Part 95

Fructification of two kinds, namely, of minute and oblong or globular spore-cases, containing reddish or orange-colored powdery microspores; and of mostly 2-valved tumid larger ones, filled by 3 or 4 (rarely 1--6) much larger globose-angular macrospores; the former usually in the upper and the latter in the lower axils of the leafy 4-ranked sessile spike, but sometimes the two kinds are on opposite sides all along the spike. (Name a diminutive of _Selago_ an ancient name of a Lycopodium, from which this genus is separated, and which the plants greatly resemble in habit and foliage.)

[*] _Leaves all alike and uniformly imbricated; those of the spike similar._

1. S. spinosa, Beauv. _Sterile stems prostrate_ or creeping, small and slender; _the fertile thicker, ascending, simple_ (1--3' high); _leaves lanceolate, acute, spreading, sparsely spinulose-ciliate_. (S. selaginoides, _Link._)--Wet places, N. H. (_Pursh_), Mich., Lake Superior, Colorado, and northward; rare.--Leaves larger on the fertile stems, yellowish-green. (Eu.)

2. S. rupestris, Spring. (Pl. 21, fig. 1--4.) _Much branched in close tufts_ (1--3' high); _leaves densely appressed-imbricated, linear-lanceolate_, convex and with a grooved keel, _minutely ciliate, bristle-tipped_; those of the strongly quadrangular spike rather broader.--Dry and exposed rocks; very common.--Grayish-green in aspect, resembling a rigid Moss. Very variable farther west and south. (Eu.)

[*][*] _Leaves shorter above and below, stipule-like; the lateral larger, 2-ranked._

3. S. apus, Spring. Stems tufted and prostrate, creeping, much branched, flaccid; leaves pellucid-membranaceous, the larger spreading horizontally, ovate, oblique, mostly obtuse, the smaller appressed, taper-pointed; those of the short spikes nearly similar; larger spore cases copious at the lower part of the spike.--Low, shady places; not rare, especially southward.--A delicate little plant, resembling a Moss or Jungermannia.

2. ISOETES, L. QUILLWORT. (Pl. 21.)

Stem or trunk a fleshy more or less depressed corm, rooting just above its 2-lobed (or in many foreign species 3-lobed) base, above covered with the dilated and imbricated bases of the awl-shaped or linear somewhat quadrangular leaves, which include four air-tubes, intercepted by cross partitions. Sporangia pretty large, orbicular or ovoid, plano-convex, very thin, sessile in the axils of the leaves, and united at the back with their excavated bases (the thin edges of the excavation folding round partly cover them, forming the _velum_), traversed internally by transverse threads; those of the outer leaves filled with large spherical macrospores, their whitish crustaceous integument marked by one circular, and on the upper surface by three radiating elevated lines (circumscribing a lower hemisphere, and three upper segments which open valve-like in germination); those of the inner leaves filled with very minute and powdery grayish microspores; these are always obliquely oblong and triangular.--Mostly small aquatics, grass-like or rush-like in aspect, some always submerged, others amphibious, a few living in merely moist soil, maturing their fruit in late summer and early autumn, except n. 7 and some forms of n. 6.

This genus is left essentially as it was elaborated for the 5th edition by the late Dr. GEORGE ENGELMANN. The present editor has added to the range of a few species, and given var. robusta of n. 3.

[*] _Growing under water, only accidentally or in very dry seasons out of water; leaves without stomata (except in forms of n. 3) and peripherical bast-bundles._

1. I. lacustris, L. (Pl. 21, fig. 1--5.) Leaves (10--25 in number, 2--6' long) dark green, rigid; sporangium ovoid or circular, the upper third, or less, covered by the velum, the free part pale and unspotted; both kinds of spores the largest of our species; macrospores (0.32--0.38'' wide) covered with short and twisted crested ridges, which often anastomose; microspores (0.017--0.020'' long) smooth.--Mountain lakes, Penn., N. Y., and New Eng. to Lake Superior, and northward, often with n. 3. (Eu.)

