Pinus ponderosa var. arizonica

(Engelmann) Shaw

Pines Mexico 24, plates 4, 17, fig. 4. 1909.

Common names: Arizona pine
Basionym: Pinus arizonica in Rothrock, Wheeler, U.S. Geogr. Surv. West 100th Merid. Rep. 6: 260. 1878
Treatment appears in FNA Volume 2.

Trees to 30m; trunk to 1.2m diam. Twigs mostly purple or red-brown, usually glaucous. Buds slightly resinous. Leaves mainly 4–5 per fascicle, 7–17cm × 1–1.2(–1.5)mm. Pollen cones mostly yellow. Seed cones often asymmetric, 5–8cm; apophyses at abaxial base often strongly raised, frequently mammillate; umbo low, broadly pryamidal, and merely acute or with very short apiculus. Seed body 3–4mm; wing to 15mm. 2n =24.


Habitat: Slopes, canyons and rims, and tablelands
Elevation: 2100–2500m

Discussion

The least common, least accessible ponderosa pine in the flora is Pinus ponderosa var. arizonica. It has leaves ranging widely in number per fascicle and in length, perhaps an expression of intergradation with P. ponderosa var. scopulorum, with which it is sympatric over broad areas.

Texas (Chisos Mountains) pines that are referred by some workers to P. ponderosa var. arizonica, belong to P. ponderosa var. scopulorum.

Selected References

None.

Lower Taxa

None.