Single Leaf Pinyon

(Pinus monophylla)

Color Photographs: © by and courtesy of Charles Webber, California Academy of Sciences

Single Leaf Pinyon Pine (Pinus monophylla)

Identifying Characters: The deciduous bundle sheath on old needle bundles and the dry, pinyon-juniper habitat of this species will identify it as a pinyon. Needles occur in bundles of 1 (rarely 2). Needles 1 to 2.25 inches long.

Similar Species: Single Leaf Pinyon occurs extensively with Two Needle Pinyon but is usually immediately separable because of its one needle bundles compared to 2 needle bundles in Two Needle Pinyon. However variability exits in both species in the number of needles per bundle. Needles are slightly longer on average in Single Leaf Pinyon (1 to 2.25 inches in Single Leaf Pinyon versus 0.75 to 1.5 inches in Two Needle Pinyon. The ranges of Single Leaf Pinyon and Mexican Pinyon do not overlap. The four needle bundles of Four-leaf Pinyon separate that species from Single Leaf Pinyon.

Measurements: A relatively small tree 15-30 feet in height and 1 to 1.5 feet in diameter.

Cones: Cones round to ovate, 2 to 3 inches in length; cones resinous with thick, quadrate cone scales; seed wingless, large, and edible.

Needles: Needles 1 to 2.25 inches long, 1 needle to a bundle; bundle sheath shed after the first year; color of needles gray-green with fine white lines; needles sout, stiff, and sharp-pointed.

Bark: Dark brown or gray, smooth in young trees and becoming furrowed into scaly plates and ridges in older individuals.

Native Range: Singleleaf pinyon is the predominant tree species in the Great Basin. It dominates extensive areas in the dry mountain ranges of Nevada, southern and eastern California, and western Utah. Some stands are in Baja California, northwestern Arizona, and southeastern Idaho. (Silvics of North America. 1990. Agriculture Handbook 654.)

Habitat: Found on dry, rocky slopes or open woodland with juniper or nearly pure stands.

NOTES: Some populations of Single Leaf Pinyon in California have been considered a separate species (californiarum) by some conifer systematists.