Scotch pine

(Pinus ayacahuite ayacahuite)



Tree to 45 m tall and 200 cm dbh, with a straight, round trunk and pyramidal to conical crown with regular branch whorls, becoming more irregular and open in old trees. Bark is thin, smooth, and ash-grey on young trees, with age becoming rough, gray-brown, divided into small rectangular plates. Branches long, slender, spreading horizontally, lower branches often drooping. Twigs slender, smooth, light gray with foliage grouped toward the end. Leaves 5 per fascicle (very rarely 6), slender, flexible, (8-)10-15(-18) cm × 0.7-1.0 mm, straight or slightly twisted, flexible but not drooping, abaxial surface bright green, adaxial surfaces glaucous with stomata, margins serrate with minute, widely spaced teeth; stomata only on ventral surfaces; resin canals 2-4(-7), external; fibrovascular bundle single; fascicle sheaths 15-20(-25) mm long, pale brown, early deciduous. Pollen cones crowded at ends of new shoots, ovoid to short cylindrical, 7-10 mm long, yellow, turning orange-brown. Seed cones borne near ends of main branches, usually in whorls of 2-4, with a peduncle to 25 mm long that falls with the cone, pendent, slightly curved, almost cylindrical, tapering toward apex, 15-40 cm × 7-15 cm when mature and open, yellow-brown, resinous; ripening in the fall and soon deciduous. Cone seed scales 100-150, thin, narrow, flexible, 5-7 cm long, apophyses elongate, apex rounded to obtuse, generally reflexed and curled; umbo terminal without a prickle and nearly always resinous. Seeds 2 per scale, light brown with dark spots, 8-10 × 6-8 mm with an adnate 20-35 × 8-12 mm wing. Cotyledons usually 11-13 (7-8 in Guatemalan specimens). Wood soft, cream-white, light, not very resinous. Pollen dispersal, in south-central Mexico, typically in May (Perry 1991, Farjon and Styles 1997). In habitat, it is difficult to confuse this species with any other. It occupies higher and drier sites, and has much longer cones, than Pinus chiapensis.

Taxonomic tree:

Kingdom: Plantae
Class: Pinopsida
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