, San Nicholas,
and Santa Barbara Islands. In these colonies it monopolizes the ground
surface so that only a few other plants can become established. Such
colonies occur on the east and west flanks of the north peak, the east
flank of the south peak, and near the north and south ends of the eastern
terrace. Only a few plants of Hordeum murinum, Chenopodium murale,
or Suaeda californica pubescens seem able to maintain a foothold in
these colonies. If they survive the competition they grow luxuriantly and
Hordeum will remain green for weeks longer along the margin of a
Mesembryanthemum colony than elsewhere. One of the most remarkable
features of the pure stands is that they appear to occupy exactly the
same areas for years. Thus the large colony on the east side of the south
peak had been seen from Santa Catalina by the writer, with the aid
of field glasses, fifteen years earlier, occupying the same area it does
today.
Suffrutescent communities. The greater part of the western terraces
appears to have been free from such extensive burning and cultivation
as the upper part of the western terrace. Low native suffrutescent shrubs
and herbs occupy most of the area. While Hordeum is abundant in
most of the openings it holds a distinctly subordinate position. Suaeda
californica pubescens is a dominant in the upper portion of the main
terrace at the foot of the main ridge and in a cross-drainage depression
that opens toward the northwest. Mesembryanthemum crystallinum and
M. nodiflorum are present in small or medium sized colonies among the
Suaeda.
Edaphic and climatic conditions are very similar to those on the
east terrace. The surface soil is fine, containing 39.19 per cent silt and
clay, and there is an exceptionally large amount of colloidal material
present, possibly due to the droppings of the gulls which nest here.
Lycium californicum is dominant throughout the middle and western
end of the main western terrace, where the elevation is a little higher,
the soil somewhat shallower and of coarser texture, and the wind veloc-
ity somewhat greater. Galium aparine occurs closely associated with the
Lycium, and Achillea millefolium lanulosa occurs in isolated clumps,
where the habit of the plant closely resembles that of the variety mari-
tima which has been previously reported only from the San Francisco
Bay region. Brodiaea capitata is also found on the southwestern slopes
of the terrace.
No. 3 DUNKLE: PLANT ECOLOGY, CHANNEL ISLANDS 279
Larus occidentalis, the western gull, nests throughout the whole main
western terrace, and the area, as a whole, forms a Suaeda-Lycium-Larus
biome. The two nesting sites of Larus on the eastern terrace also sup-
ports a vigorous growth of Suaeda.
The main western terrace ends in an abrupt rocky slope which drops
about sixty feet to the smaller western terrace, which extends to the
vertical cliffs at the extreme western end of the island. ‘he west facing
section of the rocky slope has an Echeveria-Opuntia community with
Echeveria albida, Opuntia prolifera, and Tillaea erecta as the most
abundant plants. The southern face of this slope drops to low cliffs just
back of a narrow beach, and is well covered with Opuntia littoralis,
which is very similar to the southern slopes of Anacapa Island. ‘The
greater part of this lower western terrace is an Atriplex californica
community, but near the foot of the rocky slope, where the soil is deeper
and the wind not so strong, there is a luxuriant growth of therophytes,
geophytes, and chanaephytes.
Coreopsis association. Coreopsis gigantea is the dominant plant of
the island, occurring as individual plants and small colonies in all parts
of the island, but the largest and most representative growth occurs on
the lower half of the long eastern terrace. This is an area of broad, flat
ridges sloping gradually down to the relatively low eastern bluffs. ‘This
section of the terrace is traversed by a series of five shallow canyons.
A unique schrub community dominated by the grotesque Coreopsis
covers all this part of the island, except for the northeast headland,
extending, where there is enough soil, almost to the splash zone. Typical
associated species are Opuntia littoralis, O. prolifera, Convolvulus oc-
cidentalis macrostegius, Lycium californicum, Artemisia californicus in-
sularis, and Echinocystis macrocar pa.
The Coreopsis grows to an average height of four feet on the ridges
and up to eight feet in the canyons. Since the branches grow at right
angles to the main trunk the Coreopsis shrub forms an intricate tangle
which would be almost impossible to penetrate were it not for the
extreme brittleness of the plant. A comparatively light touch will break
off branches or even the main trunk. This fact might account for its
disappearance where extensive grazing has occurred. Only on the eastern
island of Anacapa is there a comparable growth of Coreopsis, and there
it is being rapidly destroyed by the rabbits infesting that island. In the
canyons of Santa Barbara, where the Coreopsis may have an under-
growth of O. littoralis and is bound together by long, vigorous lianas
of Convolvulus, of the thickness of a fountain pen, or by Echinocystis,
the growth does become impenetrable. Coreopsis puts out its feathery
280 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 13
foliage after the winter rains begin and blooms in March. By the end
of April the leaves have withered and most of the new growth has
died back to the club-like permanent branches. The plant remains ap-
parently lifeless during the summer and fall.
The Coreopsis association is found in all soils, from the coarse,
shallow soils of the eastern bluffs, to the fine, deep soils of the terraces,
and on the lee slopes of the central ridge. However, as may be expected,
sea bluff plants enter the association of the bluffs, and grassland plants
enter the upper limits of the Coreopsis belt. Wherever openings, such
as trails or other clearings, appear in the Coreopsis the introduced plants,
as well as other plants of the grassland crowd in; but in unbroken
stands none of the grassland plants seem able to establish themselves.
Since Coreopsis, either singly or in small, scattered colonies with many
young plants, occurs in much of the grassland and seems to withstand the
competition very successfully, it is highly probable that the Coreopsis
association may ultimately replace most of the introduced grasses and
forbs, provided the island remains undisturbed over a sufficient length
of time. The Coreopsis association, thus, appears to be a climax for the
eastern terrace and the lower slopes of the ridge. Isolated Coreopsis
plants are to be found in every community on the island, except for
the wind-swept ridges and headlands. This would tend to support the
hypothesis that originally most of the present exotic grassland was
occupied by a scrub association, and that Coreopsis may have occupied
a dominant place in many of the low, suffrutescent plant communities.
The Coreopsis association appears to have roughly the same environ-
ment as previously stated for the exotic grassland, except that the former
may also be found in coarse, shallow soils. Both seem to possess about the
same wind tolerance as the windier habitats contain neither Coreopsis
nor Hordeum and Avena.
The Santa Barbara Song Sparrow (Melospiza melodia graminea
C. H. Townsend) seems to have a distribution on the island almost
coterminous with that of the Coreopsis association. Howell (1917, p.
81) states: “In the type locality the first of May, 1908, I found these
birds fairly swarming, flushing from the short scrub at my approach and
flitting to the top of nearby bushes.”
CANYONS
The short, shallow canyons offer a rather difficult problem as their
dominant vegetation shows little deviation from other parts of the
Coreopsis belt. The canyons appear young geologically, and their micro-
No. 3 DUNKLE: PLANT ECOLOGY, CHANNEL ISLANDS 281
climates are on such a small scale that but few typical canyon commun-
ities occur. Species typical of canyon habitats on other islands are either
absent or very restricted in number. Coreopsis and Convolvulus grow
luxuriantly in all parts of the canyons.
Opuntia littoralis is a co-dominant with Coreopsis and Convolvulus
on southern slopes. Among other species are Lotus argophyllus orni-
thopus, Eschscholzia, Muhlenbergia microsperma, Hemizonia fascicu-
lata ramosissima, and Amblyopappus pusillus. On the canyon bottoms
and the lower, northern exposures grow several grasses which are
apparently limited to these areas such as Melica imperfecta, Bromus
rubens, and B. vulgaris. In such localities will also be found Phacelia
floribunda. Plants that seem limited to the north exposures of the
canyons include Gilia gilioides, Nemophila racemosa, Aphanisma bli-
toides, and Polypodium californicum Kaulfusi. Additional plants found
on other northern slopes as well as on those of the canyons include
Trifolium gracilentum, Pterostegia drymarioides, and Eriogonum
giganteum compactum.
The soils on both slopes of the canyons are very coarse with those
of the northern exposure slightly finer and with a larger content of
humus. On these steep canyon slopes the run-off of storm water has
carried away many of the finer and lighter constituents of the soil,
though this surface erosion has been somewhat checked by the heavier
plant cover of the northern exposures. Thus the northern exposure had
36.2 per cent of gravel and 3.6 per cent of silt and clay, while the
southern exposure had 43.1 per cent and 4.2 per cent respectively.
Since observations on other Channel Islands have shown that
similarly oriented, but larger, canyons possess much greater differences
between the plant communities of their northern and southern exposures
than do the small Santa Barbara canyons, it is apparent that even greater
enviormental differences must be found on the opposite slopes of these
larger canyons. These differences must exist in their evaporation rates,
their temperatures, and their soils.
SEA BLUFFS
The sea bluffs, cliffs, and headlands possess much the same soil
composition as do the canyon slopes, i.e., a coarse soil containing less
than 10 per cent of silt and clay. They present various exposures and
slope angles, and differ greatly in their exposure to wind. The sea winds,
coming from great ocean distances and cooled by their contact with
the water, possess a greater relative humidity than they maintain after
282 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 13
a relatively short passage over the land. With this high humidity it
might seem paradoxical that the sea winds could be the master factor in
the evaporation rate, yet such is the case. This is partly due to the
high average velocity of the winds and partly to the adabiatic warming
of the air on the descent of the lee side of the island. This may explain
why the evaporation rates on the lee side of the island are about equal
to those on the windward side. Repeated direct observation has shown
that the velocity is much greater on the sea bluffs, headlands, and the
ridges than on the terraces or in the canyons. The average evaporation
rates obtained from the former locations were markedly higher than for
any station located elsewhere. The profiles of the island, figures 7 and
8, show the relationships of the evaporation rates at different locations,
particularly the greater rates of the sea bluffs as compared with those
of the terraces.
The sea bluffs present an almost unlimited variety of exposure to
wind and sun, and of slope angles. There is also considerable divergence
in the depth and character of their soils, and great variety in the floristic
composition of their plant communities. Yet they have many character-
istics in common. They possess uniformly coarse soils, low extremes of
temperature, and high evaporation rates. There is a general uniformity
in respect to the life-forms of the plants and in their structural adap-
tation to the environment. In every particular the sea bluffs form a
distinct contrast to the interior of the island. The plants of the sea
blufis are mostly low perennials, usually very compact in habit. A great
number of the plants are succulent or have developed a heavy pubesence.
This is due partly to the need for the conservation of moisture in their
arid environment, and partly to the presence of sea salts in the soil.
(Braun-Blanquet, 1932, p. 193).
Many of the differences in the floristic composition of the sea bluff
communities in closely adjacent areas are the result of chance inequalities.
The vicissitudes of erosion with frequent slides, due mainly to under-
cutting by wave action, bring about different conditions and different
plant life. This combined with the steepness of the slopes makes lateral
migration difficult. Unless windborne, or carried by animals, seeds
cannot travel laterally across a steep slope. The vertical range of edaphic
factors is very narrow in so far as the ecesis of plants from zones in an
intensity or degree favorable for the ecesis of plants above or below
these slopes may often be very limited. The extent of the sea bluffs and
the large variety of plant communities, with the general similarity of
edaphic and climatic factors and of the life-forms of the plants, may
No. 3 DUNKLE: PLANT ECOLOGY, CHANNEL ISLANDS 283
well justify the term of sea bluff formation. There are frequently three
distinct zones of the sea bluff; (1) the break of the bluff, (2) the
talus slope, and (3) the splash zone.
Breaks. The break of the bluff is the place where the normal slope
of the hinterland changes angle and where both wind and water erosion
become abruptly more effective. The width of this zone may vary from
a few feet, at the edge of a perpendicular cliff, to several hundred feet
at the upper part of a more gradual slope. The zone has a fairly coarse,
residual soil which rapidly becomes more shallow as the slope increases.
The angle of the break is frequently accentuated by an outcropping of
rock—the rim-rock—which forms a broken row of cliffs. This may,
where the wave action is especially powerful, extend to the water’s edge.
The communities of the breaks show considerable variation due to
the slope exposure and the exposure to wind. On the higher, wind-
swept breaks there is little rim-rock. Astragalus Traskiae and a low
form of Hemizonia clementina are the principal suffrutescents. The
annuals include Baeria hirsutula and Malacothrix foliosa.
The still higher breaks of the south peak are not nearly so windy as
the breaks of the north peak. In addition to the plants of the north
peak may be added Atriplex californica, Mesembryanthemum crys-
tallinum, Amblyopappus pusillus, and Lotus argophyllus ornithopus.
The lower southern breaks are still more protected from the pre-
vailing wind and included the following additional plants: Mirabilis
laevis, Opuntia prolifera, Cryptantha Traskae, and Muhlenbergia
microsperma. These, with the others listed from the southern canyon
slopes form an open association which varies from place to place with
no distinct dominants. The coves of the southern breaks may be desig-
nated as an Opuntia-Lotus association.
Precipitous cliffs completely rim the western section of the island
so that the cliff breaks there are extremely narrow. This is a bleak
region with strong winds, fogs, and hundreds of nesting gulls, pelicans,
and cormorants. Atriplex californica, Mesembryanthemum crystallinum,
foliose lichens, and an occasional ruderal, such as Sonchus or Malva,
form a scanty and drab open community. There is a single plant of
Lotus growing in a shallow niche at the extreme western tip of the
island which gives the only spot of color that is to be found along these
western breaks. An occasional low, prostrate plant of Hemizonia
clementina will be found in crevices along the edge of the cliffs. This
is the same low form of Hemizonia with very short internodes and
procumbent habit which marks the Hemizonia plants found in windy
284 ALLAN HANCOCK PACIFIC EXPEDITIONS voL. 13
locations along the ridges and the breaks of the high bluffs. It is very
different from the taller, rounded, and more erect shrub form of the
species growing along the eastern bluffs.
The eastern breaks are much less abrupt than those on the other
exposures of the island. These breaks extend along the outer face of
the wide ridges separating the small canyons and extend down to the
splash zone. All the plants of the Coreopsis association are to be found
here, with other species coming in where the Coreopsis thins out on the
lower part of the breaks. These additional plants include the tall form
of Hemizonia mentioned in the last paragraph, Pterostegia drymarioides,
Trifolium tridentatum, Silene gallica, Plantago insularis, Calandrinia
maritima, and Achillea millefolium lanulosa. Nevertheless this area
can only be considered as a facies of the Coreopsis association, for
Coreopsis gigantea is the one example of constancy throughout the area.
Talus. Talus slopes on the Channel Islands frequently display an
exceedingly rich variety of plant life, and the southern and southeastern
slopes of Santa Barbara are an instance. he varying texture and depth
of soil seem to favor this. The southern slopes are perhaps the driest
and warmest slopes of the island and are moderately windy, especially
during storm periods. Because they are well protected by their lee
position in relation to the prevailing winds, only an occasional south-
western storm brings wind of high velocity. The more numerous plants
occuring here are: Echeveria Greenei, Eriophyllum Nevinii, Eriogonum
giganteum compactum, Coreopsis gigantea, Opuntia prolifera, Mirabilis
laevis, Lycium californicum, Muhlenbergia microsperma, Perityle Emor-
yi, and Amblyopappus pusillus.
Splash Zone. Immediately below the talus slopes, the cliffs or the
breaks, there is usually an undercut cliff or steep bank. This splash
zone rises directly from the water or lies back of a shallow beach. Soil
is absent or is to be found only in minute crevices because there is re-
current spraying of the zone by storm waves. Only a few halic annuals
and low perennials occur. Among such plants are Calandrinia mari-
tima, Atriplex californica, Eriogonum giganteum compactum, Perityle
Emoryi, Echeveria Greenei, Eriophyllum Nevinti, and occasional chance
grasses and forbs which have migrated from higher elevations during
favorable periods. There is apparently little variation because of slope
exposure since the proximity of the sea overshadows all other factors
here.
No. 3 DUNKLE: PLANT ECOLOGY, CHANNEL ISLANDS 285
Factors IN PLANT DIsTRIBUTION
In addition to the edaphic factors which affect the environment of
the island communities there are also other relationships which should
be noted.
Opuntia littoralis occurs in moderately extensive colonies on the
south exposures of the canyons, and on the southwest slope where the
main western terrace falls away to a narrow arm of the low western
terrace. In such localities it closely resembles Opuntia associations of
most of the other islands, such as the Opuntia-Encelia-A triplex associa-
tion on the steep southern slope of Anacapa.
Many of the island plants have a high frequency while others possess
marked fidelity. Hordeum is to be found in every section of the island
though dominant only in fine soil where there is also a moderate ex-
posure to wind. Other exotics which are widely distributed are Malva
parviflora, which has even been recognized on the inaccessible stack
off the western end of the islands, Sonchus oleraceus, Chenopodium mur-
ale, Erodium cicutarium, Mesembryanthemum nodiflorum, M. crys-
tallinum, Silene gallica, and Atriplex semibaccata. Of the native plants
Atriplex californica is to be found in every sea bluff community. 4-
chillea also occurs in many such communities, particularly on the precipit-
ous northern cliffs, as well as in different parts of the terraces. Coreop-
sis has been mentioned as occurring in every community which is not
subject to the more intense winds. On the other hand, Astragalus, Baeria,
and Malacothrix show a high fidelity to areas of severe winds. A few
plants as Lotus, Echeveria, Perityle, and Muhlenbergia appear to be
limited to southern southeastern, or southwestern slopes. A few plants,
such as Aphanisma, Platystemon, Polypodium, Gilia, and Pterostegia,
are apparently confined to the northern and northeastern areas.
Seasonal aspects consist mainly of green vegetative growth in winter,
the spring season of flowering, and the dry brown foliage of summer and
fall. However, Echinocystis blooms during the winter and Eriogonum
during the early autumn, while the prostrate form of Hemizonia may
withhold part of its blossoming until late summer.
IV PLANT COMMUNITIES OF THE ISLANDS
It has been stated earlier in this paper that the original vegetation
of the Channel Islands has been greatly affected by the activities of man.
The agencies put into play by such activities have destroyed or markedly
affected the indigenous communities over large areas. Each of the islands
286 ALLAN HANCOCK PACIFIC EXPEDITIONS VoL. 13
has been differently affected, owing to the nature of the topography,
the variations in climatic conditions, and the various degrees of human
interference.
Varied as are the different islands in topography and climate, they
possess certain basic similarities in the distribution and the aspects of
their plant communities. The western slopes of all the islands, except
San Nicolas where barren sand dunes prevail, are covered with grass-
lands, maritime scrub, or a low atriplex association. ‘he eastern and
northern slopes of the larger islands are quite generally covered with
chaparral, savannas, or scattered areas of woodland. The canyons,
which afford protection from the wind, have much the same vegetation
types as are found on the northeastern slopes. Plates 5 and 6 afford
characteristic views of these northeastern slopes. In this section the
distribution and the floristic composition of these communities, as they
now exist, will be considered.
WooDLAND COMMUNTIES
The woodland area on Santa Cruz is located on the main northern
ridge which rises to a height of 732 meters (2400 feet), while the
major part of the ridge is over 610 meters (2000 feet). This elevation
is sufficient to bring a heavier annual precipitation to Santa Cruz than
on any of the other islands.7 The prevailing winds, which are from
the northwest on San Miguel, have veered to follow the Santa Barbara
Channel and are nearly due west. As the main ridge runs slightly north
of west, the slopes are protected from the winds as well as from the
more direct rays of the sun. Thus, to judge from the evaporation data
secured on Santa Barbara Island, the evaporation rate should be not
more than 80 per cent of that on the southern slopes. The woodland
is composed mostly of closed cone pines intergrading between Pinus
muricata and Pinus remorata, with scattered groves of Lyonothamnus
floribundus asplenifolius and Quercus tomentella. In the more open
sections of this woodland there is a lower layer of arborescent forms of
Photinia arbuttfolia, Prunus Lyonit, Cercocarpus betuloides, Arcto-
staphylos diversifolia, and Ceanothus arboreus. The closed cone pines
are dominant on the higher parts of the ridge while broadleaved
sclerophylls are relatively abundant on the lower slopes near the sea.
This is particularly true of the dissected remnants of a marine terrace
“In conversation with the caretaker on Santa Cruz April 13, 1941, the
writer was shown the daily records of precipitation for that year, beginning with
January 1, 1941, a total of 52.50 inches. No more records are available.
No. 3 DUNKLE: PLANT ECOLOGY, CHANNEL ISLANDS 287
which occur at an approximate elevation of 61 meters (200 feet). Small
groves of Lyonothamnus occur also on Santa Rosa, Santa Catalina, and
San Clemente. These groves are all on the northern or northeastern
slopes. The groves on Santa Cruz are the most extensive and consist of
larger trees (plate 4a).
Quercus tomentella occurs as isolated trees about the head of eastern
canyons on San Clemente. In Gallagher’s Canyon on Santa Catalina
there is an extensive grove which has a decided forest aspect. On Santa
Rosa, Santa Cruz, and Anacapa islands this endemic oak occurs in
small, dense groves about the heads of northern canyons. The one
grove on Anacapa is shown in plate 4b. The smaller clumps of trees
farther down the canyon are Photinia arbutifolia and Prunus Lyonit.
