22 RANGE INVESTIGATIONS IN ARIZONA, 



Andropogon saccharoides^ and Bouteloua rothrocMi, together with the 

 annual Bouteloua folystachya. 



By far the greater part of the feed here is produced b}^ the winter 

 and spring annuals and the browse plants. The first of these are 

 mainl}' Indian YfYia^i {Plant ago fast igiata)^ Pectocarya linearis^ Sophia 

 pinnata^ S. incisa, Thelypodium lasiophyllum, Monolepis nuttaUiana^ 

 PJiacelia ai'izonica^ Ellma chrysanthemifolia^ SpJixrostignia chamsen- 

 erioides^ and several species of Gilia and Linanthus. There are also 

 extensive areas of Atriplex elegans^ often growing to the exclusion of 

 all else and producing from 200 to 500 or more pounds of dr}^ herbage 

 per acre. This plant, although an annual, usuall}" germinates in the 

 spring and matures in autumn, passing through the dry season in the 

 vegetative state. 



The list of shrubb}" plants which occur here and which are of more 

 or less forage value is quite large. The majorit}^ of them have been 

 mentioned under another heading. The mesquite is by far the most 

 important. Cat-claw {Acacia grcggii)^ A. constrlcta^ Parkinsonia 

 torreyana^ and Ephedra trlfurca are also abundant. Baccharis hrachy- 

 p>hylla^ B. higelovii, and Anisacanthus tlmrheri., while common in the 

 shrubby mesa region, are much more abundant along the arroyos in 

 the southern half of the field. During late spring the annual ground- 

 sel {Senecio longilohus), is a very conspicuous plant upon portions of 

 the lower areas, and purslane {Portulaca retusa)^ forms a loose cover 

 in many places in the fall. The former is probably of no forage value, 

 while the latter furnishes good feed. In places in autumn two other 

 species of purslane (/*. stelllfot'inU and P. p>ilom)-AXQ of some value on 

 the east side of the field. 



It is to the open foothills that the greatest interest attaches, for it is 

 here that the perennial grasses become numerous enough to be reckoned 

 with in the range ration. The six weeks' grama {Bouteloua aristi- 

 doides) is by far the most abundant grass over the greater portion of 

 this area, being especially abundant in the Zizijjhus lycioides areas in 

 the neighborhood of the line LI, fig. 1. In the same locality are also 

 to be found large quantities of Ar 1st Ida amerlcana and its variety 

 humholdtiana^ the latter being usually found surrounding ant hills. 

 Bouteloua rotliroclxn makes a tall, thin stand on the Ijetter portions of 

 the gently sloping stretches between the arroyos, where in favoral)le 

 years it makes a ver}'' conspicuous growth, but can not be said ever to 

 take possession, for mixed with it are invariably found much six veeks' 

 grama and Aristida americana. Growing in similar situations, and in 

 some seasons covering large areas, are to be found Bouteloua hro- 

 moides, B. eriopjoda^ and B. havardii, which, however, are the main 

 grasses on the majority of the rocky banks and ))luft's along the arroyos. 

 In the latter situations are also to ])e found Jindrop>ogoii contortus^ 

 either in solid patches or scattering bunches, and Andropogon saccha- 



