Pinus leiophylla Schiede ex Schltdl. & Cham.
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Authority
Farjon, Aljos K. & Styles, Brian T. 1997. Pinus (Pinaceae). Fl. Neotrop. Monogr. 75: 1-291. (Published by NYBG Press)
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Family
Pinaceae
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Scientific Name
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Description
Species Description - Tree, medium to tall, height to 15-30(-35) m, dbh to 20-85 cm. Trunk monopodial, erect, terete, sometimes forked higher up, often clear of branches for 3/5 of total height. Bark very thick, rough, scaly, divided into elongated, irregular, scaly plates and deep, mainly longitudinal fissures, dark grey-brown, on young trees and branches scaly, flaking, reddish brown to grey-brown. Branches long, slender, spreading or ascending, the lower ones curved down, forming an open, rounded crown. Shoots more or less scaly, with short, decurrent pulvini, initially reddish brown or glaucous, soon grey-brown. Cataphylls small, ca. 6 mm long, lanceolate-subulate, soon recurved, light orange-brown with hyaline-ciliate margins, early deciduous. Vegetative buds ovoid-conical, obtuse, the terminal buds 10-15 X 5-7 mm, the laterals smaller, not or slightly resinous, light brown; the scales imbricate, subulate, with ciliate margins and free apex. Fascicle sheaths 12-20 mm long, with 5-6 initially imbricate, ligulate, ciliate-margined, early deciduous scales, leaving the full-grown fascicles devoid of a sheath. Leaves in fascicles of (2-)3-5(-6), spreading in lax or rigid tufts near the ends of branches, persisting 2-3 years, sometimes subpendulous, straight, variable in length on the same branch, (4-)6-15(-17) cm X 0.5-1.3(-1.5) mm, the margins (minutely) serrulate, acute or acute-pungent, light green or glaucous-green. Stomata on all faces of leaves, in (3-)4-8(-9) lines on the convex abaxial face, in (2-)3-4 lines on each adaxial face, generally correlated with the width of the leaf. Leaf anatomy: Cross section triangular, with a convex abaxial side; hypodermis 1-2-layered, rarely thicker and intruding into the mesophyll; resin ducts (1-)2-6(-7), medial, occasionally 1-2 internal; stele terete or slightly oval in cross section; outer cell walls of endodermis not thickened or thickened; vascular bundles 2, distinct but connate or with partly merged xylem strands. Pollen cones crowded near the proximal end of a new shoot in a short, dense cluster, subtended by large, subulate, scarious bracts, cylindrical, 10-15(-20) X 4-6 mm, yellowish pink, maturing to light brown. Microsporophyll with relatively large, conspicuous pollen sacs. Seed cones subterminal, solitary or in whorls of 2-5 on stout, 10-20 mm long, spreading or recurved peduncles, persisting a few years after seed dispersal. Immature cones broadly ovoid to subglobose, with pungent spines, initially pink, later purplish green to purplish brown, maturing in three seasons. Mature cones (narrowly) ovoid when closed, nearly symmetrical, (broadly) ovoid when opened, (4-)5-7(-8) X (3-)4-5.5 cm when open. Seed scales ca. 50-70, parting gradually, eventually spreading wide, straight or recurved near the base of the cone, oblong, with nearly straight margins, dark purplish brown turning greyish on the abaxial side, purplish brown with lighter, greyish marks of seed wings adaxially. Apophysis mostly uniform around the cone, raised, transversely keeled, with the central section of the second season’s growth distinctly marked as a narrow band around the umbo, rhombic in outline, up to 15 mm wide at mid-cone, dull brown to grey-brown. Umbo dorsal, pyramidal, transverse-rhombic in outline, up to 5 mm wide, with a blunt prickle, darker than the apophysis. Seeds obliquely ovoid, slightly flattened, small, 3-4(-5) mm long, dark grey-brown with black spots. Seed wings articulate, effective, held to the seed by two claws, the membrane partly covering the seed on one side, obliquely oval, 10-18 X 4-8 mm, yellowish brown, translucent, with a dark tinge. Cotyledons or seedlings not observed. Adventitious shoots sprout from the trunk or stump after fire or cutting and may develop into a small tree.
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Distribution
SW United States (SE Arizona, SW New Mexico); in Mexico along the Sierra Madre Occidental, the “Eje Volcánico Transversal” and in the Sierra Madre del Sur as far SE as the highlands of central Oaxaca.
United States of America North America| Mexico North America|