2. I. Tuckermani, Braun. Leaves (10--30, 2--3' long) very slender, awl shaped, olive-green, the outer recurved; sporangium ovoid or circular, the upper third covered by the velum, the free part sometimes brownish-spotted; macrospores (0.22--0.28'' wide) on the upper segments covered with parallel and anastomosing ridges, the lower half reticulated; microspores (0.013--0.015'' long) smooth or very delicately papillose.--Mystic and other ponds near Boston, together with the next (_Tuckerman, W. Boott_).

3. I. echinospora, Durieu. Leaves slender, awl-shaped; sporangium ovoid or circular; macrospores (0.20--0.25'' wide) beset all over with small entire and obtuse or slightly forked spinules. (Eu.)--In this European form, the leaves are very slenderly attenuated (3--4' long), the upper margin of the sporangium only is covered with the narrow velum, the free part is unspotted, and the slightly papillose microspores are larger (0.015--0.016'' long).

Var. Braunii, Engelm. Leaves (15--30 in number, 3--6' long) dark and often olive-green, straight or commonly recurved, half or two thirds of the sporangium covered by the velum, the free part often with light brown spots; macrospores as in the type; microspores smaller (0.013--0.014'' long), smooth. (I. Braunii, _Durieu._)--Ponds and lakes, New Eng. to N. Y., Penn., Mich., and northward, often with the two preceding.--Frequently with a few stomata, especially in Niagara specimens.

Var. robusta, Engelm. Stouter; leaves (25--70, 5--8' long) with abundant stomata all over their surface; velum covering about one half of the large spotted sporangium; macrospores 0.18--0.27'' wide.--Lake Champlain, north end of Isle La Motte (_Pringle_).

Var. muricata, Engelm. Leaves (15--30, 6--10' long) straight or flaccid, bright green; about one half of the almost circular sporangium covered by the velum, unspotted; macrospores (0.22--0.27'' wide) with shorter and blunter spinules; microspores as in the last variety, or rarely spinulose. (I. muricata, _Durieu._)--In some ponds north of Boston (_W. Boott_).

Var. Boottii, Engelm. Leaves (12--20, 4--5' high) awl shaped, stiffly erect, bright green, with stomata; sporangium as in the last; macrospores as in the type, but a little smaller and with very slender spinules. (I. Boottii, _Braun_, in litt.)--Pond in Woburn, near Boston, partly out of water (_W. Boott_).

[*][*] _Growing partly out of water, either by the pond drying up or by the receding of the ebb tide; leaves with stomata, and in n. 6 and 7 with four or more peripherical bast-bundles._

4. I. saccharata, Engelm. Leaves (10--15, 2--3' long) slender, olive-green, curved; sporangium small, ovoid, only the upper edge covered by the velum, nearly unspotted; macrospores (0.20--0.22'' wide) minutely tuberculate; microspores (0.012'' long) papillose.--On Wicomico and Nanticoke Rivers, eastern shore of Maryland, between high and low tide (_Canby_).

5. I. riparia, Engelm. Leaves (15--30, 4--8' long) slender, deep green, erect; sporangium mostly oblong, upper margin to one third covered by the velum, the free part spotted; macrospores very variable in size (0.22--0.30'' wide), the upper segments covered by short crested ridges, which on the lower hemisphere run together forming a network; microspores larger than in any other species except n. 1 (0.013--0.016'' long), mostly somewhat tuberculated.--Gravelly banks of the Delaware, from above Philadelphia to Wilmington, between flood and ebb tide; margins of ponds, Lake Saltonstall, Conn. (_Setchell_), and northward.--Distinguished from the nearly allied I. lacustris by the stomata of the leaves, the spotted sporangium, the smaller size of the macrospores and their reticulation on the lower half.

6. I. Engelmanni, Braun. Leaves long (25--100, 9--20' long), light green, erect or at last prostrate, flat on the upper side; sporangium mostly oblong, unspotted, the velum very narrow; macrospores (0.19--0.24'' wide) covered all over with a coarse honeycomb-like network; microspores (0.012--0.014'' long) mostly smooth.--Shallow ponds and ditches, from Mass. (near Boston, _W. Boott, H. Mann_) and Meriden, Conn. (_F. W. Hall_), to Penn. and Del. and (probably through the Middle States) to Mo.--By far the largest of our species, often mature in July.