Scattered trees of Quercus MacDonaldii occur in broad, upland
canyons of Santa Catalina. Q. agrifolia grows on Santa Rosa and Santa
Cruz, both in canyons and on protected slopes. A few trees of Q. chrys-
olepis and Photinia arbutifolia macrocarpa are to be found in pro-
tected canyon heads on San Clemente, while Prunus Lyonii is in some
of the western gorges of this island in the form of trees up to 15 meters
(49 feet). Photinia, Prunus, Cercocarpus betuloides and its varities,
and Sambucus coerulea occur, usually as scattered trees, in the canyons
of Santa Catalina.
On Santa Catalina a rather open riparian association varies from
canyon to canyon, according to altitude, soil and available water supply.
Among the trees and arborescent shrubs are Populus trichocarpa, P.
Fremontii, Salix lasiolepis, S. Laevigata, Quercus tomentella, Q. Mac-
Donaldii, Photinia, Sambucus, Prunus, and Cerocarpus. In Cherry
Valley there is an extensive, almost pure stand of Prunus which forms
a most picturesque, miniature woodland. The riparian woodlands of
Santa Cruz and Santa Rosa consist mainly of the same species as on
Santa Catalina with the addition of Q. agrifolia. It is highly significant
that several of the mainland riparian and near-riparian genera are
entirely lacking on the islands, for examples, Platanus, Alnus, Myrica,
and Umbellularia.
In forested areas on the islands there is very little undergrowth, due
principally to two factors: (1) the utilization of all the available water
by the trees because the precipitation is usually below the amount
ordinarily required for tree growth, and (2) the intolerance of most of
the island plants to shade, especially to the deep shade of the dense
foliage of the everygreen sclerophylls. Woodland can be considered as
climax only in limited areas where local edaphic conditions favor the
retention of soil water, or where underground drainage carries water
288 ALLAN HANCOCK PACIFIC EXPEDITIONS voL. 13
near enough to the surface as to make it available to the trees. Such
areas are those on the northern slope of Santa Rosa and Santa Cruz,
the northeastern slope of Santa Catalina and San Clemente, and the
larger canyons. The desiccating effect of wind on exposed slopes has
been indicated by the evaporation rates of the exposed stations on the
Santa Barbara ridges. As little or no tree growth occurs on slopes
exposed to the wind it would appear that this is a most powerful factor
in the limitation of woodlands.
MARITIME SHRUBS
It has been previously stated that shrub originally occupied much
of the interior upland area on Santa Barbara Island. Since uplands
and terraces similar to those of Santa Barbara are to be found on all
of the other islands it may be inferred that shrub was originally abundant
on all the islands. It has been nearly exterminated on San Miguel and
San Nicolas, but shrub of some kind is still locally abundant on all
the other islands. Chaparral, coastal sagebrush, Coreopsis shrub, Opuntia
littoralis shrub, and desert shrubs are the common forms. Many varieties
of chaparral and coastal sagebrush occur on different islands and in
different parts of the same island, but desert shrub is limited to San
Clemente and Coreopsis shrub to Anacapa and Santa Barbara.
Chaparral. Santa Rosa, Santa Cruz, and Santa Catalina have the
greatest areas of chaparral at the present time. On Santa Catalina it
is dominated by Quercus dumosa, but that of the two northern islands
is more varied and resembles, in many respects, the mainland chaparral
of the Santa Inez mountains in its short and its tall chaparral aspects.
The chaparral of the northern and eastern slopes is much higher than
that occurring on southern slopes, whereas it is rarely developed at all
on western slopes if these are exposed to the prevailing winds..In favor-
able locations the larger shrubs of the chaparral tend to become arbor-
escent. This condition has been furthered by the browsing of animals,
particularly goats, which has effectively pruned the lower branches.
The broad sclerophyll shrubs are found both in the chaparral and
growing as isolated, arborescent specimens. There is no true chaparral
on San Clemente or Anacapa although several of the sclerophyll shrubs
occur on these islands. The distribution of the species represented in
the chaparral is shown in table 4. Chaparral is apparently limited to
areas where the annual precipitation is over 12 inches.
Coastal sagebrush. Coastal sagebrush may at one time have been
present on all the islands but is now non-existent on San Nicolas and
San Miguel, and very limited on San Clemente. It is present only on
No. 3 DUNKLE: PLANT ECOLOGY, CHANNEL ISLANDS 289
seaward slopes on Anacapa but exists in many and varied locations
on the three larger islands. The coastal sagebrush, Artemisia californica
or the variety insularis is on all the islands. On southern exposures the
species grows stiffly erect and compact, while on northern or eastern
exposures it grows with long, flexuous branches and longer leaves. As
this association is commonly found on hillsides and canyon slopes the
soil is rather coarse in texture and often relatively shallow. There is a
great difference in the evaporation rates of southern and northern ex-
posures as was indicated in the preceding section.
TABLE 4
DISTRIBUTION OF CHAPARRAL SHRUBS
ON THE FOUR LARGER ISLANDS
Islands
ey
oo s 8 ge 8
A - Abundant ee Oks G
X - Occasional ge) ee
Se scnenceues
DODD
MOTHERS UTTIO Se IN UEC tre >. Sa, Gay, ee
Mendromeconytarcorgit Well soe. 2 oe Se eee x Als XG
[el ENON ETc PA Caere DURE 2 alll A ee PE ep RRR er Ra Cask PAHS URNA A Dip. 7 aap.
Peilrei Loli VV alps cst ee cea ne oe eee Die Ke
Cerecocarpus’ betuloides NUE A224 A ee ee ie Oe xX Xo Rir-
Vict es MIO MS eT lessee Oh a a eee a PG? hE. Gi)
Vis THUGS OTIS! Ne PSOM: ects 8 ee ee ee a Se Rt ERD es
iter as kiaes GTR Gy serene a nee, eh le eae ead Sia eee - - X -
Photiniacarputitoiia ctor le ee A ke X A =
WabsMACKOCAT Pa VINEN occ fe en eh Use Lo ee = sees CARS lee
Wills COTim a CDSOMG cose taste Ue es ee vac Lee aa ean gs ieee ee ee eee - - X -
Rhammus crocea/insularis; Sar. 8 ee eee >. > GD. Gi. 8
Ceanothus -arhboreus: Greene enc eg Ke EG ARS
GinerassiiGlias Orr ce ee eal eas Eas ee i ee MOS ee
CMe PACALDUS INSUl ALIS: UU yk se res ee Sa ee oe eee pee. Gre BB. S
Rebjselauritia’ Natt ose oe ee ence nl Je eee eee eee Xe. AS Ae
CUVETSEloba hs te. Gr fete oa a a ee Be, Ghee. Gh a.
REO Vata VV AOS 25 ccc cans EE A a Ot ee ae, lua’. cana, @
Re integritolia Benth. & Hooks.222 252 Gis eee Dey Oak Poe
Asctostaphylos| diversifolia Parry; 2 ee eee XG VAS XG =
AP tomentosa {Dimless ees ce ee eS ca a > Gand. Gem, eet
AS mnsularis Green epi h 2 ses koh eae eee Dae. ep, ia
WAS (SUUDCONG ata: Te aStyy el cae ere eS Ee ee ee ee » a Sk ic
ey abs: CA
Fassia er: Gray sa se po de --
290 ALLAN HANCOCK PACIFIC EXPEDITIONS voL. 13
There are many variations in this association. One form occurs on
terraces where the soil is much deeper and more finely textured than on
the canyon slopes. This terrace type forms the unique and remarkable
Coreopsis association which occurs on Santa Barbara and the eastern
island of Anacapa and was described in the preceding section. Isolated
plants of Coreopsis gigantea have been reported from each of the Channel
Islands, usually growing in inaccessible situations on rocky bluffs. ‘Che
eastern bluffs of Santa Catalina Island, those which are steep enough to
deter grazing animals, support a scattered growth of poorly developed
plants. A rocky hill near Empire Landing on Santa Catalina has the
largest colony of Coreopsis to be found on any of the larger islands
at the present time.
The principal communities of this association are given in table 5,
with the main constituents of each community and their distribution.
Several species which are to be found in nearly every variation of the
coastal sagebrush are listed first.
Maritime Desert shrub. The only desert shrub of the islands is
located on the southern third of San Clemente Island. On the higher
terraces it is composed almost wholly of Opuntia prolifera. On middle
terraces Opuntia littoralis and Cereus Emoryi appear, while on the
lowest terraces other low shrubs enter into the composition, including
Lyctum californicum, Artemisia californica insularis, Encelia californica,
Lotus argophyllus adsurgens, Euphorbia misera, and Castilleja grisea.
No record of the annual precipitation is available for this area but an
estimate of six inches is given in the section dealing with climate.
SEA BLUFF COMMUNTIES
Because of the great extent of the coast line in relation to the total
area of the Channel Islands the most diversified plant life is that of the
sea bluffs. IThese communities have received detailed treatment in the
preceding section. Similar habitat conditions exist on all the islands.
Plants of such genera as Atriplex, Echeveria, Eriogonum, Astragalus,
Eriophyllum, Opuntia, Mirabilis, Polpodium, Lycium, and Achillea are
usually present, but the composition varies with different islands. A list
of the plants of these communities is given in table 5.
The floristic combinations differ with almost every varitation of
slope angle and exposure. Yet there is a characteristic pattern of life-
forms where the sea is always in the immediate foreground. The soil
is usually shallow and rocky, and both the diurnal and the annual
No. 3 DUNKLE: PLANT ECOLOGY, CHANNEL ISLANDS
TABLE 5
THE CONSTITUENTS OF THE COASTAL SAGEBRUSH
Dominants starred oe
eg
<
Species of general distribution
SSalwia mellitera -Greeme 220-2 eyes et ss -
Wat PODESIONITINZ, lpn soit et ey de ete -
*Rhus integrifolia, Benth. & Hook. +..-::2:22e22 x
| As Bay acid Col of Weal Roa ALL Cnc a MR une o eee PENeE oe x
icycrum calisormicwiy Nutt, 22.25 eee -
*Eriogonumigiganteum Wats... :cc22<2-ncne. sk ce -
Var. formosum Ki. Brand @, (222800 -
Vata Compactiiny 1 unkle) a ee -
Achillea millefolium lanulosa Piper .....................--- ».¢
Southern slopes
Pellaea andromedaetolia Fee, 2.2:-22.-:.2...- cee x
MirabilisilaevissGurran, si ee -
Vary Cedrosensis) Miunz <0) oo -
Viar.-cordmolia Wunkte, 22a -
*Lotus argophyllus niveus Ottley 02 -
var. /Ormitnopus Ottley, 22.) ek Se ie -
Watradeurcens, Unkle. ee ee -
Zausehneria californica Pres). 2o:.--:-.2 -
war; willosa Jepson. 203s eee -
ssp; aneustifolia. Meck =. 8 ees -
Zeana Greene c= tata ee ee: -
*Salvia apiana: Jepson f2..2 42 e e , -
*SOBranee Pel Wau gs oe See ec eet x
*@vtunea littoralis Cockerell). 2-2) ee >
Os prohitera Enmelan, j- 0s a occas xX
*Brickellia californica Gray 32.2.5 ae.
“Encelia calitormica Nutt, 22220. -
*Artemisia californica Less. f. erecto ............------------ a gre
Santa Cruz
Santa Rosa
m
mm
San Miguel
San Nicolas
Channel Islands
Santa Barbara
291
Santa Catalina
San Clemente
292 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 13
Channel Islands
f & ¢
sido eben Skee Me eC e
ominants starre : : js = 3 ‘. : 2
SUE eR CII GN)
GDNDDHND NH
Widls MSU ALIS HVE Arete as eek ea ee eaee . Gaae ai es e, Ga, Garton). G
Convolvulus occidentalis cyclostegius Jepson ~....... a Ute on se) eee, ee
North and east slopes
*Polypodium californicum Kaulf. -..........-.-.-.--+- ase, n>. Caer ae me >, C1 >. G
yar. ainsi D.C. Baton cs se KX Sie Silene SG ee
*Mimulus loncifiorus Grant .—..-25 STD, Gane. Cee tana ee rea) a
Ware meaTris qoramt isi Sh aie ee. Gen ae ee
SVM lemunca. ia 7 voi a Re eR ees en ae
*Mimulus pumiceus Steud. 22. bil pa!) \ jee phe) ee es Scene
*Eriophyllum confertiflorum Gray —..........----.--.---+---- >, ES, GaP, RES, Ge mt HE SS
War. saxihorium (Gray. cnc ane ah esi (MRL Vint ceed aes aA eS
par trai atin Gay crac cee ee i ne eee, CY Gree ee OMG naa. Sti,
*Artemisia californica Less. f. flexilia .................------ Tae. aye. Geechee, GP
Lotus scoparius dendroideus Ottley -...............-.------+- ie. ae ee. yf
war. (braskiae Ottley ccs... ee Se eee ee. a>. <
WaT. VieAtChin Otleyrcs te ee eo Ce ee an, GON Gu kil el
Erysimum msulare Greene. 222... -2-2 22a = ees OE yee pert mere
Convolvulus occidentalis macrostegius Munz ......... DK ey, ee Bae Ce
Echinocystis macrocarpa Greene ~.......-...-...--..-...---.. a. A ne hae oe, any. ara, <
E, guadalupensis Dunkle: nic. 222s SOR KS ced a
Terraces
*iycrum ‘ealstornicum Nutt, 2.058 es oa ht ee Gale. Ga. ine. GO.
Re 4wrernucosaiih Teast wees ee lessee eat seve tecwecene, Te on, er aad
Pe Rue MOM tit GCA eect, ee ee. i ee ea
*Grindelia rubricaulis latifolia Steyermark -........... Me eX se
Var. platyphylla Steyermark 202.22 >. tae. Cle I ea, Ph
Baccharis pilularis consanguinea C. B. Wolf -....... >. Ga. Gam, vp, Gir, Gem. Ge. G2 <
Aplepappus:canus Blake wl 2 DR KE a) a ee ete
*Coreopsis gigantea ball) ee OC EO) a VR
Eriogonum arborescens Greene ......--..---s---0s----enee001 SX Sy a eee
Grindelia arenicola Steyermark |..2)-.2.2- 2... Ton. See. ee ie ean dla
*Artemisia californica insularis Munz ................----- », are Cate. Cae, Gaye, ©
No. 3 DUNKLE: PLANT ECOLOGY, CHANNEL ISLANDS 293
TABLE 6
THE CONSTITUENTS OF THE
SEA BLUFF COMMUNITIES
Channel Islands
hl
Ngeeze s
*Dominants HSMN AMS NETS fe &
gue a ew armies
qe ae ev ee
OD wn ww Mm "ods
Species of general distribution
eA triples californica VLOG. fie ee DR Kl I RE ee ee
PAC PICHITC Ss NG LS ca te sece teehee ten ac ae oo, Ee) Se se ees
FeSO SOLO (oh eg D5 1 6 Re tere en ek Oe EP Ke) XO Oy ea ee
PARP cRSOMGN NCIS Siac accent Te ih te ee ene a? ee. ce. >. Ge, >.
*Rhus interrifolia Benth. & Hook. \..2.0.cc0ccccececsee cs Ke OE OG ta es
‘i ycrum canrormicum Nutt. 22... 2.ci ee. ee. >. Ce. al Cay
Achillea millefolium lanulosa Piper ......................--. | IX. DR DENG Ae es
Wind exposure
Souaed a) MOELeyanau WV ats. cose ec = Re DE EX TS ee ee
Se CalecOniniCa VW Wats cis 2 cere geet ye D. GP. ORre i, 48 0-
Val. DUDESCeEnS | CDSOM 22. ee ee, ee ee ee. une. Ge!
Spereularia macrotneca Heynhh. ¢...3 scene >. a. ae, Hae SP. ed. Ms
rots 2 Le Pe Caio) Oe eT a aos Wr eee te Se. ee ena it, SPS C
Astrawalus Traskiae Hastw. ci.2.1ico ce ee eee ter a>. GD, Pe eG
PANG Wt MG GAY) cee eee Some eee Ee en rk. CoC
AesDougclasively rir Ge eS Be ee ha ee Xe = KS a a eae
AL NE PATE LETISIS) GPE CN Cec cesesed ensayo tedect encccdeeneeeeeaees eet >. Ge, Saw. Ga. ar Fe oe
eA IEMEOD SIS: MOD icity a Me XX OO en ee
Cryptantha Fraskae Johnston, :2.2--2 2 ee =, ee el Van ENG KE tee ee
Gimnaritima Greene seen es es ae eae ee = = = 6 1 xe See
Aplopappus venetus sedoides Munz .............------------ = Oe) Ok) =) a eee
BP ey AiV EDU OM TOUGES GIVEN Z) ese saseeet oe ecco cece =) OX. OE Xs Ra ae ee ae
iat ei riha CEUS VIM Zoo oe es ee eee = KX = Sites Ga eee
Hemizonia clementina Brandg. f. prostrata .........--- Dee eee ee . Siyte. OP2D,
Baeria chrysostema eracilis\ Wall, XX, ee KS, OX Oe OS Xe ee
BahirsucwlayGreene: c= oe a ee ee = RY a Ee 2 ea =
Malacothrix foliosa ‘Gray 2 ee SP. ee ae a hg pre 2G
North and east exposure
*Polypodium californicum Kaulfusii D. C. Eaton... KX X X - - KX X X
Peocomlert FLOok., 6 GYM cx ee eee peer SS ae a a ces
P. vulgare hesperium Nels. & Macbr. -.......-.....--....-- XS et CSS an Raa
Pityrocramma, triancularis Maxon =. XS Oe BS rae te rane
iP viscosa: Weatherby.22.- ee CMRe. Cae Crew ele Vie, @
Adiantum: Jordani-C, Mull, 2 ee >. ae, Ge, yr ON PND, 6 > G
Pellaea mucronata D.C, Baton eee Se. Sen. See ee ae). GaN
Cheilanthes californica, Metts 2.2 5 ee | RR ong, Nate sey vet Poe oml sted
Aphanismablitoides Nutt; 3: ee Ane’. i> Cetera ast ts a, Gulpy ig >. 4
~Priozonum orande Greene 2-8 >. AP, GARD IP. GME” Sane ei, GA. 2
294 ALLAN HANCOCK PACIFIC EXPEDITIONS VOR. 15
Channel Islands
22s
et Jory teat eee
Se es cea
*Dominants Dy Os ae B
5S s az a a VY
qe eS aueSine
GAO OD HD HO WO ww
Vide HU DESCEMS VIN See es ae SD. GA. ERD, teen Or ae |e
Ie Mere Te UN CRE iey 2 cot Gu fei ats ee = i NG 1S wll Fe ie Oe
Silene acimi ata cael sacs eee ee aS DK COKE es Te eee coe
upinus: albitrons: penth.: 2st ee eae p Cie Sie. Ga, Ven Ci ay, Bg
‘Pritolium teiaentatum) Lindl, 22.2..2- 2. sya. Gap. Gap. Gi he. Gate, Sg
war aeiculare MeMermott 0... se OE Xe Stal pia one
Meieracwemtumis Wi. )6e 0G 2 eek ecko else Xidete, (Xe su es as
Wall INCONSPICUUM OR CLM. Sos o oso. 8 hess coast ee Se? Ge. Se ame be
ae cstenophyilum NGC, 25.2005. a ea ee nee. (ne. Com. Gam. hak a. .G
Castilleja hololeucaGreené 22.22.0533... >. Sie, ie, Gea, Same eal he Ne | i
CO TOMOLOS a CRE NCc eri ees ek eee eae ek aM) ele pe SA
Cinanacapensis;OUnkle x0 23.0. KG) ea he) eee ao fo
GOATS) Piece Ne eee es hat Sa ed Le wa. Sag. Ee, Gan ee Cn
CDourlasis ‘Benth, 2262320. oe ete DOL XG OE ee a, ven ey ee
Aplopappus canus) blake 25 2252 coc eee IX GX ee Os er ee
RISC LON PLAUCUS IGP, chee ee eee cease De ERE OX te are
Corethrozyne filaginifolia Nutt, -............2.----...-... ss © Se oH Oe
COLT ep eee 1 Ee oh rea aan eens ee ome ae. Sey. E,W a>, Gog
sae cele {6 2 1E) We ool) 1 | ot eRe Ce ee ere oe se >, Sa. aa, Se? GS ae Hr
Macy eee chon 20) 8: RO) oo |] i nace ent aren a ee lene ae MS ee 2 eee Aa
Eriophyllus staechadifolium depressum Greene ..... URC Oe Mad ae ee ge
*E \comrertisOrumay Gray 22 ccce eae ae os cease ects Dia. Ga. ON. Ce ae a. Car.
Var claxthnorum,: Gray. <6. ee Sy i OK Pet cee Meno a
PEN AD ATEN 06 UN Coie: h ete eee eS Sta eee. Gar. Ore ak oe ee. ys
iB vantemisitolra Gray o2...00 6 ee ete =) Xe =~ Somer Ja ea
Hemizona clementina Brandg. f. erecta ...............-.-. MS te Se KS ee
Sun exposure
Pecheveria aloida pereer qian sta cee nae eee. ee. Shr: Gay, &
coal Olen CF Gales TV ec Ol 6 74 of) me ac Oa a og ea Er VER EX se ENG ae
Be eVIPeNS POOR ya cxe ete eS se etek ae et ae a a. Se.
