412 ORDER 156. MARS1LEACE.E. 



SVBKINGDOM, CKYPTOGAMIA, 



OR FLOWERLESS PLANTS. Vegetables destitute of true stamens 

 and pistils, gradually descending to a mere cellular structure, 

 with reproductive organs of 1 or 2 kinds, producing, instead of 

 seeds, minute, dust-like bodies (spores) having neither integu- 

 ments nor embryo. 



PROVINCE, ACROGENS. Flowerless plants, having a regular 

 stem or axis which grows by the extension of the apex only, 

 without increasing in diameter, generally with leaves, and 

 composed of cellular tissue and scalariform ducts. (Ferns, 

 Mosses, Club-mosses, Horsetails, &c.) 



ORDER CLVI. MARSILIACE^E. PEPPERWORTS. 



Herbs creeping or floating, with the leaves petiolate or sessile, circinate in 

 vernation. Fruit (sporocarps) situated at the base of the leaves or leaf- 

 stalks, containing the capsular sporanges of one kind with 2 kinds of spores, 

 or of 2 kinds with the different spores separated. 



* Leaves compound, on slender petioles, with 4 leaflets. Stems creeping MAHSILIA. l 



* Leaves simple, grass-like, radical. Stem a corm ISOKTES. 2 



* Leaves minute, lobeil, imbricated. Stem filifurm. floating free AZOL^A. 3 



1. MARSILIA, L. Sporocarps at the base of the leaf-stalks, of one 

 kind, 2-celled, cells transversely many-celled, separating into two lobes at 

 maturity. Sporangia inserted on each horizontal partition, of 2 kinds, 

 some 1-spored, others oc-spored. n Stems creeping and rooting. Leaves 

 petiolate, apparently radical, of 4 whorled leaflets, resembling clover. 



1 M. quadrifolia L. Lfts. round-cuneiform, as broad as long, glabrous ; sporocarp* 



oblong, smoothish, 1, 2, or 3 on each short peduncle, as large as a peppercorn, u Pet- 

 ioles 3 yhigh. Margin of pond, Litchfield, Conn. (Prof. Eaton). Leaves floating. 



2 IW. vcstata Hook & Grev. Lfts. cuneiform-obovate, longer than broad, glab. ; sporo- 



carps glob. -oval, 2|", hisp., 1 only on each short (3") peduncle. 2-toothedon back. S-W. 



3 M. uiicinata Brann. Lfts. cuneiform-obovate, hispid, petioles 12' high; sporo- 



carp* 2", subeessile at the base of the petioles, clothed with rust-colored wool. Iowa. 



2. ISOETES, L. QUILT WORT. Sporocarps oval, 1-celled, of 2 kinds, 

 sessile in the axils of the radica* ^vs. and adhering to them. Spores in the 

 outer sporangia larger, globular; in the inner minute, powdery. U? 

 Leaves linear, grass-like, clustered on the short corm. 



* Species growing under water, generally wholly submersed, in ponds, &c. .Nos. 18 



* Species growing in shallow water, or in damp grounds, emersed Nos. 4 1 



1 I. lacustrisL. Lvs. 2 6', subulate, rigid, erect-spreading : sporocarps round-ovate, 



unspotted, the larger spores with crested ridges. Varies with the leaves cetaceous- 

 subulate and recurved, the pporocarps rarely a little spotted. N. 



