50 RANGE INVESTIGATIONS IN ARIZONA. 



Of the perenniul species not previously mentioned there is a large 

 number which, although not of great importance in themselves, in the 

 aggregate furnish considerable feed. Pappopliorum wrightii occurs 

 in places in the open foothills and is of a great deal of importance, and 

 the closely related species P. vaglnatain is generally found in depres- 

 sions where water accumulates. In the protection of bushes almost 

 exclusively at the present time is to be found the so-called black grama 

 of this region {Muhlenhergia porteri), which is said to have been very 

 plentiful at one time upon open ground. This is a very interesting 

 species, inasmuch as it is one of the few grasses of the region which 

 has perennial culms. Confined as it is to the protection of shrubbery, 

 it, together with a large amount of other vegetation, is left unmolested 

 during the fall, while the grasses on the open ground are grazed oti'. 

 During the winter, however, this, as well as Fanicum lachnanthum 

 and other grasses which tend to seek this protection, are grazed off 

 clean, even when they form a tangled mass with cat-claw, mesquite, 

 and cacti. It is very interesting to note that the grasses are not 

 injured by this form of grazing nearly so much as in the open spaces. 

 These protected areas under shrubbery, concerning which considerable 

 has been said during recent years, are often grazed as closely as any 

 other, but the grazing comes after the maturity of the grasses.. Vege- 

 tation growing in these protected areas has several advantages. The 

 ground is not trampled by stock, and is kept in better condition by the 

 gophers, which almost invariably burrow here. The leaves and twigs 

 of the bushes and joints of the cacti also furnish some protection to 

 them. Upon the sandy bottom CliivtocJihxi annpoHita and Sporoholun 

 strlcfjis furnish some feed, while Tr'nMorix fascicidata makes a thin 

 growth on moist areas and heavier soil. It is the mountain areas that 

 furnish the greatest quantity of valuable feed in southern Arizona. 

 The most important grasses are the perennial gramas, bluejoints, 

 Leptochloa (luhia, Li/rurns phltokU^, and several species of Mnhlen- 

 lerg'ia: All of these are well mixed and produce a very tall growth, 

 ranging from one-half foot to 3 feet high, but the stand is always very 

 thin, except in the most favorable situations where water and sedi- 

 ment are deposited in the more gently sloping ravines where the 

 steep mountains break off into open foothills. 



Upon the sand hills in the valley of the Little Colorado there are 

 several characteristic grasses, of which sand grass {Calamovilfalongi- 

 folla), drop-seed, {Sporohohis giganteus), and 2Iuhlen'bergia pungens 

 are the most important. 



PIGWEED FAMILY. 



A large quantity of feed is produced by the different plants which 

 belong to the large natural group of pigweeds. While much of it is 

 browse, there is nevertheless some herbaceous feed furnished by the 



