Pinus cembroides subsp. lagunae (Rob.-Pass.) D.K.Bailey
-
Authority
Farjon, Aljos K. & Styles, Brian T. 1997. Pinus (Pinaceae). Fl. Neotrop. Monogr. 75: 1-291. (Published by NYBG Press)
-
Family
Pinaceae
-
Scientific Name
-
Type
Type. Mexico. Baja California Sur: Sierra de la Laguna, 15 Feb 1978, M.-F. Robert-Passini 10021 (holotype, P; isotypes, ENCB, INIF).
-
Synonyms
Pinus cembroides var. lagunae Rob.-Pass., Pinus lagunae (Rob.-Pass.) Passini
-
Description
Subspecies Description - Tree, small to large, height to 20-25 m, dbh to 80-120 cm. Trunk monopodial, short to medium size, contorted or more or less straight, branching low or sometimes higher. Leaves in fascicles of (2-) 3, very rarely 4, spreading, persisting 3-4 years, mostly straight, lax, (2.5-)4-7(-8) cm X (0.7-)0.8-0.9 mm, dull green to greyish green. Stomata: Leaves amphistomatic, in 2(-3) intermittent lines on the convex abaxial face, in 2 lines on each adaxial face. Apophysis of seed scales raised, transversely keeled or radially keeled or ribbed, mostly reddish brown, sometimes lustrous. Seeds 10-16 X 6-10 mm; integument thick, 0.5-0.8 mm; macrogametophyte ("endosperm" of authors) pinkish when fresh. Cotyledons 5-17, grey-green.
-
Discussion
Distribution and Ecology : Mexico: Endemic in the Sierra de la Laguna at the S tip of Baja California, where it is estimated to occupy around 20,000 ha. The Sierra de la Laguna is a batholitic uprising of granitic rock, flanked by older sedimentary rocks and rising to 2090 m. Pinus cembroides subsp, lagunae occurs in the highest N part of the range, at 1600-2050 m. It is best developed on and around the high meadow (La Laguna) of sandy loam but occurs also in valleys with coarse gravel or granite boulders and on granitic slopes. It is commonly associated with Quercus devia, which is more abundant than Pinus in most areas. No other pines occur in Baja California Sur. On dry slopes Yucca, Calliandra, and Dodonaea are found in the understorey. The climate is subtropical; annual precipitation in the area is ca. 750 mm, almost all of which comes from summer rainstorms.
Phenology: Pollen dispersal occurs in May-June (Passini & Pinel, 1987). -
Distribution
Mexico North America| Baja California Sur Mexico North America|