Pinus densata

Masters 1906

Common names

高山松 gaoshan song (high mountain pine) [Chinese] (Wu and Raven (1999)).

Taxonomic notes

Closely related to P. yunnanensis. Li (1997) contends that morphological study (Wu 1956) and molecular analysis (Wang and Szmidt 1990) suggest this is a hybrid, P. yunnanensis × tabuliformis, which arose during the Tertiary. The three species are now ecologically partitioned, with P. yunnanensis occurring farther south, P. tabuliformis occurring farther north, and P. densata occupying high mountain environments. This hypothesis is now well-supported with additional molecular work by Ma et al. (2006), who make the unprecedented suggestion "that populations of P. densata have unique evolutionary histories and most likely independent origins." Think of what that means: there may be individual trees of P. densata that are only related to each other through an intermediary that belongs to a different species.

Syn.: Pinus prominens Masters; P. sinensis D. Don var. densata (Masters) Shaw; P. tabuliformis Carrière var. densata (Masters) Rehder; P. wilsonii Shaw 1911 non Roezl 1857 (Wu and Raven 1999).

Description

Trees to 30 m tall and 130 cm dbh with an ovoid-conical crown, spreading in old trees. Bark red-brown, scaly and plated when young, turning dark gray-brown with irregular square, thick plates. First-year branchlets stout, shiny yellow-brown, turning reddish in second and third year. Winter buds brown, ovoid-conical, 15 × 6 mm, slightly resinous, scales white fringed at margin, acuminate at apex. Needles persisting for 3 years, 2(-3) per fascicle, straight, slightly twisted, 8-14 cm × 1-1.5 mm, stomatal lines on all surfaces, resin canals 3 or 4, marginal, occasionally 1 or 2 medial, base with persistent sheath initially 5-10 mm, margin finely serrulate, apex acute. Pollen cones yellow-brown, cylindric, 10-18 × 3-4.5 mm. Seed cones solitary or in pairs, pendulous, sessile or shortly pedunculate, shiny dark brown at maturity, narrowly ovoid before opening, ovoid or broadly ovoid when open, 4-6 × 4-7 cm, persistent. Seed scales with prominent apophyses, rhombic, 4-7 mm thick, sharply transversely keeled; umbo dorsal, with a short prickle. Seeds light gray-brown, ellipsoid-ovoid, 4-6 mm; wing 15-20 mm. Pollination in May; cones mature in October of the second year (Wu and Raven 1999).

Distribution and Ecology

China: S Qinghai, W Sichuan, Yunnan; SE Tibet, at elevations of 2600-3500(-4200) m. Forms pure stands or, below 3000 m, mixed with Pinus armandii and P. yunnanensis (Li 1997, Wu and Raven 1999). Hardy to Zone 6 (cold hardiness limit between -23.2°C and -17.8°C) (Bannister and Neuner 2001).

Remarkable Specimens

Ethnobotany

Observations

Remarks

The epithet may be from the Latin densatio, "thickening", referring to the apophyses.

Citations

Ma Xiao-Fei, Szmidt, A.E., Wang Xiao-Ru. 2006. Genetic structure and evolutionary history of a diploid hybrid pine Pinus densata inferred from the nucleotide variation at seven gene loci. Molecular Biology and Evolution 23(4):807-816. mbe.oxfordjournals.org/cgi/content/abstract/23/4/807, accessed 2009.04.10.

Masters, M.T. 1906. On the conifers of China. Journal of the Linnaean Society, Botany 37:418. Available online at www.botanicus.org.

Wang X.R. and Szmidt, A.E. 1990. Evolutionary analysis of Pinus densata, a putative tertiary hybrid. 2. A study using species-specific chloroplast DNA markers. Theoretical and Applied Genetics 80: 641-647.

Wu C.L. 1956. The taxonomic revision and phytogeographical study of Chinese pines. Acta Phytotaxonomica Sinica 5(3):131-162.

See also