Var. gracilis, Engelm. Leaves few (8--12 only, 9--12' long) and very slender; both kinds of spores nearly as in the type.--Southern New Eng. (Westville, Conn., _Setchell_) and N. J. (_Ennis_); entirely submersed!

Var. valida, Engelm. Trunk large and stout (often 1--2' wide); leaves (50--100, even 200, 18--25' long) with an elevated ridge on the upper side; sporangium oblong or linear-oblong (4--9'' long), {1/3}--1/2 or more covered by the velum; spores very small; macrospores 0.16--0.22'' wide; microspores 0.011--0.013'' long, spinulose.--Del. (_Canby_) and Penn. (_Porter_). Sept.

7. I. melanopoda, J. Gay. Leaves (15--50, 6--10' long) very slender, keeled on the back, straight, bright green, usually with dark brown or black shining bases; sporangium mostly oblong, with a very narrow velum, brown or spotted; macrospores very small (0.14--0.18'' wide), smoothish, or with faint tubercles or ridges; microspores (0.010--0.012'' long) spinulose.--Shallow ponds, and wet prairies and fields, central and northern Ill. (_E. Hall, Vasey_), and westward. June, and sometimes again in Nov.--Trunk more spherical and more deeply 2-lobed, and both kinds of spores smaller than in any other of our species; leaves disappearing during the summer heat. Closely approaching the completely terrestrial species of the Mediterranean region.

ORDER 135. MARSILIACEAE.

Perennial plants rooted in mud, having a slender creeping rhizome and either filiform or 4-parted long-petioled leaves; the somewhat crustaceous several-celled sporocarps borne on peduncles which rise from the rhizome near the leaf-stalks, or are more or less consolidated with the latter, and contain both macrospores and microspores.

1. MARSILIA, L. (Pl. 25.)

Submersed or emersed aquatic plants, with slender creeping rootstocks, sending up elongated petioles, which bear at the apex a whorl of four nervose-veined leaflets, and at or near their base, or sometimes on the rootstock, one or more ovoid sporocarps. These sporocarps or fruit usually have two teeth near the base, and are 2-celled vertically, with many transverse partitions, and split or burst into 2 valves at maturity. The sporocarps have a ring along the edges of the valves, which at length swells up and bears the sausage-shaped compartments from their places. The compartments contain macrosporangia and microsporangia intermixed. (Named for _Aloysius Marsili_, an early Italian naturalist.)

1. M. quadrifolia, L. Leaflets broadly obovate-cuneate, glabrous; sporocarps usually 2 or 3 on a short peduncle from near the base of the petioles, pedicelled, glabrous or somewhat hairy, the basal teeth small, obtuse, or the upper one acute.--In water, the leaflets commonly floating on the surface; Bantam Lake, Litchfield, Conn., and now introduced in many places. (Eu.)

2. M. vestita, Hook. & Grev. Leaflets broadly cuneate, usually hairy, entire (2--7'' long and broad); petioles 1--4' long; peduncles free from the petiole; sporocarps solitary, short-peduncled (about 2'' long), very hairy when young; upper basal tooth of sporocarp longest, acute, straight or curved, lower tooth acute, the sinus between them rounded. (M. mucronata, _Braun_.)--In swamps which become dry in summer; Iowa and southwestward.

ORDER 136. SALVINIACEAE.

Floating plants of small size, having a more or less elongated and sometimes branching axis, bearing apparently distichous leaves; sporocarps or conceptacles very soft and thin-walled, two or more on a common stalk, one-celled and having a central, often branched receptacle which bears either macrosporangia containing solitary macrospores, or microsporangia with numerous microspores.

