The Structure and Life-History of the Hay-Scented Fern. BY HENRY SHOEMAKER CONARD, PH. D. WASHINGTON, D. C. PUBLISHED BY THE CARNEGIE INSTITUTION OF WASHINGTON. 1908. The Structure and Life-History of the Hay-Scented Fern. BY HENRY SHOEMAKER CONARD, PH. D. WASHINGTON, D. C. PUBLISHED BY THE CARNEGIE INSTITUTION OF WASHINGTON. 1908. CARNEGIE INSTITUTION OF WASHINGTON PUBLICATION No. 94 THE COHNMAN PRINTING CO. CARLISLE, PA. C7 PREFACE. Aside from certain personal interests and opinions, the impulse to the present investigation came from a study of recent papers by Jeffrey, Boodle, and Gwynne-Vaughan. But since we shall never know the true relations of a plant to its surrounding's until we have worked out its complete life- history, it seemed to me very desirable to have all of our knowledge of this species collected into a unit . Therefore the study was carried beyond the problems suggested by the papers referred to. The work was begun in odd moments of an instructorship at the Uni- versity of Pennsylvania, but nearly all of it was actually done in the Botanical Laboratory of the Johns Hopkins University, and this paper is to be regarded as Contribution No. 7 from that Laboratory. I was there as ' 'James Buchanan Johnston Scholar" from February, 1905, until June, 1906. For the opportunity to carry on this investigation in a peculiarly stimulating atmosphere, I am deeply indebted to those who administer the affairs of the university. It is an especial pleasure to express appre- ciation of the constant friendly interest taken by Prof. Duncan S. Johnson. The fundamental teachings of Prof. W. K. Brooks have also molded many of my thoughts and expressions. Thanks are due to Mr. I. F. Lewis for a collection of material from Long Island; to the late Mr. E. R. Heacock for my first pot of prothallia and "sporelings;" to Dr. C. E. Waters for infor- mation and for the excellent photographs, plates 1 and 2; to Henry Holt & Co. for the use of two copyrighted pictures; to Capt. John Donnell Smith for library facilities; to Mr. J. D. Thompson, of the Library of Congress, and Mr. Joseph H. Painter and Mr. W. R. Maxon, of the United States National Museum, for looking up certain papers not otherwise accessible to me; and to the officers of the Academy of Natural Sciences of Philadel- phia for the use of several rare old books. All of these obligations are now gratefully acknowledged. HENRY S. CONARD. GRINNELL, IOWA, April, 1907. THE STRUCTURE AND LIFE-HISTORY OF THE HAY-SCENTED FERN. By HENRY SHOEMAKER CONARD, Professor of Botany, Iowa College. HISTORICAL INTRODUCTION. The hay-scented fern, Dennstcedtia punctilobula (Michx.) Moore (= Dicksonia punctilobula Willd.) first appeared in botanical literature in 1803, when it was described by Michatix as follows: \Nephrodium~\ punctilobulum. N. majusculum: stipite nudo, ramis pinnulisque pu- bescentihus: fronde longa, bipinnata; pinnulis decurrentibus, subovali-oblongis, semi et ultra pinnatifidis; lobulis oblonguisculi, apice 2-4-dentatis, singulis unipunctiferis. Obs.: Habitus Polyp, filicis fceminas Linn. Hab. in Canada. [A. Michaux, 1803, p. 268.] There is nothing- in the text to indicate that this is a new species. Michaux' s genus Nephrodium was extremely far-reaching', being: defined in these words: "fructibus punctis subreniformibus" (p. 266). Among the species are N. thelypteroides, marginale, filix-ftzmina, and dryopteris! Swartz (1806) placed the hay-scented fern in the genus Aspidium, in which he was followed by Willdenow (1810). The latter writer, both in his own text and in his quotation from Michaux, changes the spelling of the specific name to punctilobum. But he had already (1809) described it under the name of Dicksonia pilosiuscula, and this, too, is copied in the Species Plantarum. The text of the Enumeratio (1809) is as follows: DICKSONIA. Sort subrotundi distinct! marginales. Industum duplex, alterum superficiarum exte- rius dehiscens, alterum e margine frondis inflexo interius dehiscens. i. D. frondibus bipinnatis, pinnis pinnatifidis, laciniis dentatis, rachi pilosiuscula. Polypodium pilosiusculum. Miihlenberg in litt. Habitat in Pennsylvania. (!) Q[D. An important addition to the other diagnosis is the notice of hairs upon the rachis. These are so characteristic as readily to distinguish this fern from any other in our native flora. In preparing the ' 'Species' ' , Willdenow recognized the similarity of his Aspidium punctilobum and Dicksonia pilosius- cula as expressed in the closing words of the description of the latter : An Aspidium punctilobum supra p. 270 dubie indicatum, eadem sit filix aliis ad dijudicandum relinquo? quum pinnulas neque sint decurrentes neque pubescentes. 