354 THE PLANT PHYLA 



Phylum XL LEPmOPHYTA. 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 Lbpidodendrales. Paleozoic and Mesozoic trees, 

 long extinct. 

 Family 4. Lepidodendraceae; 5, Bothrodendraceae; 

 6, Sigillariaceae; 7, Pleuromoiaceae. 



Phylum XIL 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 Pteridospermalbs. With characters of the class. 

 Family L Lyginopterideae; 2, MeduUosae; 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. 



