CXXTIU. GENBEA OP PEENS : 



lobed, two to four valved, containing about 4, rarely 1 — 3 or 8 

 larger spores or oorpuselee. Frucfifioations in the axila of bracts 

 collected in four rows into spikes wMoh are four-sided. 



Jungermannia-like or fern-like plants, frequently creeping ; the 

 stems usually much diohotomously branched, clothed with leaves 

 of two forms, disposed in four rows. The fructifications form 

 angulate spikes. — This genus is separated from Lycopodima, on 

 account of its producing two kinds of spore-oases. The stems 

 usually bear two kinds of leaves, the larger disposed in a disti- 

 chous manner, stipuliform ones being placed between them. 



§ Staehygyjia/ndrium. — ^Leaves monomorphous, disposed in several rows. 



Ex. : S. rupestris, Sprmg. I S. sangninolenta. Spring. 



S. spinosa, Pal de B. \ S. uliginosa. Spring. 



§ Diplostachyv/m. — Leaves dimorphous, disposed iu four rows. 



Ex. : S. involvens. Spring. 

 S. apus, Spring. 

 S. serpens, Kl. 

 S. Iffiviffata, Spring. 

 S. flabellata. Spring 



S. lepidophylla, Spring. 

 S, denticulata, Idni:. 

 S. increscentifolia, Spring. 

 S. inxqualifolia, Sprmg. 

 S. stolonifera, Sprmg. 



Order— MA-RBUMAC'EM. 



§ 1 ISOBTE.E. 



182. ISOETES, iMimaus, Itm. Seem. 420 j Id., Gen. PI 

 ed. 5., 1048. 

 Caxamabia, Dilletiius. 



Spore-cases sessile, solitary in the axils of the (radical) leaves, 

 adherent to their excavated dilated base, one-eeUed, traversed by 

 delicate thread-like receptacles ; of two kinds : (1) antheridia, 

 those of the central leaves, containing very numerous minute 

 oblong spores ; (2) oophoriMa, those of the outer leaves, con- 

 taining numerous larger globose-tetrahedral spores. 



Submersed aquatic plants, with a thick succulent tuberous 

 rhizome or crown, and awl-shaped radical leaves, at the base 

 of which the fructifications are borne. They have very strong 

 affinity with Lycopodmm. 

 Ex. : 1. lacnstriB, Im. 1 1. Engelmanni, A. Sr. 



