258 BOTANICAL GAZETTE [OCTOBER 
the evolutionary development of plants has never been adequately 
portrayed, even in a speculative manner. 
The vigor of growth, widely varied capacity for reproduction, 
range of endurance to unfavorable conditions, and accommoda- 
tional adjustment displayed by parasitic fungi and bacteria in 
general seem to place the greater majority of these forms in a 
Fic, 5.—Opuntia Toumeyi; this plant was found growing in a cavity of the trunk 
of a small tree of Parkinsonia microphylla in 1906, and the small joints formed during 
its parasitism are to be seen near the base and to the right; the larger joints were 
developed after the plant began an autophytic existence rooted in the soil; photo- 
graphed February rort. 
