SELAGINELLACE^. 697 



•<- 4- Spikes peduncled, i. e. the leaves minute on the fertile branches. 

 ++ Leaves homogeneous and equal, many-ranked ; stems terete. 



7. L. clavatum, L. (Common Club-Moss.) Stems creeping exten 

 sively, with similar ascending short and very leafy branches ; the fertile ter- 

 minated by a slender peduncle (4 - G' long), bearing about 2-3 (rarely 1 or 4) 

 linear-cylindrical spikes; leaves liuear-awl-shaped, incurved-spreadiug (light 

 green), tipped, as also the bracts, with a fine bristle. — Dry woods; common 

 especially northward. July. (Eu.) 



++ •»-*■ Leaves of two forms, feiv-ranked ; stems or branches fattened. 



8. L. Carolini^num, L. (PI. 21.) Sterile stems and their few short 

 branches entirely creeping (leafless and rooting on the under side), thickly 

 clothed with broadly lanceolate acute and somewhat oblique 1-nerved lateral 

 leaves widely spreading in 2 ranks, and a shorter intermediate row appressed 

 on the upper side; also sending up a slender simple peduncle (2 -4' high, 

 clothed merely with small bract-like and appressed awl-shaped leaves), bearing 

 a single cylindrical spike. — Wet pine-barrens, N. J. to Va., and southward. 



9. L. complanatum, L. (Grouxd-Pine.) Stems extensively creeping 

 (often subterranean), the erect or ascending branches several times forked 

 above; bushy branchlets crowded, fattened, fan-like and spreading, all clothed 

 with minute imbricated-appressed awl-shaped leaves in 4 ranks, with decurrent- 

 united bases, the lateral rows with somewhat spreading tooth-like tips, those 

 of the upper and under rows smaller, narrower, wholly appressed; peduncle 

 slender, bearing 2-4 cylindrical spikes. — Var. CHAMiECYPARfssus has nar- 

 rower, more erect and bushy branches, and the leaves less distinctly dimor- 

 phous. — Woods and thickets; common, especially northward. (Eu.) 



Order 134. SELAGINELLACE^. 



Leafy plants, terrestrial or rooted in mud, never very large ; the stems 

 branching or sliort and corm-like ; the leaves small and 4 - G-rowed, or 

 subulate and elongated ; sporangia one-celled, solitary, axillary or borne 

 on the upper surface of the leaf at its base and enwrapped in its margins, 

 some containing large spores (macrospores) and others small spores (micro- 

 spores). The macrospores are in the shape of a low triangjular pyramid 

 with a hemispherical base, and marked with elevated ribs along the angles. 

 In germination they develop a minute prothallus which bears archegonia 

 to be fertilized by antherozoids developed from the microspores. 



1. Selag^nella. Terrestrial; stems slender ; leaves small ; sporangia minute and axillary. 



2. Isoetes. Aquatic or growing in mud ; stems corni-like ; leaves elongated and rush-like , 



sporangia very large, enwrapped by the diluted bases of the leaves. 



1. SELAGINELLA, Beauv. (PI. 21.) 



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 