SMirabilis laevis Curran, ..22003 2 ee Ce. ae. Sa a ee. Gato. ale
Wate CCUTOSENSISH VIM Zt ec wen ee Se ae ee ee a oe.
Var. COrdioliay DMM KIE |. 5.28 oe et cers es hs SE a ete eo
*Lotus argophyllus ornithopus Ottley ....................-.- a, a an ee. Ge OND, ia >.
Var.cadsurcens: unkle: cfs sees ee ey ay
PAtriples DCE vyetis VV ats: tore een cn ee ea MO UX fe Xe ee ee
Basphorbia misera Benen, wee ee nL a en. ee. Ge»,
Phacelia floribunda» Greene: 20/2: ete Se ee ae eer
Brrophylium Nevinit: Gray: i aso ee ee oer an ny AOR: Sth, 0) 2
PetitylesImoryy (a OTs: see ee sesh a a) eee Gar, ae. aac re tae ee, | 4
Senectose yon: Grays esi 2 ek ie cy eee Ue TR ae, Oe e—t C es i, Gh >. &
Castilleraermeaounkle 2: ea ee Pe Shir pais ees ah ery A Gas! dW cea
No. 3 DUNKLE: PLANT ECOLOGY, CHANNEL ISLANDS 295
ranges of temperature are very small. The pounding of the surf makes
the air and the soil decidedly saline. Nevertheless the wide variety of
edaphic and orographic conditions usually prevents any one plant, or
combination of plants, from being dominant over any extensive area.
The communities can be treated conveniently by the relation of their
slope exposures to wind and sun.
The sun is the most powerful factor on southern exposures, so that
the evaporation rate here is relatively high. Owing to the steepness of
the slope, which causes a high run-off of precipitation, and the high
evaporation rate, there is more bare soil and rock than there are plants.
The aspect of these slopes from the sea has led many casual observers
to conclude that the islands are mostly desert.
The western exposures are influenced by the prevailing winds and
are of three types: low headlands where there is a decidedly saline
influence, high rocky ridges, and high rounded bluffs where the soil
is deeper and of somewhat finer texture. The low headlands are marked
by Atriplex and other low mat-like plants of rather drab appearance.
The rocky ridges are covered with foliose lichens where the wind
ascending the slope is frequently laden with condensing moisture. Many
of the niches between the irregular blocks of rock are occupied by low
shrubs, semi-shrubs, and perennials. On the high, rounded bluffs low
annuals such as Baeria and Malacothrix form veritable carpets of green
and gold in the spring, interspersed with matted perennials like Astra-
galus, Hemizonia, and A plopappus.
The north and east exposures, which are sheltered from the wind
and the more direct rays of the sun, are in sharp contrast to other
slopes. There is usually a luxuriant growth of grasses, ferns, clovers,
and other forbs, suffrutescent perennials, and low shrubs. ‘hese remain
green and in bloom until mid-summer. One of the best developed ex-
amples of this Eriogonum-Eriophyllum association is on the long, north-
eastern, talus slope of the western island of Anacapa. Here the suffru-
tescents and forbs form a tangled mat, through which one may proceed
only with diffculty. A section of this long slope is illustrated in plate 18.
Shrubby lupines are on all the islands except Santa Barbara, but
the variation in species is great and their different characteristics so
interwoven that positive identification is yet uncertain. These are ap-
parently varities of an original parent stock which has been differenti-
ated into geographic races. The variable characteristics resemble those
of the closely related mainland species but are combined into different
patterns in the insular races. So confused is the nomenclature that five
different names have been applied to plants of a single colony. With
296 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL..13
this in mind the shrubby lupines of the islands will be considered here
as forms of Lupinus albifrons. ‘These lupines rarely grow with other
plants into any semblance of an association, but rather as isolated plants
on rocky bluffs, or as small colonies on slopes near the sea.
GRASSLANDS
Grasslands dominated by vernal soft-leaved annual. grasses are
present on all of the islands and may be a climax formation on many
of the broad ridges, rolling hills, and wide terraces. Much of what is
now grassland, however, seems to have been shrub before the period
of overgrazing. This is indicated because most of the dominant grasses
are introductions, and because wherever grazing has been discontinued
for some years, as on Santa Barbara, San Clemente, and the two western
islands of Anacapa, shrubs and suffrutescents are beginning to re-establish
themselves. At present, however, the major part of the insular area is
grassland. The dominating grasses at the present time are Hordeum
murinum, Avena fatua, and Bromus mollis except for a typical bunch-
grass area on San Clemente, covering much of the middle section of
the island. This area is dominated by the indigenous perennial grass
Stipa pulchra, with Stipa lepida, Melica imperfecta, and Muhlenbergia
microsperma as sub-dominants.
Various low species of annuals and perennials are usually inter-
mingled with the grasses, much as in the grassland of the mainland coast.
Many of these are exotics, such as Silene gallica, Medicago hispida, and
Atriplex semibaccata. ‘There are relatively few endemics among the
grasses or the annuals which are associated with them. Such annuals
as are endemic seem to be generally associated with coarser, more rocky
soils on steep slopes. The grasslands of the islands, except for those
on protected north slopes, all occur in fine texttured soils. ‘This, agrees
with the findings of Lundegardh (1931, p. 115) who states that deep-
rooted plants occur in coarse soils, while shallow-rooted plants occur
in soil of finer texture. On the coarse soils of protected northern ex-
posures the evaporation rate, as shown for the northern aspect of Cave
Canyon on Santa Barbara, is apparently low enough to permit the
retention of water in the interstices of the coarser particles, sufficiently to
meet the needs of the shallow-rooted grasses. This grassland on sheltered
slopes in canyons and on sea bluffs contains such genera as Agrostis,
Bromus, Melica, and Festuca. ‘These grasses are associated with a
different group of annuals and low perennials than are to be found on
the more exposed hills and terraces. Here again these plants are usually
No. 3 DUNKLE: PLANT ECOLOGY, CHANNEL ISLANDS 297
the same species which occur in similar situations on the mainland.
Typical genera are Lupinus, Gilia, Cryptantha, Trifolium, Amstnckia,
Lepidium, Phacelia, Nemophila, Platystemon, Eschscholtzia, Caulanthus,
Thysanocarpus, Lithophragma, Layia, Orthocarpus, Viola, and Gna-
phalium.
SAVANNAS
The grasslands very frequently merge by imperceptible degrees into
shrub savannas. Various low shrubs and suffrutescents from the coastal
sagebrush form a low shrub savanna, the species of which vary with
different habitats and different islands. Plate 5a shows such a typical
low shrub savanna on the western island of Anacapa. The light colored
shrubs at the right are 4 plopappus canus, with a typical, rounded clump
of Eriogonum arborescens in the rear center, and with Baccharis pilu-
laris consanguinea at right left.
On islands where chaparral shrubs occur, isolated specimens will
be spaced through the grassland on the terraces and mesas, particular-
ly on the slopes of ridges. Ceanothus, Rhamnus, Crossosoma, Adenos-
toma, Rhus, and Photinia are most frequently found in such areas.
Broad upland valleys frequently have scattered trees and arborescent
shrubs forming a tree savanna. Pinus muricata often forms open sa-
vannas on Santa Rosa and Santa Cruz Islands, and with it are often
interspersed large, rounded, arborescent sclerophylls such as Arctosta-
phylos diversifolia, Quercus agrifolia, Photinia arbutifolia, and Cerco-
carpus betuloides. On Santa Catalina a similar association exists but is
dominated by Quercus MacDonaldii, arborescent forms of Quercus
dumosa, Prunus Lyonti, Photinia arbutifolia macrocarpa, Cercocarpus
betuloides, C. betuloides multiflorus, C. alnifolius, Ceanothus megaca-
pus insularis, and Rhamnus megacarpus insularis. On San Clemente
Island Quercus tomentella, Q. chrysolepis, and Photinia arbutifolia
form very small areas of savanna. These savannas are usually on terraces
or on rolling hills about wide upland watercourses. ‘Che trees most
frequently occupy slopes or swales where they receive some protection
from the wind.
MARSHES
There are salt marshes or salt lagoons on Santa Catalina, San Cle-
mente, San Nicolas, Santa Rosa, and Santa Cruz islands. All of these
marshes are rather temporary in their nature and no endemics occur.
298 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 43
The most common of the salt marsh plants are Salicornia subterminalis,
Lepturus cylindricus, Frankenia grandifolia, Heliotropium Curvassicum
oculatum, and Jaumea carnosa.
Fresh water marshes and springy hillsides occur on all the islands
with the exception of those of volcanic origin. On Santa Barbara, San
Clemente, and Anacapa the lava forms no bedding planes and the water
is not carried out to the surface, except for small seepages near the water
level. Typha angustifolia is found on Santa Catalina, Santa Rosa, and
Santa Cruz. Anemopsis californica grows on Santa Catalina, San
Miguel, San Nicolas, Santa Rosa, and Santa Cruz. Rorippa nasturtium-
aquaticum is on Santa Cruz and Santa Catalina, while Conium macula-
tum has been reported from these two islands and San Nicolas, and
Jussiaea californicum as well as Scirpus californicus on Santa Cruz,
while Scirpus Olneyit occurs on San Nicolas and Santa Rosa.
There are two very temporary small playa lakes, one on Santa
Catalina and one on San Miguel. These hold water for such short
periods that they probably contain no specialized vegetation, at least
none has yet been reported.
SAND DUNES
There are well developed sand dunes on San Clemente, San Nicolas,
and San Miguel, while embryonic dune areas, back of broad sand
beaches, occur on Santa Catalina. Franseria bipinnatifida, Abronta
maritima, and Atriplex leucophylla are the most common and most
widespread of the dune plants. Abronia alba and Franseria chamissonts
occur on San Miguel, San Nicolas, and San Clemente. Cakile edentula
californica, Abronia latifolia, and Mesembryanthemum chilense are to
be found on San Miguel, the latter also on Anacapa. Platystemon calt-
fornicus ornithopus occurs on the sand dunes of both San Miguel and
San Nicolas.
V PHYTOGEOGRAPHY OF THE ISLANDS
The problems of the affinities, origins and distributions of the plants
of the Channel Islands have been discussed and in some cases studied
by practically every botanist and geologist who has visited the islands.
Any attempt to understand these matters involves the interpretation of
past geological events and of the climatic changes which may have
affected this insular area. Some material for this understanding has
already been presented in previous sections of this paper and will be
intergrated here. Final solutions must await the accumulation of data
of greater extent.
No. 3 DUNKLE: PLANT ECOLOGY, CHANNEL ISLANDS 299
GEOGRAPHIC VARIATION
The plant life of the Channel Islands is remarkably rich and varied
for such a limited area. Combining Eastwood’s list (1941) and Dunkle’s
supplementary list (1942a) there are 957 species and varieties for the
islands. A critical examination would reveal considerable synonymity
and a consequent reduction of this number to about 830. In addition
the 150 introduced plants would reduce the number of indigenous plants
to about 680. The plant life is particularly remarkable on account of
the wide differences between the insular flora and that of the adjacent
mainland. This difference consists of approximately 18 per cent of en-
demism, considerable variation in frequency between species on the
islands compared with the same species on the mainland, and many
noticeable differences in size and growth-form.
Several plants which are, at least locally, common and vigorous
on the islands but relatively rare on the mainland are:
Pityrogramma triangularis Eriodictyon Traskiae
var. viscosa Arctostaphylos diversifolia
Pinus Torreyana Baeria hirsutula
Erysimum insulare Coreopsis gigantea
Ribes viburnifolium
There are a number of species which are usually shrubby on the
mainland but are much more frequently arborescent on the islands, or
have related insular species or varities which are commonly arborescent.
These include:
Quercus dumosa Ceanothus arboreus
Photinia arbutifolia C.. crassifolius
var. macrocarpa C. megacarpus
Cercocarpus betuloides var. insularis
var. alnifolius Rhamnus crocea
Prunus ilictfolia var. insularis
Prunus Lyonit Arctostaphylos diversifolia
There are also several genera, usually herbaceous on the mainland,
which have suffrutescent or woody species or varieties on the islands.
Among these insular forms are:
Spergularia macrotheca S. Clokeyi
var. Talinum Castilleja hololeuca
Erysimum insulare C. grisea
Lotus argophyllus C. anacapensis
var. niveus Hemizonia clementina
var. adsurgens Malacothrix Blairii
Solanum Wallacei
300 ALLAN HANCOCK PACIFIC EXPEDITIONS voL. 13
It may also be noted that a small number of suffrutescent or woody
shrubs of the mainland frequently have exceptionally long, trailing
or procumbent branches on the islands. Among these are Cereus Emoryi,
Brickellia californica, and Artemisia californica. Other differences in
suffrutescence o1 pubescence will be treated in the following section.
Among many other plants there are minor differences in peduncle length,
leaf margin, bract length or form, size of flower, leaf or fruit, or degree
of pubescence which may or may not merit varietal rank. Most of these
preceding differences between mainland and island plants are due ap-
parently to long isolation on the islands affected by some genetic vari-
ation; or to environmental differences of soil, humidity, or temperature;
or possibly to longer intervals between devastating fires, floods, or other
catastrophic agencies.
ENDEMISM
A study of the insular endemics is necessary for a just conception of
the island flora, its composition, its phylogeny, and its phytogeography.
The term endemics as used here relates to species, sub species, varieties,
or distinctive forms which are found only on the islands or, in some
cases, locally on the adjacent mainland. Preceding sections indicate the
nature of the insular isolation and some of the factors of the environ-
ment which have brought about large amounts of endemism for such
a limited area, probably intensified by the effects of genetic variation
in isolated environment. A typical example of this variation, with its
associated endemism is Lotus argophyllus.
DEscRIPTIVE KEY FOR
Lotus argophyllus
Calyx teeth as long as the tube.
Stems woody, branches stocky with short nodes, silvery-canescent.
L. argophyllus niveus Ottley.
Santa Cruz Island.
Stems herbaceous.
Umbels approximate at the ends of the branches, blade of banner
shorter than claw, silvery canescent.
L. argophyllus Fremontiu Ottley.
Sierra Nevada Mountains.
Umbels scattered along branches, blade of banner exceeding claw,
silky canescent.
No. 3 DUNKLE: PLANT ECOLOGY, CHANNEL ISLANDS 301
L. argophyllus ornithopus Ottley.
Santa Cruz, Santa Catalina,
Santa Barbara, San Nicolas.
The Santa Barbara, San Nicolas
forms have peduncles approximately
one-fourth the length of the peduncles
in the Santa Catalina form.
Calyx teeth shorter than the tube.
Stems woody, branches short virgate, leaves more or less imbricated
on the branches.
L. argophyllus adsurgens Dunkle.
San Clemente Island.
Stems herbaceous, decumbent.
Umbels sessile or nearly so.
L. argophyllus Greene.
Pine belt of Southern California Mountains.
Umbels short peduncled.
Umbels approximate at ends of branches, blade of banner sub-
equalling claw, silvery canescent.
L. argophyllus argenteus Dunkle.
San Clemente Island.
Umbels scattered along branches, blade exceeding claw. Leaflets
5, broadly elliptical, satiny canescent.
L. argophyllus decorus Ottley.
San Gabriel, San Bernardino, and
San Jacinto mountains.
Leaflets 5-7, narrowly-elliptical, silky canescent.
L. argophyllus Hancocktt Dunkle.
San Clemente Island.
This species well illustrates how various genetic tendencies have
been interwoven into an intricate pattern. The island varieties of Erio-
gonum latifolium and of Platystemon californicus show similar ten-
dencies.
Other endemics which illustrate the effect of the environmental
influences are those which have developed a higher degree of pubescence
on the foliage than is to be found in related mainland species or varie-
ties. This, according to Lundegardh, is the effect of a relatively high
alkaline content of the soil (Lundegardh, 1931), but here the wind is
probably at least an equally potent cause of pubescence. Examples of this
type of development include:
302 ALLAN HANCOCK PACIFIC EXPEDITIONS VoL. 13
Quercus tomentella Scrophularia californica
Eriogonum gigantum var. catalina
Cercocarpus betuloides Castilleja hololeuca
var. T'raskiae Phacelia floribunda
Astragalus Nevini A plopappus canus
Astragalus Traskiae Eriophyllum Nevinit
Solanum Weallacet
A study of the endemics of the Channel Islands leads to a clear
conception of the essential floristic unity of the island group. The large
majority of the endemics are to be found on three or more of the islands.
Many of those limited to one island are apparently, for the most part,
recent initial endemics, many possessing only varietal status. Many of
the endemics seem closely related to and apparently derived from Cali-
fornia species. Others, however, do not appear to be closely related
to any existing California species. ‘(hese may be considered to be relicts
from a Pleistocene Mexican invasion which only locally survived the
colder or wetter climates of the glacial stages. Some of these may even
be relicts from the hypothetical ancient land of Catalinia. There are
also a number of plants endemic to the area covered by the maritime
climate, many of which are more numerous and more vigorous on the
islands than on the mainland coast. Since both prevailing winds and ocean
currents are such as to make migration from the islands to the mainland
more probable than the reverse migration, such plants may probably
have originated on the island and will be listed with the insular en-
demics. Table 7 presents the distribution of the insular endemics, in-
cluding plants found otherwise only on Guadalupe Island or the im-
mediately adjacent mainland coast.
Table 7 shows eighty plants endemic to the area of the Channel
Islands, with twenty-four more occurring otherwise on Guadalupe
Island and seventeen others growing otherwise only in mainland coastal
areas which possess a maritime climate. Of the eighty strictly Channel
Island endemics fifty are to be found on two or more of the islands,
twenty-six are common to islands of both the northern and southern
groups, eighteen are common to one or more islands of the northern
group and nine are common to one or more islands of the southern
group. This would tend to support the hypothesis that all of the islands
were at one time part of a common land mass, but that the northern
islands have, at another time, formed a separate geological province.
The greater separation of the islands of the southern group is shown
not only by the smaller number of endemics common to two or more
of these islands, but there are twenty-two endemics limited to single
No. 3 DUNKLE: PLANT ECOLOGY, CHANNEL ISLANDS 303
TABLE 7
PLANTS ENDEMIC TO THE CHANNEL ISLANDS,
OR OCCURING OTHERWISE ONLY ON GUADALUPE ISLAND
OR RARELY IN MAINLAND AREAS OF MARITIME CLIMATE
Northern Southern
Islands Islands
E
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e522 886 & 3
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LADD HBHBAABO
PINACEAE (Pine Family)
Pinus remorata Mason 223. ek Xx xX
Pres Torreyanarl avry x
FAGACEAE (Oak Family)
Quercus MacDonaldit Greene ..........-.--.------ Xx x x
Quercus tomentella Engelm. ..............--..------ ee ex x x x
POLYGONACEAE (Buckwheat Family)
Eriogonum arborescens Greene ..........--------- x x x
Eriogonum giganteum Wats. .......---------------- x x
var. formosum K. Brandg. ....<....-.---<----.—- x
Wat. compacium, Wunkle 22)... x x
Eriogonum grande Greene ..........----------------- SEX Nx x hx
WaT MUuvesceds WINN co A Sane
CHENOPODIACEAE (Pigweed Family)
A phanisma blitoides Nutt. ......-.-----.------------- x Xoo seexe dx
NYCTAGINACEAE (Four O’clock Family)
Abroniniaiua PWastwe cot a ee ee <u Gx x xX
Abronia maritima Nutte -.:2-----2-25.---.--s-0---> So oe) x x x x
Mirabilzs laevis Curran .......--..-—..---:--.---- x x x x x
WaT ECATOSENSTS MUN Z) cele x
war. cordiyolra Dunkle:....2 cnt xX
CARYOPHYLLACEAE (Pink Family)
Spergularia macrotheca Heynh. ............------ x ex x kK x ex
Vales) DAMNUT AC DSOM gets ee ee x x
PAPAVERACEAE (Poppy Family)
Platystemon californicus Benth. .........--..----- x4 3. eee x x
var. .ornithopus Muiz, .2-. 202. Se axe nse x
yar cians Dunkle 2365 it 2 x
Dendromecon Harfordii Kell. ..........----------- x x x
Eschscholtzia elegans Greene ........-..----------- baal in. 105°< yee hip aie
Mainland Maritime
304 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 1S
TABLE 7 (continued)
Sees: s Ss
no CUR Me LNs BC. Cr
CRUCIFERAE (Mustard Family)
Thysanocarpus laciniatus Nutt. -...--------------
Wiad UY TIE OSIES) VEUIWZ sees seen eee eee
var. conchuliferus Jepson ......-.----------------- xX x
Erysimum insulare Gray .....----------------------- x x X
Arabes filsfolia Greene 2222222 x
Arabis maxima Greene ......---------------------00---
var Glopmannit MuUnz oo ne x
a
a
a
CRASSULACEAE (Stone-crop Family)
Echeveria Greene Berger ........-------------------- SCs xX X
Echeveria virens Berger ....----:--------+----0-------" x xX
Echeveria albida Berget ....---------+---------------~ X xt oe oe
SAXIFRAGACEAE (Saxifrage Family)
Jepsonia malvaefolia Small ........-.-.------------ z Mek x x x
Heuchera maxima Greene .....-..------------------- x x x
Ribes viburnifolium Gray .....---------------------- x x
Ribes malvaceum Smith ........-.--------------------=
var. clementimum Dunkle .........-.------------- xX
CROSSOSOMATACEAE (Crossosoma Family)
Crossosoma californicum Nutt. .....-..------------ x xX xX
ROSACEAE (Rose Family)
Lyonothamnus floribundus Gray ....------------- x
var. asplenifolius Brandg. ....---.-.------------- x x xX
Photinia arbutifolta Lindl. -...........---------------
Vat. muacrocarpa MiunzZ — 2... x x
Adenostoma fasciculatum H. & A. ........-----
vat. prosiratum Dunkle ..........2.--=.--—--- x
Prunus Lyonit Sarge cee seat Ne . x x
Cercocarpus betuloides Nutt. .........-.------------
var. multiflorus Jepson -----...-.--.----—---------— x x
var. alnifolius Dunkle —....-.—.:......._...-..-. eae
var. Lraskiae Duankle 252... t-te Xx
va
LEGUMINOSAE (Pea Family)
Lupinus clementinus Jepson ........----------------- x
Lupinus Morani Dunkle .........--..---------------- x
Trifolium gracilentum T. & G. -.....-------------
Vat Palinert McDer. 22) x ox x oe
Lotus argophgllus Greene: 2...
