I; Jli •;• '.'_'••' n, Timothy Field haraceae of America. I he Characece of America. By DR. T. F. ALLEN. Part /. TRODUCTION. MORPHOLOGY. CLASSIFICATION. /It THE CHARACE^E OF AMERICA PART I. CONTAINING THE INTRODUCTION, MORPHOLOGY AND CLASSIFICATION BY TIMOTHY FIELD ALLEN, M.D., LLD. FELLOW OF THE NEW YORK ACADEMY OF SCIENCES ; CORRESPONDING MEMBER OF THE BUFFALO ACADEMY OF NATURAL SCIENCES, OF THE PORTLAND SOCIETY OF NATURAL HISTORY, ETC. WITH FIFTY-FIVE ILLUSTRATIONS NEW YORK No. 10 EAST 36™ STREET OHNGRAHWNjR. THE CHARACE/E OF AMERICA. INTRODUCTION. THE publication of this work has been postponed from time to time in order to accumulate material for a more complete ac- count of the species growing in this country. The demand for in- formation concerning these plants is, however, so pressing, that it is thought best to issue the first part of the work now, to be followed, after a year or two, by the second part, which will contain descrip- tions of the species now known to inhabit American waters. The determination of the species of Characeae should not be undertaken without a previous acquaintance with the structure and development of the plant in general; indeed, no classification, worthy to be called such, was possible, till the researches of the late Prof. A. Braun laid a sure foundation in the morphology of the Charad, and with Prof. Braun Characeae began, as it were, a new existence in the scientific world, almost comparable to the birth of the Lin- naean system. Old names of species were found to be indefinite and misleading, and, in most cases, they had to be discarded en- tirely and replaced by others. Braun's "Fragmenta" have been edited by Dr. Nordstedt, who also arranged a synoptical key to all the species. This key is now translated, with the permission of Dr. Nordstedt, revised, in ac- cordance with his recent notes (September, 1887), and made to in- clude new species. We have repeatedly stated in this work that very little of it is original; the investigations concerning germination, development, structure, and the principles of classification have all been made by authors who have been properly credited with their work. In some places the language of these authors, especially of Prof. Braun, has been literally translated. The illustrations are 44169 mostly original, but Figures i to 5 and 9-17 are copied from de Bary; Figures 6 and 7 from Nordstedt, 18 to 20 and 38 and 39 from Sachs and Goebel. CHARACE^: are neglected by botanists in general, who seem to have an aversion to all aquatic plants ; mainly, it is presumed, from the fact that the collection of aquatics is a specialty. One must go pre- pared with dredge and rake, with paper and muslin, in order to gather successfully plants of this sort. It has come about that very few bits of Characeae have been gathered here and there by expedi- tions and by individuals, in America, up to recent years; but it is evi- dent that these plants abound in our waters, and that our Chara-flora is varied and strongly characterized. Probably not one-half of the American species have as yet been brought to light, but it is confi- dently anticipated that a better knowledge of their structure and classification will result in a more widespread interest in them. These plants, often delicate or brittle from an incrustation of lime, are easily destroyed by waves, so that they are rarely found on ex- posed shores, unless in water deep enough to be beyond the reach of the surface movements. They flourish best in sheltered bays and smaller ponds, especially if a tolerably uniform level of water be maintained. Great changes of level are destructive, alike to species that love the sun and grow in shallower water and those that hide away in the depths. It is rare, therefore, that Chara hunting is profit- able in ponds or lakes which feed canals or factories ; one prefers the land-locked sheets of water fed by springs, especially if there be a sandy bottom. Temperature has but little influence upon them, though the South has its distinctive species, as well as the North. One species, at least, Ch. fragilis, is universal ; found in every coun- try and clime, in ice water at the North and in the hot springs of the Yellowstone, " hot enough to cook an egg in four minutes " (see specimens in the Herbarium of Harvard College). The best condition of the plant for examination is when it has mature fruit. The time at which this occurs is usually late summer or early fall, though a few species mature early in the spring and die off in the summer. At the South the species are often in good condi- tion the year round, the old fruit holding on even after new shoots have started from the old nodes. To gather Characeae successfully a dredge must be used; for shal- low water a small fine-toothed rake is preferred, but for deeper water 5 (one rarely finds them at a depth greater than ten feet), the dredge and line is essential. The best dredge for all purposes is the one recom- mended by Prof. Nordstedt, made as follows : A disk of lead about three inches in diam- eter and three-fourths of an inch thick, has im- bedded in its circumference a row of hooks, about ten in number; through the centre of this disk is passed an iron rod, which projects about three inches below the disk and about nine inches above ; to the ring in the upper end, to- ward which the points of the hooks are directed, a cord