66 UNIVERSITY OF MISSOURI STUDIES [208 



habit are root-parasites, notably Comandra umbellata and the 

 Gerardias. 



V. ANTHK0P0PHYTE8. 



The anthropophytic vegetation, inasmuch as it is either di- 

 rectly under human control, or consists of species which grow 

 under a great variety of conditions and in a wide range of soils, 

 does not fall readily into distinct societies. Moreover certain 

 weeds are usual with certain crops. Thus the common chess 

 (Bromus secalinus), and the cockle (Agrostemnm Githago) oc- 

 cur wherever winter wheat is grown. In cultivated grounds 

 weeds adapt themselves to such conditions as are imposed upon 

 them by man. Obviously weeds in a meadow or a grainfield suf- 

 fer less interruption than weeds growing in a cornfield or a gar- 

 den. 



The anthropophytic vegetation consists of five sorts of 

 plants: First, pasture and meadow plants; second, field and 

 garden crops: Third, orchard and vineyard plants; Fourth, or- 

 namental plants; Fifth, weeds and escapes. The field and gar- 

 den crops, as well as the orchard, vineyard, and ornamental 

 plants, possess little ecological interest, since they grow under 

 conditions that render any spontaneity impossible. In general 

 the same is true of escapes, which either persist in a few patches, 

 or lead a brief and fugitive Hfe. The flora of pastures and 

 meadows, however, is more important. 



1. Pascuales. Pasture plants. Since the sward of 

 pastures is invariably the blue grass {Poa pratensis), there is 

 but one association of pasture plants. 



a. Pascuales pooides. The blue grass association of 

 pasture plants occurs not only in pastures, but in all tame or 

 half-wild open places, such as orchards, roadsides, yards, and 