Var. niveus Ottley ie ee x x
War..aasurgens Dunkle 2.2 x
var. ornithopus Ottley .........----------------+0--- x) xR Scorx
NO. 3 DUNKLE: PLANT ECOLOGY, CHANNEL ISLANDS 305
TABLE 7 (continued )
AS S08 SS 50 8
nC (RoE NU BVever
mo
<<
Varargentews Dunkle, 2.120. acetone ccs x
war. ancocki Dunkle jo xX
TOUS SCOP APIUS (OUI OY, <2 cts isc sc chew ste mcns eae
War. dendrovdeus) Ottley™ 2... ..ecces eset abe Se Be x
Wars Draskiar Ottley iit. lu x x
Astragalus leweopsts Wort. .2c2.. cis
war. brachypus Greene <2 2 csc ceeece x x x
Astragalus trichopodus Gray ..........--0-00-------
var. capillipes Munz & McBur. ...........--.. x
Astragalus Neowin Gray 2 x xX
Astragalus Traskiae Eastwy, ..........--.-0----0« xX x
Astragalus miguelensis Greene ........----------» Me eee
RHAMNACEAE (Buckthorn Family)
Rianne, Croced Natt. icse sce atencete ee
Waly €0SUTQEIS SATs ecco i x x x xX X
Ceanothus arboreus Greene .........----------------+ x x x
Wats Glau ries! VEpSOR a. ts ke x
Ceanothus megacarpus Nutt. .............--.-------
Wie? amsularis MUI ooo eect aes xXx x x x xX xX
MALVACEAE (Mallow Family)
Lavatera assurgentiflora Kell, ..............-+---- Mee x x xX
Malvastrum clementinum Munz & Jtn. ..... X
Malvastrum nestoticum Robinson ..........---- Xx
ONAGRACEAE (Evening-primrose Family)
Zauschnerta californica Presl. ..........--0-----=
Mate <1 OSG - EPSOM tec. ae ee A x OX X
Ocenothera guadalupensis Wats. .......---------- XX
Oenothera cheiranthifolia Bornem. ..........--.
WAT elt UMN Ze ed ee xX xX xX
UMBELLIFERAE (Carrot Family)
Lomatium insulare Mu .........-0----00----00--- Xx
Sanicula bipinnatifida Dougl. ............---------
Var. Hof mannit Munz 22.22 a 4
CORNACEAE (Dogwood Family)
Cornus glabrata bent. ee
var. catalinensis Dunkle n.c. ...........--.------ xX
ERICACEAE (Heath Family)
Arctostaphylos insularis Greene .......-.--------- Xx xX xX
Var pubescens Eastw 22.2222
Arctostaphylos diversifolia Parry .....--.------- Xx xX X x
CONVOLVULACEAE (Morning-glory Family)
Convolvulus occidentails Gray .....---.----------
Var: macrostegius Munz x x ex Mii S oe) &
306 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 13
TABLE 7 (continued)
PPR Peta DN a A IN cree tC GT tat AC SN Se Lec Le
AS) eS .S SS \2:S: S: “GiM
nC ER Mie NB (CoCia ie
POLEMONIACEAE (Phlox Family)
CL TGRTG GS REDE: TUASCW oes tle ctaee
Gila Neu Gray. 2120 Se. ane ub xX
wm
a
~*
HYDROPHYLLACEAE (Waterleaf Family)
Nemophila racemosa Nutt. 202.25 x > Che GED, Chili Ga Glike. <
Phacelia phyllomanica Gray ....------------------~
Phacelia floribunda Greene ......-.------------------ x x xX
Phacelia insularis Munz ....-------------------------=- Xx x
Phacelia Lyon (Gray, 3k x
Eriodictyon Traskiae Eastw. .....------------------ X Xx
a
a
BORAGINACEAE (Borage Family)
Amsinckia spectabilis F. & M. ......-..------------
War. -7tCola?. JONMSCON) 22.228. es asec xX xX X
Cryptantha Clevelandit Greene -......-.--------- x x x xX x xX xX
Cryptantha Traskae Johnston .........------------ x x x
LABIATAE (Mint Family)
Salvia Brandeget Munz .......-..-----------0--------~ x x
SOLANACEAE (Nightshade Family)
Lycium californicum Nutt. .......-------------------- x XK XS KX
Lycium verrucosum Eastw. ...---------------------- Xx
Lycium Richit Gray 2-2 eX
ware Passe? JOumMSton (22 eee eee xX x
Solanum Wallace: Parish -....--.-----------------.- “7X xX
Solanum Clokeyi Munz ...----..-.--..-.--------------- x x
SCROPHULARIACEAE (Pigwort Family)
Galucsia'speciosa; Gray aaa nen i x x x
Scrophularia californica Cham, .....-.------------
WAL UCOIGIIHG VCDSOM yo a Aes x xX x x
Mimulus latifoltus Gray 2 --2--<--.--------- x x
Mamulus Traskiae Gramt - 2.2552 x
Mimulus Flemingit Munz .....----------------------- x x x
Castilleja anacapensis Dunkle ..........----------- x
Castilleja hololeuca Greene ..........--------------- eM Gp ope
Castilleja grisea Dankle 2-0... --- x
PLANTAGINACEAE (Plantain Family)
Plantago insularis Eastw. ......-.-------------------~ Seu bee fp am.
RUBIACEAE (Madder Family)
Galium catalinense Gray -....-0.--------0-0000--- x xX x x
Galium californicum H. & A. «...---.--0---------
var. miguelense JepSON ........-------------0------- Ke
Galium angustifolium Nutt. -....--.-----.-----------
var. foliosum Hilend & Howell -.......------- x oe
No. 3 DUNKLE: PLANT ECOLOGY, CHANNEL ISLANDS 307
TABLE 7 (continued)
ei Se (Sigs Ss §$ Ss. s7'G M
n C RUM. UNE CA Chiaw
CUCURBITACEAE (Gourd Family)
Echinocystis guadalupensis
CW ats:) <Damikle: nies) .2- 2 tk ee a x
COMPOSITAE (Composite Family)
Aplopappus canus Blake: -2.2..1.0.25-.c0c20023: x x x x x
A plopappus venetus Blake ..................---0--0+.
var .scootdes Niunz <7 xX x
Corethrogyne filaginifolia Nutt. ................--
Wilts FODUSIA Geen: - sie Sais calls 'a) Si
Erigeron glaucus Wer... vx xx x
Corcopsts, giganica, Falls 222. Sone Se Se Xx xX x X xX x
Hemizonia clementina Brandg. ..........--------- x Ke ih) ewe
Eriophyllum Nevinii Gray «0.1.2.0. x x x
Eriophyllum staechadtfolium Lag. .........-.-..
War. depress Greene: ...2..-:2---nesntesonessen-s oN se
Artemisia californica Wess. .22 ok:
VAT CASUTATES WUUNZ, ote x x x
Senecio yoni Gray 22.51 ee x x x x x
Stephanomeria tomentosa Greene ..........----- x x
Malacothrix indecora Greene ..........------------ x xX X
Malacothrix Blairit Munz & Jtn. ..........-.-.-- xX
Malacothrix saxailis T.. & G,. 2.3222.
Vib Sue pitCata Vial) cee ho ee xX x xX xX
Hteractum argutum Nutt. ...-.......------0--------- xX xX x
islands in the southern group and only nine limited to single islands
in the northern group. San Clemente has eleven local endemics, Santa
Catalina seven, and Santa Cruz five.
The distribution of the endemics shared with Guadalupe is most
interesting. Eighteen plants are common to Guadalupe and the southern
group, while eleven are common to Guadalupe and both the northern
and southern groups. In addition five others are common to Guadalupe,
both groups of islands, and to the adjacent coastal area of maritime
climate. It would seem that if birds, winds, or ocean currents were
responsible for the common endemics they would also be found along the
mainland coast. The affinity of these two island regions is even more
apparent when it is realized that all but three of the common endemics
are to be found on San Clemente, the island closest to Guadalupe though
it is almost two hundred and fifty miles distant.
308 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 13
AFFINITIES OF ISLAND PLANTS
The origin of the present plant life of the islands is inevitably
bound up with the geological vicissitudes of the past. During the warm,
moist conditions of the early Miocene, when the ancient land of Catalinia
was presumed to have been connected with the mainland (Reed, 1933),
a large element of the flora then existing must have reached the insular
area. Following the hypothetical almost complete submergence of Cata-
linia during the upper Miocene and its re-emergence during the Pliocene,
the region may have been invaded by a Mexican flora which was adapted
to the relatively warm and dry climate of that time. While there is no
direct evidence of land connections with the mainland during the Plio-
cene a large element of Baja California flora on the islands seems to
render probable some temporary connection, which may have been
established during these millions of years.8 “The Mexican element of
the insular flora contains such genera as Crossosoma, Cereus, Galvesia,
and Lycium. Many of the endemics listed in table 7 are probably of
Mexican derivation. Thirty-two other plants of probable Mexican
affinity which are to be found also to the south are included in table 8
under the heading “‘southern.”
NorTHERN ELEMENTS
Another large element of the insular flora is shown in table 8 by
the sixty-five “northern” plants which are otherwise mostly found
north of the Cuyama River. Munz (1935) lists thirty-five plants of
the nothern group of islands which otherwise occur mostly from
Monterey County northward on the mainland. Leconte (1888) has
stated that during the glacial periods of the Pleistocene there must
have been a southward migration of northern flora, which reached the
islands during periods of uplift sufficient to have created) mainland
connections. At the same time the warmer climate of the islands and
the protected coves along the coast must have harbored many of the
Mexican and Great Basin plants which are presumed to have reached
the islands from mainland California during the milder climates of
the Miocene and Pliocene. Thus this glacial invasion may have included
many relicts of previous northward Mexican migrations as well as
the many plants of northern affinity which have so enriched the flora
of the islands, especially those of the northern group.
8This was also held tenable by Le Conte (1888) who stated that the islands
were probably connected with the mainland during the late Pliocene and early
Quaternary.
No. 3 DUNKLE: PLANT ECOLOGY, CHANNEL ISLANDS 309
TABLE 8
DISTRIBUTION OF CERTAIN NON-ENDEMIC
INDIGENOUS CHANNEL ISLAND PLANTS
Occuring in Areas outside of Cismontane Southern California
Northern Southern Other
Islands Islands Areas
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POLYPODIACEAE (Ferm Family)
Polystichum munitum Presl..........----------- x x Xx x
Athyrium Filix-foemina Beroh. .............-
Var. siichense Rupts <2) X xX x
Pityrogramma triangularis D.C. Eat. ..... x xX x xX ox xX xX
Var. wescosa Weatherby ..-::....-..-.-.....-. Xx x XK xX xX xX
Pellaca mucronata D. C. Eat, 2.5... se Gee 58 Sey
Notholaena Newberryi D. C. Eat. ........... xX Xx xX
Adtantum pedatum Vo ioc2
VEAP SHE CIDE? CILMP AR UD Es iccesicecc-o os ceco ces x Xx
Polypodium californicum Kaulf, ..........-... See 8 Sk x
Polypodium Scoulert Hook. & Grev. .....--- x x x x
EQUISETACEAE (Horsetail Family)
Egutsetum® hyetalé Vn ccc.--cccenocestetesesenen neta
var. californicum Milde. ............-...-----. x x
NAIADACEAE (Pondweed Family)
DOSTCTA TATU Meo das Uicectnsantdes tatagahae es x x x x Xx
Phyllospadix Torreyt Wats. «....--.-—--..- oe x EX ee x x
Phyllospadix Scoulert Hook. .........------------ x x
GRAMINEAE (Grass Family)
Aristida Gdscensionts Ly .22--2--0-cc---eoono------
KEN x x Xi
Siva: pulchra’ Mitehe: 22s xxxx xxxx x
Sizpa Jepida’ Hitches = ee x xxx x x x x
Muhlenbergia microsperma Kunth. ......... see ee x x x x x
Dissenthelium californicum Benth. ......... x x x x x x
Melita: imperfecta. “Vrin: 2... 2 x x xX x x x <
Distichlis staacta Ry db. 2
var. laxa Fawcett & West —..--2 Xe XG ee Xxx xX
Pon. Douglas Nees... x x x
Pestuca octoflora Walt... os 2
Wits, PEntelid Ueto eeste echoes Nan cio 'edh dese x x
Bromus marttimus Hitche.° —-—.....-....-- x x x
Bromus carinatus H. & A, ....--.----------------—-
var. Hookertanus Shear. <.......-—------.-- ee ol) we x x x
310 ALLAN HANCOCK PACIFIC EXPEDITIONS voL. 13
TABLE 8 (continued )
ASS) Sy S. bn S 8) 4S Sc Ne Ds See
n GROVE) NB CCl) vole fom
CYPERACEAE (Sedge Family)
Carex pansa Bailey. 2-8 ete estons xX X
Carex montereyensis Mkze. .....-..-------------- x x
Garex gracilior Mkze., 2c. cca, x x x
JUNCACEAE (Rush Family)
arula campestris Coe eee
elles GIG ESTA INLCV OR ctor ec x xX xX
LILIACEAE (Lily Family)
Allium praccox Brands. .2i.22 tee, x x x x xX
brodivaca taxa \epson cn. xo) No
Brodiaca’ capttata Benth) 22... Xe a ie Ke x x
Calochortus albus Dougl. 20.
VidEs PIPOCIIICS OREEIG hence ene so x x
Calachorius Juteus Dough: x x x
ORCHIDACEAE (Orchid Family)
Epipactis gigantea Doug. ........-..----------= x x
Habenaria Michaeltu Greene ..........-.-------. x x x
Habenaria unalischensis Spreng. ...-..------- x x
URTICACEAE (Nettle Family)
Hesperocuide tenella Torr. --2..-.-2. x x x x x
POLYGONACEAE (Buckwheat Family)
Pterostegia drymarioides F. & M. ........-.-- OS clb s x x x x x x
CHENOPODIACEAE (Pigweed Family)
Suaeda californica Wats. -..cccccete<2-c2o- x x x xX x x
NYCTAGINACEAE (Four O’clock Family)
Abrontva latifolia Ese. 2. oie eet xX x
PORTULACEAE (Purslane Family)
Calandriniaciitata WC)
War. Mensiest. Macbr. 2..: kc tte x xxx xX xX
Calandrinia maritima Nutt. ......-.------------- x x Xx xX xX x
Montia perfoliata Howell .........----------------- X x xX Ko Kk Mex Ke & x
CARYOPHYLLACEAE (Pink Family)
Stellarta. nitens Nutt 22 week eee » ae > ae a x xX
Spergularia macrotheca Heynh. ......-..------. xox x ox x x xX
RANUNCULACEAE (Buttercup Family)
Ranunculus hebecarpus H. & A. .......-------- x x x
PAPAVERACEAE (Poppy Family).
Eschscholtzia californica Cham. ..........----.
Vat. maritima Jepson is 2 costs, x me
No. 3 DUNKLE: PLANT ECOLOGY, CHANNEL ISLANDS S11
TABLE 8 (continued )
AWS SS) Si -S
hb CREM. NE
Q®P
Q
fo)
a
°
—
Platystemon californicus Benth, ...............
Var. wuiens Brandg.. Jo x x xX
CAPPARIDACEAE (Caper Family)
Tsomerts arvarea: Nutt. ..2n0.c00
Viaba WL OROSds COWS, <n Nee xX x x x
CRUCIFERAE (Mustard Family)
Caulanthus lasiophyllus Payson ...........---- X KX xX <x Ko xe x
Lepidium lasiocarpum Nutt. ......--.----------- xx ase x x xx
Capsella procumbens Fries, .............--.---.---
var. Dacidsonti: Mhanz 2.2... el X x x
RESEDACEAE (Mignonette Family)
Oligomeris linifolia Macbr. ..............-.-.----- x oo lo Kes x x x
CRASSULACEAE (Stone-crop Family)
Vallaca.erecia W..& As Chile 2:22). XK Re RES x
SAXIFRAGACEAE (Saxifrage Family)
Lithophragma affinis Gray «....-..-------------+- x x
Lithophragma Cymbalaria T. & G. ......... x x x
Ribes malvaceum Smith ............--.----------- Xx x xX
Rives Wienziesi:. Purshs 022 x x
ROSACEAE (Rose Family)
Holodiscus discolor Maxim ..............--------- x Xx X
Rubus witijolius C..8S. 2 x x x x
Potentilla giandulosa Lindl. ..................--. x x
Potentilla anserina Ws, coe eet xX x
Alchemilla cunetfolia Nutt. .............---------- x x x x
LEGUMINOSAE (Pea Family)
Lapinus manus Doug.) 2 Se x x
Lupinus albifrons Benth, ..222.0.---2-- 2... xox eee ix xX
Lotus grandiflorus Greene ...........--..--0--0--+- x x x x
Bots scoparius Ottley <2.
War’ eatchi, Ottley nant. koe xX x x
Trifolium amplectens T. & Gy ........0.--0----- Xe XX ex: x KG x
Trifolium microcephalum Pursh. ........----. xx Xa as x
Astragalus lewcopses Vorrs 222 x x xX x
Vac exnguay Nutt. = et ee Selb oe oe Od > ie aD. < xX
Eathyrus sirecius Nutt. 2223 x x Mx x
POLYGALACEAE (Milkwort Family)
Polygala californica Nutt. ........-2..--...-----.-- Xx xX
EUPHORBIACEAE (Spurge Family)
Euphorbia misera Benth. ..........-.-------------— x xX
ANACARDIACEAE (Sumac Family)
Rhus iagrina Nutt ee SN ee Ob < x x Xx
342 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 13
TABLE 8 (continued )
A'S: SS.) iS S$) S'S) ND s5G
nC iR M.UNUB CiCrl one tocd
eee ene ae ee ee
RHAMNACEAE (Buckthorn Family)
Ceanothus cunoatus Nutt. -......-...-------------- x X
Ceanothus crassifolius Torr. ......-------------- Xx x x X xX xX
MALVACEAE (Mallow Family)
Malvastrum fasciculatum Greene ......-----. xX xX X
FRANKENIACEAE (Frankenia Family)
Frankenia grandifolia C. & S. -.-.--..-0------- eno ds aoe ub. X x x
CISTACEAE (Rock-rose Family)
Helianthemum scoparium Nutt. -—....-.------- x x x X
LOASACEAE (Loasa Family)
Mentzelia micrantha T. & G., ...-..------------ 2 x xX x xX Xx
Mentzelia dispersa Wats. ....-.---------------0---- x xX
Menizelia affinis Greene —....-..-....----~ x Xx
CACTACEAE (Cactus Family)
Opuntia prolifera Engelm. .......-...-.----------- xX xX xX x x x xX X
Cereus Emoryt Engelm, -.--....----.---------------- x xX X
ONAGRACEAE (Evening-primrose Family)
Oenothera contorta Dougl. ......-----------------»
War, Strigilosa: IMIUNZ, ose ce csans x X
Oernothera cheiranthifolia Hornem. ........ xX x xx xX
UMBELLIFERAE (Carrot Family)
Lomatium caruifolium C. & R, ...-------------- x x
ERICACEAE (Heath Family)
Vaccinium ovatum Pursh. ........---------------- . x x xX
PRIMULACEAE (Primrose Family)
Dodecatheon Clevelandit Gray .....----------- x x x x xX
PLUMBAGINACEAE (Leadwort Family)
SialiCesariica (Blake jis ee
WAT, ELLIS alae eo oe reaceccenore xX X
POLEMONIACEAE (Phlox Family)
Gilta tenuiflora Benth. .-..------—------------ F x x x
Gilia gilioides Greene 2
VAL WEI IIL TOS VE PSOW cesecce cance seniceras a Denis co X
HYDROPHYLLACEAE (Waterleaf Family)
Ellisia chrysanthemifolia Benth. -........----- Se hs cae x x
Emmenanthe penduliflora Benth. ........-.--- x x x xX
BORAGINACEAE (Borage Family)
Harpagonella Palmeri Gray ......-.-.-------:--- x x xX
Pectocarya penicillata A. DC. .......-------- J x x xX x
Amsinckia vernicosa H. & A, -...-.----.00----- x xX
No. 3 DUNKLE: PLANT ECOLOGY, CHANNEL ISLANDS Sis
TABLE 8 (continued)
A msinckia intermedia F. & M. .............----
Cryptantha maritima Greene ........----.-----.