5 6 STRUCTURE AND LIFE-HISTORY OF HAY-SCENTED FERN. Schkuhr (1809, p. 125, plate 131) referred to this fern as Dicksonia bubescens* He has been followed only by Presl (1836, p. 136). Desvaux (1827) made this species the type and only member of his g-enus Sitobolium. His diagnosis of the genus reads: "Sori globosi; in- volucrum fornicatum globulosum a basi ad apicem dehiscens" (pp. 262, 263). No specific diagnosis is given. t J. Smith (1841) changed the spelling1 to Sitolobium, and Newman's text (1851) gives Litolobium. G. Kunze writes thus in Linnaea (23:249): Sitobolium (male Sitolobium)," but in 1848 the printer makes him say "Litolobium (not Sitolobium)." Link's (1841) g-enus Adectum\ is too late ever to be more than a synonym. The identity of the plant, however, has never been in doubt, for it stands absolutely unique amid its native surroundings. The list of synonymy on page 45 will serve to show how the name has been bowled about. Its gfeneric affinities are briefly discussed on page 42. We will simply state that its place is at present established in Bernhardi's (1800) genus Dennst&dtia (type: D.flaccida= Trichomanes flaccidum Forst.), and we *On plate 131 marked Dicksonia pubescens. Text on p. 125 reads: II. DICKS. ^pubescens in margin of page] frondibus subtripinnatis, foliolis lanceo- latis, pinnis oblongis, laciniis ovatis dentatis, stipite glabro, rachi pubescente. Sw. Mohr. in Litt. Nephr odium punctilobuhim, maiusculum; stipite nudo, ramis pinnulisque pubescen- tibus: fronde longa, bipinnata; pinnulis decurrentibus, subovali-oblongis, semi et ultra pinnatifidis; lobulis oblongiusculis, apice 2-4-dentatis, singulis unipunctiferis. Mich. Flor. Bor. Amer. n. p. 268. Habitat in Canada. Habitus Polypod. filic. fern. Mich. Weichhaariger Dicksonischer Farn. Mit fast 3-mal gefiedertem Laube, lanzet- fdrmigen Blattern, langlichen Blattchen, eyrunden, gezahnten Lappen, glatten Strunke und eine weichhaarigen Spindel. Dieser Farn erhielt ich stiickweise aus Pennsylvanien auch unter Polypodium pilo- siusculum Willd., wonach ich zwar die eigendliche Grosse nicht, aber nach dessen Theilen doch die 3-fache Fiederung erkennen kann. . . . [The next paragraph de- scribes the plate, closing with the words] Alle Rippen der Blattchen and Lappen sind, wie die Spindel, mit gegliederten Haaren bekleidet. tDesvaux's full text reads: SITOBOLIUM N. Sori globosi; involucrum fornicatum globulosum a basi ad apicem dehiscens. i. S. punctilobum N. Nephrodium punctilobum Mich., Fl. am. bor., n, p. 268. Aspid. punctilobum Sw., Syn.t p. 60. Dicksonia pilosiuscula Willd., En. hort. ber., p. 1076. Dickson. pubescens Schk., Fil., t. 131. J Link's full text is as follows: ADECTUM. Frons tripinnatisecta. Sori subrotundi marginales ad sinus frondis. Indusium undique ad sorum adnatum eumque tegens, demum medio dehiscens et circulare. A. Dicksonia defectu sporidochii valde differt. i. A.pilosiusculumiv. tripinnatifida, pinnellis brevibus, antice et superne incisis, stipite rhachi costisque pubescentibus. D. Fr. 1-2 ped. alta, pinnae 3 poll. Igae., pinnulae 3 lin. Igae. Dicksonia pilosiuscula W. sp. 484. W. E. 1076. ^.^.2.464. H. b. 2.10. Raddi bras. 63. Dicksonia pubescens Schkuhr kr. 125 /. 132. Hab. in sylvis opacis ad rupes Pennsylvaniae et Virginiae nee non in locis montosis prope Tejuco Brisiliae. Perenne. [p. 72.] HISTORICAL INTRODUCTION. 7 follow Moore (1857) and most recent scholars in accepting- the name Denn- stcedtia punctilobula (Michx.) Moore. Two varieties of D. punctilobula have been described in recent years. Dennst&dtia punctilobula var. cristata Maxon (1899) was found in Massa- chusetts by F. G. Floyd. Under cultivation the percentage of crested fronds produced varies greatly. "Some fronds have not only had the apex of every pinna doubly or trebly crested, but the apex of the frond itself has frequently been bifidly divided with heavily crested apices" (Davenport, 1905) . I have several times seen fronds with the rachis bifur- cated 10 cm. or more below the apex. Each fork, then, bears a normal continuation of the leaf. Waters (1903) considers this condition "fre- quent." He also states (p. 289) that "A form with rather narrow fronds, the pinnae unequal in length and with the teeth of the ultimate segments very deeply cut, so that each vein forms the midrib of a narrow tongue- like segment, has been named D. pilosiuscula schizophylla. ' ' Of course this name should read Dennsttedtia punctilobula schizophylla. On the relation of these varieties to the typical form I have no opinion to express. In botanical literature other than taxonomic or noristic the hay-scented fern scarcely appears. Descriptions of its habit of growth, its glands, and long, slender rhizome are given by Williamson (1878, p. 117, plates XLV, XLVI), Eaton (1879-1880, pp. 341-343, plate 44), Clute (1901, pp. 225-231), and Waters (1903, pp. 288-290). Frances Wilson writes an appreciative general account of these features in the Asa Gray Bulletin (1897), and Waters (1903) adds to a pleasing text photographs which are exquisite and true to life. Parsons (1899) and Eastman (1904) refer to this fern in a popular way. Eaton (1879-1880) and Waters (1903) speak of the concentric arrange- ment of light and dark tissues in the rhizome (cf. fig. 67), and the tax- onomic writers tell of the indusium in detail. De Bary (1884) describes the vascular bundle of Dennst&dtia (naming this species along with three others in parenthesis) as having a tubular bundle, "which is closed as far as the foliar gap; the bundle which enters the leaf arises from the whole margin of the gap as a continuous concave plate \_cf. fig. 82], which is only occasionally split up at its base into several bundles lying side by side." Gwynne-Vaughan in 1901 (p. 85) mentioned the present species as showing thick- walled elements in the phloem of the petiole. In 1903 (p. 691) he includes D. punctilobula in a list of nineteen ferns with typ- ical and practically identical solenostelic structure, as described by him in Loxosoma cunninghamii. A page of text is devoted to a summary of the facts of structure in the group. A summary of taxonomic literature, with synonymy, is given on our pages 44 and 45 following. 