CYCADOPHYTA 355 
Family 7. Zamiaceae. Tropical trees with staminate 
and seed cones.—Zamia, Macro- 
zamia, Dioon. 
Class 29. BENNETTITINEAE. Flowering-plant Ancestors. 
Mesozoic plants with pinnate leaves, 
long extinct. 
Order BENNETTITALES. With the characters of the class. 
Family 8. Bennettitaceae. 
Class 30. CORDAITINEAE. Conifer Ancestors. Paleozoic 
to present, trees and shrubs with 
typically parallel-veined _leaves, 
mostly long extinct. 
Order CorpaITaLes. Branching trees with elongated 
parallel-veined leaves. (Extinct.) 
Family 9. Cordaitaceae. 
Order GrykGoaLes. Maidenhair Trees. Branching trees 
with fan-shaped,  parallel-veined 
leaves. (All extinct but one species.) 
Family 10. Ginkgoaceae. But one genus remaining. 
—Ginkgo. 
Order GneTALes. Joint Firs. Anomalous woody plants 
of doubtful relationship, probably to 
be placed here, but the sperms not 
motile. 
Family 11. Ephedraceae. Small Equisetum-like 
shrubs with reduced, opposite leaves. 
_ —Ephedra. 
a 12. Gnetaceae. Shrubs and trees with large, 
opposite, pinnately veined leaves.— 
Gnetum. 
Family 13. Tumboaceae. Short, thick-stemmed 
woody plants with two large, oppo- 
site, parallel-veined leaves.—Tum- 
boa (Welwitschia). . 
Phylum XIII. STROBILOPHYTA. The Conifers 
Minute gametophytes developed in naked seeds produced by 
the large, leafy-stemmed and rooted sporophytes; sperms 
not motile. (Sp. about 400.) 
Class 31. PINOIDEAE. Mostly trees with increasing stems - 
