458 



COMPOSITAE (COMPOSITE FAMILY) 



brine the soil being cleaned of all plant-growth for a season 

 rather than allow the pest to gain a foothold. Large areas can 

 be finally suppressed by putting the ground under cultivation, 

 plowing deeply during very dry weather, and exposing the root- 

 stocks as much as possible ; after this summer fallowing put in a 

 hoed crop, and give such persistent and careful tillage as to kill 

 surviving rootstocks by depriving them of leaf growth. 



WHITE-LEAVED FRANSERIA 



Franseria discolor, Nutt.) 

 (Gaertneria discolor, Kuntze.) 



Other English names: Bur Ragweed, Creeping Ragweed. 

 Native. Perennial. Propagates by seeds and by rootstocks. 

 Time of bloom : July to September. 

 Seed-time : September to November. 



Range : The Plains region west of the Missouri River, to Wyoming, 

 Colorado, and New Mexico. 



Habitat : Dry soil ; prairies ; meadows 

 and pastures, cultivated fields, waste 



FIG. 320. White-leaved 

 Franseria (Franseria discolor) . 

 X*. 



A near relative of the Common Rag- 

 weed, but much more pernicious be- 

 cause of its creeping rootstocks. Stems 

 twelve to eighteen inches tall, much 

 branched, and spreading, hoary with 

 white hairs. Leaves alternate, smooth 

 and green above but densely white- 

 woolly beneath, coarsely toothed, long 

 and bipinnate, the lobes narrow and 

 very irregular, separated by narrow, 

 winged segments, the petiole similarly 

 winged. Flowers of two kinds, the 

 sterile ones in narrow terminal racemes, 

 the heads, about one-sixth of an inch 

 long, on very short pedicels ; the fertile 



hea< Jf the axil 1 S b f loW ' ***& F '" 

 small clusters; the involucre forms a 



tiny bur, about a sixth of an inch long, 