8 STRUCTURE AND LIFE-HISTORY OF HAY-SCENTED FERN. SPOROPHYTE. The hay-scented fern occurs generally in open woods (fig-, l) or clear- ings or on roadside banks. It prefers well-drained, stony or sandy soil, and usually forms thick beds. In the Catskill Mountains of New York and in New England it grows on the cleared hillsides in dense patches 8 to 15 m. in diameter. Its range is from New Brunswick to Alabama and Minnesota (Britton and Brown, 1896, 1 :12). The leaves are from 50 to 90 cm. high, lanceolate, and thrice pinnatifid. A light-green color and dense pubescence combine to give the fern a soft, feathery appearance. The glandular hairs exhale a delicate fragrance when brushed, which has been likened to new-mown hay; hence the common name.* The stems are found 5 to 15 cm. beneath the surface of the soil — long, slender, much-branching rhizomes (fig. 3). These spread rapidly from year to year, and give rise to the densely matted beds of the fern. Roots of threadlike fineness arise plentifully from all parts of the rhizomes and ramify through the soil. THE ROOT. The roots are numerous, cylindrical, with copious, two-ranked branching. They extend more horizontally than vertically in the soil, and do not descend below 20 cm. from the surface. The color is black in mature portions, shading in the younger parts through reddish-brown and brownish -yellow to creamy white at the apex. Although but 0.5 mm. in diameter (maximum 0.545 mm.; minimum 0.49 mm.; average 0.523 mm.), they are tough and wiry in texture. The rootlets (secondary roots) are about half as thick as the main roots. Tertiary roots, similar to the secondary, frequently occur. Only rarely does a root arise from the base of a leaf, and then it is usually within 4 mm. of the center of the rhizome. TABLE i. — Acropetal development of roots from stem. Length of root. Distance from apex of stem. Branching. Collected. mm. mm. 32 No branches Univ. of Pa., 8/6/'o4. 4-77 6 40 . & 32 No branches .... •• Fallsington, Pa., io/4/'o3. 3-2 4 78 . ^ 4-5 6 40 One branch 4.7 mm. long, i cm. from stem. Many branches .... Do. Do. From any part of the stem roots may come out, but more frequently from the lower side. A stem 5 cm. long, including the tip, showed eleven roots, inserted as shown in fig. 9. They arise in acropetal succession very *The names fine-haired fern, mountain fern, gossamer fern, and hairy Dicksonia are given by Clute (1901, p. 231), and sweet grass fern by Eastman (1904, p. 67). vSPOROPHYTE. near to the stem apex (see table l) and lengthen rapidly. I have one which is 24.5 cm. long and the broken ends were frequently found at a distance of 20 cm. from the stem. It is likely that these lengths are not much exceeded. The rootlets are generally alternate on opposite sides of the primary root-axis, but many exceptions occur. Two rootlets are often TABLE 2. found conseciitively on one side, and in one case five were seen . Successive root- lets may be as much as 8 mm. apart or almost or quite opposite (figs. 6, 7, 8; table 2). None occur usually within 12 or 15 mm. of the stem. Table 2 shows irregularities in alter- nate arrangement of rootlets on opposite sides of roots. The figures indicate distance in millimeters of each rootlet from the one next above it, and columns show alternation. The root-cap is rather long and pointed (fig. 23). From the initial cell of the root outward ten rows of cells may be seen in a strongly developed specimen, five in a slender root of a sporeling. Outside of these cell-layers a worn-out layer is seen, in the act of sloughing off . The inner layers are small-celled and rich in protoplasm. The outermost cells are four times the diameter of the inner, but still nucleated . Indeed , small , dense , nucleolus-like nuclei are seen even in the layer that is shedding. The cap thins out layer by layer along the sides of the root, and the cells become very long and narrow. The outermost layer persists some distance above the next inner one. No sign of statolith bodies has been seen in any part of the root-cap. In development, each terminal segment of the root-initial gives rise to a single layer of root-cap cells.* The segment divides first by an anti- clinal wall parallel to one of the sides of the initial (figs. 10, 11, 26). In successive cap segments the first wall of one stands either directly over or at an angle of 60° to that of the preceding or following one, and not at Root 1. Root 3. Right. Left. Right. Left. Stem Stem 13-5 13.0 3-5 3-5 1.6 2.0 3-2 2.0 3-5 I . $ 1.8 3-3 3-5 3-5 3.O 3 -° 4.0 1.5 6.2 8.0 4.0 3-3 0.2 4-5 4.0 6.5 2.0 3-5 6-5 Root 2. 3-° 4.0 (?^ 2.O / 4.0 5-5 6.0 2-5 3-5 5.0 0.5 I . I 3-0 4.0 3-3 i-5 Root 4. 4.4 6-5 3-8 (?) 5 -° 2-5 1.6 2.5 6.5 1.8 5-0 3.0 8.0 *In a few cases periclinal walls were seen in three to five or six of the median cells, making the segment two-layered at that point (fig. 24). 