242 The Plant World. 



of a gulch. Again near the main crest of several gnarled indi- 

 viduals V. ere noted, advancing on the open side of the forenoon 

 sun to a height of 8,500 or 9,000 feet. 



The most remarkable range of any species on this route 

 up the Santa i ita ]\Iountains is possessed by Y^icca schottii. 

 Found on the sunny southeast mountain side at a height of fully 

 9,000 feet, it v. as common and conspicuous at 8,000 in similar 

 habitats. Like a number of other species already noted, it 

 vanished in the Canadian forest of Douglas fir, ^vafer ash, walnut 

 and lujnne at the head of the canyon, only to reappear far below 

 at the lover edge of the Transition, and to continue down to 

 5,500 feet into the Emory oaks of the middle Upper Sonoran. 

 Ihus it spans a vertical distance of two-thirds of a mile, and 

 like the other interrupted species, unquestionably continues with- 

 out interruption wherever a more open route is followed. 



In the Chiricahua Jlountains, the different species behave 

 likewise. As elsewhere noted * Quercus reticulata accomplishes 

 complete re\-ersion within a rise of 2,000 feet. Pinus arizonica 

 as already indicated, shows the same features as in the Santa 

 Ritas. Douglas fir descends to 6,500 feet, on some steep, strictly 

 north slopes only, but while still manifesting preference for the 

 north sides, becomes somewhat "careless" of aspect about the 

 highest elevations. Mexican white pine, found at the head of 

 Chaperon Canyon at 7,500 feet on one of its steepest and shadiest 

 north slopes, increases upv^ard and is strongly and generally 

 represented about the summits, on south as v^ell as north sides. 

 Where the high elevations fall off southerly toward 

 head of Rucker Canyon, the three preceding species hide their 

 lower limits in the gulches at points several hundered feet higher 

 than elsewhere, as may be expected. The handsome white fir 

 {Abies concolor), much more restricted in range, having been 

 seen in company with Pinus strobiformis at the lowest station of 

 this species above noted, seeks only the shady pockets and 

 springy spots below, but is at home more openly on some Doug- 

 las fir slopes at higher altitudes, particularly about Long Park. 

 Even the boreal Engelmann spruce {Picea engelmannii, limited 

 in characteristically dense forests to the highest northerly slopes, 

 descending to 9,000 feet in places, on the immediate summit of 

 Cave Peak at 9,700 feet, the highest summit of this range, begins 



•Plant World. XI. 120. 1908. 



