191] FLORA OF BOULDER, COLORADO 43 



IV. SPECIAL CLASSES OF PLANTS 



Independent of the five great zones of vegetation are two 

 special classes of plants : A. The saprophytic and parasi- 

 tic plants (SAPROPHYTICALES ET PARASITI- 

 CALES). B. The plants which largely owe their presence to 

 human agency (ANTHROPOPHYTICALES). These 

 consist of the various cultural plants, of weeds, and of es- 

 capes. 



A. SAPROPHYTICALES ET PARASITICALES 



Besides the saprophytic and parasitic fungi there are a 

 few phanerogams, which are destitute of chlorophyl and are 

 true saprophytes or parasites. The following are known to 

 occur in the region : 



Corallorrhiza Corallorrhiza (saprophytic in rich soil) 



C. multiflora (saprophytic in rich soil) 



Razoumofskya Americana (parasitic on lodgepole pine) 



R. cryptopoda (parasitic on bull pine) 



Pterospora Andromedea (parasitic on the roots of bull 

 pine) 



Cuscuta curta (parasitic on Iva xanthifolia and other 

 coarse herbs) 



C. indecora (parasitic on Thennopsis pinetorum and other 

 legumes) 



Thalesia fasciculata (parasitic on Artemisia frigida and 

 other Composites) 



There are also a few root-parasites with green foliage, 

 notably Comandra pallida, Gerardia Besseyana, and the Cas- 

 tillejas. 



B. ANTHBOPOPHYTICALES 



Only three kinds of anthropophytic plants need concern 

 us here: a. Forage plants (Faenales), which have become 



