16 KANGE INVESTIGATIONS IN ARIZONA. 



mature seed in abundance in tliree months after being sown. This 

 was especially the case with Andropogon saccJmi^oides, Bouteloua 

 hirsuta, and B. oligostachya^ and less conspicuously true of B. 

 curti'pendula. Bouteloua rothrocMi and Leptochloa dulna produced 

 mature heads from practically every plant which grew. Bouteloua 

 rothrocMi produced fine, large bunches, with an abundance of mature 

 seed. It should be noted that the latter is but a short-lived perennial 

 at best. It is therefore not so surprising that it should produce an 

 abundance of seed the first season. Trichloris fasciculata often pro- 

 duces two crops of seed — one in May and the other in September— in 

 neglected spots and fence corners in the Salt River Valley. 



THE LARGE INCLOSURE. 



During the spring of 1903 arrangements were made for enlarging 

 the work begun upon the mesas near Tucson in 1900. Permission 

 having been granted by the Department of the Interior, an irregular 

 tract of land upon the Santa Rita Forest Reserve, containing -±9.2 square 

 miles, jor 31,488 acres, in the four townships Nos. 18 and 19, in ranges 

 11 and 15 east, Gila and Salt River meridian, was inclosed by a four- 

 wire fence, completed early in June (fig. 1). Practically all stock was 

 excluded from the tract by the lOth of June. This area differs very 

 materially from the desert mesas upon which the small inclosure is 

 situated, as will be seen from the descriptions given below. Much of 

 it is situated within the altitude where perennial grasses are produced, 

 and it is therefore capable of sustaining much more stock tnan the 

 small inclosure upon the mesa. 



TOPOGRAPHY. 



The portion of the Santa Rita Forest Reserve which, after a prelimi- 

 nary survey, it was decided to fence is located in the northern foot- 

 hills of the Santa Rita Mountains. It has a general northwesterly 

 slope toward the Santa Cruz River (PI. Ill, fig. 2). All of the region 

 is well drained and there is consequently no accumulation of alkali at 

 any point. Considerable quantities of water flow over portions of the 

 area at certain seasons of the year. The presence of Atriplex canescens 

 in the northwestern portion does not necessarily indicate that there are 

 accumulations of soluble salts in the soil at this point. 



The field, as a whole, contains typical foothill pasture lands of the 

 region at this altitude. Along the eastern side there are rocky, steep 

 bluffs rising 500 to 800 feet above the general level of the area. To 

 the west and south of this point there are gently sloping areas free 

 from brush. On the west half of the north side there occurs a con- 

 siderable area of ''washed country," while the east half of this side is 

 a typical arid, creosote-bush area where no grass of any consequence 

 ever grows. None of the higher mountain areas has been included on 



