Common Names

Knobcone pine (Kral 1993).

Taxonomic notes

Syn: Pinus tuberculata Gordon 1849, not D.Don 1836; P. tuberculata var. acuta Mayr (Millar 1986, Kral 1993).

Description

Tree: Tree to 24 m tall or, on very poor sites, a shrub; dbh to 80 cm, trunk usually straight; crown usually conic (Kral 1993, M.P. Frankis e-mail 6-Mar-1999).
Bark: Purple-brown to dark brown, shallowly and narrowly fissured, with irregular, flat, loose-scaly plates, on upper sections of trunk nearly smooth (Kral 1993).
Branches ascending, shoots slender, red-brown (Kral 1993).
Leaves: Three per fascicle, spreading or ascending, persisting 4-5 years, (8-)9-15(-20) cm × (1-)1.3-1.8 mm, straight or slightly curved, twisted, yellow-green, all surfaces with fine stomatal lines, margins serrulate, apex abruptly conic-subulate; sheath (1)1.5-2 cm, base persistent. Buds ovoid to ovoid-cylindric, dark red-brown, aging darker, ca. 1.5 cm, resinous; scale margins fringed, apex attenuate (Kral 1993).
Cones: remaining closed for 20 years or more, or opening on burning, in whorls, hard and heavy, very asymmetric, lanceoloid before opening, ovoid-cylindric when open, 8-16 cm, yellow-brown or pale brown, sessile or on a peduncle to 1 cm; maturing in 2 years (Kral 1993, M.P. Frankis e-mail 6-Mar-1999).
Cone scales: Apophyses toward outside base increasingly elongate, mammillate or raised-angled-conic, downcurved near base, scarcely raised on branchlet side, rhombic; umbo central, low-pyramidal, sharp, upcurved (Kral 1993).
Pollen cones: Ellipsoid-cylindric, 10-15 mm long, orange-brown (Kral 1993).
Seeds: Compressed-oblique-obovoid; body ca. 6-7 mm, nearly black; wing narrow, to 20 mm. 2n=24 (Kral 1993).

Range

USA: Oregon & California, specifically: "In the Coast Range maountains of southern Oregon and northern California (on the Siskiyou Mountains, Trinity Alps, Mount St. Helena Summit, etc.), on the Santa Cruz Mountains, on Point Pinos, near Carmel, Monterey County, and the eastern slopes of the Santa Lucia Mountains, Monterey County; on Mount Shasta (4000 to 5600 feet); on the west slopes of the northern Sierra Nevada, at 1500 to 4500 feet, south to the south side of the San Bernardinos at 2500 to 4000 feet. Lacking otherwise in the southern Sierra Nevada and southern Coast Ranges (Peattie 1950). See also Thompson et al. (1999). Also in Mexico: Baja California Norte. Fire successional on dry slopes and foothills (Kral 1993).

Big Tree

Diameter 109 cm, height 36 m, crown spread 20 m, located in Shasta County, CA (American Forests 1996).

Oldest

In cultivation in Britain not known to exceed about 80 years (M.P. Frankis e-mail 6-Mar-1999).

Dendrochronology

Ethnobotany

USDA hardness zone 7 (inland Oregon origins), otherwise zone 8.

Observations

Besides the specific range notes given above, Arno and Gyer (1973) specify several locales around Yosemite National Park and it is also found in dry associations with Sequoia sempervirens at Redwood National Park (ICE Flora and Fauna Database).

Remarks

"Pinus attenuata, mostly a chaparral species, bears cones at an early age. Its seed crops are heavy, and a hot fire permits the seeds to be released. It forms hybrids with P. muricata and P. radiata" (Kral 1993).

This species is the only common host of the dwarf mistletoe Arceuthobium siskiyouense (Hawksworth and Wiens 1996).

Citations

Millar, C.I. 1986. The Californian closed-cone pines; a taxonomic history and review. Taxon 35: 657-670.

See Also

Farjon and Styles 1997.

Little 1980.

FEIS database.

This page co-edited with M.P. Frankis, Mar-1999.