354 THE PLANT PHYLA 



Phylum XI. LEPEDOPHYTA. The Lycopods 



Minute gametophytes, producing branching, small-leaved, 



rooted sporophytes. (Living species about 



700, but very many extinct.) 



Class 25. LYCOPODINEAE. Lower Lycopods. Isosporous; 



leaves without ligules. 

 Order LYCOPODIALES. Gametophytes much larger than 



the spore. 

 Family 1. Lycopodiaceae. Ground Pines. Dendroid, 



evergreen plants. Lycopodium. 

 Family 2. Psilotaceae. 

 Class 26. LEPIDODENDRINEAE. Higher Lycopods. 



Heterosporous; leaves with ligules. 



Order SELAGINELLALES. Small plants; stems not thicken- 

 ing. 



Family 3. Selaginellaceae. Club Mosses. Moss-like 

 plants bearing terminal cones. 

 Selaginella. 

 Order LEPIDODENDRALES. Paleozoic and Mesozoic trees, 



long extinct. 



Family 4. Lepidodendraceae; 5, Bothrodendraceae; 

 6, Sigillariaceae; 7, Pleuromoiaceae. 



Phylum XII. CYCADOPHYTA. The Cycads 



Minute gametophytes developed in naked seeds produced by 



the large, leafy-stemmed and rooted sporophytes; 



sperms motile. (Living species about 140, but 



very many extinct.) 



Class 27. PTERIDOSPERMEAE. Seed Ferns. Paleozoic, 



fern-like plants, long extinct. 



Order PTERIDOSPEBMALES. With characters of the class. 



Family 1. Lyginopterideae; 2, Medullosae; 3, Clad- 



oxyleae; 4, Protopityeae; 5, Araucari- 



oxyleae. 



Class 28. CYCADINEAE. Common Cycads. Mesozoic to 



present plants with pinnate leaves. 

 Order CYCADALES. With the characters of the class. 



Family 6. Cycadaceae. Mostly tropical trees with 

 staminate cones only. Cycas. 



