810 Obdkb 151.— MARSILEACEiE, 



Subkingdom, CRYPTOGAMIA, 



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 r 

 Mosses, Club-mosses, Horsetails, etc.) 



Order CLVII. MARSILEACE,^. Pepperworts. 



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

 tion. Fruit (sporocarps) situated at the base of the leaves or leafstalks, containing 

 the capsular sporanges of one kind with 2 kinds of spores, or of 2 kinds with ths- 

 different spores separated. 



Genera 6, species 20? inhabiting ditches and inundated places in nearly all countries, but 

 obiefly In temperate latitudes. 



1. MARSIL'EA, L. Sporocarps at the base of the leaf-stalks, of one 

 kind, 2-celled, cells transversely many-celled ; spores inserted on each 

 horizontal placenta. — If. Stems creeping, rooting-; lvs. petiolate. 



1 M. quadrifolia L ? Glabrous ; prostrate stems slender, wiry, 8 to 16' long ; 

 lvs. palmately 4-foliate, on filitorm petioles 1 to 3' high, lfts. broadly obovate or 

 fan-shaped, obtuse ; fr. (sporocarps) round-oval, borne on short, axillary stalks, 

 and as large as a pepper-corn. — Sent from La. by Dr. Hale. Perhaps tho locality 

 is beyond our limits. 



2 M. vestita, a very delicate species, with stems and petioles as fine as threads, 

 with the qoaternate leaflets and the very small sessile sporocarps clothed witlk 

 minute, silky, brown hairs, is sent from Iowa, near the Mississippi R. by Dr. 

 Couzens. It probably grows in 111. Height of lvs. 1 to 2'. 



2. ISOE'TES, L. Quill-wort. (Gr. ioog t equal, trog, year ; alike 

 all the year round ?) Sporocarps oval, membranous, 1-celled, immersed 

 in tho dilated base of the frond ; spores subglobous, slightly angular, 

 attached to numerous filiform receptacles, those in the outer fruits larger, 

 angular, triple or in 4s, apparently of a different nature. 



L. lacustris L. Lvs. caespitous, subulate, semiterete, dilated and imbricated at 

 base. — A curious aquatic, in water at or near the margin of ponds and rivers, N. 

 Kng; and Mid. States, often wholly submersed. Lvs. radical, numerous, tufted, 

 simple, 2 to 10' long, somewhat spreading, containing numerous cells divided by 

 longitudinal and transverse partitions. Fr. whitish, rather large, in tho excavated 

 base of the leaves which dilated portion is ordinarily as long as wide; in var. 

 BlPARiA, broader than long; in var. E\'GEr.MANxr, longer than broad. 



3. AZOL'LA, Lam. (Gr. a£w, to dry, okkvpt, to kill ; quickly 