is attached. The dredge weighs about two and a half pounds and catches all sorts of "weeds" growing on the bottom. Messrs. Flynn & Doyle, carriage makers, at Bantam Falls, Conn., have made these dredges for me at a cost of four dollars each. The dissection of these plants is perfectly simple. The delicate species are placed in water till their normal form is restored (if they have been dried), and a portion is put in a " cell " on a glass slide and examined under a two-inch objective; sometimes, but rarely, a higher power is needed for determining fine points, such as the structure of the cortex. Should the species be incrusted with lime a piece should be placed in a little strong vinegar till the lime is completely dissolved, then washed in pure water and examined. Specimens foul with mud must be cleaned in water, with a camel's hair brush ; but this is liable to detach the globules of fruit, and is only occasionally to be resorted to. Should it be desirable to preserve bits for future reference, they are best mounted in glycerine jelly, in " cells " deep enough to avoid crushing, and shallow enough to per- mit free examination (flattened brass curtain rings make excellent cells). When the jelly has dried at the edges turn on a ring of white zinc cement. THE writer has prepared a few sets of Exsiccatae for distribution to Herbaria and persons interested in the study of Characese. The num- ber of sets has necessarily been limited, for very few besides himself have contributed plants, and it has been judged best not to offer them for sale. The plan has been to offer a part (containing ten species or varieties), to any one who would contribute about 100 specimens of one variety required. This plan is good in theory, but it restricts the distribution of sets; at present, however, no better way presents itself, and the offer is still open. After a time, when a larger number of duplicates has been ob- tained, the sets will be more widely scattered. Even now, four numbers are exhausted and cannot be supplied to new applicants till more be collected; these Numbers are 16, 22, 24 and 27. The species comprised in the Exsiccatae hitherto issued are : 1. Nitclla tennis sima, Desv. , forma brevifolia. 2. " intermedia, Nordst, nov. sp. 3. " megacarpa, Allen, nov. sp. 4. Chara intermedia, A. Br., forma tenuior, elongata. 5. " intermedia, A. Br., var. Americana, A. Br. 6. " contraria, A. Br., forma brachyphylla, humilior. 7. " sejuncia, A. Br., forma elongata. 8. " coronata, A. Br.,var. Schweinitzii, A. Br. 9. " gymnopus, A. Br., var. Michauxii, A. Br. 10. " hydropitys, A. Br. ,vir. Seplentrionalis, Nordst. in lit. 11. " coronata, Ziz. Forma, microcarpa, microptila, verti- cillata (var. gracilis, Allen). 12. " coronata, Ziz. Forma, meiocarpa, metioptila, partim unilateralia. 13. " corona/a, Ziz. Forma, macrocarpa, meioptila, verti- cillata. 14. " coronata, Ziz. Forma, macrocarpa macroptila, verti- cillata, zonulare incrustata. 15. " excelsa, Allen. Bull. Torrey Bot. Club, 1882. 1 6. " evoluta, Allen. Bull. Torrey Bot. Club, 1882. 17. " fcetida, A. Br. , Forma, brachyphylla, clausa, elongata, macroteles. 1 8. " fcetida, A. Br. Forma, incrustata, laxior. 19. " conlraria, A. Br. 20. " fragilis, Desv. Forma, tenuifolia, microptila, munda, humilior. 21. " fragilis, Desv. Forma, microptila, incrustata, laxior. 22. " delicatnla, Ag. non Desv. Ch. fragilis var. delicatula, A. Br. 23- " gymnopus var. elegans, A. Br. 24- " gymnopus var. Humboldtii, A. Br. Forma stolonifera. 25. " sejuncia, A. Br. Forma, condensata, robustior. 26. " aspera, (Dethard.) Willd. 27. " aspera, (Dethard. ) Willd. Var. Macounii, Allen, in Bull. Torrey Bot. Club, 1882. 28. Nitetta flexUis, Ag. 29. Nitella flexilis, Ag. Forma, longifolia, elongata. 30. " flcxilis Ag. var. subcapitata, A. Br. 31. " tcnuissima, Kittz., forma longifolia. 32. " glomerulifera, A. Br. (N. capitata, in Halstead). 33. " opaca, Ag. 34. " minuta, Allen, nov. sp. 35. Tolypella cornosa, Allen. 36. fimbriata, Allen. 37. " inter texta, Allen. 38. Chara Jiydropitys, var. genuina, A. Br. 39. " sejuncta, A. Br., forma tenuifolia. 40. " gymnopus, var. armata, A. Br. (Sandwich Islands). 4oa. Nitella trtcellularis, Nordst. (from New Zealand). The fifth fasiculus, in preparation, will include Chara crinita, Ch. hornemanni (from Florida), Ch. gymnopitys (alpha), Ch. hydropitys, var. perfecta (from Mexico), Nitella morongii, Allen, and some varieties of the more common species. Correspondence is cordially invited and the determination of species will be cheerfully undertaken, particularly as a more ex- tended knowledge of localities will the better enable the author to give, in the second part of this work, the geographical distribution of the different species. The second part will contain a description of all the American forms, and it is intended to facilitate their determination by an illustra- tion of each species. CHARACE^E are essentially Algae, though they cannot be included in any of the groups of that class. They possess a complicated structure, and in habit, as well as in the apparent distinction of parts, as stem and leaves, seem allied to the Cormophytes. Reproduction is peculiar and exhibits a higher development than is found in other Algoid plants. The Antheridium produces swarming spermatozoids, the Oogonium becomes enveloped even before fertilization, it does not produce zoospores, but a