10 STRUCTURE AND LIFE-HISTORY OF HAY-SCENTED FERN. 45°, as stated by Nageli and Leitgeb (1868, p. 76). The halves are next cut into quadrants by anticlinals at right angles to the first wall (figs. 11, 12, 25). The succeeding" walls in the quadrants are heterodromous and may be parallel to either of the preceding or be oblique (figs. 13, 25). No further regularity was found in the division of root-cap segments. The initial cell of the root is a triangular pyramid with its longest axis in the axis of the root (figs. 23, 27, 28). Lateral segments are cut off around the initial on one side after another in regular order. I noted ten roots (fig. 27) in which the succession of segments was counter-clockwise (proceeding from older to younger segments) and four in which it was clockwise, as one views the cell from its outer (cap ward) base. Each lateral segment divides first by a periclinal wall near its outer margin (figs. 14, 15, 23, 27-29). The next wall is a radial anticline which passes inward from near the middle of the first, and strikes one of the sides of the segment near its inner angle, dividing the inner cell into "sextants" (fig. 16, 11; segment 3 in figs. 27-29). Thus there is in each segment a larger (major) and a smaller (minor) sextant. In transverse section of the root we see the three major sextants meeting at the center of the sec- tion (figs. 29-33), with three alternating minor sextants which do not reach quite to the center. The "sextant wall" meets that side of the seg- ment which is adjacent to the next older segments, (kathodic wall) and is therefore katadromous. As all of the segments in any root are alike in this respect, the divisions are said to be homodromous. Soon after the sextant wall is formed in the inner part of the segment it is laid down also in the outer part (fig. 17; segment 4 in figs. 27-29). A second pericline is now laid down near the middle of each inner sextant cell (figs. 18^ 23; segment 5 in figs. 27-30). As this wall forms the boundary between the plerome and outer tissues, it may be called the periplerome wall. Another periclinal laid down in the two outer sexants divides these into two layers, the definitive epidermis (piliferous layer) and hypodermis (fig. 19; segment 6 in figs. 27-31). Both of these tissues remain one-layered throughout. Subsequent divisions in them are all anticlinal, either radial or transverse (figs. 23; 27-33). Almost simul- taneously periclinal walls are formed on each side of the periplerome wall, near and parallel to it (figs. 14, 20, 21, walls vi and vii; 23). In the majority of cases, however, the outer one seems to precede. The result- ing cells constitute the definitive endodermis and pericycle. The cells of the former are from the beginning flattened, of the latter nearly cubical (figs. 23, 31, 33). If we group the segments into cycles of three , beginning with the latest formed (,cf. figs. 27, 28), we find walls i and n (figs. 14-22) already in one or more of the youngest cycle. Walls n, in, and iv are found in the second cycle, and vi and vii in the second or third. In the second or SPOROPHYTE. 11 third cycle of segments longitudinal radial anticlines are also formed in the outer members of the segment, dividing the sextants into halves (figs. 21, 22, viu). As yet each segment consists of but one layer of cells. Transverse anticlines occurring throughout the segment in the third or fourth cycle make it two-layered (fig. 23). A second series of divisions in the same plane cuts the outer tissues (epidermis, hypodermis, cortex) into four vertical layers. These cleavages occur first in the epidermis, but their order of sequence is rapid and apparently varied. The pericycle is late in becoming divided; and the endodermis of a certain pair of oppo- site sextants lacks the radial division for a long time, as will be described in speaking of the origin of lateral rootlets. The large cell remaining between the endodermis and hypodermis (figs. 14, 20, 21, 23) gives rise to all of the cortex. After its transverse anti- clinal division it rapidly undergoes one to three periclinal and as many radial divisions. The periclinals probably take place in centrifugal order. The result is a cortex of two to four concentric layers, each with 14 to 24 cells. The last divisions are complete in the fourth, or at least the fifth cycle of segments {cf. figs. 28-33). The triangular cells lying within the pericycle (fig. 21) divide either by a periclinal wall into two parts or by two tangential walls into three parts (figs. 22, 29-31). The tips of the three major sextants and of one minor (occasionally two) become tracheids of the metaxylem. The cells between the tracheids and the pericycle of this minor and of the major opposite to it become protoxylem cells (figs. 14, 22, 29-33); the inter- mediate parts of the other two majors, and all within the pericycle in the two remaining minors (with the exception noted above) go to form phloem (figs. 14, 22, 29-33). As the elements elongate, the transverse limits of the segments are soon obliterated (fig. 23). Four or at most five cycles only can be recog- nized. The sextants, however, may often be distinguished until quite a late period (fig. 33). The above-described order of the early divisions of the segment (walls i to vn, figs. 14-22) is easily followed in its main outlines in good serial sections of any leptosporangiate fern root. But English and German text-books* still adhere unanimously to the statement of Nageli and Leitgeb that the first division in the segment is the sextant wall, fol- lowed by that which separates periblem and plerome. The first error was corrected by Lachmann (1885; 18S7',Jide Van Tieghem and Douliot), and *Nageli and Leitgeb, 1865, 1868; Pteris Campbell, 1895, p. 328-329, fig. i65A ; 1905 hastata, plate 14, fig. 7. p. 333. Sachs, 1875, pp. 124-125, fig. io2A. Strasburger, 1897, pp. 31 1-313, figs. 139, 140. De Bary, 1884, pp. 18-19, ^g8- 7Ai 8A- Sadebeck, 1898, p. 61, fig. 4iA. Goebel, 1887, pp. 214-215, fig. 162. Strasburger, Noll, etc., 1898, pp. 150-151, Bower, 1889. fig. 165. Vines, 1894, pp. 149-150, figs. 114, 115- Haberlandt, 1904, p. 74, fig. 14. 