Pinus cembroides Zucc.

Authority

Farjon, Aljos K. & Styles, Brian T. 1997. Pinus (Pinaceae). Fl. Neotrop. Monogr. 75: 1-291. (Published by NYBG Press)

Family

Pinaceae

Scientific Name

Pinus cembroides Zucc.

Description

Species Description - Shrub or tree, height to 3-15(-25) m, dbh to 10-8()(-120) cm. Trunk monopodial, very short (shrubs), branching immediately above the ground, or short to medium size, contorted or more or less straight, branching low. Bark thick, rough and scaly, breaking into small, irregular, shaggy plates, sometimes divided by longitudinal but shallow and irregular fissures, not easily exfoliating, grey, exposing yellowish to orange-yellow inner bark; on young trees and branches thin, smooth but soon flaking, grey or greyish brown. Branches of first order long, usually heavy, spreading or trailing on the ground, or ascending, irregularly disposed in most trees; of second and higher orders long, contorted, spreading, assurgent or ascending. Crown an open or dense shrub or broad, open, irregular. Shoots orange-brown or slightly glaucous at first, soon grey, rough with small, non-decurrent or short decurrent pulvini. Cataphylls small, 2-4 mm long, subulate or triangular, acute-acuminate, with erose margins, light brown, caducous, leaving a small ridge above the pulvini. Vegetative buds ovoid-oblong to oval-cylindrical, the terminal buds 5-8 X 3-5 mm (sometimes up to 10 mm long), the laterals smaller, not or slightly resinous, light brown or ochraceous; the scales subulate, with spreading or recurved, darker brown apex. Fascicle sheaths short, 4-6 mm long, loosely imbricate, the scales (pale) brown, soon recoiling, then pale straw-coloured to grey, forming a small rosette at the base of the fascicle but deciduous before the leaves fall. Leaves in fascicles of (2-)3(-4, rarely 5), spreading or assurgent, in small, often regularly spaced tufts persisting (3-)4-5(-7) years, curved or less often straight, lax or sometimes rigid (especially short leaves), (2-)3-6(-8) cm X (0.6-)0.7-l(-l .2) mm, margins entire, apex acute-acuminate or pungent; colour variable, dull green to glaucous-green, with or without white adaxial faces; sometimes producing a few resin drops. Stomata: Leaves amphistomatic, or epistomatic in one variety, in 2-3(-4) lines on the convex abaxial face (or none), in 2-3(-4) lines on each adaxial face. Leaf anatomy: Cross section transverse-triangular or half-terete (2-leaved fascicles); hypodermis uniform, 1-, more commonly 2-Iayered; resin ducts 2, rarely only 1, external on the abaxial side; stele terete; outer cell walls of endodermis not thickened; vascular bundle single. Pollen cones crowded on the proximal half of new shoots, in more or less elongated, spiculate clusters; subtended by cataphyllous bracts with hyaline margins; small, ca. 5 X 3 mm, the larger ones proximally; microsporophylls subpeltate, with erose margins. Seed cones subterminal from lateral buds, solitary, paired or more rarely in whorls of 3, on very short, 3-5(-8) mm long peduncles which remain with the fallen cones. Immature cones subglobose to ovoid, 8-10 mm long, purplish, or yellowish green, soon light brown to reddish brown, maturing in two seasons. Mature cones seemingly sessile, irregularly globose or ovoid-globose when closed, spreading often wider than long when opened, with a flattened base, irregular in size and shape, often resinous, (2-)3-5(-7.5) X 3-6(-7) cm when open. Seed scales 25-40(-50), parting easily and widely, narrowly and more or less weakly attached to the rachis and hence moveable, spreading or reflexed, only the central 10-15(-20) fertile, irregular, up to 15-20 mm wide, concavo-convex, with 1-2 deep seed cavities bordered by membranous seed wing remnants (I seed commonly aborts), ochraceous to (light) brown abaxially, usually darker brown with reddish brown seed cavities on the adaxial side, weathering blackish brown or greyish black. Apophysis raised, transversely keeled or radially keeled or ribbed, rhombic to pentagonal in outline but irregular, upper margin entire or undulating, often angular or curved, in all shades from yellowish green or ochraceous to reddish brown, sometimes lustrous. Umbo dorsal, flat or raised and curved, 2-4(-5) mm wide, greyish brown to blackish brown, with a minute prickle, often resinous. Seeds obovoid-oblique, often acutish, sometimes faintly ridged, 10-16 X 6-10 mm, greyish brown to blackish grey, or light brown; integument thick, 0.51 (-1.1) mm; macrogametophyte ("endosperm" of authors) pinkish or white when fresh. Seed wings absent when the seed is detached from the scale, the rudiments of it remaining with the scale. Cotyledons (5-)6-12(-17), grey-green.

Distribution

United States: SE Arizona, SW New Mexico, SW Texas; Mexico: A wide range running from the interior slopes of the Sierra Madres into the interior of south-central Mexico, where it reaches its southernmost point in Puebla. An outlier occurs in the Sierra de la Laguna at the southern tip of Baja California.

United States of America North America| Mexico North America|