Pinus douglasiana

Martínez 1943

Common names

Pino, ocote [Spanish] (Perry 1991).

Taxonomic notes

Type: Nayarit, Cerro Juanacata, July 1940, M. Martínez 3429 (holotype, MEXU) (Farjon and Styles 1997). This species belongs to Pinus subsection Ponderosae; see the "Taxonomic notes" for Pinus ponderosa for further discussion.

Description

Trees to 45 m tall and 100 cm dbh with usually a single straight, round trunk, clear of branches for 2/3 of its length. Crown pyramidal at first, in older trees becoming rounded, varying from dense to open. Bark first smooth, red-brown, later becoming scaly, rough, scaly, divided into large, irregular plates separated by deep fissures. Shoots smooth, or rough with prominent decurrent pulvini, dark brown, not glaucous. Foliar units form dense tufts. Leaves in bundles of 5, persisting 2-2.5 years, usually lax and drooping, 2-35 cm x 0.7- 1.2 mm, light yellowish green to glaucous green, apex acute. Stomata are on all faces of leaves, in 3-4 lines each face. Fascicle sheaths persistent, (15-)20-35 mm with 7-10 imbricate, bracteate, light lustrous brown scales with ciliate margins, weathering grayish brown. Pollen cones numerous, crowded near the basal end of a new shoot, cylindrical, 20-25 x 4-5 mm, pinkish brown at maturity. Seed cones form near the end of a new shoot in whorls of 1-4 on stout, recurved, 10-15 mm long peduncles which fall with the cone. Immature cones ca. 15 x 10 mm, purplish or glaucous. Mature cones ovoid when closed, often slightly curved, broadly ovoid with a flattened base when opened, then 7-10 x 5-7 cm. Seed scales ca. 110-130, parting to release the seeds, thin woody, light brown with often indistinct lighter marks of seed wings. Apophysis nearly flat or raised and transversely keeled, radially striate or grooved, rhombic or pentagonal in outline, nearly symmetrical around the cone, 11-17 mm wide; light brown, reddish brown or dark brown. Umbo raised, transversely rhombic, 5-7 mm wide, darker than the apophysis, without a prickle. Seeds obovoid, flattened, 4-5 x 3-3.5 mm, light grey or brown, often with dark spots. Seed wings articulate, held to the seed by two oblique claws, 18-24 x 7-9 mm, light yellow-brown, translucent (Farjon and Styles 1997). See García Esteban et al. (2004) for a detailed characterization of the wood anatomy.

In most respects this species is very similar to P. pseudostrobus. The cone peduncle falls with the cone in P. douglasiana, but remains on the branch in P. pseudostrobus. Also, P. pseudostrobus has less drooping foliage than P. douglasiana (Farjon and Styles 1997).

Distribution and Ecology

Mexico: Mainly Jalisco, Michoacán, México, and N Morelos, but extending N into Nayarit and the Sierra Medre Occidental crest between Sinaloa and Durango, and extending S locally into Guerrero and Oaxaca (Farjon and Styles 1997).

Distribution data from USGS (1999).

Found at (1100-)1400-2500(-2700) m elevation, in warm to temperate climate with annual precipitation of about 1000 mm. Occurs mostly in mixed pine and pine-oak forests, but at the highest and wettest sites it is associated with Abies sp., Picea sp. (in Durango) or Hesperocyparis lusitanica. More commonly, it is found with Pinus pseudostrobus, P. herrerae, P. leiophylla, P. lawsonii, P. ayacahuite in the S part of its range, P. oocarpa at low elevations, and P. devoniana in drier sites (Farjon and Styles 1997). See also Thompson et al. (1999).

Remarkable Specimens

Ethnobotany

An important timber tree within its range, typically logged with its congeners in mixed stands (Farjon and Styles 1997).

Observations

Remarks

The epithet honors Margaret Bell Douglas (1880-1963) (Martínez 1943), noted southern Arizona horticulturalist. Along with Pinus stormiae, this makes two independent American women that Martínez honored by naming pines for them.

P. douglasiana is parasitized by the mistletoe Cladocolea cupulata Kuijt (Loranthaceae) (Kenaley and Mathiasen 2006), and by the dwarf mistletoe Arceuthobium globosum subsp. grandicaule (Hawksworth and Wiens 1996).

Citations

Martínez, M. 1943. Una nueva especie de Pinus Méxicano. Madroño 7:5-7. Available: Biodiversity Heritage Library, accessed 2021.12.18.

See also