Monographs Details: Pinus arizonica var. arizonica
Authority: Farjon, Aljos K. & Styles, Brian T. 1997. Pinus (Pinaceae). Fl. Neotrop. Monogr. 75: 1-291. (Published by NYBG Press)
Family:Pinaceae
Synonyms:Pinus ponderosa var. arizonica (Engelm.) Shaw
Description:Variety Description - Tree, usually tall, height to 30-35 m. Leaves in fascicles of 3-5 (predominantly 3-4), rigid to slightly lax, straight or slightly curved and twisted, (8-) 10-20(-23) cm X 0.9-1.4(-l.6) mm. Stomata on all faces of leaves, in (3-)4-8 lines on the convex abaxial face and in (3-)4(-5) lines on each adaxial face (the abaxial number of lines correlated with width of leaf). Seed cones ovoid to broadly ovoid, often slightly curved, (4.5-)5-7 X 3.5-6 cm when open. Seeds obliquely ovoid, slightly flattened, 4-6 X 3-3.5 mm. Seed wings obliquely ovate, 12-15 X 4-6 mm. Remarks. There seems to be clinal variation in the number of leaves per fascicle, with trees having predominantly 3(-4) leaves more frequent in Sonora, Chihuahua, and Coahuila; those with predominantly 5 leaves are more frequent in Durango. Exceptions do occur: 3-leaved in Sinaloa: H. S. Gentry 7242 (MICH); (4-)5-leaved in Sonora: J. T. Marshall 134 (UC), S. S. White 3360 (MICH).

Discussion:

Distribution and Ecology:SW United States: Arizona, New Mexico. Mexico: Mainly in the Sierra Madre Occidental south to S Durango, scattered in Coahuila, NE Zacatecas, and Nuevo León. Forming pure stands or more commonly mixed with Quercus spp., other pines (e.g., Pinus engelmannii, P. strobi-formis), and occasionally Juniperus flaccida at lower, or J. deppeana at higher, altitudes. On various substrates, but the best stands in valleys and on mesas with deep soil, in moderately dry to mesic forest with light winter frost occurring, at (1300-)2000-2700(-3000) m. Annual precipitation is low to moderate, 700-900 mm, mostly falling during the winter months.

Phenology: Pollen is dispersed in springtime, dependent on altitude and latitude; exact time not recorded.
Distribution:Mexico North America| Chihuahua Mexico North America| Coahuila Mexico North America| Durango Mexico North America| Nuevo León Mexico North America| Sinaloa Mexico North America|