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Pinus cembroides
Zuccarini 1832
Common NamesMexican piñon, stoneseed piñon, threeleaf piñon, pinyon pine (2); pino piñonero (5).Subsp. cembroides var. bicolor : Border piñon (7). Taxonomic notesThe systematics of this pine are more hotly debated than those of probably any other species in the genus. It is a widespread and morphologically diverse species, which has led to the description of numerous varieties and subspecies, most of which were later raised to the rank of species by their respective authors. Three are held as species in this treatment: P. discolor Bailey & Hawksworth, P. orizabensis (D.K. Bailey) Bailey & Hawksworth and P. johannis Robert.The remaining infraspecific taxa include:
DescriptionShrubs or trees typically to 15 m tall and 30 cm dbh, strongly tapering, much branched; crown rounded. Bark red-brown to dark brown, shallowly and irregularly furrowed, ridges broad, scaly. Branches spreading-ascending; twigs red-brown, sometimes finely papillate, aging gray to gray-brown. Buds ovoid to short cylindric, pale red-brown, 0.5-1.2 cm, slightly resinous. Leaves (2-)3(-4) per fascicle, spreading to upcurved, persisting 3-4 years, 20-60 × 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. Pollen cones ellipsoid, to 10 mm, yellow. Seed cones maturing in 2 years, shedding seeds and falling soon thereafter, spreading, symmetric, ovoid before opening, broadly depressed-ovoid to nearly globose when open, 1-3.5 cm, 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. As with other piñons, the seeds rest in a deep cone-scale declivity and upper cone scale tissue holds the seeds in place, so seeds do not readily fall out and are readily available to avian dispersers. Seeds ovoid to obovoid; body (7-)12-15(-20) mm, brown, wingless. 2 n =24 (1, 5).RangePiñon-juniper woodland at 700-2400 m. USA: SE Arizona, SW New Mexico, W Texas (3,5). See also (8). In Mexico, occurs in mountainous parts of most states N of latitude 20°, with subsp. orizabensis found a bit farther south (4).Big TreeDiameter 90 cm, height 20 m, crown spread 13 m, located in Big Bend National Park, TX ( American Forests 1996 ).OldestDendrochronologyEthnobotanyObservationsRemarks" Pinus cembroides is the common piñon of Mexican commerce. Populations of the Edwards Plateau, Texas, are disjunct about 150 km 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 Piñon 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" (5, 8).Citations(1) Ronald M. Lanner, e-mail communication, 20-Dec-1999.(2) Elmore & Janish 1976 . (3) Lanner 1981 . (4) Perry 1991 . (5) Robert Kral in Flora of North America online . (6) Farjon & Styles 1997 . (7) Lanner 1981 . (8) Robert S. Thompson, Katherine H. Anderson and Patrick J. Bartlein. 1999. Atlas of Relations Between Climatic Parameters and Distributions of Important Trees and Shrubs in North America. U.S. Geological Survey Professional Paper 1650 A&B. URL= http://greenwood.cr.usgs.gov/pub/ppapers/p1650-a/pages/conifers.html , accessed 22-Jan-2000. See also: |
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