272 Proceedings of the Ohio State Academy of Science. 



2. With simple, long, grass-like leaves containing a ligule and forming 

 a rosette on a short 2- or 3-lobed stem; heterosporous, the sporan- 

 gia in the bases of the leaves \'. Isoeteae. Quillworts. 



2. With numerous, small, lanceolate, subulate, or scale-like, 1-nerved 



leaves covering the stem. 3. 



3. Leaves without a ligule; homosporous, sporangia single in the axils 



of the sporophylls which are arranged in cones or in zones alter- 

 nating with foliage leaves III. Lycopodie.\e. Clubmosses. 



3. Leaves with a ligule; green cells often with onh^ 1 large chloroplast; 

 heterosporous, the sporangia single in the axils of the sporophylls 

 which are arranged in cones.... VI. Sei..\gixelle.\e. Selaginellas. 



