Western Sierra Madre Region. 641 
on Alamos Mountain of Quercus grisea (= 0. undulata), Q. californica (= O. 
Kelloggüi) and on the oaks 73llandsia recurvata. 
Low ranges, or the bluffs of dry ravines, or of watered valleys are covered with Quereus 
grisea, (Q. Emoryi having been left behind) associated with Pinus chihuahuana and more rarely 
P. mierophylla?). The most abundant tree of these forests next to Quereus grisea is Pinus ari- 
zonica, ranging through 3,000 feet of elevation from the valleys and canyons of the base to the 
canyons on high cool slopes. Pinus cembroides grows on the warmest and most arid slopes and 
on ledges with meager soil. Juniperus pachyphloea has an altitudinal range of 5,000 feet, 
attaining its full development in rich and watered canyons. On the driest crests of ridges near 
the summits, Juniperus tetragona occurs, while in better soil at still higher altitudes is Juniperus 
oceidentalis var. conjugens, and Pseudotsuga Douglasii is found in high canyons associated with 
inus arizonica and Abies concolor. 
Above these trees on the cool talus of cliffs grows Populus tremuloides. The sides and 
bottoms of wet canyons 'are characterized by Quercus reticulata with Q. hypoleuca, Q. fulva. 
Sparsely scattered over these mountains is Arbutus xalapensis, while Arbutus petiolaris is 
“ eonfined entirely to the northern verge of ridges. Among the oaks the underbrush consists of 
Ceanothus Fendleri, C. azureus, C. parvifolius (on rocky hills), Arctostaphylos pungens with Pinus 
cembroides, Spiraea discolor var. dumosa about the ledges of the summits. At 8000 fi in the 
Tarahumara country pines cover the higher elevations in an uninterrupted forest and oaks the 
lower slopes of the mountains. Pinus oocarpa grows on the summit of Alamos Mountain, 
Park Formation. Many of the valleys are park-like with a grassy sward 
with agaves interspersed and groups of fresh green trees pointing to places 
where the ground is wet or moist?) during the dry season from January w 
June. Here are found species of Helianthus (10—ı2 feet high), Salvia, Sam- 
bucus and Bambusa, which forms a light green undergrowth, and along the 
smaller streams occur ash trees, alders, madrona and Zuonymus with Mimulus, 
Aquilegia, Thalictrum and an Amaryllis with carmine red flowers, visited by 
humming birds. Species of Viola, Vicia and Lupinus grow in the pine forests 
at 7,400 feet. ae d 
The flora of the canyons and mountain water courses is composec 
of Acalypha subviscida, Gouania domingensis, Vitis arizonica, Raus Palmeri, 
Leucaena lanceolata, Sedum alamosanum and species of Sieyosperma, en 
Brickellia, Baccharis, Melampodium, Zexmenia, Tagetes, Salvia, Muhlenbergıa. 
2. Forest Formations in higher elevation. 
The Chirieahua, the Huachuca, the SantaRita, the Rincon and the 
Santa Catalina Mountains form the northern extension of the So 
Sierra Nevada Mountains into Arizona, and lying south of the great 2 
Plateau the presence of many Mexican trees. unites ae 
Phytogeographically speaking, with the flora of Mexico proper. u 
elevations are from 9,000 to 10,000 feet and good forest is not common DEP" 
7,000 feet. 
m u 
I) PRINGLE, C. G.: Garden and Forest I: 238, 429, 441. 
2) Lumnorz, Caru: Unknown Mexico I: 408. 
Harshberger, Survey N,-America. 