12 STRUCTURE AND LIFE-HISTORY OF HAY-SCENTED FERN. the second by Van Teighem and Dotiliot in 1888. The latter authorities indicate that in some ferns {Ptcris, Adiantum, Aneimia, etc.) the outer cell (figs. 14, 16, 17) may give rise to two or three layers of cortex in ad- dition to the epidermis (see table of cell-lineage in fern roots, p. 46). Such ferns are in the minority. The same writers state that in Rqnisetum, Osmunda, and Todea the first periclinal wall is between the central cyl- inder and cortex, but that this is not the case in any other Pteridophytes which have a single initial in the root. I have found the account here given for Dennstcedtia as to the origin of epidermis, hypodermis, cortex, and endodermis to apply equally to root-tips of Cibotium regale, Aspidium molle (fig. 48), Lygodium japonicum, Onoclea sensibilis (fig. 51), Ceratopteris thalictroides (fig. 50), and Aspidium viar- ginale (fig. 47). In Pteridium aqnilinum and Didymockl&na lunulata (fig. 49) the epidermis and two layers of cortex are derived from the same part of the segment. Above the region of cell division in the root-tip there intervenes a brief region of elongation. Beyond this, viz, about 2.5 mm. from the apex, root-hairs appear. Each hair is ... -, . ,1 /- ^1 TABLE 3. — Root-hairs. a cylindrical outgrowth from the lower (distal) end of an epidermal cell. The cavities of cell and hair are continuous, and contain but one nucleus (fig. 252) lying variously in the wall-layer of protoplasm. In functional hairs the nucleus is seen near the swollen apex. The walls of the hairs are thin, of a clear, brownish-yellow color, and are often molded around irregular particles of earth. Table 3 gives the exact dimensions . A transverse section of the region of functional root-hairs (figs. 34, 35, 44) shows the epidermis, hypodermis, four or five (rarely three) layers of cortex and a well-defined endodermis. A single layer (rarely doubled in places) of pericycle surrounds the cylindrical, diarch bundle. Protoxylems abut directly upon the pericycle at diametrically opposite points, and between them lies a group of two to four (rarely five) large tracheids. Extending around within the pericycle from each side of each protoxylem is a row of three to seven sieve-tubes. Midway between the protoxylems and lying against the pericycle is the small-celled, dense protophloem. Between the phloem and xylem are cells of conjunctive parenchyma. The epidermis (piliferous layer of Van Tieghem, etc.) at the level we are speaking of is fully mature, and consists of cells four to six times as long as wide. In cross-section they are nearly isodiametric, of slightly variable depth and width, and bulging out a little on the outer side. The Length. Diameter. Remarks. mm. mm. 0-5+ 0.014 Broken off. o.3+ 0.014 Do. O.2 0.014 Entire; immature? SPOROPHYTE. 13 walls are brownish-yellow, like those of all of the cells outside of the endodermis. The subjacent hypodermal cells are about three times as wide and twice as deep radially as those of the epidermis, and similarly elongated. The first cortical layer is composed of cells nearly twice as larg-e in cross-section as the foregoing, but like the last in length and character of wall. Intercellular spaces occur rarely at the angles of these cells. The cells of the second cortical layer are smaller again, often as narrow as the epidermal cells. The two innermost layers are still smaller. In the last three layers, especially the middle one, thickening of the walls begins even before the root hairs are fully mature (fig. 43). At this stage the endodermal cells are already very long, narrow, and practically empty. Pericycle and conjunctive parenchyma are full of dense, granular contents. They are probably multinucleate, since the cells are very narrow and long, but nearly always show a nucleus in cross-sections. The pericycle cells are often much larger in the region of the protophloem than elsewhere (fig. 35). The protophloems have already passed their greatest density and prominence and the sieve-tubes now appear mature. Each protoxylem consists of one or two extremely slender spiral elements, with one or two slightly wider scalariform tracheids on either side. The two or four large central tracheids of the metaxylem show as yet no thickening of the walls (figs. 34, 35, 36, 43,44). TABLE 4. — Statistics of transverse section of root. No. of cells in— Cortex. No. of cells in— Epiderm. Hypoderm. No. of layers. No. of cells In outer layer. No. of eel Is in inner layer. Endoderm. Pericycle. 64 30 4 *22 20 19 21 49 19 4 14 24 18 20 40 !? 4 ... ... ... 40 20 4 H 23 16 *7 46 26 *i8 13 10 13 t6i 27 22 20 15 *9 tS2 28 4 or 5 ... 