THE FAMILIES, GENERA AND SPECIES OF PTERIDOPHYTA. 479 



Leaves without a ligule (i.e. a scale at the upper 

 end of the leaf-base or sheath, as in grasses). 

 Plant isosporous (i.e. spores all of one kind). 



XI. LYCOPODIACE^. 

 Leaves ligulate; plant heterosporous (i.e. bearing both 

 macro — and micro — spores. 



XIL SELAGINELLACEjE. 



Family Xl.—LYCOPODIACEAl. Club-mosses. 



Sporangia situated singly at the base of the sporophylls, 

 which form, as a rule, a dense terminal cone; reniform, uni- 

 locular, and opening like a mussel-shell by two valves. Spores 

 all of one kind (isosporous), giving rise on germination to 

 fairly large, partly green, monoecious prothalli. — Perennial 

 herbs. Stems (in ours) long and much branched, thickly 

 covered with small, simple, triangular or scale-like leaves, 

 spirally developed in some species. Roots dichotomously 

 branched; developed in acropetal succession (i.e., the youngest 

 root nearest the apex of the main root). Leaves without 

 ligule. 



(Jne genus i. Lycopodium. 



I. Lycopodium, Linn. 



Branching apparently dichotomous. Leaves narrow, 

 usually placed spirally upon the stem, but in some 

 species forming four ranks as in most Selaginellas. Many 

 species have a vegetative reproduction by the aid of small 

 bulbils developed in the leaf-axils. 



Sporangia borne all along the stem, in the axils of 

 ordinary leaves. Stems at first upright, then 

 pendulous. Leaves 3 lines long, ^ line broad. 



I. veriicillatuni. 

 Sporangia on the upper part of the branches only, 

 borne in the axils of more or less differentiated 

 bracts. 

 Leaves i or 2 lines long, subulate, with a distinct 



midrib; sporangia in distinct short spikes 4. ccrnunm. 

 Leaves il to 4 lines long, linear or subulate, chan- 

 nelled, finely toothed; sporangia in distinct cylin- 

 drical or forked spikes 5. clavatum. 



Leaves 4 to 6 lines long, 1 line broad, obliquely 

 lanceolate or falcate, pointed; sporangia in a cylin- 

 drical spike on a nearly leafless peduncle. 



6. caroliniaiutni. 

 Leaves 6 lines long, i line broad, arranged in about 

 8 lines, all round the stem; spikes forked. 



2. giiidioidcs. 

 Leaves up to 9 lines long, less than a line broad. 



- 3. dacrydioidcs. 

 I. L. vcrticiUaiiDU. Linn. — (Jn rocks or epiphytic on trees. 

 Mac-a-mac, Ly., McLca 31; Houtboschberg, Ze., 6,800 ft., 

 Schlcchfer 3.757. 



