Vol 



ume 



Number 



The Plant Worldj^^^^ 



JUNE, 1908 



DISTRIBUTIONAL FEATURES OF SOME 

 SOUTHWESTERN SHRUBS. 



By J. C. Blumer. 



Certain shrubs of the southwestern United States exhibit 

 distributional features of great interest. Sev^eral species have 

 been observed to change their topographic location, and 

 especially their aspect or slope exposure, with altitude. 



Chief among these may be mentioned Lipp'ui wnghtii 

 A. Gray, one of those plants that are widely distributed geo- 

 graphically, but far from covering extensive areas in any one 

 locality, are usually found in small numbers only, fitting 

 snugly into their own special habitat. This little suffrutes- 

 cent shrub, richly scented, pointed out to the writer by Mr. 

 Thos. J. Riggs, of San Simon, Arizona, as a producer of 

 excellent honey, was first seen under rocks that jutted from 

 the northern base of the Chiricahua Mountains into the San 

 Sim.on \ alley as a promontory looks into the sea. The eleva- 

 tion of this point is a little below that of old Fort Bowie, a 

 few miles to the westward, or not far from 3500 feet above 

 sea-lev^el. It was later noted at Paradise, situated at 5400 

 feet in the same mountain range, on sunny rocks bordering 

 Walker Creek, and on bouldery bluffs along Cave Creek, at 

 about the same elevation, both places of southerly exposure, 

 or opposite to that of the Fort Bowie station. At Paradise 

 it does not grow on the opposite side of the creek. It was 

 then noted for half a dozen more localities about the lower 

 altitudes of the Chiricahuas, extending from old Fort Bowie 

 to College Peak, each time on rocky declivities. In two 



