DEVELOPMENT OF PLANTS 



331 



cell, as in previous cases, a feature to be noted in the following 

 division. 



117. Family 2. Selaginellaceae. — This family includes but a 

 single genus, Selaginella, of over 600 species. Only a few forms 

 occur in the temperate regions, the majority being confined to 

 tropical countries, where they often form one of the most attrac- 

 tive features of the forest vegetation owing to the symmetry of 

 their branching and the rare delicacy of their foliage (Fig. 241). 



Fig. 241. A common cultivated Selaginella: i, habit of the plant — s, 

 strobili; b., a branch bearing roots, r. lA, portion of stem, showing leaf ar- 

 rangement. — H. O. Hanson. 



For these reasons they are extensively cultivated and familiar 

 objects in conservatories and florists' shops. The so-called res- 

 urrection plant, Selaginella lepidophylla, lives in the very arid 

 sections of the southwestern United States, and during drought 

 reduces its surface to a nest-like ball by rolling up its branches 

 into tight coils. In this condition it appears as a brownish dead 



