694 



WEED FLORA OF IOWA 



Fig. 535. Common Brake (.Pteris aquiUna). A troublesome weed following 

 flres in the northwest, also under similar conditions in some parts of 

 northeastern Iowa. 



(Drawing by Charlotte M. King.) 



forests of Douglas fir. In places, the red cherry {Prunus emar- 

 ginata) may occupy the soil for a long time. Cusick states that 

 the "elkweed" of eastern Oregon, more commonly called fireweed, 

 the only herbaceous plant to follow the fires, is followed in a year 

 or so by the lodge pole pine {Pinvs murrayana) and Oregon fir 

 {Psevdotsuga taxifolia). In western Oregon it takes more time; 

 the ground is covered with a thick growth of blackberry plants. 

 In the Rocky mountains the conditions are somewhat different. 

 The first year after a fire very few plants will grow; but among 

 the first, mention may be made of fireweed (Epilohium angusti- 

 folium), thistle {Cirsium drummondii and the variety acaulescens, 

 C. eriocephalum and foliosum), groundsel (Senecio ccmus), (and in 

 moist places 8. triangularis), painted cup (Gastilleja integra), wild 