resting-spore, and this, in germinating, does not produce immediately the sexual plant, but an intermediate, a-sexual protonema, from which the sexual plant rises as a lateral sprout. Other Algoid plants have enveloped oogonia (Coleochaetae and some of the Floridse). Some Algae even develop a pro-embryo, and some botanists have attempted to trace a genealogy from the green Algae, through the Characeae, to the higher Cryptogams, looking upon the Characese as an intermediate group which still holds on in the struggle for existence. These plants grow wholly under water, generally in shallow, but sometimes in deep water (over six feet). Usually the seeds ger- minate in the spring and the mature plants bear fruit early in the fall, but some species are perennial, in deep water, throwing out young shoots in the spring from old thickened nodes or from small subterranean bulbs which have been filled with starch the previous year. Other species germinate late in the season, live over winter, and mature the following spring. Numerous observations are re- quired to determine the habits of our American species, many of which are peculiar to this country. It is certain that in America, as in Europe, a locality may cease to furnish a species for some years, after which it will reappear, due, probably, to the persistence of the little nutlets, whose hard shell resists for a long time external influ- ences inimical to life. Species are wonderfully constant in their local- ity, constant even in minute characteristics, and ponds or lakes lying but a fe\v miles apart may contain species or varieties peculiar to each, which seem never to encroach on the other. It is quite probable that aquatic animals rarely, if ever, feed on these plants, and the seeds do not seem to be disseminated by them. The strong, disagreeable odor (of sulphureted hydrogen), exhaled by nearly all Characese, seems protective to the extent of causing them to be let alone, but productive of a restricted habitat in some cases. Some species, however, are everywhere common. Chara fragilis, Desv., is constantly met with North, South, East and West, in cold water and in hot springs hot enough to cook an egg ; this species is cosmopolitan, found over the whole globe, even in Australia, which otherwise has quite a distinct Chara-flora ; Chara foetida, A. Br., is nearly as widespread; Ch. coronata, Ziz. , not so common in Europe, is here very abundant and varied; of our peculiar species, the varie- ties of Ch. gymnopus are most common, var. elegans, van Mich- auxii, var. Humboldtii and Ch. sejuncta (very wide spread). Forms of Nitella polyglochin are almost characteristic of America (microcarpa, megacarpa and intermediate forms). Nitella prelonga, A. Br., is a pronounced Southern species, large and fine. It is yet too soon to speak positively of the geographical range of our Charads; so little interest has been taken in them that sufficient data are not at hand. HISTORICAL. THE botanical history of the Characeae is marked by numerous changes in classification, which have varied with the notions of differ- ent botanists concerning the place of these plants in the vegetable kingdom. Vaillant first separated them from Hippuris and Equise- tum (Hist, de 1'Acad. Royal, d. sc. 1719), and collected nine species under the name Chara (xapa. ) This name had been used prior to this time by Hevel (Prodr. Astron.) for a constellation, and it is possi- ble that the appearance in water of the whorled leaves of one of these plants may have suggested the name of a star for them. Linnaeus at first classed them with the Crypto-gamia, with Lemna, between Marsilea and Fucus, among the Algae. Following Linnaeus, most of the older authors adopted this classification. B. Jussieu placed them between Conferva and Spongia. Schreber (in his Genera] recognized the globular bodies which he noticed in the axils of the leaves as male and female organs ; the round red globules he called Antheridia; the larger oval bodies, spir- ally wound, with a toothed crown, were called female flowers ; the teeth were considered stigmata, and the nucule the seed. These two bodies found on the same plant, near each other, though the so-called Antheridia lacked the essential characters of Anthers, seemed to Schreber to determine the position of these organisms among flowering plants as Monandria monogynia. Linnaeus adopted this view, and in the later editions of his works we find them classified according to Schreber's notions, Moncccia monau- dra; many pupils and authors following Linnaeus retained this classi- fication (for example, Nuttall], which, indeed, has held, until very re- cent times (Bertolini Flor. Italica, Willdenord Flor. Berol.). Baumgar- ten placed them among the Mo?idria digynia, and Pursh, on account of the so-called five stigmata, Polygynia. Louis Claude Richard, in Humb. et Boupl. nov. gen. 1815, fifet em- ployed the family name, Characece, and following him Kunth, Wallroth (1815), Martius, etc., restored them to the Cryptogams; Kunth placing them between Marsiliaceae and Piperaceae ; Wallroth, near Conferva. The investigations of Vaucher (Mem. de la Soc. Phys. de Geneve, 1821), and of Kaulfuss (Ueber das Keinren von Chara, 1825), led to a more definite knowledge of the character of the fruit, which has been 10 increased by the observations of Bischoff (Crypt. Genv., 1828), Miil- ler (Bot. Zeit, 1845), Pnngsheim (Jahrb. f. Wiss Bot., 1863), Nord- stedt (Act Univ. Lund., 1866), and de Bary (Bot. Zeit., 1875). Refer- ences to the work of these and other observers will be made while treating of the development of the plant. To Alex. Braun, however, is due, more than to any other man, a knowledge of the complete structure of all parts of the plant, and especially correct notions of the relations of the genera and species of Characeae, and of the proper methods of their classification. The oospore consists of a cell surrounded by a moderately thick wall of cellulose, filled with colorless fat, grains of starch, and masses of protoplasm. External to the cellulose layer, and joined to it, is a thick shell, usually brown or black, formed by the enveloping cells and furrowed in a spiral fashion by their twisting. This envelope, consisting of five cells which arise from the base of the spore, is called the sporostegium (spore-capsule), and the whole fruit, including the spore proper, its basal cell and enveloping cells, the Sporo-phy- diurn.* The furrows on the nucleus, caused by the five enveloping cells of the sporostegium, are separated by ridges, often very prominent, or, again, scarcely to be noticed; the prominence of these ridges is con- stant in each species, and frequently serves as a distinguishing mark ; the number of ridges on the nucleus, due to the number of turns of the enveloping cells, is also constant and characteristic in different species. These ridges are frequently continued downward between the basal cells, and then form, as in Chara fragilis, after the soft parts de- cay, fine sharp points, which serve clearly to distinguish the base of the nucleus, from the apex ; the latter is often terminated by a single point, caused by the prominence of the last spiral. When the ridges are not prominent the base can be distinguished from the apex only * NOTE. — In Braun, Sachs and Goebel, the fruiting organs are termed "Anther- idiuin" and " Eiknospe, " the latter referring to the spore-bud, which was held by Braun to be an axillary growth. Braun suggested the term Sporophyas for this growth (namely, the complete fruit, oospore, basal and enveloping cells). This term h«i£ not yet been adopted by later writers, nor, indeed, has any other term been suggested. Braun, in his latest descriptions, uses the term sporangium, which heretofore we have used, though it is not exactly appropriate. Celakowsky, in Flora, 1878, dissents from Braun's view of the "bud" nature of the spore- shoot, and considers the spore a metamorphosed leaf — a leaf has no significance in Characeae, more than the simple outgrowth of a nodal cell — but, following Cela- kowsky's view, Sporophydium would still be a good term. He proposes "envel- oped-oogonium," but does not suggest an appropriate technical term. We have, therefore, concluded to follow the suggestion of Braun and replace the inappropri- ate "Sporangium " by the most fitting Sporophydium, which will, we trust, be gen- erally adopted. II by its somewhat broader or truncated appearance ; in many species the two ends can scarcely be distinguished. The nucleus of some species, for example, Chara intermedia, becomes densely incrusted (like the stem) with a deposit of lime, which seems to be imbedded in a delicate soft hyaline matrix; this deposit must be dissolved by a dilute acid before the nucleus can be studied. GERMINATION. — The germination of the Characeae has been exam- ined by Vaucher*, Kaulfussf, Bischoff|, Pringsheim§, Nord- stedt|| and A. de Bary^[. To Pringsheim belongs the credit of having discovered the true character of the first outgrowth of the spore, but Nordstedt first clearly and accurately traced, step by step, the whole process; this work, published in Swedish, not being acces- sible to students generally, was reviewed and enlarged by the inves- tigations of Prof, de Bary. From these authors our account and illus- trations of the process are taken. As germination is about to commence, the granules of fat and starch in the upper part of the oospore give place to finely granular protoplasm (Fig. i, a de-calcified nucleus of Ch. fcetida, A. Br., n). This partially clear spot fills the upper end and has the form of a plano-convex lens, with its convex- ity upward and its plane surface pressing against and clearly sepa- rated from the remaining contents of the cell. Along this line of de- Fig, i. marcation a septum forms, which divides the oospore into two cells, the smaller upper one, the first no- dal cell, from which all growth proceeds, and the larger lower basal cell filled with fat and starch, the reserve material for nour- ishing the germinating plant. The upper cell enlarges and splits the shell along the line of its angles into five parts ; it then pro- trudes a little into the water and undergoes fissation, by. a vertical * Mem. de la Soc. d. Phys. de Genevere.lSai. f Erfahrungen ueber das Keiinen der Charen, Leipzig, 1825. JDie Crypt. Gewachse, Niirenberg, 1828. §Die Vorkeime d. Charen, 1862, and also, Ueber die Vorkeime und die Nackt- fiissigen Zweige den Charen Jahrh f. Wiss. Bot. III., 1863. || Nagra iakttagelser Ofver Charac. gronig, Lunds Univ. Arsskrift II. ^f Zur Keimungsgeschichte der Charen, Bot. Zeit., 1875. 