1. AZOLLA, Lam. (Pl. 21.)

Small moss-like plants, the stems pinnately branched, covered with minute 2-lobed imbricated leaves, and emitting rootlets on the under side. Conceptacles in pairs beneath the stem; the smaller ones acorn-shaped, containing at the base a single macrospore with a few corpuscles of unknown character above it; the larger ones globose, and having a basal placenta which bears many pedicellate microsporangia which contain masses of microspores.

1. A. Caroliniana, Willd. Plants somewhat deltoid in outline (4--12'' broad), much branched; leaves with ovate lobes, the lower lobe reddish, the upper one green with a reddish border; macrospores with three attendant corpuscles, its surface minutely granulate; masses of microspores glochidiate.--Floating on quiet waters, from Lake Ontario westward and southward,--appearing like a reddish hepatic moss.

* * * * *

SALVINIA NATANS, L., was said by Pursh to grow floating on the surface of small lakes in Western New York, and has more recently been said to occur in Missouri. It has oblong-oval floating leaves 4--6'' long, closely pinnately-veined, which bear conceptacles and branching plumose fibres on their under surface.

SUBCLASS II. CELLULAR ACROGENS, OR BRYOPHYTES.

Plants composed of cellular tissue only. Antheridia or archegonia, or both, formed upon the stem or branches of the plant itself, which is developed from the germinating spore usually with the intervention of a filiform or conferva-like prothallus.--Divided into the _Musci_, or Mosses, and the _Hepaticae_.

DIVISION I. HEPATICAE.[1] (LIVERWORTS.)

[Footnote 1: Elaborated for this edition by Prof. L. M. UNDERWOOD, of Syracuse, N. Y.]

Plants usually procumbent, consisting of a simple thallus, a thalloid stem, or a leafy axis; leaves when present 2-ranked, with uniform leaf-cells and no midvein; thalloid forms with or without a midvein, smooth or scurfy or scaly beneath and usually with numerous rootlets. Sexual reproduction by antheridia and archegonia, which are immersed in the thallus, or sessile or pedicelled upon it, or borne on a peduncled receptacle. The fertilized archegonium develops into a capsule (_sporogonium_) closely invested by a calyptra, which ruptures above as the ripened capsule (containing numerous spores and usually elaters) pushes upward. It is also commonly surrounded by a usually double involucre, the inner (often called _perianth_) more or less tubular, the outer tubular or more often foliaceous, sometimes wholly wanting. Propagation is also effected by offshoots (_innovations_), runners (_flagella_), or by _gemmae_, which appear at the margin of the leaves or on the surface of the thallus, often in special receptacles.

ORDER 137. JUNGERMANNIACEAE. SCALE-MOSSES.

Plant-body a leafy axis or rarely thallose. Capsule borne on a slender often elongated pedicel, splitting at maturity into 4 valves. Elaters mixed with the spores, mostly bispiral (unispiral in n. 1--3, 32, and 33, 1--3-spiral in n. 5 and 28). Antheridia and archegonia dioecious or monoecious, in the latter case either mingled in the same inflorescence, or separated upon the same branch, with the antheridia naked in the axils of the lower leaves, or on separate parts of the same plant. Leaves 2-ranked, incubous (i.e. the apex of each leaf lying on the base of the next above), or succubous (i.e. the apex of each leaf lying under the base of the next above), or sometimes transverse, with frequently a third row of rudimentary leaves beneath the stem.

Artificial Key to the Genera.

Sec. 1. Plant-body a leafy axis.

[*] Leaves complicate-bilobed (i.e. folded together) or with a small basal lobe.

[+] Lower lobe smaller than the upper.

[++] Root-hairs borne on the stems or underleaves.

1. Frullania. Lower lobe mostly saccate, more or less remote from the stem. Branches intra-axillary, the leaves on either side free.

2. Jubula. Lower lobe saccate; branches lateral, a basal leaf borne partly on the stem, partly on the branch.

3. Lejeunea. Lower lobe incurved, more or less inflated.

5. Porella. Lower lobe ligulate. Perianth triangular, the third or odd angle ventral.

[++][++] Root-hairs rising from the lower lobes.

4. Radula. Perianth compressed. Underleaves none.

[+][+] Upper lobe smaller than the lower, or the two somewhat equal.