21 15 20 tso 26 3 21 17 13 16 i with 3 14 with 4 10 with 5 3 with 6 * Immature. flections of one root, 16 ^ apart. Following all these parts upward in an old root, we find that the epider- mis and outer soft layer of cortex wither after the root-hairs die, and are ultimately sloughed off (fig. 46). The bundle is now protected by the two or three inner cortical layers, whose walls have thickened so as almost to obliterate the lumen. Lignification in the metaxylem takes place slowly. In a section showing a withering epidermis, and the inner cortex indurated 14 STRUCTURE AND LIFE-HISTORY OF HAY-SCENTED FERN. so that the cell-walls are about one-fourth the width of the lumens, there are (fig. 44) two large tracheids slightly thickened, and two in the center wholly unthickened and containing protoplasm. Only with the decay and disruption of the outer layers of the root do the inner cortex and xylem become fully mature (fig. 45). This occurs from 3.5 cm. to 10 cm. from the root tip. One can not as a rule, obtain a transverse section showing all of the tissues mature and intact. These facts have an important physiological significance. We suppose the water-supply of the plant to come in through the root-hairs. But where these are functional the xylem, always considered the water-con- ducting tissue, is decidedly immature. It is evident that lignified walls are not necessary for the conduction of water in the cells. It may be, however, that the inner cortex, whose walls thicken at such an early period, is for a time active in water conduction. In 25 out of 95 roots examined (/. . 8. Posterior lower left octant =Root j It must not be supposed, however, that this arrangement is invariable. On a prothallus with two embryos one has the root-intitial in octant 8, the other in 7. Octants 2, 3, 5, 7 are smaller than 1, 4, 6, 8. The first division in 2, 4, 6, 8 is parallel to the basal wall and near to it. In 8 the succeeding divisions are parallel to the other primary walls, and then to the curved outer wall. The resulting tetrahedral central cell is the root initial. It continues to divide in the way which is characteristic for roots (?. v.) (figs. 235,236). THE YOUNG SPOROPHYTE. 39 The two posterior upper octants (5,6) divide irregularly into a mass of polyhedral cells, the foot. Those in contact with the base of the arche- g-onium become closely applied to the wall, and the boundary between prothallial and embryonic tissues is often difficult to determine. Neigh- boring- cells of the two anterior upper octants are also involved in the for- mation of the fully matured foot (figfs. 235, 236, 246). Octants 2 and 7 divide irreg-ularly and serve only to fill up their respec- tive corners of the embryo plant. Octant 1, after cleavag-es mostly parallel to the basal and quadrant walls, ultimately gives rise to the stem-initial, lying: close to the octant wall, /. > til II CELL-LINEAGE IN FERN-ROOTS. s * :- ; §?~ -^ s ^ £ S 3 o> £ tT S _ri2 J 5 « d B &S b* d £S i* a 9 Sid1 * o ~ > « s; *& 3! t 3*4 II! Se gig S,z% ioo'oooo'sS^'cioo ' ts -o -c -d -o •cJ n> ® *- *o x ; i i l^s ' - -(N^HCC rtex rtex of c :|j| HI :-^S^ : o o o :£o£ !&B& • c3 OJ c« ver r 2 ver Se rtic tela 18 rte gO O O IN cS O *^ O ^ o »* 151j3 « « * i5 Sll II^H ?5 g : 03 O O O fe-OTS-d t^ooo 0-0-00 8555 :— : — =>~ :- :-" :- 1 1'1 "f •K- «- WS a: infer two 1 ever forme i'liMjlj • : 0 ^ rt ** *3 M • • • !! mil ej 5 :=§! § 8 T3 = «:* :fi ^ 8' J i P be a* «> Polypodium aurei dime falca vulg Pteris aquilina. . . aquilina. .. arguta blumeana . cretica cretica. . . . cretica hastata. . . hastata. .. serrulata.. Scol open d Hum o Struthiopteris ger Do Gleichenia Gleichenia circins flabell rupest Schizceace Aneimia fraxinifc hirta phyllitic Lygodium japoni scande scande Osmundac Osmunda regalis. Todea barbara. . . wronii Marsiliact Marsilia drummo Si ila O. »- : 3 3 fel ^€5 *5j" 'C 4 a £ Salviniact Azolla Carolinian! flliculoides Equisetac Equisetum hiema varies trachj Ferns in general . * Van Tieghena t Only one cap-s 48 STRUCTURE AND LIFE-HISTORY OF HAY-SCENTED FERN. BIBLIOGRAPHY. ATKINSON, G. F. 1894. The Study of the Biology of Ferns. BALL, E. H. 1876. The Indigenous Ferns of Nova Scotia, in Proc. and Trans. Nov. Scot. Inst. of Nat. Sci., 4: 155. BAUKE, H. 1876. Entwicklungsgeschichte des Prothalliums bei den Cyatheaceen, ver- glichen mit derselben bei den anderen Farrnkrautern, in Jahrb. f. wiss. Botanik, 10: 49-116, pis. 6-10. BERNHARDI, D. I. I. 1800. Tentamen alterum filicesin genera redigendi, in Schrader's Journal fiir die Botanik. Gottingen, vol. 2, parts i and 2, pp. 121-136. BIGELOW, J. 1814-1840. Florula Bostoniensis, ed. i, 1814; n, 1824; in, 1840. BOODLE, L. A. 1901. Comparative Anatomy of Hymenophyllaceas, Schizaeaceae, and Gleicheniaceas. II. On the anatomy of the Schizaeaceae. In Annals of Botany, 15:359-423. June. BOWER, F. O. 1889. The Comparative Examination of the Meristems of Ferns as a Phylogenetic Study, in Annals of Botany, 3: 305-393 BRICK, C. 1897. Review of Wilson, 1897, in Botan. Jahrsber. 1897, 1: 470. BRITTON, N. L. 1901. Manual of the Flora of the Northern States and Canada, p. 19. - and BROWN, AD. 1896. An Illustrated Flora of the Northern United States, Can- ada, and the British Possessions, 1: 12. CAMPBELL, D. H. 1887. The Development of the Ostrich Fern, in Mem. Boston Soc. Nat. Hist., 4: 17-52, pis. 4-7. 1895; 1905. The Structure and Development of the Mosses and Ferns. Macmillan, New York: ist and 2d ed. CHAPMAN, A. W. 1860-1897. Flora of the Southern United States; ed. i, 1860; n, 1883; in, 1897. CHRIST, H. 1897. Die Farnkrauter der Erde, Jena. CHRYSLER, M. A. 1904. The Development of the Central Cylinder of Araceae and Liliaceae, in Botanical Gazette, 38: 161-184, pis. xn-xv. Sept. 23, 1904. CLUTE, W. N. 1901. Our Ferns in their Haunts. New York; 332 pp. CONARD, H. S. 1906. Morphology of Fern Stem, in Johns Hopkins Circulars, pp. 95- 98. May. COPELAND, E. B. 1902. The Mechanism of Stomata, in Ann. of Bot.. 1 6: 327-364, pi. 13. June. DARLINGTON, WM. 1853. Flora Cestrica; ed. i, 18375111, 1853. Philadelphia. DAVENPORT, G. E. Dicksonia pilosiuscula var. cristata, in Rhodora, 2: 220-226. Not seen. - 1905. Reversions and their Fluctuations, in Fern Bulletin, 13: 106-107. DE BARY, A. 1877; 1884. Comparative Anatomy of Phanerogams and Ferns. German ed., 1877; English trans., 1884. DESVAUX, N. A. 1827. Prodrome de la Famille des Fougeres, in Mdm. Soc. Linn. Paris, 6: 171-337. See pp. 262-263. DIELS, L. 1899. Polypodiaceae in Engler and Prantl's Natiirlichen Pflanzenfamilien, 1-4: 217-218. Sept. 12, 1899. EASTMAN, H. 1904. New England Ferns and their Common Allies. Boston. 