12 septum, into two cells (Fig. 3 first division of the nodal cell seen from above; Fig. 4 seen from the side, the protoplasmic mass some- what shrunken). These cells grow and elon- gate, becoming cylindrical in form, as shown in Fig. 5. One of these cells bends down as it lengthens and be- comes a root ; this divides at its base, close to or partly with- in the nucleus, into a complex root-node, consisting of several Fig. 2. nodal eel's, from which several rootlets arise. Fig. 6 represents a section through the primary node— "r," the rootlets; "p," the protonema; "pr. r," the primary root-node; "sm.," spore membrane. Fig. 7. Front view of node of Ch. coronata; letters as above; "sh.," shell of nucleus. These and all subsequent roots form, by acropetal division, a series of much elongated cells with swollen joints (nodes); these nodes are like two feet, united by their soles in opposite directions, and from the dorsum of the foot, directed toward the point of the root, single rootlets, or bunches of rootlets, arise by a superficial proliferation of cells. Fig. 8 represents a root- node of Nitella megacarpa, Allen, with two young rootlets (drawn from nature, T. F. A. ) The other cell, arising by the divis- ion of the primary nodal cell, grows in an ascending direction, opposite to that of the primary root, and elongates into a tube which divides by horizontal fis- sation into three to seven cells; these become filled Math chlorophyll and assume the appearance of a leaf of a Charad. This ceases to elongate and is now the protonema (pro-embryo), from which the perfect plant arises in the follow- ing manner : The lowest cell of the pro- tonema undergoes -divis- ion near its upper part, by a septum which inter- poses a cell between the first and second cells of the protonema; this intermediate cell now divides by two septa into three cells ; the middle of these three speedily elongates and separates the other two. The lower of these two cells becomes a second root-node (as distinguished from the primary root-node which developed directly from the first nodal cell), the upper ~pr-r. Fig. 7. becomes a stem node (Fig. 17, "rn." a root- node, "s" the stem-node). The lower cell, which is to develop into a root-node, under- goes repeated fissation by vertical septa, as il- lustrated by Figs. 9 to 12 (Fig. 12 representing a fully developed root-node with "a," "c," "d,"' protruding rootlets). This completes the development of the roots. From the upper of the two cells a stem node develops as follows : This cell divides by a septum into two nearly equal halves (Fig. 13). In each half peripheral cells arise, first on one side, then on the other (Figs. 14 and 15), until a circle of cells is completed, inclosing two me- dian cells. The formation of this node is simi- lar to that of all nodal forma- tions in the fully developed plant. The first cell now throws off another peripheral cell, which divides, by a verti- cal septum, into two cells, which stand for the nodal cells of the new stem (" n," Figs. 15 and 1 6). In Fig. 16 a side view of the node "v" is the vege- tation cell, growing upward and elongating into the first stem (cell) of the perfect plant; the two nodal cells, "n," remain as small nodules on the side of the node, or develop into accessory leaflets (stipulse). The other peripheral cells of this stem-node develop into very simple leaves of unequal length ; these leaves always remain at the lowest stage ; they never develop nodes nor bear fruit. The extension of the original protonema often exceeds the length of the leaves of this provisional verticil and may easily be mistaken for one of them, especially as it is crowded out of its nor- g. Fig. 9. Fig. 10. Fig. 12. mal direction by the growth of the main stem. The unrestricted growth of the true plant has now commenced and the plant at this point has the appearance of Fig. 1 7 (taken from A. de Bary, repre- senting the germination of Ch. crinita), "p," the main protonema; "p'p','' ac- cessory and undeveloping protone- mata, which sometimes arise; "s," the stem-node, with unequally developed leaves; the real protonema seems like one of these leaves ; above this node the true plant first appears and hairs are developed on its first internode ; "s'," imperfectly developed nodes of the accessory protonemata. In perennial species (Ch. fragilis, Ch. gymnopus vars., etc.), shoots arise from old plants (second generation), which closely resemble the sprouts of the first generation (pro- tonema). Old root- and stem-nodes of perennial species swell and become filled with nourishment (starch prin- cipally), and from these nodes new shoots arise, as from the seed; these shoots are called caulescent protonemata ; they develop root- and stem-nodes and behave quite like the true pro- embryo. Pringsheim (1. c.) has studied these structures with special care. '•The first shoot of the fully developed plant is fre- quently not the only one which rises from the verticil of the protonema; in Tolypella there are so many that the verticil of the protonema becomes the starting point of a whole bundle of shoots of varying sizes and ages. In N. syncarpa (Europe) these adventitious shoots rise not from the stem-, but from the root-node; this swells to the size even of a pea, and sends numerous roots downward and shoots (as many as fifty) upward. Some of these incline downward and form other swellings with roots and shoots (caulescent protonemata). In Chara aspera, however, the protonema-verticil remains undeveloped, producing neither leaves nor