SOLANACEAE (Nightshade
Family)
Lyciuim: Frentontit Gray 2.22...
Datura metelordes DC. 2222058 ck
SCROPHULARIACEAE (Figwort Family)
Linaria canadensis Dum.-Cours. ...........---
Var. Jexana- Pennell 2... 0i
Antirrhinum Nuttallianum Benth. ...........
Gasnllerailanjolta He & Ay 2.0 ee
Gastilleja foliolosa TA; & Ay ee...
Orthocarpus purpurascens Benth. .............
CAMPANULACEAE (Bellflower Family)
Specularia biflora Gray .......
Githopsis specularioides Nutt. ...........--..---
CUCURBITACEAE (Gourd
Echinocystis fabaceae Naud
Family)
COMPOSITAE (Composite Family)
A plopappus venetus Blake ..
War. jurjuraceus Munz 0:02... ot.
Aster radulinus Gray ..........-
Micropus californicus F. & M, ......---------
Pilagorarizonica Gray 2.
Evax sparsifolia Jepson .......
var. brevifolia Jepson ......
Gnaphalium Sprengelit H. & A. .........------
Layia glandulosa WH; & As 2228s
Baeria chrysostoma F. & M.
WaT Gracies: ELA oiet in oe es x
Bacria aristaia Cove ee 28
Baeria hirsutula Greene ...........--.--------------
Amblyopappus pusillus H. & A. ..........----. x
Artemisia californica Less, .......--.-------------- x
Microseris linearifolia Gray ..............------.
Microserts Eimdleyi Gray) 2
var, Cleveland Gray So oS x
Malacothrix incana T. & G.
A goseris heterophylla Green
A goseris apargioides Green
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314 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 13
DEsERT ELEMENTS
A considerable number of insular plant species have also been re-
ported from the California deserts. Table 8 lists fifteen of these, not
including many species of Mexican affinity which also occur in our
deserts. Several of these fifteen plants occur only on the islands or the
immediate coastal area and then again only in the desert. It may be
presumed that the relatively high alkalinity, and the high winds of both
maritime and desert habitats produce an environment somewhat alike
in these respects. Also precipitation is relatively greater in interior
cismontane California than in either maritime or desert areas (U.S.
Weather Bureau, 1930) and these plants may not be able to compete
successfully with more mesic plants in the intervening area. Whether
the incursion of the ocean to the edge of the desert in the Cenozoic
(Reed, 1933) and subsequent retreat stranded some of these halic or
xeric plants in the desert or whether there was free migration along,
the margins of this ancient seaway is now impossible to determine.
Where so few species are involved no generalization can be established
since no satisfactory correlation can be obtained within the range of the
probability of error.
Guadalupe relationships. The plants listed in table 8 as occurring
also on Guadalupe Island present a similar problem to that of the en-
demics (p. 303). Guadalupe Island lies nearly two hundred and fifty
miles south of San Clemente Island and fifty miles west of Cedros
Island and the coast of Baja California. Among the one hundred and
sixty-three species of plants reported from Guadalupe (Eastwood, 1929),
thirty-five are probably introduced, and ninty-one are to be found on
the Channel Islands. It is most remarkable that only two native, non-
Californian species are found on both Guadalupe and Cedros. Of the
twenty-seven species which occur on both islands ten are probably intro-
duced and fifteen occur on the Channel Islands.
Genera are a better guide in studies of affinity than species alone,
especially when the present relationships may have roots in the geologic
past. Thus there are nine families and fifty-seven genera of the Guada-
lupe flora not reported from Cedros by Eastwood (1929), including
such outstanding genera as Polypodium, Eschscholtzia, Trifolium,
Ceanothus, Epilobium, Solanum, Castilleja, Plantago, and Stephano-
meria. On the other hand, eight families and sixty-six genera of the
Cedros flora, including such typical Mexican genera as Ephedra, Astra-
galus, Euphorbia, Echinocactus, Phaseolus, Viscainoa, Agave, Zizyphus,
Petalonyx, Teucrium, Acalypha, and Echinopepon, have not yet been
No. 3 DUNKLE: PLANT ECOLOGY, CHANNEL ISLANDS S15
reported from Guadalupe. All of the thirty-five genera common to the
two islands are to be found in California. It thus seems logical to con-
clude that the flora of Guadalupe Island shows a greater affinity with
the Channel Islands than with Cedros Island.
The Guadalupe flora appears to be composed of three elements: (1)
a large Mexican component, of southern California affinity, part of
which is also on Cedros; (2) a large number of ancient Catalinia relicts
not on Cedros; and (3) a California element, with many plants of
northern affinity, common to the Channel Islands and mainland Cali-
fornia but not present on Cedros. Insular endemics and Catalinia relicts,
common particularly to Guadalupe and San Clemente and their com-
mon volcanic nature, indicate the possibility of former land connection.
Migration of plants by the agency of birds would be possible but it is
difficult to understand why they would so exclusively favor the Guada-
lupe-Channel Islands route to that of the Guadalupe-Cedros. There
is a southeastern drift of ocean water along the edge of the continental
shelf that might possibly carry drift from the Channel Islands to Guada-
lupe but with the tendency of the shelf waters to drift shoreward there
is at least an equal chance that plants would be carried to Cedros. In
this connection it is not probable that seeds or plants of any of the land
species would be able to survive ocean transportation for the distance
involved.
In view of the trend of the edge of the continental shelf, the exten-
sive banks and submarine ridges lying south and southwest of the Chan-
nel Islands, and the great epeirogenic activity which has taken place in
this area during past geologic periods, it seems simpler to assume that
there may have been land connection sometime between the two re-
gions. Definite geological evidence is, at present, insufficient to lend
more than nominal support to this assumption. However, in view of
the trend of the submarine ridges, the apparent absence of transverse
ranges in Baja California, and the trend of the “Santa Ana Embayment”’
of the Miocene (Reed, 1933), the suggestion is made that if a land
connection ever existed it would most probably have been in the nature
of a peninsula reaching south from Catalinia, possibly in the Vaqueros
formation of the Miocene. Such a suggestion has been incorporated in
the accompanying map of Catalinia, figure 12.
Since the time this study was made there has been considerable
oceanographic, taxonomic, and geologic work on the areas including
Cedros, Guadalupe and San Clemente. While the author has not been
able to review this thoroughly the general impression gained has tended
to substantiate these conclusions.
316 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 13
Plant migrations. It seems probable that most of the indigenous
island flora is a remnant from the ancient land of Catalinia or reached
the islands by land bridges of the early Pleistocene. However, Holder
(1910) states that the Indians of the Channel Islands had certain
commercial relations with the mainland Indians. It is very possible
that there may have been considerable exchange of insular and mainland
floras through this intercourse. Millspaugh and Nuttall (1923, p. 220)
report possible circumstances by which Nicotiana glauca may have
been carried to Santa Catalina. In 1902 the chance combination of an
east wind with a large grass fire on the adjacent mainland was followed
by a greater increase in the number of Nicotiana plants the following
year. In view of the very small seeds of this species, the updraft from
the fire may possibly have carried the seeds high enough for the east
wind to have blown them to the island. While no examples have been
substantiated, birds have undoubtedly been an agency in carrying seeds
from island to island and also from the mainland to the islands, or vice
versa.
That plants could be carried to the islands by ocean currents or by
prevailing winds seems highly improbable for two reasons: (1) land
plants or their seeds rarely survive submergence in salt water; (2)
both the prevailing winds and the ocean currents are generally directed
shoreward by the configuration of the islands and that of the mainland
coast.
Due to the upwelling of bottom waters along the edge of the con-
tinental shelf off the coast of California, combined with the general
southeastern set of off-shore currents, the water about the islands,
probably largely bottom water, is clear and cool. As the prevailing
northwest wind passes Point Conception it veers more to the east,
following the east-west trend of the Santa Barbara coast. During the
late winter and early spring the southeastern drift of the ocean follows
the same general course, paralleling the coast. However, Tibby (1939,
pp. 13-14) reports that a reverse current seems to develop within the
borders of the continental shelf in the vicinity of the Tanner and Cortez
Banks, flowing northwesterly about San Clemente and Santa Barbara
islands. “This current turns east in the Santa Cruz Basin and then
south to join the inshore current. Later in the spring the area of this
double reverse is increased and the northern drift includes the waters
about San Nicolas and the islands of the northern group. During the
summer a current, apparently originating far down the Baja California
coast, flows northward into the broad gap between Santa Catalina
and Anacapa. Here it divides, one branch flowing northwesterly about
the northern islands, the other turning toward the coast.
No. 3 DUNKLE: PLANT ECOLOGY, CHANNEL ISLANDS S17
At all times of the year there appears to be a gentle shoreward
drift of surface waters toward the southern California coast (Leconte,
1888). Thus driftwood is found on the southern and western beaches
of most of the islands, the northwestern on San Miguel, and rarely on
the eastern and northern beaches. Such driftwood as is found consists
mainly of material from vessels and debris carried to the ocean by the
streams of central and northern California. If these conditions have
prevailed in past geological periods it is highly improbable that plants
could have migrated from the southern California coast to the islands
by means of ocean currents.
VI Lire-ForMs OF ISLAND PLANTS
The life-forms of the island plants seem principally those which
best enable the plants to survive the long, unfavorable season of summer
and fall. The modifications which have been evolved to meet this un-
favorable season are not greatly different, in most respects, from those
generally seen in plants of the Mediterranean climate. However, the
maritime climate differs definitely from the Mediterranean types present
In interior cismontane southern California. Accordingly it may be
expected that there will be corresponding differences in the growth
forms of the two regions.
Plants adapted to the Mediterranean type of climate are marked
by sclerophyllous foliage for trees and shrubs, and by a high percentage
of therophytes (annuals), hemicryptophytes (perennial herbs and low
suffrutescent semi-shrubs), geophytes (plants with bulbs, tubers, or
rhizomes), and chamaephytes (suffrutescent shrubs and low woody
shrubs). Maritime plants and those of xeric conditions sometimes
develop a succulent form (Raunkiaer, 1934). On the islands a stronger
maritime influence, the oceanic type of climate, has accentuated the
development of certain of these characteristics. In order to understand
better the modifications which have taken place it will be advisable to
examine the island forms in some detail.
Very few deciduous shrubs or trees are to be found on any of the
islands except Santa Catalina, Santa Rosa, and Santa Cruz. Even here
they rarely play a dominant role, and then only in very limited riparian
areas. Populus and Salix are on all three of these islands, and Acer
macrophyllum is occasionally met on Santa Cruz. two herbaceous
shrubs are exceptions to the hard-wood shrubs and are more typical of
moist, subtropical conditions. These shrubs, apparently formerly much
more abundant, are Coreopsis gigantea and Lavatera assurgentiflora.
318 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 13
Coreopsis has very finely divided leaves which wither at the beginning
of the dry season, while Lavatera has thin, broad, simple, ever-green
leaves. Quercus tomentella, Quercus MacDonaldit, Ceanothus arboreus,
Prunus Lyonii, and Dendromecon Harfordii have leaves somewhat
larger than those of related mainland species. The larger leaves of these
insular endemics are also reminiscent of a warmer and more moist
condition in the past.
CHAPARRAL
The chaparral, except for that of the warmer, interior slopes of
Santa Cruz, differs from most of the mainland chaparral in its com-
parative size. Brandegee (1888) has stated that many shrubs of the
mainland become arborescent on the islands, apparently owing to effects
of the moist sea breezes. The lower evaporation rate, caused by the
higher humidity and the lower summer temperature, in places sheltered
from the stronger winds would undoubtedly tend to make for a longer
growing season. Furthermore, the possibly greater freedom from fires
would result in greater longevity. Quercus dumosa becomes decidedly
arborescent on the islands, growing into small trees which may reach a
height of ten meters (33 feet) in favorable localities. Photinia arbutt-
folia and its two varieties, Cercocarpus betuloides and its three varieties,
Sambucus coerulea, Arctostaphylos diversifolia, Ceanothus megacarpus,
and Rhamnus crocea insularis are usually arborescent. Many other
shrubs, such as Rhus laurina, Rhus integrifolia, Malvastrum fasctcu-
latum, and Prunus ilicifolia are very frequently arborescent in form
if not in size. Browsing by goats and self-pruning resulting from light
deficiency for the lower branches are two of the factors which may
contribute to this arborescent form.
On the three larger islands Quercus tomentella, Lyonothamnus
floribundus, and L. floribundus asplenifolius develop into trees which
may reach fifteen meters (50 feet). On San Clemente Lyonothamnus
rarely exceeds ten meters (33 feet), and on Anacapa Quercus is rarely
over six meters (19 feet) in height. On these smaller islands there is
less protection from wind as well as a lower annual precipitation.
The average (fire-type) chaparral on the mainland varies from one
and one-half to two meters (5 feet), with Adenostoma and Photinia
up to four meters (13 feet) (Cooper, 1922). This agrees with the
average height of the chaparral on the southern ridges of Santa Cruz.
There is a tall, “unburned” chaparral in favorable locations in the
mountains of southern California and northern Baja California. In all
No. 3 DUNKLE: PLANT ECOLOGY, CHANNEL ISLANDS 319
the examples of this examined by the writer the common species were
of a distinctly shrubby habit. “he semi-arborescent Quercus dumosa
association of Santa Catalina varies from four to six meters (13-19
feet), approximately the height of the taller mainland chaparral, while
the arborescent Arctostephylos-Photinia-Quercus association of Santa
Cruz averages between five and eight meters (16-26 feet). On the
four larger islands individual examples of Photinia, Sambucus, Cer-
cocarpus, and Prunus may reach a height of twelve meters (40 feet),
though Sambucus is only occasionally a component of the chaparral.
SUFFRUTESCENT PLANTS
The suffrutescent habit is one of the most characteristic features
of the insular vegetation and is much further developed than in main-
land communities. ‘he winter season on the islands rarely brings frost.
Because of the warmer winters and the more moist summers many
perennial herbs do not die back to the surface of the ground during the
unfavorable seasons. This condition has perhaps been stabilized by the
long period of isolation. To illustrate, Lotus argophyllus has two var-
ieties, miveus and adsurgens, which have developed a suffrutescent habit.
The suffrutescent species of Castilleja which are endemic to areas of
maritime climate are C’. foliolosa, C. grisea, C. hololeuca, and C. ana-
capensis. In the genus Eriogonum the following species and varieties
are suffrutescent: E. grande, E. grande rubescens, E. arborescens, E.
giganteum, E. giganteum formosum, and E. giganteum compactum.
Most of the herbaceous perennials on the western headlands are
suffrutescent. Here the heavy fogs of summer are driven against the
headlands and precipitate an appreciable amount of moisture. On Guada-
lupe heavy fogs are condensed upon the trees to such an extent that
small streams are formed, which are supposed to give rise to some of the
few springs of the island (Eastwood, 1929).
It has been shown that wind is probably the most important factor
in evaporation on the islands. Wind, however, rapidly loses its velocity
as the surface of the ground is approached (Lundegardh, 1931). The
upper branches of erect shrubs will dry out from wind but those upper
branches, even though dead, usually persist and aid in reducing the wind
velocity about the base of a plant. This is well illustrated in the case
of Coreopsis, whose withered leaves and flower stalks hang about the
trunk of the plant until after new foliage has appeared in the winter,
and afford a high degree of protection to the trunk and its main branches.
320 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. Ale
This protection is enhanced by the highly gregarious nature of the plant,
which is indicated by the fact that isolated plants rarely reach the height
of those in dense colonies.
The desiccating effect of wind on the Channel Islands is great enough
to affect some of the plants which, in the interior of the mainland,
would normally be shrubs. There is, on the islands, a distinct tendency
for the tips of the upper branches to die back during the dry season.
This condition is noted in the insular varieties of Lotus scoparius, L.
Dendroideus, L. Traskiae, and L. Veatchii. Rubus viitfolius, Holodiscus
discolor, and Sambucus coerulea also show this same tendency.
Properly included in the group of suffrutescent plants may be certain
low, evergreen herbs (Raunkiaer, 1934), such as Atriplex californica,
Atriplex leucophylla, Astragalus Nevinit, A. Traskiae, Frankenia grand-
ifolia, Heliotropium Curassavicum oculatum, and Heuchera maxina. In
addition to these there are many other suffrutescents, both on the islands
and the mainland. Again, several of the introduced plants are suffru-
tescents. Since these last two groups of plants owe their habits to the
Mediterranean climate and not primarily to their insular environment
they will not be listed at this time.
Suffrutescent plants are especially prevalent in many parts of the
Mediterranean region, according to Raunkiaer (1934), and have an
important place in his floristic spectrum for that region. Suffrutescents,
in addition to those previously mentioned, occurring in areas of mari-
time climate include the following:
Suaeda californica Grindelia rubricaulis
var. pubescens var. robusta
Mirabilis laevis var. latifolia
var. cedrosensis var. platyphila
var. cordifolia Corethrogyne filaginifolia
Spergularia macrotheca var. virgata
var. Talinum var. robusta
Heuchera maxima var. incana
Lupinus longiflorus var. latifolia
L. arboreus Hemizonia clementina
L. Chamissonis Encelta californica
L. albifrons Eriophyllum confertiflorum
var. Douglasit var. trifidum
Erysimum insulare Malacothrix saxatilis
Cryptantha maritima var. tenuifolia
Galium catalinense var. implicata
G. Nuttallu M. Blairu
No. 3 DUNKLE: PLANT ECOLOGY, CHANNEL ISLANDS 321
ANNUALS
Large areas of the islands are now dominated by therophytes. There
are numerous extensive areas that, because of fire, over-grazing, or
cultivation, are now occupied almost exclusively by annual species which
are usually associated with suffrutescent plants. These annuals are
largely introduced grasses and forbs. However, in places exposed to the
full sweep of the winds, native annuals are dominant. The following
are examples of these native therophytes:
Muhlenbergia microsperma Plagiobathrys californicus
Lepidium nitidum var. gracilis
Tillaea erecta Cryptantha Traskae
Lupinus bicolor C. intermedia
var. microphyllus Baeria chrysostoma
var. umbellatus var. gracilis
Eromocarpus setigerus B. hirsutula
Gilia multicaulis Malacothrix indecora
G. dianthoides M. foliosa
G. Neviniti M. californica
Salvia columbariae Amblyopappus pusillus
Plantago insularis
In open grassy or rocky places on the north exposures of canyons
there are such annuals as:
Pterostegia drymarioides Papaver heterophyllum
Parietaria floridana Trifolium gracilentum
Montia perfoliata var. Palmeri
Platystemon californicus Amsinckia spectabilis
var. nutans A. intermedia
In all the associations there are many annuals and the majority of
introduced plants are of this category.
GEOPHYTES
Geophytes are not extremely abundant on the islands but one species
or another is to be found in nearly every locality. While not so frequent
as in the “maqui” of the Mediterranean region (Hardy, 1925) they yet
form a larger proportion of the island flora than the normal floristic
spectrum would predict. Next to annuals they are best adapted to a
long, dry period. Most of the forms are geophytes, hemicryptophytes, or
endophytes, and may be considered here whether their vegetative buds
are actually below the surface of the ground, at the surface, or under
S22 ALLAN HANCOCK PACIFIC EXPEDITIONS voL. 13
rocks. Other plants, true geophytes or hemicryptophytes, with their
propagating buds at or below the surface of the ground, include the
following:
Carex praegracilis
Eleocharis mamillata
Juncus balticus
Allium praecox
Zygadenus Fremontii
Bloomeria Crocea
Brodiaea capitata
B. laxa
B. synandra
Calachortus splendens
C. catalinae
C. luteus
Chenopodium californicum
(often suffrutescent).
Jepsonia malvaefolia
Oxalis californica
O. pilosa
Lomatium insulare
L. caruifolium
Bowtesia septentrionalis
Torillis nodosa
Sanicula arguta
S. bipinnatifida Hoffmanit
Conium maculatum
Berula erecta
Caucaulis microcarpa
Echinocystis macrocarpa
Daucus pusillus
FLoristic SPECTRUM
LIFE-FORMS OF SANTA BARBARA ISLAND NATIVE PLANTS
Santa nibarbaka sce eek
Normal, Spectrum) 23) 33
The percentage distribution of
the species among the life-forms.
S EMM M N Ch H G HH TH*
10! 20) NOS 2 ay 10) 82 a8
13
6 17.20 “92733 ot (3
*The initials for the life-forms of 400 plants of the Mediterranean islands, as
used by Raunkiaer (1934) are as follows:
S—Stem succulents.
E—Epiphytes.
MM—Mega Mesophanerophytes.
Trees or large shrubs, 3-20 m. high.
M—Microphanerophytes. Woody plants 2-8 m. high.
N—Nanophanerophytes. Woody plants 4-2 m. high.
Ch—Chamaephytes. Vegetative buds not over 25-30 cm. above surface.