161 pp. EATON, A. 1836. Manual of Botany for North America. Albany. — and WRIGHT, J. 1840. North American Botany; ed. vm. EATON, D. C. 1879. The Ferns of North America. 2 vols., 1879-1880, 81 plates. Salem, Mass. FEE, A. L. A. 1850. Genera Filicum (Cinquieme Memoire sur la Famille des Fougeres). Exposition des Genres de la Famille des Polypodiace'es. Paris and Strasbourg. FORD, S. O. 1902. The Anatomy of Ceratopteris thalictroides, in Annals of Botany, 16: 95-122, pi. 6. March. FOWLER. New Brunswick Catalogue. GILBERT, B. D 1905. Observations on North American Pteridophytes, n, in Fern Bulletin, 13: 100-104. GRAY, ASA. 1848-1889. Manual of the Botany of the Northern United States; ed. i, 1848; 11, 1856; in, 1858; iv, 1859; v, 1880; vi, 1889. GOEBEL, K. 1887. Outlines of Classification and Special Morphology, English trans- lation. — 1900. Organography of Plants. Transl. by Balfotir, 1: 14-17- GWYNNE-VAUGHAN, D. T. 1901. Observations on the Anatomy of Solenostelic Ferns I. Loxosoma. In Annals of Botany, 15: 71-99. 1903. Ditto, n, 1. c., 17: 689-743. HABERLANDT, G. 1904. Physiologische Pflanzenanatomie, ed. 3. BIBLIOGRAPHY. 49 HOOKER, W. J. 1840. Flora boreali-americana, 2: 264. London. - 1846. Species Filicum, vol. i. — and BAKER, J. G. 1874. Synopsis Filicum, ed. i, 1868; n, 1874. JANSE, J. M. 1895. Les endophytes radicaux de quelques plantes Javanaises, in Ann. du Jardin Botanique de Buitenzorg, 14: 53-201, pi. v-xv. (Vol. 14 is dated 1897.) JEFFREY, E. C. 1897. The Morphology of the Central Cylinder in Vascular Plants, in Report of the British Assoc. for the Adv. of Sci. 1897, pp. 869-870. JOHNSON, D. S. 1898. On the development of the leaf and sporocarp in Marsilia quadrifolia L., in Annals of Botany, 12: 119-147. June. KELLER, I., and BROWN, S. 1905. Handbook of the Flora of Philadelphia and Vicinity. Phila. Bot. Club. KNY. 1875. Die Entwickelung der Parkeriaceen dargestellt an Ceratopteris thal- ictroides Brongn., in Nova Acta d. Leopoldinisch Carolinische Akademie der Naturforscher, 37: 1-80, pi. 18-25. KUNZE, G. 1848. In Silliman's American Journal of Science and Arts, 2d series, 6: 80-89. "Notes on some ferns of the United States," written 1846. - 1850^. Einige Bemerkungen iiber Dicksonia, in Botan. Zeitung, 8: 57-62. - 1850^. Index Filicum (sensu latissimo), in Linnaea, 23: 209-323. LACHMANN, P. 1877. Structure et croissance de la racine des Fougeres, in Bull. Soc. bot. Lyon. Not seen. — 1885. Recherches sur la morphologic et 1'anatomie des Fougeres, in Comptes Rendus, 101: 603. Not seen. - 1887. Structure et croissance de la racine des Fougeres, et 1'origine des radicelles. Bull. Soc. bot. de Lyon. LAWSON, Geo. 1864. Synopsis of Canadian Ferns and Filicoid Plants, in Trans. Bot. Soc. Edinb., 8: 20-50. vidi. Also in Edinb. New Philos. Journ., N. S., 19:io2- 116,273-291, 1864; Canad. Naturalist, N. S., 1: 262-380, 1864. Not seen. - 1888. The Fern Flora of Canada. A. W. Mackinlay, Halifax. Not seen. L'HERITIER DE BRUTELLE, C. L. 1788. Sertum Anglicum. Folio, 36 pp., 34 plates. Not seen. LINK, H. F. 1841. Filicum species in horto regio botanico Berolinensi cultae. 179 pp. Not seen. LINNAEUS, C. 1753. Species Plantarum. LOWE, E. J. 1867. Ferns: British and Exotic, vol.8. London. MACOUN, J. 1890. Catalogue of Canadian Plants. Part v, Acrogens. Geological and Natural History Survey of Canada, vol. 2. Montreal. — and BURGESS, F. W. 1884. Canadian Filicineae, in Trans. Roy. Soc. Canada, 2: 163-227; sec. 4. MAXON, W. R. 1899. A variety of Dicksonia, in Fern Bulletin 7": 63-64. Not seen. METTENIUS, G. H. 1856. Filices horti botanici Lipsiensis. MICHAUX, A. Hort. med. Paris. Cat. not seen. — 1803. Flora Boreali-Americana, 2: 268. MOORE, THOS. 1857. Index Filicum. NAGELI, C., and LEITGEB, H. 1865. In Sitzber. baier. Akad. Wiss. — 1868. Entstehung und Wachsthum der Wurzeln in Beitr. z. wiss. Botanik, Hft. iv, pp. 74-160, pis. xi-xxi. NEWMAN, E. 1841-1851. The Phytologist, 5: 236, fide Moore, 1857. NUTTALL, THOS. 1818. The Genera of North American Plants, and a catalogue of the species to the year 1817. Philadelphia. PARSONS, F. T. 1899. How to Know the Ferns. New York. POIRET, J. L. M. 1811, Article "Dicksonia," in Lamarck, Encyclopedic Methodique Botanique. Supplement, tome II, p. 472. Paris, 1811. PRANTL, K. 18750. Hymenophyllaceen. Leipzig. 1875^. Verzweigung des Stammes, in Flora, No. 34. Not seen. PRESL, K. B. 1836. Tentamen pteridpgraphiae, seu genera filicarum praesertim juxta venarum decursum et distributionem exposita. Prag. PROVANCHER, L. 1862. Flore Canadienne. Quebec. 842 pp. Not seen. PURSH, F. 1814. Plants of North America, 2: 664. RADDI, J. 1825. Plantarum Braziliensium nova genera et species novas vel minus cognitaa. Florentiae. Russow, EDM. 1871. VergleichendeUntersuchungen iiber die Leitbundelkryptogamen. in M6m. de 1'Acad. Imp. de St. Pe'tersbourg, ser. vn, 19: 80. SACHS, J. 1875. Text-book of Botany. English transl. 