Physiological Anatomy of Xerophytic Selaginellas 103 
Fig. I. Xerophytic species. 1, Selaginella pilifera Mexican desert; 2, from 
shady and moisty greenhouse ; 4, S. Pringlei from Mexican desert; 5, S. rupincola 
from Arizona desert ; 6, S. sanguinolenta from Karrum Valley Afghanistan. 
Hygrophytic species ; 3, .S'. Galeottei from shady and moist greenhouse. 
Note similarity in size of leaves of xerophytic forms, and difference in size 
of dorsal and ventral leaves of the hygrophytic one. 