H—Hemicryptophytes. Vegetative buds at surface of soil.
G—Geophytes. Vegetative buds in the soil.
HH—Hydrophytes.
Th—Therophytes. Annuals.
The native plants of Santa Barbara Island have been used for the
construction of a floristic spectrum to illustrate the relative frequency of
the different types of insular life-forms. Exotic plants have not been
NO. 3 DUNKLE: PLANT ECOLOGY, CHANNEL ISLANDS 323
included as all but one of the twenty-one introduced plants of Santa
Barbara are therophytes. Here also are none of the larger woody shrubs
or trees of chaparral and woodland. The small number of native species,
however, is fairly representative of the most extensive of the communities
of the other islands: i.e. the sea bluffs, the coastal sage brush, and the
suffrutescent-grassland community.
The therophyte percentage for both native and exotic annuals is
60 per cent, which compares well with figures for various islands in the
Mediterranean Sea as reported by Raunkiaer (1934). The chamaephyte
and the geophyte percentages are also exceptionally large as should be
the case for a Mediterranean climate. The number of succulents is also
large, as would be expected in a dry maritime habitat. On the larger
islands the percentages would be slightly altered by the inclusion of many
more phanerophytes, yet the spectrum shown here would be roughly
typical of the wind-swept areas of all the islands.
VII ConcLusIoNn
The Channel Islands possess a flora that is distinctive and responsive
to the insular environment. Geologists have postulated, during past
epochs, the existence of a former land mass (Catalinia) which included
the area through which these eight islands are now scattered, and which
probably extended farther to the south and west. The evidence presented
by the distribution of the indigenous and endemic species of island plants
confirms the conclusion of a former common land mass.
The geographic separation from the mainland, the distinctive climate,
and certain edaphic factors have brought about a rich endemic flora. In
addition many other island plants show minor variations in form.
The direction of the prevailing wind gives an oceanic type of climate,
while the dry summers and mild, moist winters are characteristic of the
Mediterranean type. The maritime climate of the islands and of a
narrow coastal strip of the mainland may be divided into three types
upon the basis of the mean annual precipitation and certain characteristics
of the vegetation. The climate, subject to the interruption of intermit-
tent cycles, has gradually become drier since the Pleistocene epoch.
Tropical subsidence air causes excessively dry periods during the spring
and fall.
The alkalinity of many of the island soils, the wind intensity, and
the long period of summer aridity have favored the development of
succulence and leaf pubescence. Ihe moist, warm winters have probably
favored the development of suffrutescence in both herbaceous perennials
and shrubs.
324 ALLAN HANCOCK PACIFIC EXPEDITIONS voL. 13
There is a definite causal relationship between wind velocity, the
mechanical composition of the soil, and the evaporation rate. That is,
where the wind velocity is high the soil is coarse and the evaporation
rate high, and where the wind velocity is low the soil is finely textured
and the evaporation rate low. The wind appears to be the master factor
in the distribution and delimitation of the major plant communities.
The pre-Pleistocene flora of the insular area probably contained
many plants which migrated there from the mainland during the lower
Miocene, when mainland connections have been postulated for the
ancient land of Catalinia. Thus the major affinity of the indigenous
island plants is with cismontane southern California. There is also a
remarkable relationship between the plants of the Channel Islands and
those of Guadalupe Island. The pre-Pleistocene flora was greatly en-
riched, during Pleistocene time, by migrations from the north, at a
time when Catalinia was again connected with the mainland. Presum-
ably the islands have not been connected with the mainland since that
epoch. The direction of the prevailing winds and the ocean currents
render unlikely the migration of mainland plants to the island by those
agencies since the separation.
The nature of the native vegetation has been greatly modified by
human activities during the last four centuries, but particularly in the
past century when the islands were used for grazing. The overgrazing,
which was practiced for nearly a century, has been followed by such
great erosion by wind and water that, in many areas, the original climax
has disappeared. Much of what is now barren sand dunes, wind-eroded
uplands, or exotic grasslands was probably once covered by chaparral,
coastal scrub, or a mixed community of coarse, native grasses, forbs,
and low suffrutescents. Some areas, free from overgrazing for several
years, are now dominated by exotic grasses and are pang gradually
invaded by plants of the mixed community mentioned.
The presence of grazing animals on the islands since the Pleistocene,
prior to the occupation of the island by the white man, is doubtful. Many
of the weak-stemmed, herbaceous perennials and semi-shrubs once abun-
dant on the islands have been driven out of the areas which can be
reached by grazing animals. Most of the introduced plants are from
parts of the world possessing maritime or Mediterranean climates, where
grazing has been carried on during historic time.
The sea bluffs occupy a considerable part of the insular area and
present a variety of habitats. The edaphic conditions are subject to
continuous change owing to the unceasing wave erosion. The gradual rise
in the ocean level since glacial time has brought new areas under wave
No. 3 DUNKLE: PLANT ECOLOGY, CHANNEL ISLANDS 325
attack. This has resulted in very narrow beaches or steep cliffs and
bluffs bordering the islands. The bluffs possess a large number of en-
demics and shelter many remnants of the indigenous flora. Owing to high
wind velocity, the evaporation rates on the bluffs are higher than in the
interior of the islands. The soils of the bluffs are shallow and the soil
particles coarse. The variety in slope angle and exposure occasions great
variation in the communities of the upper slopes. In communities of the
shore and splash zone there is less variation because of the predominating
influence of the sea.
Canyon, terrace, and hillside communities are differentiated in ac-
cordance with the pattern of similarly situated mainland communities,
though on the islands the differences are somewhat more sharply ac-
centuated owing to the higher velocities of the island winds. Woodlands
exist only in areas protected from wind and the direct rays of the sun,
and where the average annual precipitation is over 13 inches, or where
there is underground water available. Grasslands occur on fine-textured
soils on terraces, gentle slopes, and uplands exposed to moderate winds.
In many parts of the grassland, where it has not been too heavily pas-
tured, there are tree, shrub, and semi-shrub savannas. Northerly and
southerly exposures of canyons are sharply differentiated in respect to
their evaporation rates, plant life-forms, and floristic composition of the
plant communities.
The succulent and thickly pubescent plants of the sea bluffs and the
trees and shrubs with sclerophyll foliage maintain a more or less uniform
appearance throughout the year. Generally, however, the winter is a
season of growth, the early spring of flowering, while summer and fall
are rest periods. There is little undergrowth in closed communities.
The limitations of this study have left many interesting problems
unsolved. Too little time has elapsed since heavy grazing has been
discontinued to present a clear picture of the tendencies of plant succes-
sion. Furthermore, it is probable that further field work on San Cle-
mente and San Nicolas islands will disclose additional evidence of plant
variation. The scope of the present investigation has not included in
detail the nature of the physiological and morphological modifications
resulting from insular isolation, nor how genetic or environmental fac-
tors have influenced variation. Neither has attention been given to modi-
fications which enable many of the plants of sea bluff and headland to
maintain growth and vigor during the long dry season.
326 ALLAN HANCOCK PACIFIC EXPEDITIONS voL. 13
VIII ANNOTATED LisT OF THE VASCULAR
PLANTS OF SANTA BARBARA ISLAND
POLYPODIACEAE
Polypodium californicum Kaulf. var. Kaulfusii D.C. Eat. California Polypody.
Perennial geophyte. One colony on north exposure of Cave Canyon. Also
on Anacapa and Santa Catalina islands; mainland coast to Marin County.
Endemic to areas of California maritime climate.
NAIADACEAE
Phyllospadix Torreyi Wats. Surf Grass.
Marine perennial. In rock channels below low tide level. On all the islands,
including Guadalupe; Indigenous.
GRAMINEAE
Stipa pulchra Hitche. Beautiful Needle Grass.
Suffrutescent perennial. Occasional in low scrub savanna. On all the islands;
Baja California to Central California. Indigenous.
Muhlenbergia microsperma (DC) Kunth. Dropseed Grass.
Annual. Southern exposures generally. Also on Santa Cruz, Anacapa, Santa
Catalina, San Clemente, and Guadalupe islands; adjacent mainland and
Mexico. Indigenous.
Polypogon monspeliensis (L.) Desf. Rabbitfoot Grass
Annual. One plant in splash zone of Landing Cove. Also on San Miguel,
Santa Rosa, Santa Cruz, San Nicolas, Santa Catalina, and Guadalupe
islands; mainland. Introduced from Europe.
Avena fatua L. Wild Oat.
Annual. Dominant in several small areas on eastern terrace. On all the
islands, including Guadalupe; mainland. Introduced from Europe.
Melica imperfecta Trin. Small-flowered Melica.
Perennial. Infrequent in shaded canyon bottoms, On all the islands; Baja
California to central California. Indigenous.
Lamarckia aurea (L.) Moench. Golden-top.
Annual. Forming small colonies in openings of Coreopsis association. On
all the islands, including Prince Island off San Miguel; mainland. Intro-
duced from the Mediterranean region.
Bromus marginatus Nees. Margined Brome Grass.
Perennial. Infrequent in canyons. Also on the four northern islands; San
Diego County to British Columbia. Indigenous.
Bromus rigidus Roth. Ripgut Grass.
Annual. Infrequent in canyons. Also cn San Miguel, Santa Rosa, and Santa
Catalina islands; mainland. Introduced from Europe.
Bromus rubens L. Red Brome Grass.
Annual. Locally common in canyons. Also on Santa Rosa, Santa Cruz,
Anacapa, and Santa Catalina islands; mainland. Introduced from Europe.
Bromus vulgaris (Hook.) Shear. Narrow-flowered Brome Grass.
Perennial. Infrequent in canyons. Also on San Miguel, Santa Cruz, and
Santa Catalina; mainland north in mountains to British Columbia and
Montana. Indigenous.
Bromus sterilia L. Barren Brome Grass.
Annual. Infrequent in canyons. Also on Guadalupe Island; northern Cali-
fornia. Introduced from the Mediterranean region.
Hordeum murinum L. Common Foxtail.
Annual. Dominant on terraces and the central ridge. On all the islands;
mainland. Introduced from Europe.
LILIACEAE
Brodiaea capitata Benth. Wild Hyacinth.
Geophyte. Widespread on the terraces. On all the islands; mainland to
Oregon. Indigenous.
No. 3 DUNKLE: PLANT ECOLOGY, CHANNEL ISLANDS S27
POLYGONACEAE
Eriogonum giganteum Wats. var. compactum Dunkle.
Round-headed Queen Anne’s Lace.
Suffrutescent perennial. Locally common on north, south, and east bluffs.
Endemic to Santa Barbara and Santa Catalina islands.
Pterostegia drymarioides F. & M. Maiden-hair Buckwheat.
Annual. Common on eastern bluffs in Coreopsis association. On all the
islands, including Guadalupe, except San Nicolas; Baja California to Oregon.
Indigenous.
CHENOPODIACEAE
A phanisma blitoides Nutt. Seaside Blitum.
Annual. Occasional on eastern bluffs and northern canyon exposures, es-
pecially in shallow caves. Also on the four northern islands, Santa Catalina,
San Clemente, and Guadalupe islands; adjacent mainland coast. Probable
relict, endemic to areas of southern California maritime climate.
Chenopodium californicum Wats. Soap Plant.
Geophyte, occasionally suffrutescent. Common on eastern terraces and in
canyons. On all the islands; cismontane southern to central California.
Indigenous.
Chenopodium murale L. Nettle-leafed Goosefoot.
Annual. Common in Suaeda-Larus biome and widespread on the ridge,
terraces and canyons. On all the islands; mainland. Introduced from Europe.
Atriplex californica Mog. California Saltbush.
Suffrutescent perennial. Abundant on headlands and bluffs. On all the
islands; Baja California to central California. Endemic to areas of Cali-
fornia maritime climate.
Atriplex rosea L. Red Scale.
Annual. Occasional on eastern bluffs. Unreported from the other islands;
mainland. Introduced from Europe.
Atriplex semibaccata R. Brown Australian Saltbush.
Suffrutescent herb. Common on all the terraces. On all the islands; mainland.
Introduced from Australia.
Suaeda californica Wats. var. pubescens Jepson. Sea Blite.
Suffrutescent semi-shrub. Widespread on terraces, abundant in nesting places
of Larus occidentalis Audubon, the Western ‘Gull. On all the islands;
mainland coast from Baja California to central California. Endemic to
areas of California martime climate.
NYCTAGINACEAE
Mirabilis laevis (Benth.) Curran. Four O'clock.
Suffrutescent perennial. Locally common on southern breaks and _ talus
slopes. Also reported on Santa Rosa, Santa Cruz, and Santa Catalina; dry
canyon slopes and washes on mainland. Taxonomic status uncertain. In-
digenous.
AIZOCEAE
Mesembryanthemum crystallinum L. Ice Plant.
Succulent annual, but apparently perennial in the large colonies. On all
the islands; mainland coast. Introduced from Africa.
Mesembryanthemum nodiflorum L. Small-leaved Ice Plant.
Succulent annual. Widespread on the terraces with small, closed colonies.
On all the islands; mainland coast. Introduced from the Mediterranean
region and Africa.
PAPAVERACEAE
Platystemon californicus Benth. var. ciliatus Dunkle. Pigmy Cream Cup.
Annual. One colony on windswept northern bench, in coarse, shallow soil.
Endemic to Santa Barbara Island.
Eschscholtzia elegans Greene. Island Poppy.
Annual. A single plant on south exposure of Cave Canyon. On all the
islands, including Guadalupe. Insular endemic.
Papaver heterophyllum (Benth.) Greene. Wind Poppy.
Annual. A single report for Santa Barbara, by Bond. On all the islands
except San Nicolas; mainland. Indigenous.
328 ALLAN HANCOCK PACIFIC EXPEDITIONS voL. 13
PORTULACACEAE
Calandrinia maritima Nutt. Sea Kisses.
Annual. Occasional on northern and eastern bluffs. Also on Santa Rosa,
Santa Cruz, and Santa Catalina islands; mainland coast to Baja California.
Endemic to areas of southern California and Baja California maritime
climate.
Montia perfoliata (Donn.) Howell. Miner’s Lettuce.
Annual. Infrequent on north exposures of canyons. On all the islands;
mainland from Mexico to British Columbia and Utah. Indigenous.
CARYOPHYLLACEAE
Spergularia macrotheca (Hornem.) Heynh. Sand Spurrey.
Perennial herb. Occasional on terraces and the central ridge. On all the
islands; mainland coast. Endemic to areas of California maritime climate.
Silene gallica L. Windmill Pink.
Annual. Common and widespread on terraces and bluffs. On all the islands;
mainland. Introduced from Europe.
CRUCIFERAE
Lepidium nitidum Nutt. Common Peppergrass.
Annual. Common on the ridge and sea bluff breaks. On all the islands;
mainland to desert and to Washington. Indigenous.
Brassica nigra (L.) Koch. Black Mustard.
Annual. A single plant by trail on eastern terrace. Also on Santa Cruz,
Santa Catalina, and San Clemente islands; mainland. Introduced from
Europe.
CRASSULACEAE
Tillaea erecta Gaertn. Baby Fuzz.
Annual. Common on western breaks. On all the islands, including Guadalupe,
except Anacapa; mainland to Oregon; Chile. Origin uncertain, but pos-
sibly introduced very early from Chile.
Echeveria Greenet (Rose) Berger. Greene’s Echeveria.
Succulent perennial. Locally common on southern bluffs. Santa Rosa and
Santa Cruz islands also. ‘Taxonomic status uncertain. Insular endemic.
Echeveria albida (Rose) Greene. White-flowered Echeveria.
Succulent perennial. Local and rare on western bluff. Also on San Clemente,
Santa Catalina, and Prince islands. ‘Taxonomic status uncertain; if FE.
Traskae Berger is valid, this yellow-flowered form is limited strictly to
Santa Barbara Island. Insular endemic.
LEGUMINOSAE
Medicago hispida Gaertn. Bur Clover.
Annual. Eastern terraces and bluffs. On all the islands; mainland. Introduced
from Europe.
Trifolium tridentatum Lindl. Three-toothed Clover.
Annual. Occasional on eastern bluffs. On all the islands except San Nicolas
and Anacapa; mainland north to British Columbia. Indigenous.
Trifolium gracilentum T. & G. var. Palmeri (Wats.) McDer.
Palmer’s Island Clover.
Annual. Occasional on eastern breaks and north canyon exposures. Also on
Santa Cruz, San Clemente, Santa Catalina, San Nicolas, and Guadalupe
islands. Insular endemic.
Trifolium microdon H. & A. Butterfly Clover.
Annual. Occasional on the terraces. Also on Santa Cruz, Santa Catalina,
and San Nicolas islands; central California to British Columbia; Chile.
Origin uncertain.
Lotus argophyllus (Gray) Greene var. ornithopus (Greene) Ottley.
Silvery Clover.
Suffrutescent perennial. Occasional on southern bluffs and southern canyon
exposures, with one plant on western cliff break. The form here is similar
to the San Nicolas form (Hosackia venusta Eastw.) which has peduncles
.5-1.5 mm. long. The variety ornithopus has many variants on the islands
and the taxonomic status of the different forms is, as yet, involved and un-
certain. Insular endemic.
No. 3 DUNKLE: PLANT ECOLOGY, CHANNEL ISLANDS 329
Astragalus Traskiae Eastw. Trask’s Astragalus.
Suffrutescent perennial, Common on western and northern, wind-swept
breaks of the ridge and western bluffs. Also on San Nicolas and San Cle-
mente islands. 4. Nevinii Gray and A. leucopsis (T. & G.) Torr. have
also been reported from Santa Barbara but not verified. Insular endemic.
GERANIACEAE
Erodium Botrys Bertol. Broad-leaf Filaree.
Annual. Reported only by Bond. Also on Santa Rosa Island; mainland.
Introduced from Europe.
Erodium cicutarium (L.) L’Her. Red-stemmed Filaree.
Annual. Abundant on terraces, the ridge, and bluffs. On all the islands;
mainland. Introduced from Europe.
Erodium moschatum (L.) L’Her. White-stemmed Filaree.
Annual. Occasional on northern canyon exposures. On all the islands, except
Anacapa; mainland. Introduced from Europe.
MALVACEAE
Malva parviflora L. Cheese-weed.
Annual. Widespread and locally abundant on terraces, the ridge, and head-
lands. On all the islands except Anacapa; mainland. Introduced from Europe.
CACTACEAE
Opuntia prolifera Engelm. Coast Cholla.
Succulent shrub. Common on southern, eastern, and western bluffs. On
all the islands, including Guadalupe, except San Miguel and Santa Cruz
islands; mainland coast south to Baja California. Probable element of early
Mexican invasion; endemic to areas of southern California and Baja Cali-
fornia maritime climate.
Opuntia littoralis (Engelm.) Cockerell. Coast Prickly Pear.
Succulent shrub. Common on eastern terrace and southwestern bluffs. On
all the islands; mainland south to Baja California. Probably of Mexican
afhnity; endemic to areas of southern California and Baja California mari-
time climate.
ONAGRACEAE
Oenothera cheiranthifolia Hornem. Beach Primrose.
Perennial herb. Reported only by Hemphill. Also on San Nicolas, San Miguel,
Santa Rosa, and Santa Cruz islands; mainland coast from Surf north to
Oregon. Indigenous.
CONVOLVULACEAE
Convolvulus occidentalis Gray var. macrostegius (House) Munz.
Giant Morning Glory.
Suffrutescent climber. Common on eastern terrace and canyons, in Coreopsis
association, and on southern bluffs. Reported from all the islands, but only
common and well developed on the southern islands, including Guadalupe.
Insular endemic.
POLEMONIACEAE
Gilia gilioides (Benth.) Greene. Blue Star Gilia.
Annual. Occasional on northern canyon exposures and northern breaks.
Also on Santa Cruz, Santa Catalina, San Clemente, and Guadalupe islands;
mainland north to Oregon and east to Nevada. Indigenous.
HYDROPHYLLACEAE
Nemophila racemosa Nutt. Pale Nemophila.
Annual. Occasional on northern exposures of canyons. Also on Santa Cruz,
Santa Catalina, San Clemente, and Guadalupe islands; mainland coast to
Baja California. Endemic to areas of southern California and Baja California
maritime climate.
Phacelia floribunda Greene. Flowery Phacelia.
- Annual. Common in shaded parts of canyons. Also on San Clemente and
Guadalupe Islands. Integrading with P. hispida Gray on Santa Barbara.
Insular endemic.
Phacelia hispida Gray Hairy Phacelia.
Annual. Occasional in canyon bottoms, and northern exposures, intergrading
with the preceding. Also on Santa Rosa, Santa Cruz, and Anacapa islands;
mainland to Baja California. Indigenous.
330 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 4S
BORAGINACEAE
Amsinskia intermedia F. & M. (A. sanctae barbarae Brand.)
Coast Fiddleneck.
Annual. Common on eastern terrace in grassland. Also on the four larger
islands; mainland from Baja California and Arizona northward through
California. A variable species that undoubtedly includes many insular
segregates. Indigenous.
Cryptantha Clevelandii Greene var. hispidissima (Greene) Johnston.
Hairy Cryptantha.
Annual. Infrequent on northern exposures of canyons. Also on Santa Rosa,
Santa Cruz, San Miguel, San Clemente and Guadalupe islands; mainland.