50 STRUCTURE AND LIFE-HISTORY OF HAY-SCENTED FERN. SADEBECK, R. 1873. In Verb. Hot. Ver. Prov. Brandenburg, 15. 1874. Farnblatt. — 1878. Vascular Cryptogams in Schenck's Handbuch. — 1898. Pteridophyta in Engler and Prantl's Natiirlichen Pflanzenfamilien, 1-4 A. SCHKUHR, C. 1809. Vier und zwanzigste Klasse des Linnd'schen Pflanzensystems, oder Kryptogamische Gewachse. SCHOUTE, J. C. 1903. Die Stelar-theorie. Jena. SMALL, J. K. 1903. Flora of the Southeastern United States. New York. SMITH, J. 1841. Enumeratio Filicum Philippinarum, in Hooker's Journ. of Botany, 3: 392-422. 1842. An Arrangement and Definition of the Genera of Ferns, with observations on the affinities of each genus, in Hooker's London Journ. of Botany, 1: 419-438. - 18460, in Bot. Mag. Comp., 36. Not seen. 1846^. Catalogue of the Ferns grown at Kew. Not seen. SPRENGEL, K. 1827. Caroli Linnaei Systema vegetabiliurn, vol. 4. Not seen. STRASBURGER, E. 1897. Das Botanische Practicum, ed. 3. STRASBURGER, NOLL, etc. 1898. Text Book of Botany, English translation. SWARTZ, O. 1800. Genera et Species Filicum, in Schrader's Journ. fiir die Botanik, 2: 1-120. - 1806. Synopsis Filicum. TANSLEY, A. G., and LULHAM, R. B. J. 1902. On a new type of Fern-stele, and its probable phylogenetic relations, in Annals of Botany, 16: 157-164. March. THOMAE, K. 1886. Blattstiele der Fame, in Jahrb. f. wiss. Bot., 1 236- Sagittal sections of embryo and calyptra, 25 M apart; b, stem initial; d, mar- ginal cell of first leaf; n, foot. 237. Longitudinal section of old antheridium. 56 STRUCTURE AND LIFE-HISTORY OF HAY-SCENTED FERN. PLATE 22: 238. Transverse section of protostele below first leaf-gap. X 210. 239. Transverse section o± stem through the first leaf-gap, o. No inner phloem. Siphonostelic structure occurs o.i mm. higher up; tr, region of first leaf- trace. X 210. 240. Transverse section of siphonostele between first and second leaves. 241. Transverse section of siphonostele midway between third and fourth leaves. 242-245. Serial transverse sections of the center of the stele at the origin of the inner endodermis. 241 to 242 is 60 /*; 242 to 243 is 10 /a; 243 to 244 is 20 /A; 244 to 545 is 70 p. All between third and fourth leaves. X 210. PLATE 23: 246. Sagittal section of young fern attached to prothallus; ;;?, stem-initial; o, calyptra r, root; /r, first leaf; u, prothallus. X 75. 247. Detail of transition from root to stem, from same series as fig. 246; ;;/, anterior; r, posterior; u, upper part. 248. Slightly oblique transverse section of petiole of third leaf of sporeling; d> upper side. X2io. 249. Glandular hair from leaf of adult plant. X 43. 250. Transverse section of petiole of first leaf, showing sectioning of marginal cells. Endodermis dotted; m, marginal cell. X 360. 251. Sinus of leaf-margin of seedling; dotted cells are epidermal. Surface view of cleared specimen. X 350. 252. Young rhizoids and tips of mature ones from root of three-leaved sporeling of fig. 267. X 350. 253. Optical section of spongy parenchyma of first leaf of sporeling; cleared in gly- cerine. X 350. 254. Epidermis and developing stomata on sporeling leaf; m, stoma mother-cells. X43- PLATE 24: 255. Horizontal section of calyptra (11} and embryo through root and rudiment of first leaf (tr}. X 360. 256. Diagrammatic cross-section of sporeling plant through third leaf-gap; tr, petiole 0, leaf-gap. 257. Diagrammatic cross-section of stele and starchy cortex of sporeling stem at fourth leaf-gap; o, leaf-gap. X 75. 258. Hairs of third leaf of sporeling No. 3; b, acicular; ;;z, moniliform ; n, glandular. X 350. 259. First leaf of sporeling No. 2. X 5. 260. Second leaf of same plant. X 5. 261. Second leaf of plant No. 3. X 5. 262. Third leaf of plant No. 3. X 5. 263. Third leaf of another plant. X 5. 264. Fourth leaf of plant No. 3. X 5. 265. Fourth leaf of plant No. 4. X 5. PLATE 25: 266. Lower epidermis of first leaf of sporeling. X 350. 267. Three-leaved sporeling (No. i) with portion of prothallus («) still attached. 1, 2, 3, first, second, and third leaves. 268. Surface view of petiole of second leaf of sporeling (No. i), with stoma. 269. Sporeling stem with roots and leaves cut off. Drawn from nature by Miss M. E. Rogers. 270. Forked stem of seedling, i, primary root leading up to the original simple stem. Drawn from nature by Miss M. E. Rogers. Plate 1 FIG. i. Habitat of D. punctilobula, Massachusetts. FIG. 2. Leaves as they grow. Plate 2 FIG. 3. Rhizome, natural size, showing fork, leaf-bases, and leaf-shoots. FIG. 4. Leaf-bud with two unequal leaf-shoots, natural size. FIG. 5. Portion of pinna showing pinnules, lobes, crenations, sori, and hairs. X about 10. PLATE 3. 6 Dorsz vi xi x ix PLATE 4. PLATE 5. PLATE 6. 43 PLATE?. 47 PLATES. PLATE 9. Plate 10 68 69 PHOTOMICROGRAPHS. FIG. 67. Rhizome, transverse section. FIG. 68. Vascular bundle of petiole, transverse section. FIG. 69. Rachis of leaf, transverse section. PLATE 11. PLATE 12. PLATE 13. 103 PLATE 14. in PLATE 15. PLATE 16. PLATE 17. PLATE 20. PLATE 21. 336 PLATE 22. PLATE 23. 255 PLATE 25. 266 258461 THE UNIVERSITY LIBRARY UNIVERSITY OF CALIFORNIA, SANTA CRUZ SCIENCE LIBRARY This book is due on the last DATE stamped below. To renew by phone, call 459-2050. Books not returned or renewed within 14 days after due date are subject to billing. - Series 2477 3 2106 "00254 3731