 | Pinus washoensis Mason & Stockwell 1945Common NamesWashoe pine (2), 'North Plateau' Ponderosa pine.Taxonomic notesPinus washoensis is likely synonymous with the type subspecies of P. ponderosa (q.v.). However, its cones are fairly distinctive and I am not fully persuaded that the described P. washoensis populations do not warrant distinction as a variety or even a subspecies of P. ponderosa. Genetic analyses will probably be required before the ponderosa/washoensis problem is resolved in a satisfactory manner. This page is retained on the Database to provide information on what is at least a distinctive set of Ponderosa populations.Description"Trees to 60 m; trunk to 100 cm diam., straight; crown pyramidal. Bark yellow-brown to reddish, fissured, plates scaly. Branches spreading-ascending; twigs stout, orangish, aging gray, rough. Buds ovoid, red-brown, 1.5-2 cm, not resinous; scale margins fringed. Leaves (2)3 per fascicle, spreading-ascending, persisting (2)4-6(7) years, 10-15 cm × ca. 1.5 mm, slightly twisted, gray-green, all surfaces with stomatal lines, margins finely serrulate, apex acuminate; sheath 1-2 cm, base persistent. Pollen cones cylindric, 10-20 mm, red-purple. Seed cones maturing in 2 years, shedding seeds soon thereafter, not persistent, spreading, slightly asymmetric, ovoid-conic before opening, broadly ovoid when open, 7-10 cm, tan or pale red-brown, sessile, abaxial surface of scales darker and sharply contrasting in color with adaxial surface; apophyses slightly raised, low pyramidal; umbo central, narrowly pyramidal, tapering into short, reflexed, fine prickle. Seeds ellipsoid; body ca. 0.8 cm, gray-brown; wing to 16 mm. 2n=24" (2).RangeUSA: NW Nevada and adjacent California at 2100-2500m in dry montane forests (1, 2).Big TreeDiameter 104 cm, height 27 m, crown spread 16 m, located in Thomas County, CA (3).OldestDendrochronologyEthnobotanyObservationsRemarksSpecies is rare enough to be of conservation concern (2)."Pinus washoensis often occurs in large stands and resembles P. jeffreyi. The number and posture of seed-cone scales fall within the ranges given for P. jeffreyi. The abaxial surface of these scales has a significantly darker pigmentation, however; such a color contrast is not apparent in P. jeffreyi. Forest geneticists have developed hybrids between P. washoensis and related yellow pines, but no natural hybrids have been observed" (2). Citations(1) Silba 1986.(2) Kral in Flora of North America online. (3) American Forests 1996. See also: |
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