Indigenous.
Crypthantha maritima Greene. Pin-cushion Cryptantha.
Suffrutescent perennial. Occasional on southern bluff breaks. Also on Santa
Catalina, San Clemente, San Nicolas, and Guadalupe islands; mainland to
Arizona and Baja California. Indigenous.
Cryptantha intermedia (Gray) Greene. | Common Cryptantha.
Annual. On eastern terrace in cactus clumps. Also on the four larger islands;
mainland from Baja California to northern California. Indigenous.
Cryptantha Traskae Johnston. Trask’s Cryptantha.
Annual. Occasional on ridges. Also on San Nicolas Island. Insular endemic.
SOLANACEAE
Lycium californicum Nutt. Coastal Box Thorn.
Suffrutescent shrub. Widespread and frequently dominant on all terraces,
southern bluffs, and western headlands; frequently a component of the
Suaeda-Larus biome. Also on other southern islands; mainland coast to
Baja California. Endemic to areas of southern California and Baja California
maritime climate.
PLANTAGINACEAE
Plantago insularis Eastw. Island Plantago.
Annual. Occasional on southern bluffs. Also on the other southern islands;
adjacent mainland coast. Endemic to areas of southern California maritime
climate.
CUCURBITACEAE
Echinocystis macrocarpa Naud. Common Man-root.
Climbing geophytic herb. Abundant in canyons and on eastern bluffs. On
all the islands; mainland to edge of desert. Indigenous.
COMPOSITAE
Heliantheae
Coreopsis gigantea (Kell.) Hall. Giant Coreopsis.
Suffrutescent shrub with fleshy trunk. Common in all but the most extremely
wind-swept areas; dominant on the lower eastern terrace, bluffs, and can-
yons. Undoubtedly dominant over more extensive areas before cultivation
of the terraces. On all the islands, including Guadalupe; adjacent mainland
coast. Endemic to areas of southern California maritime climate.
Madieae
Hemizonia clementina Brandg. Island Bush Tarweed.
Suffrutescent schrub. Forma frostrata, a low prostrate form with short
internodes, abundant on main ridge and southern breaks. Forma erecta, a
small, rounded shrub with erect branches and long internodes, common on
the breaks of the eastern bluffs. H. clementina also on Anacapa, and the
other southern islands, with related species on Guadalupe Island. Insular
endemic.
Hemizonia fasciculata (DC) T. & G. var. ramosissima (Benth.) Gray.
Slender Tarweed.
Annual. Common on eastern terrace. Also on Santa Catalina and San
Clemente islands; adjacent mainland coastal areas. ‘Taxonomic status un-
certain. Probably indigenous.
NO. 3 DUNKLE: PLANT ECOLOGY, CHANNEL ISLANDS S51
Helenieae
Perityle Emoryt Torr. Cliff Daisy.
Annual. Common on talus slope of southern bluffs and at upper edge of
splash zone. On all the islands, Except San Nicolas; mainland to Mexico.
Closely related forms on Guadalupe Island. Indigenous.
Baeria chrysostoma F. & M. var. gracilis (DC) Hall. Gold Fields.
Annual. Occasional in shallow soil of exposed ridges. On all the islands,
including Guadalupe; mainland throughout California to edge of desert.
Indigenous.
Baeria hirsutula Greene. Succulent Gold Fields.
Annual. Abundant on rounded, windy breaks and headlands. Also on Santa
Catalina, Santa Rosa, Santa Cruz, and San Miguel islands; coastal central
California. Endemic to areas of California maritime climate.
Eriophyllum Nevinit Gray. Island Dusty Miller.
Low suffrutescent shrub. Occasional on upper part of splash zone; also on
the two adjacent islets. Also on Santa Catalina and San Clemente islands,
with a related form on Guadalupe Island. Insular endemic.
Amblyopappus pusillus H. & A. Coquimbo.
Annual. Abundant on southern bluff breaks, the central ridge, and eastern
terrace. On all the islands, including Guadalupe; adjacent mainland coast;
South America. Origin uncertain, possibly a very early introduction.
Anthemtdeae
Achillea millefolium L. var. lanulosa (Nutt.) Piper. Yarrow.
Suffrutescent perennial. Common and widespread on terraces and northern
exposures. On all the islands; mainland from Mexico to British Columbia.
Closely approaches var. maritima Jepson, and taxonomic status in view of
later revisions of species. Maritime variant of a cosmopolitan complex.
Artemisia californica Less var. insularis (Rybd.) Munz. Island Sage Brush.
Suffrutescent woody shrub. Common and widespread on eastern terraces,
southern exposures of canyons, and southern bluffs. Also on San Nicolas
and San Clemente islands.
Cichorieae
Malacothrix foliosa Gray. Lava Daisy.
Annual. Abundant on windy breaks and headlands. Also on Santa Cruz
and San Clemente islands. Insular endemic.
Sonchus oleraceus L. Sow Thistle.
Annual. Common and widespread in all parts of the island. On all the
islands; mainland. Introduced from Europe.
332 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 15
GLOSSARY
Abundant—A frequency term which indicates that the individuals of a species
constitute a large fraction of all the plants within a specified area.
Adaptation—The structural responses which plants develop on becoming adjusted
to changed environmental conditions.
Adiabatic—A change of atmospheric temperature in consequence of compression
or expansion accompanied by an increase or decrease of atmospheric pressure.
Anemometer—An instrument measuring the rate of flow of air past a given
point.
Arborescent—Tree-like in form or size, or both form and size.
Association—A plant community with definite physiognomy, ecological structure,
and general uniformity of floristic composition; showing climax adjustment
toa particular complex of environmental conditions.
Atmometer—An instrument for measuring the rate of evaporation from a satur-
ated surface. .
Biome—A community composed of both plants and animals.
Biotic—Referring to such environmental factors as result from the interrelations
of living organisms.
Bluff—A cliff or a headland, consisting of a broad, steep face, usually with a
rounded break at the summit.
Break—A change of direction in the slope angle at the summit of a cliff or
bluff.
Breccia—A rock composed of angular fragments united by a matrix.
Chamaephytes—Low shrubs or semi-shrubs with perennial stems that are woody
at the base and whose propagating buds for the next season are not over
30 cm. above the surface.
Cismontane—In southern California it refers to the area between the main
interior mountain masses and the coast, that is, the area draining directly
to the ocean.
Clif—A high, steep rock or bank, used here to refer to nearly perpendicular
slopes which have an angular break at the summit.
Colony—A group of one or more species of plants which has developed as an
immediate consequence of invasion.
Common—A frequency term indicating that the species may be found without
difficulty in a specified area.
Constancy—The consistent presence of a species in different parts of a given
area, or in different examples of a plant association.
Corrasion—Refers to the action of surface wear by physical processes, as by
the impact of solid particles driven by wind or water; distinguished from
corrosion, which is a process of chemical wear.
Desiccation—The drying out of a region by increased aridity; the drying out
of a plant at the end of the growing season.
Dominant—The plant species, one or more, exerting control over the habitat,
usually the largest and most frequent species.
Ecesis—The establishment of a plant species in a new area, involving migration,
germination, development, and repeated reproduction.
Edaphic—All characteristics of the substratum in which plants grow.
Endemic—A plant whose natural distribution is limited to a certain area, or a
few nearby areas, used here in a relative sense.
Epeirogeny—The process of the surface adjustment of large areas by vertical
uplift or depression, operating over a long period of time.
Exotic—A plant which has been introduced into an area where it is not native.
Facies—A portion of a community in which one or more dominants have been
replaced by other species, the general aspect of the community remaining
unchanged.
Feral—Untamed or uncultivated; referring here to an animal which has reverted
from the domesticated state.
Floristic—Relating to the species and other taxonomic categories of plants in a
given community.
Forb—A general term for all herbaceous plants which are not grasses.
NO. 3 DUNKLE: PLANT ECOLOGY, CHANNEL ISLANDS 333
Formation—Vegetation occupying a natural area characterized by rather uniform
climatic or edaphic conditions, having a more or less physiognomy, but with
communities of different floristic composition, these last being sometimes
termed the plant associations of the formation.
Geophyte—A perennial plant whose propagating organs for the growing season
lie below the surface of the earth, as in bulbs, corms, tubers, and many
rhizomes.
Halophyte—A plant which grows on saline or alkaline soil.
Hemicryptophyte—A perennial plant with its propagating organs at the surface
of the soil, as in the case of many rhizomes, herbs with a tap root, and
certain low suffrutescents.
Hydrotherm—A combination of two graphs showing precipitation and temperature
at stated intervals in a given locality.
Hygrograph—An instrument producing a continuous record of relative humidity
for a certain period.
Hydrophyte—A plant which lives in the water or in wet or saturated soils.
Hygro-thermogram—A combination of two graphs showing both temperature and
relative humidity for a specified time in a given locality.
Indigenous—Native to a given area; not introduced.
Initial endemic—A plant species of recent origin and not spread beyond a very
limited area, because of lack of time or difficulty in migration, or both.
Tsohyet—A line indicating areas of equal precipitation.
Local—A frequency term indicating that a given plant species may be found
in one or only a very few parts of a given area.
Limiting factor—A condition that limits the development of a plant species or
of a plant community.
Master factor—One, of the paramount environmental conditions exerting more
or less of a controlling influence over a type of vegetation.
Megaphanerophyte—A tree over 30 meters (100 feet) high; most forest trees.
Mesophanerophyte—A tree or large shrub 8 to 30 meters (25 to 100 feet) high;
most trees or large shrubs of woodlands or savannas.
Microphanerophyte—A shrub or small tree 2 to 8 meters (6% to 25 feet) high;
most shrubs of the chaparral.
Nanophanerophyte—A woody plant %4 to 2 meters (10 inches to 6% feet) high;
most shrubs of the coastal sage brush, fire-type chaparral, and desert shrub.
Nearctic region—An obsolescent term referring to North America as far south as
Mexico.
Normal spectrum—A list of percentages of the life-forms of Raunkiaer which is
supposed to represent their proportions under the average conditions for the
entire world. This is used as a norm with which to compare the biological
spectrum of any region, the important feature being the amount of deviation
of that region from the normal.
Orogeny—The process of mountain building, characterized by tangential stresses
operating for periods of relatively short duration geologically.
Occasional—A frequency term used to indicate that a given plant species is
relatively uncommon and that it might not be found without considerable
search.
Rain shadow—An area to leeward of an elevation, with less precipitation than
occurs on the windward side.
Relict endemic—A plant species of more general distribution in the geologic
mass, whose range has been restricted by changing environmental conditions,
to one locality, or a few nearby communities.
Riparian vegetation—Vegetation growing along streams or rivers.
Savanna—Grassland with trees or shrubs growing well separated or in small
groups.
Sclerophyll—A term referring to the foliage of vegetation found in climatic re-
gions with arid summers; leaves evergreen, reduced in size, and more or
less thickened and coriaceous.
Scrub—Any community in which shrubs, suffrutescents, or dwarf trees dominate.
Sere—A plant succession.
Society—A plant assemblage within an association, consisting of subordinate
species which have assumed temporary dominance.
334 ALLAN HANCOCK PACIFIC EXPEDITIONS voL. 13
Suffrutescent—Perennial plants in which the upper parts of the branches die
back during an unfavorable season, but at least the lower part of the stem
or stems is more or less woody and perennial.
Therophyte—An annual plant, dying at the close of a single growing season.
Thermograph—An instrument for producing a continuous record of temperature
during a certain time in a given locality.
Tolerant—A term referring to the ability of a plant to withstand unfavorable
elements of its environment; as shade tolerant, lime tolerant, etc.
Troposphere—That part of the earth’s atmosphere in which there is a regular
decrease of temperature with increasing altitude; below about 11 kilometers
(37,000 feet).
Tufa—A rock composed of indurated volcanic ash.
Widespread—A term applying to plants which occur in many parts of a given
area, but not abundant in any part.
W oodland—Vegetation composed predominately of tree life-forms, growing in
an open condition without a closed or interlacing canopy.
ee
No. 3 DUNKLE: PLANT ECOLOGY, CHANNEL ISLANDS 335
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1936. The Genus Eriogonum: a preliminary study based on geographic
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1939. Report on returns of drift bottles released off southern California,
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Truomiroy, I. K.
1940. The geographic-complex method for study of the climate. Mo.
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342 ALLAN HANCOCK PACIFIC EXPEDITIONS VOLS
FIGURE 1
The Channel Islands of southern California
(Taken from U.S. Coast and Geodetic Survey Chart 5020) depths
indicated in fms.
‘ : bei
ssiuiua® pquawe #9 urs.
x.
apisuvaIgQs
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40g
DUNKLE
NG..3
344 ALLAN. HANCOCK PACIFIC EXPEDITIONS VoL. 13
FIGURE 2
The Channel Islands of southern California
showing relative areas. The southern islands have been shifted
west 30° north as indicated, adapted from U.S. Coast and Geo-
detic Survey Charts 5202 and 5101A.
2
PLANT ECOLOGY, CHANNEL ISLANDS FIG.
DUNKLE:
Sah
/ Wd) ojvos
~~ (emia
lial / Janb6IW ves
346
ALLAN HANCOCK PACIFIC EXPEDITIONS VOLS
FIGURE 3
Approximate limits of maritime Mediterranean climates in Cali-
fornia north of upper dash line represents semi-humid maritime.
Between dash lines represents arid maritime. South of lower dash
line represents desert maritime.
~
-
~
~
amy ~~~
vos
JS] S0J021IN
uv
‘S[ Dunyoyo.
Dyues
7s] Didi
ys Dye
Y, CHANNEL ISLANDS
‘
J
0S
a1Ua2% >
juiog
Y
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an
—
So)
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IPISIINY F
o1424U09
PLANT
DuIpsOULIG
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DUNKLE:
348 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 13
FIGURE 7
Instrumental records for Station Al, on the east bluff of- Santa
Barbara Island. Solid lines represent average daily evaporation,
the upper line of black-cup atomometers, the lower of white-cup
atmometers. Dash lines represent temperature, the upper line maxi-
mum temperatures, the lower, the minimum temperatures.
NO. 3 DUNKLE: PLANT ECOLOGY, CHANNEL ISLANDS FIG)
May3l Jun27 Jul.26 Aug25 Sep27 Novl . Decé
Dotted line represents average hourly wind velocity.
Numbers represent (1) cubic centimeters, (2) degrees centigrade,
(3) miles per hour.
350 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL.
FIGURE 4
Hydrotherm for the Channel Islands
Numbers on the chart represent degrees Centigrade and centimeters
of precipitation. The initials are of the months beginning with April.
13
NO. 3 DUNKLE: PLANT ECOLOGY, CHANNEL ISLANDS FIG. 4
RW ab deo AC So OeaN: De wd ee
eS)
ALLAN HANCOCK PACIFIC EXPEDITIONS VoL. 13
FIGURE 5
Selected hydro-thermogdaph records for Santa Barbara Island, 1941.
Numbers represent per cent of relative humidity and degrees
Fahrenheit. Thin line represent relative humidity, heavy lines
represent temperature.
————————
DUNKLE: PLANT ECOLOGY, CHANNEL ISLANDS FIG. 5
ST Ae ee pee US tes) WE ia URED PR
Sram (AUR oa IMR SC Aa :
i GPO YT ERR SRO a
Week of April 6 to /5
ss WT cae
Sn oT
Iau CS ee
a0 ACN PAR, SN
“1 a,
inal
‘20. 2, eT
NG 2
Week of May 5/ to June 7
GEE SO gee
week of July 2 to9
354 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL.
FIGURE 6
Selected hydro-thermograph records for Santa Barbara Island, 1941.
Numbers represent per cent of relative humidity and degrees
Fahrenheit. Thin lines represent relative humidity, heavy lines
represent temperature.
13
NO. 3 DUNKLE: PLANT ECOLOGY, CHANNEL ISLANDS FIG. 6
Week of November & to 93
bYeehk of December 2/ to 28
356
ALLAN HANCOCK PACIFIC EXPEDITIONS VOL.
FIGURE 8
Comparison of evaporation rates. with black-cup and white-cup
atmometers on the southern and northern exposures of a canyon.
Station B1, southern exposure—solid lines
Station B2, northern exposure—dash lines
Upper solid and upper dash lines show average daily evaporation
of black-cup atmometers.
Lower solid and dash lines show average daily evaporation of
white-cup atmometers. Numbers represent cubic centimeters.
May 3! Jun 28 Jul. 27 Avug.26 Sep.27 Oct 3l
Dec 6
iS)
on
CO
ALLAN HANCOCK PACIFIC EXPEDITIONS VOL.
FIGURE 9
Santa Barbara Island, showing distribution of vegetation
communities.
0O
WAY
blan‘x
Coreopsis association.
Mesembryanthemum crystallinum colonies.
Lycium californicum societies.
A stragalus-Baerta-Malacothrix community.
Sea bluff break community.
Suaeda-Larus Biome.
Opuntia Iittoralis.
Echeverta-Eriogonum-Eriophyllum community.
Grassland.
Webster Point
360 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL:
FIGURE 10
North-south profile of Santa Barbara Island with evaporation rates.
Profiles through south peak, north peak, and east terrace.
Evaporation given in even hundreds.
Evaporation given in average cubic centimeters per day.
13
MOMS DUNKLE: PLANT ECOLOGY, CHANNEL ISLANDS FIG. 10
Soe ALLAN HANCOCK PACIFIC EXPEDITIONS VOL.
FIGURE 11
East-west profile of Santa Barbara Island with evaporation rates.
Elevation given in even hundreds.
Evaporation given in average cubic centimeters per day.
13
11
FIG.
ISLANDS
PLANT ECOLOGY, CHANNEL
DUNKLE:
NO.9
364
ALLAN HANCOCK PACIFIC EXPEDITIONS
FIGURE 12
Catalinia in the Pliocene, with the Peninsula of Guadalupia.
(Adapted from Reed, 1933, p. 252)
A ne
—_-
\g
& =
s Y, Boys
Ys ~*~ GZ
a &
Lp YA.
366
ALLAN HANCOCK PACIFIC EXPEDITIONS
PIA!
a. Anacapa Island from the west summit.
b. Lyonothamnus grove, Santa Cruz Island.
VOL. 13
NO. J DUNKLE: PLANT ECOLOGY, CHANNEL ISLANDS Piso
Plate la
Plate 1b
368 ALLAN HANCOCK PACIFIC EXPEDITIONS voL. 13
PLAEES2
Santa Barbara Island from the south.
bo
NO. 3 DUNKLE: PLANT ECOLOGY. CHANNEL ISLANDS PL.
370 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL; 13
PAI 3
San Miguel Island from 22,000 feet elevation.
S12 ALLAN HANCOCK PACIFIC EXPEDITIONS VOLES
PEALE.
a. Emerald Bay at Johnson’s Landing, Santa Catalina Island.
b. Prisoner’s Harbor, Santa Cruz Island.
NO. 3 DUNKLE: PLANT ECOLOGY, CHANNEL ISLANDS PL. 4
Plate 4b
374 ALLAN HANCOCK PACIFIC EXPEDITIONS VOLS
PAGES
Quercus tomentella in canyon, Anacapa Island.
Cn
No. 3
; DUNKLE: PLé
: PLANT ECOLOGY
LOGY, CHANNEL
N} ISLANDS
ND§ PL.
376 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL eho
PLATE 6
a. Eriogonum-Eriophyllum association, Anacapa Island.
b. Scrub savanna, Anacapa Island.