shoots, and the shoot of the second generation arises from the root-node. " (A. Braun.) The development of the stem, with its nodes, leaves and various appendages, has been most thoroughly studied by Prof. Braun, to whose writings, especially to "Ueber die Richtungs-vorhaeltnisse der Saft-stroeme in den Zellen der Characeen, Fig. 14. Berlin, 1862," we are greatly indebted. The apical cell (vegetative cell) of the new shoot throws off from its base a series of cells by repeated horizontal division. The api- cal cell itself remains plano- convex, and when its energy is exhausted, persists as a terminal cell of the same form. Each cell that is thrown off from the base of the apical cell divides immediately, by horizontal fissation, into two unequal cells, the lower shal- low and bi-convex, the upper deeper and bi-concave. The lower of this pair elongates without farther division and becomes a long internodal cell, often attaining a length of several inches (internodal cells six to eight inches long are not uncommon in lake forms of Nitella megacarpa, Allen). The upper bi-con- cave cell of the above pair forms a stem-node as follows : Soon after its appearance it divides, by vertical fissation. into two equal halving cells (see Fig. 13). In each of these half cells a series of pe- ripheral cells arise, by excen- tric division and in regular order, beginning first on one side of the septum, then on the other, and proceeding in alternation till the circle is closed. These peripheral cells are the starting points of an equal number of leaves. In Nitella the number of leaves i6 is nearly always six; in Chara there may be as many as sixteen. The peripheral cells of successive nodes are not exactly on a line, but each node deviates by half the interval between the peripheral cells, so that a regular spiral is produced ; in species with a large number of leaves the divergence is small, with sixteen leaves a divergence of J^, in Nitella there is usually a divergence of -^. When, as in most species of Chara, the stem is corticated by longitudinal series of cells, this divergence is easily seen, especially as the stems usually twist more and more as they grow older, but in the naked species (Ni- tellse and some Charse) the torsion is noticed only by means of the clear line between the granules of Chlorophyll, the " indifferent line" which marks the boundary between the up and down streams of the circulating protoplasm ; this indifferent line seems to coincide with the primary septum which divides the nodal cell into halves. The direction of this divergence is to the right, upward. LEAF. — The vegetative cell of the leaf arises from a peripheral cell of the stem-node, but, unlike the vegetative cell of the stem, it produces a limited series of nodal and internodal cells, nearly con- stant in number for each species, and terminates by a tip, usually pointed, divided by sim- ple septa into two or more simple cells. The basal node is somewhat com- plicated in structure, since it develops, in some spe- cies, cells for stipules and cortex, and even for ac- cessory leaflets and spor- angia. A clear under- standing of this basilar node of the leaf and of the organs which de- velop from it, is essential, since the groundwork of much of the classification of Characese is founded upon the variations of these organs. The parent cell of the basilar node (Fig. 18, node on the side of the Fi p-b), swells and protrudes from 17 stem, it gives off, by division, a complex mass of cells which comprise the basilar node of the leaf. From this node are developed the cortex cells and stipules found in Chara, the adventi- tious leaflets (which do not develop nodes like true leaves), and even organs of fructification (especially in the genus Tolypella). In the genus Nitella the basilar node of the leaf is much more sim- ple than it is in Tolypella and Chara. In Nitella only a few cells sur- round and support the base of the leaf, and these cells rarely, if ever, give rise to any organs (except to adventitious leaflets in some species, as in our N. clavata). There may be only a circle of four cells, or even in the same species, as in N. flexilis, an indefinite num- ber of cells may develop. DEVELOPMENT OF THE CORTEX. — From the upper and lower por- tions of the basilar node cells arise, which extend upward and down- ward closely pressed against the central internodal cell of the stem. These cells grow, pari-passu, with the elongating stem cell, they spread laterally, and, as a rule, entirely encircle the stem and form a complete cortex. The first view of these cells is shown in Fig. 1 8, c and c'. A front view is shown in Fig. 19, c, which repre- $ sents the side of a young growing stem ; a single cell from above and one from below ~.C cover the internode vertically, and, with the ad- jacent cells, completely encircle the stem. As the internodal cell of the stem elongates these cells Fig. I9. elongate and develop nodes and internodes, and, when fully developed, give off lateral cells. Since the leaves of successive verticils are not directly over each other, but diverge to the extent of half the distance between the leaves, the cortex cells which extend upward and downward from the base of each leaf (except that the oldest leaf of each verticil develops a shoot in its axil instead of a cortex cell, causing one cortex cell less in the encircling series which ascends