304 



GRAZING INDICATORS. 



weeds are establishing themselves along the roadsides and around ranch 

 houses. Of these, the bur-clover and musky alfilerilla have some forage 

 value. Barley grass is eaten green in the spring before heading out, but 

 afterwards becomes one of the most objectionable weeds for a stock range. 

 The other aliens are destined to cause irreparable injury to the ranges unless 

 kept in check and prevented from becoming firmly established. " 



With few exceptions the species listed below are summer annuals. The 

 winter annuals of southern CaUfornia are largely those noted for the desert 

 plains, but they are here relatively unimportant. It should be borne in 

 mind that, while the indicators given originally denoted overgrazing, some of 

 them, such as Avena and Erodium, have become valuable forage plants as a 

 consequence of the displacement of the native bunch-grasses, and in turn their 

 overgrazed condition is indicated by still more weedy invaders. 



Avena fatua. 

 Bromus maximus. 

 Bromus rubena. 

 Bromus hordeaceus. 



Erodium cicutarium. 

 Erodium moschatum. 

 Centaurea meliteusis. 

 Medicago denticulata. 

 Hypochaeris glabra. 

 Hypochaeris radicata. 

 Eriogonum vimineum. 

 Eriogonum nudum. 

 Lupinus micranthus. 

 Lupinua affinis. 

 Lupinus truncatus. 

 Trifolium microcephalum. 



Grass Indicators. 



Bromus tectonim. 

 Festuca myurus. 

 Hordeum maritimum gusso- 

 neanum. 



Herb Indicators. 



Trifolium amplectens. 

 Trifolium gracilentum. 

 Trifolium tridentatum. 

 Medicago lupulina. 

 Melilotus indica. 

 Raphanus raphanistrum. 

 Eryngium vaseyi. 

 Hemizonia fitchii. 

 Hemizonia clevelandii. 

 Madia exigua. 

 Madia dissitiflora. 

 Lotus strigosus. 



Hordeum murinum. 

 Polypogon monspeliensis. 

 Lamarkia aurea. 



Trichostema lanceolatum. 

 Plantago patagonica. 

 Epilobium paniculatum. 

 Phacelia heterophylla. 

 Lagopbylla ramosiasima. 

 Ptilonella scabra. 

 Orthocarpus purpurascens. 

 Centaurea cyanus. 

 Eremocarpus setigerus. 

 Lithospermum ruderale. 

 Navarretia leucophaea. 



Great Basin indicators. These are limited in the present discussion to 

 the annuals that spread over the grassy intervals of the sagebrush, especially 

 along the northern border where it is mixed with Agropyrum spicatum. While 

 a number of the annuals of the preceding list assume this role along the 

 western edge, three species of introduced weeds are more important than all 

 others combined; these are Bromiis tedorum, Sisymbrium altissimum, and 

 Lepidium perfoliatum. These occur singly or variously mixed. The most 

 extensive community is that of Bromus tedorum, while the mixed community 

 of Bromus and Sisymbrium is almost equally important. Lepidium is most 

 abundant in the Northwest, but is rapidly spreading to other regions. While 

 they owe their establishment originally to overgrazing, fire is a large factor in 

 their rapid spread. They have now replaced the native grasses and herbage 

 almost completely over thousands of square miles, and have reduced the 

 grazing value practically to that of the sagebrush alone. Bromus is the only 

 one with any real value, and this is frequently slight. It furnishes some graz- 

 ing for sheep in the spring, but quickly becomes dry and nearly worthless. 



Overgrazing in the past. The condition of the great ranges of the prairies 

 and plams before the settlement of the West and the effect of settlement upon 

 the grasses have long been mooted questions. It has frequently been assumed 

 that certain grasses have disappeared with the coming of the early settlers 



