26i 



Order V. Marsileacew. 

 Capsules scattered or serial oa the root-stock or the base of the 

 petioles, globose or ovate-oblong, coriaceous, 2-4 valved, dehiscent, 

 sporangia membranous, indehiscent ; spores of two kinds, macrospores 

 and microspores. Rootstock free-creeping, slender, vernation circinate. 

 Leaves linear- filif or la, or 4-foliate, at the summit of slender erect 

 petioles. 



This order like the preceding contains two dissimilar genera. One, 

 Pilularia, is confined to temperate regions, the other, Marsilea, to the 

 warm temperate and tropical, and is here represented. 



Genus I. Marsilea^ Linn. 



Capsules stipitate, 1-2 li. diameter, serial on the rootstock or the base 

 of the petioles- coriaceous, dehiscent, bivalved, containing numerous 

 sacklike membranous transverse sporangia which contain both macros- 

 pores and microspores; rootstock creeping; leaves 4-foliate, at the 

 summit of slender erect petioles. 



These are small perennial plants that grow gregariously in still fresh 

 water, floating on the surface, and are distributed through the tropical 

 and the warm and cool temperate regions of the world. About iorty 

 or fifty species are known. The capsules are small pea — or bean — like 

 bodies, leathery in substance, containing a series of pale thinly-mem- 

 branous transverse sack-like cells, in which the- spores stand length- 

 wise, 3-serial, the larger oblong, (macrospores) forming one series, the 

 central, and the smaller (microspores) two. The former are sev^eral 

 times larger than the latter, which, till removed, they quite conceal. 



1. M. polycarpa^ Hook and Grev. — Rootstock thick as small cord, free- 

 creeping, naked, with filiform long descending roots and scattered 

 ascending petioles, that are slender, 4-8 in. 1. naked ; leaves 4-foiiate, 

 terminal on the summit of the petiole ; leaflets wedge-shaped, the outer 

 edge rounded, at first folded together, spreading subsequently ; f-lj 

 in. in diameter each way, sessile, membranous, herbaceous ; venation 

 reticulated, fine, with no primary ribs, anastomosing, forming narrow 

 elongated linear meshes ; sporangia subglobose li. diameter, serial 

 on the lower part of the si ipes above a vacant space at the base, shortly 

 stipitate, few or many, densely tomentose, but becoming eventually 

 naked. — Icon. Fil. t. 160. Baker, Fern Al. p. 139. M. brasiliensis, 

 Mett. 



Common in ponds and trenches, lagoons, and other still water, 

 covering where found, the surface densely, with oxalis, or clover like 

 foliage, and spreading over large areas. The Jamaica plant, gathered 

 by Purdie, Feb. 1844, in ponds at Hodge's Penn. 8t. Elizabeth, is M, 

 subangulata, A. Br., and regarded by Mr. Baker as a variety of poly- 

 carpa. It is much smaller, with densely tomentose rootstocks and 

 buds, fewer and smaller sub-angular very tomentoso capsules. A speci- 

 men gathered by Miss Taylor at th j Cedars, JSt. Catherine, is larger 

 but not in fruit. Another small species with tomentose capsules, M. 

 Berteroiy A. Br. is found in St. Doi^ingo. The general range is Cuba 

 southward to Brasil. 