NO. 3 DUNKLE: PLANT ECOLOGY, CHANNEL ISLANDS PRETO
Plate 6a
Plate 6b
INDEX TO FAMILIES, GENERA AND SPECIES
Abronia alba, 298, 303
latifolia, 298, 310
maritima, 298, 303
umbellata, 260
umbellata platyphylla, 260
Acalypha, 314
Acer macrophyllum, 317
Achillea, 285, 290
millefolium lanulosa, 278, 284,
291, 293
millefolium var. lanulosa, 331
var. maritima, 278, 331
Adenostoma, 297, 318
fasciculatum var. prostratum, 304
Adiantum Jordani, 293
pedatum var. aleuticum, 309
Agave, 314
Agoseris apargioides, 313
heterophylla, 313
Agrostis, 296
Aizoceae, 327
Alchemilla cunefolia, 311
Allium praecox, 310, 322
Alnus, 287
Amblyopappus pusillus, 277, 281, 283,
284, 313, 321, 331
Amsinckia, 297
intermedia, 277, 313, 321, 330
sanctae barbarae, 330
spectabilis, 321
var. nicolai, 306
vernucosa, 312
Anacardiaceae, 311
Aenemopsis californica, 298
Anthemideae, 331
Antirrhinum Nuttallianum, 313
Aphanisma, 285
blitoides, 281, 293, 303, 327
Aplopappus, 268, 295
canus, 263, 292, 294, 297, 302, 307
venetus var. furfuraceus, 313
var. sedoides, 307
venetus sedoides, 293
var. furfuraceus, 293
var. vernonioides, 293
Arabis filifolia, 304
maxima var. Hoffmannii, 304
Arctostaphylos bicolor, 239
diversifolia, 286, 289, 297, 299,
305, 318
insularis, 289, 305
var. pubescens, 305
subcordata, 289
tomentosa, 289
Arctostaphylos-Photinia-Quercus, 319
Aristida adscensionis, 309
Artemisia californica, 289, 291, 300, 313
var. insularis, 289, 292, 307, 331
forma flexilla, 292
californica insularis, 290, 292
californicus insularis, 279
Aster radulinus, 313
Astragalus, 268, 285, 290, 295, 314
Douglasii, 293
leucopsis, 293, 311, 329
var. brachypus, 305
miguelensis, 293, 305
Nevinii, 293, 302, 305, 320, 329
Traskiae, 274, 283, 293, 302, 305,
320,329
trichopodus var. capillipes, 305
Astragalus-Baeria-Malacothrix, 358
Athyrium Filix-foemina var.
stichense, 309
Atriplex, 265, 268, 290, 295
Breweri, 294
californica, 279, 283, 284, 285, 293,
320; 327
Coulteri, 293
leucophylla, 298, 320
pacifica, 293
rosea, 327
semibaccata, 264, 276, 277, 285, 296,
327
Watsonii, 293
Avena, 276, 277, 280
fatua, 264, 277, 296, 326
Baccharis pilularis consanguinea, 292,
297
Baeria, 285, 295
aristata, 313
chrysostoma gracilis, 293
var. gracilis, 313, 321, 331
hirsutula, 274, 283, 293, 299, 313,
321, 331
Berula erecta, 322
Bloomeria Crocea, 322
Boraginaceae, 306, 312, 330
Bowiesia septentrionalis, 322
Brassica nigra, 328
Brickellia californica, 291, 300
Brodiaea, 276
capitata, 277, 278, 310, 322, 326
laxa, 310, 322
syandra, 322
Bromus, 296
[ 381 ]
382 ALLAN HANCOCK PACIFIC EXPEDITIONS
carinatus var. Hookerianus, 309
marginatus, 326
maritimus, 309
mollis, 264, 296
rigidus, 326
rubens, 281, 326
sterilia, 326
vulgaris, 281, 326
Cactaceae, 312, 329
Cakile edentula californica, 298
Calachortus albus var. rubellus, 310
catalinae, 322
luteus, 310, 322
splendens, 322
Calandrinia ciliata var. Menziesii, 310
maritima, 284, 310, 328
Campanulaceae, 313
Capparidaceae, 311
Capsella procumbens var. Davidsonii,
NE
Carex gracilior, 310
montereyensis, 310
pansa, 310
praegracilis, 322
Caryophyllaceae, 303, 310, 328
Castilleja, 314, 319
afhinis, 294
anacapensis, 294, 299, 319
Douglasii, 294
foliolosa, 294, 313, 319
grisea, 290, 294, 299, 306, 319
hololeuca, 294, 299, 302, 306, 319
latifolia, 313
Caucaulis micropora, 322
Caulanthus, 297
lasiophyllus, 311
Ceanothus, 297, 314
arboreus, 286, 289, 299, 305, 318
var. glabrus, 305
crassifolius, 289, 299, 312
cunoatus, 312
megacarpus, 299, 318
var. insularis, 299, 305, 318
megacarpus insularis, 289, 297
Cereus, 308
Emoryi, 260, 290, 300, 312
Cercocarpus, 287, 319
alnifolius, 297
betuloides, 286, 287, 289, 297, 299,
302, 318
var. alnifolius, 289, 299, 304, 318
var. multiflorus, 289, 297, 304, 318
var. Traskiae, 289, 302, 304, 318
Cheilanthes californica, 293
Chenopodiaceae, 303, 310, 327
Chenopodium californicum, 276, 277,
322, 327
murale, 278, 285, 327
Cichorieae, 331
Cistaceae, 312
VOL. 43
Compositae, 307, 313, 330
Conium maculatum, 298, 322
Convolvulaceae, 305, 329
Convolvulus, 279, 281
occidentalis cyclostegius, 292
occidentalis macrostegius, 279, 292
occidentalis var. macrostegius, 305,
329
Coreopsis, 267, 276, 277, 279, 280, 281,
284, 285, 288, 290, 318, 319, 326,
521, 358
gigantea, 263, 277, 279, 284, 289, 292,
299, 307, 317, 330
maritima, 260
Coreopsis-Melospiza, 277
Corethrogyne filaginifolia, 294, 320
var. incana, 320
var. latifolia, 294, 320
var. robusta, 294, 307, 320
var. virgata, 294, 320
Cornaceae, 305
Cornus glabrata var. catalinensis, 305
Crassulaceae, 304, 311, 328
Crossosoma, 297, 308
californicum, 304
Crossosomataceae, 304
Cruciferae, 304, 311, 328
Cryptantha, 297
Clevelandii, 306
var. hispidissima, 330
intermedia, 321, 330
maritima, 293, 313, 320, 330
Traskae, 233, 293, 306, 321, 330
Cucurbitaceae, 307, 313, 330
Cyperaceae, 310
Datura meteloides, 313
Daucus pusillus, 322
Dendromecon, 252
Harfordii, 289, 303, 318
Dissenthelium californicum, 309
Distichlis stricta var. laxa, 309
Dodecatheon Clevelandii, 312
Echeveria, 285, 290
albida, 279, 294, 304, 328
Greenei, 284, 294, 304, 328
Traskae, 328
virens, 294, 304
Echeveria-Eriogonum-Eriophyllum, 358
Echeveria-Opuntia, 279
Echinocactus, 314
fabaceae, 313
Echinocystis, 279, 285
guadalupensis, 292, 307
macropora, 279, 292, 322, 330
Echinopepon, 314
Eleocharis mamillata, 322
Ellisia chrynsathemifolia,312
Emmenanthe penduliflora, 312
Encelia californica, 290, 291, 320
Ephedra,314
NO. 3
Epilobium,314
Epipactis gigantea, 310
Equisetaceae, 309
Equisetum hyemale var. californicum,
309
Ericaceae, 305, 312
Eriodictyon Traskiae, 299, 306
Erigeron, 260
glaucus, 260, 294, 307
Eriogonum, 285, 290, 319
arborescens, 292, 297, 303, 319
cinereum, 294
giganteum, 291, 302, 303, 319
var. compactum, 291, 303, 327
var. formosum, 291, 303
giganteum compactum, 281, 284
giganteum formosum, 319
grande, 293, 303, 319
var. rubescens, 294, 303
grande rubescens, 319
latifolia, 301
Eriogonum-Eriophyllum, 295, 376
Eriophyllum, 290
artemisifolia, 294
confertiflorum, 292, 294, 320
var. laxiflorum, 292, 294
var. trifidum, 292, 294, 320
Nevinii, 263, 284, 294, 302, 307, 331
staechadifolium depressum, 263, 294
staechadifolium var. depressum, 307
Ermocarpus setigerous, 321
Erodium Botrys, 329
cicutarium, 277, 285, 329
moschatum, 329
Erysimum insulare, 292, 299, 304, 320
Eschscholtzia, 281, 297, 314
californica var. maritima, 310
elegans, 303, 327
Euphorbia, 314
misera, 260, 290, 294, 311
Euphorbiaceae, 311
Evax sparsifolia var. brevifolia, 313
Fagaceae, 303
Festuca, 296
octoflora var. hirtella, 309
Filago arizonica, 313
Frankenia grandifolia, 298, 312, 320
Frankeniaceae, 312
Franseria bipinnatifida, 298
chamissonis, 298
Galium angustifolium var. foliosum,
306
aparine, 278
californicum var. miguelense, 306
catalinense, 306, 320
Nuttallii, 320
Galvesia, 308
spesiosa, 306
Geraniaceae, 329
Gilia, 285, 297
DUNKLE: PLANT ECOLOGY, CHANNEL ISLANDS 383
dianthoides, 321
gilioides, 281, 329
var. glutinosa, 312
multicaulis, 321
Nevinii, 306, 321
tenuifolia, 312
Traskiae, 306
Githopsis specularioides, 313
Gnaphalium, 297
Sprengelii, 313
Gramineae, 309, 326
Grindelia arenicola, 292
rubricaulis, 320
var. latifolia, 320
var. platyphylla, 292, 320
var. robusta, 320
rubricaulus latifolia, 292
Habenaria Michaelii, 310
unalischensis, 310
Harpagonella Palmeri, 312
Heleniantheae, 330
Helenieae, 331
Helianthemum scoparium, 312
Heliotropium Curvassicum oculatum,
298, 320
Hemizonia, 282, 284, 285, 295
clementina, 274, 283, 284, 299, 307,
320, 330
forma erecta, 294, 330
forma prostrata, 293, 330
fasciculata ramosissima, 281
fasciculata var. ramosissima, 330
Hesperocnide tenella, 310
Heuchera maxima, 304, 320
Hieracium argutum, 307
Holodiscus, 259
discolor, 311, 320
Hordeum, 276, 277, 278, 280, 285
murinum, 264, 277, 278, 296, 326
Hordeum-Avena, 277
Hosackia venusta, 328
Hydrophyllaceae, 306, 312, 329
Isomeria arborea var. globosa, 311
Jaumea carnosa, 298
Jepsonia malvaefolia, 304, 322
Junaceae, 310
Juncus balticus, 322
Jussiaeae californicum, 298
Labiatae, 306
Lamarckia aurea, 326
Larus, 279
occidentalis, 279, 327
Lathyrus strictus, 311
Lavatera, 266, 267, 318
assurgentiflora, 262, 263, 305, 317
Layra,297
glandulosa, 313
Lazula campestris var. congesta, 310
Leguminosae, 304, 311, 328
Lepidium, 297
384 ALLAN HANCOCK PACIFIC EXPEDITIONS
lasiocarpum, 311
nitidum, 321, 328
Lepturus cylindricus, 298
Liliaceae, 310, 326
Linaria canadensis var. taxana, 313
Lithophragma, 297
affinis, 311
Cymbalaria, 311
Losaceae, 312
Lomatium caruifolium, 312, 322
insulare, 305, 322
Lotus, 268, 283, 285
argophyllus, 299, 300, 301, 319
adsurgens, 290, 301
argenteus, 301
decorus, 301
Fremontii, 300
Hancockii, 301
niveus, 291, 300
var. adsurgens, 291
var. ornithopus, 201
ornithopus, 281, 283, 294, 301
var. adsurgens, 294
argophyllus
var. adsurgens, 299, 204, 319
var. argenteus, 305
var. Hancockii, 305
var. niveus, 299, 304, 319
var. ornithopus, 304, 328
Dendroideus, 320
grandiflorus, 311
scoparius, 320
var. dendroideus, 305
var. Traskiae, 305
var. Veatchii, 311
scorparius dendroideus, 292
var. Traskiae, 292
var. Veatchii, 292
Traskiae, 320
Veatchii, 320
Lupinus, 297
albifrons, 294, 296, 311, 320
var. Douglasii, 320
arboreus, 320
argophyllus adsurgens,260
bicolor, 321
var. microphyllus, 321
var. umbellatus, 321
Chamissonis, 260, 320
clementinus, 304
longiflorus, 320
Moranii, 304
nanus, 311
Lycium, 267, 276, 278, 290, 308
californicum, 260, 277, 278, 279, 284,
290, 291, 292, 293, 306, 330, 358
Fremontii, 292, 313
Richii, 306
var. Hassei, 306
VOL. 13
verrucosum, 292, 306
Lycium-Suaeda, 277
Lycium-Suaeda-Larus, 277
Lyonothamnus, 252, 287, 318, 366
floribundus, 304, 318
var. asplenifolius, 304
floribundus asplenifolius, 286, 318
Madieae, 330
Malacothrix, 285, 295
Blairii, 299, 307, 320
californica, 321
foliosa, 274, 283, 293, 321, 331
incana, 313
indecora, 307, 321
saxatilis, 320
var. implicata, 207, 320
var. tenuifolia, 320
-saxatilis implicata, 263
Malva, 283
parviflora, 277, 285, 329
Malvaceae, 305, 312, 329
Malvastrum clementinum, 305
fasciculatum, 312, 318
nesioticum, 305
Nuttallii, 260
Medicago hispida, 264, 296, 328
Melica, 296
imperfecta, 265, 281, 286, 296, 309,
326
Melospiza melodia graminea, 280
Mesembryanthemum, 265, 274, 276,
Zions
chilense, 298
crystallinum, 264, 278, 283, 285, 327,
358
nodiflorum, 277, 278, 285, 327
Mentzelia affinis, 312
dispersa, 312
micrantha, 312
Micropus californicus, 313
Microseris Lindleyi, 313
var. Clevelandii, 313
linearifolia, 313
Mimulus Flemingii, 292, 306
latifolius, 306 ;
longiflorus, 260, 292
Vane linearis, 292
puniceus, 260, 292
Traskiae, 306
Mirabilis, 290
laevis, 283, 284, 291, 294, 303, 320,
327
var. cedrosensis, 291, 294, 303, 320
var. cordifolia, 291, 294, 303, 320
Montia perfoliata, 310, 321, 328
Muhklenbergia, 285
microsperma, 281, 283, 284, 296, 309,
321, 326
Myrica, 259, 287
NO. 3
californica, 260
Naiadaceae, 309, 326
Nemophila, 297
racemosa, 263, 281, 306, 329
Nicotiana, 316
glauca, 316
Notholaena Newberryi, 260, 309
Nyctaginaceae, 303, 310, 327
Oenothera bistorta, 260
cheiranthifolia, 260, 276, 312, 329
var. nitida, 305
contorta, 312
var. strigulosa, 312
guadalupensis, 305
Oligomeris linifolia, 311
Onagraceae, 305, 312, 329
Opuntia, 268, 285, 290
littorais, 279, 281, 285, 288, 290, 291,
312,329,358
prolifera, 259, 260, 279, 283, 284, 290,
291, 312, 329
Opuntia-Encelia-Atriplex, 285
Opuntia-Lotus, 283
Orchidaceae, 310
Orthocarpus, 297
purpurascens, 313
Oxalis californica, 322
pilosa, 322
Papaver heterophyllum, 321, 327
Papaveraceae, 303, 310, 327
Parietaria floridana, 321
Pectocarya penicillata, 312
Pellaea andromedaefolia, 291
mucronata, 293, 309
Perityle, 285
Emoryi, 284, 294, 331
Petalonyx, 314
Phacelia, 297
floribunda, 260, 281, 294, 302, 306, 329
hispida, 329
insularis, 306
Lyonii, 306
phyllomanica, 306
Phaseolus, 314
Photinia, 287, 297, 318, 319
arbutifolia, 286, 287, 289, 297, 299,
304, 318
var. cerina, 289, 318
var. macrocarpa, 289, 299, 304, 318
arbutifolia macrocarpa, 287, 297, 299
Phyllospadix Scouleri,309
Torreyi, 309, 326
Pinacea, 303
Pinus muricata, 260, 286, 297
remorata, 286, 303
Torreyana, 299, 303
Pityrogramma triangularis, 293, 299,
309
var. viscosa, 293, 299, 309
DUNKLE: PLANT ECOLOGY, CHANNEL ISLANDS 385
Plagiobathrys californicus, 321
var. gracilis, 321
Plantaginaceae, 306, 330
Plantago, 314
insularis, 284, 306, 321, 330
Platystemon, 285, 297
californicum ornithopus, 298
californicus, 298, 301, 303
var. ciliatus, 303, 327
var. nutans, 311, 321
var. ornithopus, 303
Plumbaginaceae, 312
Platanus, 287
Poa Douglasii, 309
var. laxa, 309
Polemoniaceae, 306, 312, 322, 329
Polygala californica, 311
Polygalaceae, 311, 327
Polygonaceae, 303, 310, 327
Polypodiaceae, 309, 326
Polypodium, 285, 290, 314
californicum, 292, 309
var. Kaulfusii, 292, 326
californicum Kaulfusii, 281, 293
Scouleri, 293, 309
vulgare hesperium, 293
Polypogon monspeliensis, 326
Polystichum munitum, 309
Populus, 317
Fremontii, 287
trichocarpa, 287
Portulaceae, 310, 328
Potentilla anserina, 311
grandulosa, 311
Primulaceae, 312
Prunus, 287, 319
ilicifolia, 289, 299, 318
Lyonii, 286, 287, 289, 297, 299, 304,
318
Pterostegia, 285
drymarioides, 281, 284, 310, 321, 327
Quercus, 318
agrifolia, 287, 297
chrysolepis, 287, 297
dumosa, 288, 289, 297, 299, 318, 319
MacDonaldii, 252, 287, 297, 303, 318
tomentella, 252, 286, 297, 302, 303,
318, 374
Ranunculaceae, 310
Ranunculus hebecarpus, 310
Resedaceae, 311
Rhamnaceae, 305, 312
Rhamnus, 297
crocea, 299
var. insularis, 299, 305
crocea insularis, 289, 318
megacarpus insularis, 297
Rhus, 297
diversiloba, 289, 291
386 ALLAN HANCOCK PACIFIC EXPEDITIONS
integrifolia, 289, 291, 293, 318
laurina, 289, 311, 318
ovata, 289
Ribes malvaceum, 311
var. clementium, 304
Menziesii, 311
viburnifolium, 299, 304
Rorippa nasturtium-acquaticum, 298
Rosaceae, 304, 311
Rubiaceae, 306
Rubus vitifolius, 311, 320
Salicornia subterminalis, 298
Salix, 317
Laevigata, 287
lasiolepis, 287
Salvia apiana, 291
mellifera, 291
var. Jonesii, 291
Brandegei, 291, 306
columbariae, 321
Sambucus, 287, 319
coerulea, 287, 318, 319, 320
Sanicula arguta, 322
bipinnatifida Hoffmanii, 322
var. Hoffmannii, 305
Saxifragaceae, 304, 311
Scirpus californicus, 298
Olneyi, 298
Scrophularia californica, 302
var. catalina, 302, 306
Scrophulariaceae, 306, 313
Senecio Lyonii, 260, 294, 307
Silene gallica, 284, 285, 296, 328
laciniata, 294
Solanum, 314
Clokeyi, 299, 306
Wallacei, 299, 302, 306
Solanaceae, 306, 313, 330
Sonchus, 283
oleraceus, 285, 331
Specularia biflora, 313
Spergularia macrotheca, 277, 293, 299,
303, 310, 320, 328
var. Talinum, 299, 303, 320
Salina, 293
Statice artica var. vulgaris, 312
Stellaria nitens, 310
Stephanomeria, 314
tomentosa, 307
Stipa lepida, 265, 296, 309
pulchra, 265, 296, 309, 326
Suaeda, 268, 276, 278, 279
californica, 293, 310, 320
var. pubescens, 293, 320, 327
californica pubescens, 277, 278
Torreyana, 293
Suaeda-Larus, 327, 330, 358
Suaeda-Lycium- -Larus, 279
‘Teucrium, 314
Tillaea erecta, 279, 311, 321, 328
‘Thysanocarpus, 297
laciniatus var. conchuliferus, 304
var. ramosus, 304
Torillis nodosa, 322
Trifolium, 297, 314
amplectens, 311
gracilentum, 281, 294, 321
var. inconspicuum, 294
var. Palmeri, 304, 321, 328
microcephalum, 311
microdon, 277, 328
stenophyllum, 294
tridentatum, 284, 294, 328
var. aciculare, 294
Typha angustifolia, 298
Umbelliferae, 305, 312
Umbellularia, 259, 287
Urticaceae, 310
Vaccinium ovatum, 312
Vicia exigua, 311
Viola, 297
Viscainoa, 314
Zauschneria californica, 291
var. villosa, 291, 305
ssp. angustifolia, 291
cana, 291
Zizyphus, 314
Zostera marina, 309
Zygadenus Fremontii, 322
voL. 13
ALLAN HANCOCK PACIFIC EXPEDITIONS
VOLUME 13 NUMBER 1
THE BRYOPHYTA OF fis
ALLAN HANCOCK EXPEDITION OF 1939
by
WILLIAM CAMPBELL STEERE
OF THE
DEPARTMENT OF BOTANY
AND THE HERBARIUM
UNIVERSITY OF MICHIGAN
TTHE UNIVERSITY OF SOUTHERN CALIFORNIA PRESS
LOS ANGELES, CALIFORNIA
1946
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ALLAN HANCOCK PACIFIC EXPEDITIONS
VOLUME 13 NUMBER 2
LAND PLANTS COLLECTED BY THE
VELERO III, ALLAN HANCOCK PACIFIC
EXPEDITIONS 1937-1941
(Piates 1-15, Maps 1-3)
BY
HOWARD SCOTT GENTRY
RESEARCH ASSOCIATE
ALLAN HANCOCK FOUNDATION
THE UNIVERSITY OF SOUTHERN CALIFORNIA
THE UNIVERSITY OF SOUTHERN CALIFORNIA PRESS
LOS ANGELES, CALIFORNIA
1949
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SF tet
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ALLAN HANCOCK PACIFIC EXPEDITIONS
VOLUME 13
NUMBER 3
PLANT ECOLOGY OF THE CHANNEL
ISLANDS OF CALIFORNIA
(Ficures 1-12, Piates 1-6)
BY
MERYL BYRON DUNKLE
THE UNIVERSITY OF SOUTHERN CALIFORNIA PRESS
LOS ANGELES, CALIFORNIA
1950
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