64 



hunger. Sheep eat them more readily than other stock. Many of the 

 species thrive on dry, rocky soils too poor to pr(xluce much other vege- 

 tation, and they probably do a great deal toward improving the fertil- 

 ity of these soils, and are thus indirectly beneficial ; but many ranchers 

 regard them as weeds, owing to their tendency to spread rapidly in 

 overstocked pasture lands. 



THK MILK-VETCHES. 



The milk-vetches, or rattle-weeds, as some of them are called, are 

 by far tlie best represented group of leguminous plants in the range 

 region. Of the numerous sorts some are valuable forage plants, others 



are too small to be of any value 

 or are so unpalatable that stock 

 will not eat them, and a few — the 

 so called "loco weeds" — are in- 

 jurious to stock under certain cir- 

 cumstances, causing considerable 

 loss by killing the animals eating 

 them. 



The milk-vetches occur on a 

 great variety of soil, from rich, 

 moist bottom lands to dry, sterile, 

 rocky, and gravelly ridges, often 

 forming a large proi)ortion of 

 the vegetation. In some of the 

 species the fruits are» large and 

 fleshy and are much sought after 

 by stock, particularly by sheep. 

 There are i)robably a great many 

 kinds that are of more or less 

 value as forage plants, but our 

 knowledge of the real value of 

 most of the species is very limited 

 and reports are contradictory, 

 some stockmen regarding certain 

 sorts as injurious, while others 

 maintain that they are valuable forage i)lants, stock eating them with 

 the best of results. 



Amcmg the most common and valuable kinds are bristly-fruited milk- 

 vetch {Astrm/alufi hi/iwfjiottis), ground plum or bullalo pea {A. crassi- 

 carpus), larger ground plum {A. mexicanns), and prairie milk-vetch 

 {A. adsurgenn), (see fig. 26.) Other species, regarded by maily as valu- 

 able, are Morton's milk-vetch {A. mortoni), zigzag milk- vetch {A. fiexu- 

 osus), and sleiuler milk-vetch {A. gracilis). T.ow luilkvetch (A. loti- 

 florns) and bitter milk-vetch (.1. hisitlcatns) are l)y some regarded as 

 good forage plants and by others as injurious species. Some years 



Fig. 26.— Prairie milk-vetch {Astragalus adsur- 

 gens). 