from a vertical, than in the series which descends), alternate, and in the centre of the internode they interdentate, as shown in Fig. 20, which represents an elongating cortex system. Each " c " in this figure represents a single cortex " lobe," which has developed from a single cell, as shown in Fig. 19. In Fig. 20 these cortex cells (four above and three below), have begun the development of nodes and internodes; "in" the internodal cells, and "n," "en," "n," the node; "en" the central i8 Fig. 20. nodal cell. The" internodal cells elongate to keep pace with the growing stem; they do not divide ; the nodal cell, however, divides at first into three, a central cell and two lateral cells (Fig. 20, "n," "n" and "en"). The central cell then divides into deep (lying next the stem) and superficial cells. The superficial central cell is the only one which develops spines, or papillae, so that whenever a spine is seen on the stem, we may be sure that it arises from the central node of the cortex. In this way the main cortex series is always to be distinguished, since the lateral cortex cells never develop nodes or spines. This central cell may grow out into a single spine, or it may subdivide into a number of cells and develop a bundle of spines, as in Ch. crinita. In many species which develop but a single spine, or papilla, from the node of the cortex, great variability is observed ; some varieties having numerous spines quite long, while other forms of the same species have almost smooth stems; this is particularly noticeable in Ch. fcetida, A. Br., and Ch. intermedia; our very common Ch. fragilis, with a completely devel- oped triple cortex, rarely produces any spines, or even papillae ; while our forms of Ch. gymnopus, with an equally developed cortex, some- times have numerous spines, as in sub-species elegans; sometimes have nearly smooth stems, as in sub-species Michauxii. The development of the lateral cells of the cortex-node marks im- portant groups in the classification of the species of Chara. When the lateral cells develop fully, each cell protrudes from the side of the node and extends longitudinally, forming a long cell lying by the side of the central internodal cell of the cortex and parallel to it. If •each lateral cell of the node develops, the cortex "lobe" (the full development of each original cortex cell) becomes composed of the central cell, with its node (and spine) and two lateral cells, forming a triple series. Since one cortex cell arises at the base of each leaf, it follows that there will be (as in Ch. fragilis) three times as many cells surrounding the main internodal cell of the stem as there are leaves, and the stems are said to be " triplasliche corticate" (triple corti- cated). Fig. 21 (drawn from nature) is taken from the centre of a young growing internode of Ch. fragilis; the development is nearly perfect, showing the growing lateral tubes from each side of each node ; showing- also the manner in which the cortex-tubes interdentate (from above and from below). " r," the apical cell of each cortex system; " n," the nodes; "in, "the internodal cells; "1," the lateral cells. Fig. 22 represents the fully developed cortex of Ch. fragilis. It is, however, rare that we find a perfectly regular system in Ch. fragilis ; this is more generally seen in Ch. sejuncta and the various sub- species of Ch. gymnopus. In Ch. fragilis great variability is ob- served, generally in the way of a redundancy of cortical cells in any n. w. x- T fl. n. Fig. 21. Fig. 22. Fig. 23. given section, due to the overlapping of the lateral tubes. Fig. 23 (drawn from nature) illustrates this peculiarity. " 1' " is a lateral cell which, normally, should have stopped at ' ' x, " as shown by the dotted line, but which grew on and pushed in between the other laterals; a section just above "x" would show an extra cell. The normal mode of union of the lateral cells is by horizontal (blunt) ends, as at "a," "a, "while the oblique overlapping of these ends, as at "b," "b," is, like the characteristic cortex of our dioecious Ch. aspera. In this species the cortex is only sub- triple-corticated, the variation being toward a suppression of the lateral cells. 20 Fig. 24 is drawn from the cortex of a Western variety of Ch. aspera, showing at " 1' ' a lateral cell filling out the whole space between the two central internodal cells (primary cells) of the cortex. In a section through "1"' less than the triple number of cells would be seen. In the development of the node of the cortex, the growth of the lateral cells may be entirely arrested, and these cells may remain in the node undeveloped, or they may grow into spines (Ch. crinita), or may variously develop, as will be shown presently. R * 71. *"« n\i Nl \ M Ji J \ ,R \ -f I Fig- 25. Fig. 26. In case the nodes do not develop lateral cells lying pressed against the stem as cortex cells, then only the primary cells of the cortex system are found ; we see as many cortex cells as there are leaves, and the stem is said to be " haplistocha corticata " (singly corticated). This is seen in our Ch. crinita, two cortex tubes of which are repre- sented in Fig. 25. These primary cells approximate each other closely and completely encircle the stem, forming a single cortica- tion. The nodal cells develop spines, three usually, at each node, but no lateral cortex tubes. 