[++] Leaves succubous as to their lower lobes.

15. Scapania. Involucral leaves 2; perianth dorsally compressed, the mouth truncate, bilabiate, decurved.

16. Diplophyllum. Involucral leaves few; perianth erect, round, the mouth denticulate.

[++][++] Leaves transverse.

25. Marsupella. Perianth tubular or somewhat compressed. (Compare also Jungermannia Sec. Sphenolobus.)

[*][*] Leaves palmately 3--4- (or many-) cleft.

[+] Divisions numerous, capillary. Plants large, usually in conspicuous mats.

6. Ptilidium. Leaves palmatifid with ciliate margins.

7. Trichocolea. Leaves setaceously multifid.

[+][+] Leaves 3--4-cleft or parted; plants small, mostly inconspicuous.

10. Lepidozia. Leaf-divisions two cells wide or more.

11. Blepharostoma. Leaf-divisions only one cell wide.

[*][*][*] Leaves entire, emarginate, or 2--3-toothed or -lobed.

[+] Leaves closely imbricate on short julaceous stems.

27. Gymnomitrium. Involucre double, the inner shorter.

[+][+] Leaves deeply bilobed.

8. Herberta. Underleaves large. Perianth fusiform on an elongated branch.

12. Cephalozia. Underleaves mostly wanting; perianth mostly triangular on a short branch.

[+][+][+] Leaves incubous, mostly plane or depressed.

9. Bazzania. Leaves mostly 2--3-toothed. Perianth fusiform on a short branch.

14. Kantia. Leaves mostly entire. Perianth fleshy, pendulous, subterranean.

[+][+][+][+] Leaves succubous or transverse.

[++] Underleaves entire or nearly so.

13. Odontoschisma. Involucral leaves numerous, small, incised, those of the stem rounded or retuse.

21. Mylia. Involucral leaves 2, connate at base. Large.

22. Harpanthus. Involucral leaves few, smaller than the semi-vertical emarginate stem-leaves. Small.

24. Jungermannia. Involucral leaves few, mostly larger than the entire or bidentate stem-leaves. Medium-sized or large.

[++][++] Underleaves 2--4-cleft, -parted, or -divided.

17. Geocalyx. Involucre fleshy, saccate, pendent. Leaves bidentate; underleaves 2-cleft.

18. Lophocolea. Fruit terminal on the main stem or a primary branch. Involucral leaves distinct.

19. Chiloscyphus. Fruit on a short lateral branch. Involucral leaves distinct. (See also Jungermannia.)

[++][++][++] Underleaves mostly wanting.

[a.] Leaves entire or barely retuse.

23. Liochlaena. Involucral leaves distinct, like those of the stem; perianth truncate-depressed at the apex.

26. Nardia. Involucral leaves connate at base and adnate to the perianth.

[b.] Leaves bidentate or bilobed, rarely 3-lobed.

12. Cephalozia. Branches all from beneath. Perianth on a short branch, mostly trigonal with the odd angle beneath.

24. Jungermannia. Simple or branching laterally. Perianth terminal, mostly laterally compressed.

[c.] Leaves mostly spinulose or dentate.

20. Plagiochila. Involucral leaves large; perianth laterally compressed.

Sec. 2. Plant-body pseudo-foliaceous with succubous leaf-like lobes.

28. Fossombronia. Perianth large, campanulate.

Sec. 3. Plant-body a thallus.

[*] Thallus with a distinct costa.

29. Pallavicinia. Thallus 3--6'' wide, mostly simple, the margins sinuate or undulate. Perianth tubular, at length dorsal.

30. Blasia. Thallus 3--6'' wide, lobed, dichotomous, or radiate, the margins pinnatifid-sinuate.

32. Metzgeria. Thallus narrow (1--2''), ciliate at the margins or on one or both sides.

[*][*] Thallus with an inconspicuous costa or none.

33. Aneura. Thallus rather narrow, mostly palmately or pinnately lobed. Sporogonium rising from the under side near the margin.

