Pinus strobiformis
Pinus cembroides
Chihuahua white pine, Mexican white pine, pino enano, Southwestern white pine
Mexican pinyon, pino piñonero, piñón
gray, aging red-brown, furrowed, with narrow, irregular, scaly ridges.
red-brown to dark brown, shallowly and irregularly furrowed, ridges broad, scaly.
spreading-ascending;
twigs slender, pale red-brown, puberulous or glabrous, sometimes glaucous, aging gray or gray-brown, smooth.
spreading-ascending;
twigs red-brown, sometimes finely papillate, aging gray to gray-brown.
ellipsoid, red-brown, ca. 1cm, resinous.
ovoid to short cylindric, pale red-brown, 0.5–1.2cm, slightly resinous.
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(–4) per fascicle, spreading to upcurved, persisting 3–4 years, 2–6cm × 0.6–0.9(–1)mm, connivent, 2–3-sided, blue- to gray-green, abaxial surface not conspicuously whitened with stomatal bands or if stomatal bands present, these less conspicuous than on adaxial surfaces, often with 2 subepidermal resin bands evident, adaxial surfaces conspicuously whitened with stomatal lines, margins entire to finely serrulate, apex narrowly conic or subulate;
sheath 0.5–0.7cm, scales soon recurved, forming rosette, shed early.
cylindric, ca. 6–10mm, pale yellow-brown.
ellipsoid, to 10mm, yellow.
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 and falling soon thereafter, spreading, symmetric, ovoid before opening, broadly depressed-ovoid to nearly globose when open, 1–3.5cm, pale yellow- to pale red-brown, resinous, nearly sessile or short-stalked;
apophyses thickened, slightly domed, angulate, transversely keeled;
umbo subcentral, slightly raised to depressed, truncate or umbilicate.
=24.
=24.
Pinus strobiformis
Pinus cembroides
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 cembroides is the common pinyon of Mexican commerce. Populations of the Edwards Plateau, Texas, are disjunct about 150km east and north of the main area of distribution of the species, and they have been described as a distinct variety, P. cembroides var. remota Little, on the basis of thin seed shell and a higher frequency of 2-leaved fascicles in contrast to the thicker seed shell and prevalently 3-leaved fascicles in Mexican pinyon populations to the west and south. The strong overlap in nearly all character states between the populations of the Edwards Plateau and other populations makes var. remota difficult to maintain.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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