21 In Chara evoluta, Allen, a little higher development is attained. The cortex node bears two spines, while one of the lateral cells makes a feeble attempt at developing lateral cortex tubes. Fig. 26, a portion of the cortex of Ch. evoluta, Allen, showing two nodes ; on one side of each node a small lateral cortex cell has formed, \vhile the node bears two spines, instead of three, as in Ch. crinita. In case one lateral cell develops fully and extends up and down to meet the other lateral cell, then a double cortication results. This is well seen in Ch. excelsa, Allen, which, in size and general aspect, closely resembles Ch. crinita and Ch. evoluta. It is also found in our very common Ch. fcetida, and Ch. contraria, species which represent two clearly defined sub-divisions of the diplosticlie series. In Ch. contraria (also in Ch. intermedia, Ch. excelsa, et cetera), the primary cells of the cortex system (the cells which carry the nodes), attain a larger development, while the secondary, lateral cells, re- main smaller, so that in a cross section there appears an alterna- tion of larger and smaller cells, the larger belonging to the primary (median) row of cortex tubes. On the surface we see an uneven- ness, the papillae or spines are borne on the larger cells and seem to be on the top of a ridge, while the smaller lateral cells are partly hidden between these median cells. This series of Charae is called ' ' tylacanthce. " Should, however, the lateral cells grow to a larger size than the median, then the nodes, with their papillae or spines, seem to lie in a valley between the higher lateral cells ; this series is termed " aulacanthce, " and is typified by our very common Ch. fcetida, A. Br. STIPULES. — In the development of cells in the basilar node of the leaf, two or three cells at the base of each leaf arise, superficial to the parent cortex cells, and protrude as papillae, or develop into more or less extended appendages called, by Braun, Stipules. These stipular cells remain as simple, undivided cells, though they may attain a considerable length. In Ch. stelligera, whose stem has no cortex, there are three small stipular cells at the base of each leaf, but they do not develop farther than minute papillae. In Ch. corona/a a single stipule develops on one side of each leaf, so that the stipules equal the number of the leaves and seem to alternate with them (see Fig. 27). 22 Fig. 27. This figure is taken from a form with minute stipules ; usually the stipules in this species " are very large." In our Ch. hydropitys and in many allied forms, two single stipules are developed at the base of each leaf, and the group is said to be bi-stipulalcB. In the new and interesting species, Ch. socotrensis, Nord- stedt, a third stipule frequently develops between the two normal and constant single stipules; this third stipule does not turn upward like the two normal ones, but diverges in various ways. Fig. 28 is cop- ied from Prof. Nordstedt's drawings, and represents the third stipule, variously directed. In all of these forms the stipules are single, though one, two or three times the number of the leaves. This large general series of single stipules is called Haplostephance (corona stipularis e simplice serie cellu- larum). The next series comprises Charae with double stipules. The stipular cell divides horizontally into an upper and lower cell, or apparently, in some cases, the double stipule arises from a single basal cell. Fig. 29, drawn, by camera, from a sec- tion of Ch. crinita, shows a double basal cell "b,"and the double stipule "s" directed downward, " s' ' upward. Fig. 30 shows a lateral view of a fully developed double stipular crown in our Ch. sejuncta, the upper series di- rected upward, equalling in length the lowest naked internodes of the leaves; -f^lSk JP^l^: «?• the lower series directed downward, pressed against the stem. All of this series are termed Diplostephance. It is interesting to note that in the foreign Lychnothamnus Wallrothii a Fig. 29. single stipule is developed exactly in front of (opposite) each leaf. Fig. 28. 23 In the foreign Ch. stelligera neither stipules nor cortex are devel- oped, but three small cells protrude slightly at the base of the leaf. In Ch. ceratophylla there are frequently three double stipules at the base of each leaf, see Fig. 31, showing the short inflated double stip- ules, camera drawn, x 25 diam. In the Nitellce there is no de- velopment of cortex or stipules, but in a few species of Nitella we find accessory leaves arising from a true verticil. These accessory leaves are more simple than the true leaves; they produce no nodes or fruit, and do not subdivide. We find these accessory leaves numerous in our N. hyalina and N. clavata. In the genus Tolypella fruiting organs, both sporangia and antheridia, spring from the basilar cells of the leaf in the verticil, both external and internal, often in large numbers. Fig. 30. Fig. SI- LEAVES. — As the cell which is to form the leaf protrudes from its basilar node, it divides very early into a series of cells which are des- tined to form the nodes, internodes and tip. The cells of the tip of the leaf attain their full size soonest and the disproportion of size in very young leaves is very great. These apical cells of the leaf may always be distinguished by the absence of any formation of nodes ; consequently, they are devoid of bracts, re- 24 ,>' I j