31. Pellia. Thallus wider, mostly simple or forked. Sporogonium rising from the upper surface.

1. FRULLANIA, Raddi. (Pl. 24.)

Leaves incubous, complicate-bilobed, the lower lobe usually inflated, helmet- or club-shaped; underleaves bifid, rarely entire, with basal rootlets. Dioecious or monoecious. Fruit terminal on the branches. Involucral leaves 2 or 4, larger than the stem-leaves; perianth 3--4-angled, mucronate. Calyptra pyriform, fleshy. Capsule globose, the lower third solid. Elaters truncate at each end, unispiral, adherent to the valves. Spores large, reddish, minutely muricate. Antheridia most often on a short branch, globose-oblong or cylindric. Archegonia 2--4, long-styled. (Named for _Leonardo Frullani_, an Italian Minister of State.)

Sec. 1. TRACHYCOLEA. _Perianth triangular in section, rough with tubercles or scales, or villous; lower leaf-lobe helmet-shaped, truncate at base._

[*] _Lower leaf-lobe about three fourths the size of the upper._

1. F. Oakesiana, Aust. Stems widely branching; fertile branches short; leaves obliquely orbicular, loosely imbricate, the lower lobe rotund, contiguous to the stem; underleaves ovate-rotund or subobovate, little wider than the stem, bifid; involucral leaves more or less connate, equally bilobed, the lobes entire, obtuse; perianth small, subobovate-pyriform, smooth or 1--7-nerved or alate both sides.--White Mts., on stunted spruce and birch trees.

[*][*] _Lower leaf-lobe much smaller than the upper._

[+] _Underleaves scarcely wider than the stem, ovate, bifid, the divisions entire, acute; perianth 1-carinate or smooth, except in n. 2; stems creeping._

2. F. Virginica, Lehm. Stems short, irregularly branching; leaves crowded, ovate, entire, somewhat concave, the lower lobes sometimes expanded into a lanceolate lamina; underleaves round-ovate, bifid, twice the width of the stem; perianth compressed-pyriform, tuberculate, 2--4-carinate dorsally, 4-carinate ventrally.--On bark of trees, rarely on rocks; common.

3. F. Eboracensis, Lehm. Branches clustered; leaves loose, imbricate on the branches, round-ovate, entire; perianth pyriform, slightly compressed and repand, smooth, obscurely carinate beneath and gibbous toward the apex. (F. saxatilis, _Lindenb._)--On trees and rocks; common northward.

4. F. Pennsylvanica, Steph. Stems dichotomous; leaves imbricate, flat, ovate, mucronate or rarely obtuse, entire; lower lobe marginal, large, round-cucullate; underleaves broadly ovate, deeply parted, the divisions long-acuminate; dioecious; antheridial spikes on short lateral branches, elongated; lobes of the involucral leaves acuminate, much narrowed at base, and the large underleaves carinate-concave, deeply parted, their apiculate divisions entire or toothed.--Shaded rocks, Stony Creek, Carbon Co., Penn. (_Rau_). Known only from the original description.

5. F. saxicola, Aust. Stems numerous, widely branching; leaves orbicular, scarcely oblique, flat; lower lobe near the stem, small, or rarely larger and round-galeate; underleaves scarcely wider than the stem, subovate, bifid; perianth broadly oblong, bowl-shaped with very short mouth, papillose, abruptly broad-carinate beneath, 1--many-nerved each side of the keel, 2-angled.--Sloping dry trap rocks, Closter, N. J. (_Austin_).

[+][+] _Underleaves 2--3 times wider than the stem, round or subquadrate, bifid, the divisions blunt or truncate._

[++] _Leaves lax, rather distant; lower lobe mostly expanded, ovate-lanceolate._

6. F. aeolotis, Nees. Procumbent, irregularly branched or subpinnate; leaves semi-vertical, subsquarrose, obliquely cordate, the lower lobe expanded; underleaves ovate, acutely bifid, the upper margin angular-dentate or entire; sporogonium unknown.--On trees and rocks, chiefly in mountain regions.

[++][++] _Leaves close-imbricate; lower lobe galeate, seldom expanded except on terminal leaves._