Pinus strobiformis
Pinus washoensis
Chihuahua white pine, Mexican white pine, pino enano, Southwestern white pine
Washoe pine
gray, aging red-brown, furrowed, with narrow, irregular, scaly ridges.
yellow-brown to reddish, fissured, plates scaly.
spreading-ascending;
twigs slender, pale red-brown, puberulous or glabrous, sometimes glaucous, aging gray or gray-brown, smooth.
spreading-ascending;
twigs stout, orangish, aging gray, rough.
ellipsoid, red-brown, ca. 1cm, resinous.
ovoid, red-brown, 1.5–2cm, not resinous;
scale margins fringed.
5 per fascicle, spreading to ascending-upcurved, persisting 3–5 years, 4–9cm × 0.6–1mm, straight, slightly twisted, pliant, dark green to blue-green, abaxial surface without evident stomatal lines, adaxial surfaces conspicuously whitened by narrow stomatal lines, margins sharp, razorlike and entire to finely serrulate, apex narrowly acute to short-subulate;
sheath 1.5–2cm, shed early.
(2–)3 per fascicle, spreading-ascending, persisting (2–)4–6(–7) years, 10–15cm × ca. 1.5mm, slightly twisted, gray-green, all surfaces with stomatal lines, margins finely serrulate, apex acuminate;
sheath 1–2cm, base persistent.
cylindric, ca. 6–10mm, pale yellow-brown.
cylindric, 10–20mm, red-purple.
cones maturing in 2 years, shedding seeds and falling soon thereafter, pendent, symmetric, lance-cylindric before opening, broadly lance-cylindric when open, 15–25cm, creamy brown to light yellow-brown, stalks to 6cm;
apophyses somewhat thickened, strongly cross-keeled, tip reflexed;
umbo terminal, low.
cones maturing in 2 years, shedding seeds soon thereafter, not persistent, spreading, slightly asymmetric, ovoid-conic before opening, broadly ovoid when open, 7–10cm, 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.
=24.
=24.
Pinus strobiformis
Pinus washoensis
In the northern part of the range, Pinus strobiformis overlaps P. flexilis and reportedly hybridizes with it. On average P. strobiformis has longer, more slender leaves and thinner, more spreading-tipped apophyses than are found in P. flexilis, and stomatal bands are not evident on the abaxial surface of its leaves.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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. Some workers regard P. washoensis as closely related to—or even conspecific with--- P. ponderosa.
Of conservation concern.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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USDA Plants Database
CA
OR
Flora NW
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