FAMILIES OF FLOWERING PLANTS. 5 
opment to some of the flowerless plants, while the absence of differenti- 
ated organs, such as well-marked flowers or floral leaves, emphasizes 
the same condition. 
The Gymnospermae include four orders, the Gnetales, Cycadales, 
Ginkgoales and Coniferales or Coniferae, besides several fossil orders. 
ORDER GNETALES. (FIG. 2.) 
This group includes the single family Gnetaceae. The average 
reader is not likely to meet with the plants comprised in the family. 
Of the three genera, Gnetum, with 15 species, is native of tropical 
“rom Coulter’s ‘“ Plant Relations.” Copyright, 1899, by D. Appleton & Co. 
Fic. 3.—A cultivated Cycad (family Cycadacwe) showing the crown 
of leaves and palm-like stem. 
South America and portions of the Old World; Ephedra, comprising 
20 species, is found in Mexico, South America and Asia, a few species 
reaching the extreme southwestern United States, while Tumboa, a 
genus of a single species, is restricted to a small area on the west coast 
of Africa. Gnetaceous plants as a rule are shrubs, the leaves either 
opposite or reduced to small scales. The flowers are borne in dense 
spikes, and are dioecious, that is, the male and female sporophylls 
occur on different plants. The floral envelope or perianth is small and 
membranous or scaly in texture, bearing little resemblance to a flower 
in the ordinary sense. There is great difference in habit; many 
