Scientific name: Pinus lawsonii Roezl ex Gordon 1862

Synonyms:Pinus altamiranoi Shaw

Common names: Lawson's pine

Description

Tree to 25(-30) m tall, with trunk to 0.8 m in diameter. Bark dark brown, with flaky, interlacing, narrow, platelike ridges separated by paler, wide furrows. Crown conical and dense at first, becoming open and almost spherical with age, with stout, rising branches well clothed with foliage near the ends. Twigs reddish brown with a thin waxy coating, hairless, initially rough with the bases of scale leaves, but these flaking off after the first year. Buds 8-15 mm long, not resinous. Needles in bundles of (two or) three to five, each needle (12-)16-20(-25) cm long, very stiff and straight, lasting 2-3 years, grayish green, thinly to thickly coated with wax. Individual needles with numerous conspicuous lines of stomates on both the inner and outer faces, and (one to) three to six resin canals touching and surrounding the two-stranded midvein, or the two at the outer corners midway between the midvein and the needle surface. Sheath 15-25 mm long at first, weathering to 10-15 mm and persisting and falling with the bundle. Pollen cones 10-20 mm long, yellowish brown. Seed cones 5-8(-9) cm long, egg-shaped, often slightly asymmetrical, with 50-100(-150) seed scales, green before maturity, ripening dull yellowish brown, opening widely to release the seeds and then falling with the soft, backwardly curved, 6-12 mm long stalks. Seed scales roughly rectangular, the exposed face horizontally diamond-shaped, crossed by a horizontal ridge, mostly fairly flat but strongly protruding on the basal scales away from the twig, all with a large, outwardly hooked umbo. Seed body 4-5 mm long, the clasping wing another 10-16 mm longer.

Mountains of southern Mexico, from central Oaxaca to southeastern Jalisco. Scattered trees or groves among other species in warm, moist pine-oak forest on lower and middle slopes; 1,300-2,500(-2,800) m.

Conservation Status

Red List Category & Criteria: Least Concern

(This widespread species, despite an area of occupancy that is probably under the threshold for Vulnerable, is not threatened as its population is thought to be stable)

References

Farjon, A. (2010). A Handbook of the World's Conifers. Koninklijke Brill, Leiden.

Eckenwalder, J.E. (2009) Conifers of the World: The Complete Reference. Timber Press, Portland.

IUCN Red List of Threatened Species, International Union for Conservation of Nature and Natural Resources. Cambridge, UK /Gland, Switzerland