Pinus strobiformis
Pinus balfouriana
Chihuahua white pine, Mexican white pine, pino enano, Southwestern white pine
foxtail pine
gray, aging red-brown, furrowed, with narrow, irregular, scaly ridges.
gray to salmon or cinnamon, platy or irregularly deep-fissured or with irregular blocky plates.
spreading-ascending;
twigs slender, pale red-brown, puberulous or glabrous, sometimes glaucous, aging gray or gray-brown, smooth.
contorted, ascending to descending;
twigs red-brown, aging gray to drab yellow-gray, glabrous or puberulent, young branches resembling long bottlebrushes because of persistent leaves.
ellipsoid, red-brown, ca. 1cm, resinous.
ovoid-acuminate, red-brown, 0.8–1cm, 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.
5 per fascicle, upcurved, persisting 10–30 years, 1.5–4cm × 1–1.4mm, mostly connivent, deep blue- to deep yellow-green, abaxial surface without median groove but usually with 2 subepidermal but evident resin bands, adaxial surfaces conspicuously whitened by stomates, margins mostly entire to blunt, apex broadly acute to acuminate;
sheath 0.5–1cm, soon forming rosette, shed early.
cylindric, ca. 6–10mm, pale yellow-brown.
ellipsoid, ca. 6–10mm, red.
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, lance-cylindric with conic base before opening, broadly lance-ovoid or ovoid to cylindric or ovoid-cylindric when open, 6–9(–11)cm, purple, aging red-brown, nearly sessile;
apophyses much thickened, rounded, larger toward cone base;
umbo central, usually depressed;
prickle absent or weak, to 1mm, resin exudates amber.
=24.
=24.
Pinus strobiformis
Pinus balfouriana
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 balfouriana is the true "foxtail pine." In leaf character it is hardly, if at all, distinguishable from P. longaeva, but its strongly conic-based cones with distinctly shorter-prickled, sunken-centered umbos at once distinguish it from that species.
Plants shown to be genetically distinct from the type (differences in chemistry, form, foliage, cone orientation, and seeds) have been called Pinus balfouriana subsp. austrina R.Mastrogiuseppe & J.Mastrogiuseppe. As in several other species or species complexes in Pinus, however, there is a problem with a character gradient involving related taxa. The evidence presented by D.K. Bailey (1970) and later by R.J. Mastrogiuseppe and J.D. Mastrogiuseppe (1980) could as well be used to indicate that P. balfouriana (with its two infraspecific taxa) and P. longaeva represent a single species of three subspecies or three varieties. The more conservative view of Bailey is followed here.
Of conservation concern.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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