SELAGINELLACE^E. 697 



+_ ._ Spikes peduncled, i. e. the leaves minute on the fertile branches. 

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



7. L. davatum, 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 - 6' long), bearing about 2-3 (rarely 1 or 4) 

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

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

 especially northward. July. (Eu.) 



*-* Leaves of two forms, few-ranked ; stems or branches flattened. 



8. L. Carolinianum, 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. (GROUND-PINE.) Stems extensively creeping 

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

 above ; bushy branchlets crowded, flattened, 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. CHAM^CYPARISSUS has nar- 

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

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



ORDER 134. SELAGINELLACEJE. 



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

 branching or short and corm-like ; the leaves small and 4-6-rowcd, 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 triangular 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. Selaginella. Terrestrial; steins slender ; leaves small ; sporangia minute and axillary. 



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



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



1. SELAGINELLA, Beauv. (PL 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 



