Pinus strobiformis |
Pinus albicaulis |
|
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Chihuahua white pine, Mexican white pine, pino enano, Southwestern white pine |
pine à blanche écorce, scrub pine, white-bark pine |
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Habit | Trees to 30m; trunk to 0.9m diam., slender, straight; crown conic, becoming rounded to irregular. | Trees to 21m; trunk to 1.5m diam., straight to twisted and contorted; crown conic, becoming rounded to irregularly spreading. |
Bark | gray, aging red-brown, furrowed, with narrow, irregular, scaly ridges. |
pale gray, from distance appearing whitish to light gray and smooth, in age separating into thin plates. |
Branches | spreading-ascending; twigs slender, pale red-brown, puberulous or glabrous, sometimes glaucous, aging gray or gray-brown, smooth. |
spreading to ascending, often persistent to trunk base; twigs stout, pale red-brown, with light brown, often glandular puberulence, somewhat roughened by elevated scars, aging gray to pale gray-brown. |
Buds | ellipsoid, red-brown, ca. 1cm, resinous. |
ovoid, light red-brown, 0.8–1cm; scale margins entire. |
Leaves | 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, mostly ascending and upcurved, persisting 5–8 years, 3–7cm × 1–1.5(–2)mm, mostly connivent, deep yellow-green, abaxial surface less so, adaxial surface conspicuously whitened by stomates, margins rounded, minutely serrulate distally, apex conic-acute; sheath 0.8–1.2cm, shed early. |
Pollen cones | cylindric, ca. 6–10mm, pale yellow-brown. |
cylindro-ovoid, ca. 10–15mm, scarlet. |
Seed(s) | 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 remaining on tree (unless dislodged by animals), not opening naturally but through animal agency, spreading, symmetric, broadly ovoid to depressed-ovoid or nearly globose, 4–8cm, dull gray- to black-purple, sessile to short-stalked; scales thin-based and easily broken off; apophyses much thickened, strongly cross-keeled, tip upcurved, brown; umbo terminal, short, incurved, broadly triangular, tip acute. |
2n | =24. |
=24. |
Pinus strobiformis |
Pinus albicaulis |
|
Habitat | Arid to moist summit elevations, montane forests | Thin, rocky, cold soils at or near timberline, montane forests |
Elevation | 1900–3000m (6200–9800ft) | 1300–3700m (4300–12100ft) |
Distribution |
AZ; NM; TX; n Mexico
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CA; ID; MT; NV; OR; WA; WY; AB; BC
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Discussion | 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.) |
Although two reliable dendrologists, G. B. Sudworth (1917) and N. T. Mirov (1967), include Utah in the distribution of Pinus albicaulis, more recent workers have not found it to occur there. The fresh-cut wood of Pinus albicaulis is sweet-scented. Seeds are dispersed mainly by Clark's nutcracker [Nucifraga columbiana (Wilson), family Corvidae]. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 2. | FNA vol. 2. |
Parent taxa | Pinaceae > Pinus | Pinaceae > Pinus |
Sibling taxa | ||
Synonyms | P. ayacahuite var. brachyptera, P. ayacahuite var. reflexa, P. ayacahuite var. strobiformis, P. flexilis var. reflexa, P. reflexa | Apinus albicaulis |
Name authority | Engelmann: in Wislizenus, Mem. Tour N. Mexico 102. (1848) | Engelmann: Trans. Acad. Sci. St. Louis 2: 209. (1863) |
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