Bishop, obispo, pricklecone, dwarf marine, umbrella, bull, pitch, or Santa Cruz Island pine. Older texts call it "obispo" because it was described from near San Luis Obispo; English speakers corrupted that to "bishop," the English translation of "obispo."
Along with Pinus attenuata and P. radiata, this is one of the "closed cone" pines, Pinus sect. Attenuatae. All three species are serotinous pines of the California-Baja California coast, although some have suggested that P. greggii of central Mexico warrants inclusion in this section as well.
Synonymy (Millar 1986, Kral 1993):
Trees with small symmetrical cones, found mainly toward the southern end of the species' range, are sometimes treated as P. remorata. Hoover (1966) thought this character to be inconsequential; he treated it as a forma, the lowest rank of botanical recognition. The earliest name at varietal rank for trees with small symmetrical cones is Lemmon's var. anthonyi, a name overlooked by many subsequent authors.
Trees in the north of the range differ in having glaucous foliage and a taller, narrower crown habit; see Remarks, below.
Trees to 24 m and 90 cm dbh, straight to contorted, crown rounded, flattened, or irregular. Bark dark gray, deeply furrowed into long ridges, scaly-plated. Branches spreading-ascending, often contorted. Shoots slender to stout, orange-brown, aging darker brown, rough. Needles two per fascicle, spreading to upcurved, persisting 2-3 years, 8-15 cm × (1.2-)1.5(-2) mm, slightly twisted, dark yellow-green (glaucous blue-green in northern populations), all surfaces with stomatal lines, margins strongly serrulate, apex abruptly conic-acute; sheath to 1.5 cm, base persistent. Buds ovoid-cylindric, dark brown, 1-2.5 cm, resinous. Pollen cones ellipsoid, to 5 mm long, orange. Seed cones maturing in 2 years, serotinous, persisting for up to 70 years (or more; longer than any other pine; often old cones are enveloped by the growing branch or trunk), mostly in whorls, mostly asymmetric, lanceoloid-ovoid before opening, curved-ovoid when open, 4-9 cm long, rich glossy chestnut-brown, sessile or on stalks to 2-4 mm long, mostly downcurved. Cone scales with a deep red-brown distal border (the sealing band, yellow-brown on fresh cones but darkening with age) distally on adaxial surface; apophyses usually much thickened, the abaxial ones progressively more angulately dome-shaped toward base of cone; umbo central, a stout-based, curved claw. Seeds obliquely ellipsoid; body 6-7 mm, dark brown to near black; wing 15-20 mm. 2n=24 (Kral 1993, M.P. Frankis e-mail 1999.03).
USA: California; Mexico: Baja California Norte; at 0-300 m elevation. Occurs in scattered locales along the coast and offshore on Santa Cruz and Santa Rosa Islands of California, and Islas Cedros and Guadalupe in Baja. Habitats include dry ridges to coastal, windshorn forests, often in or around bogs or in other nutrient-poor soils. The species is rare enough to be of conservation concern (Kral 1993). Hardy to Zone 8 (cold hardiness limit between -12.1°C and -6.7°C) (Bannister and Neuner 2001). See also Thompson et al. (1999).
This species is listed as endangered in Mexico under NOM-ECOL-059-94.
Diameter 139 cm, height 34 m, crown spread 12 m. Locality: Mendocino County, CA (American Forests 1996).
Can be seen along the northern end of Inverness Ridge at Point Reyes National Seashore, and at Patrick Point State Park, both in California.
The species was discovered in 1835 by a young Irish botanist named Thomas Coulter, memorialized by another species he collected that year, Pinus coulteri. He collected it near Mission San Luis Obispo, thus the name "Bishop" pine (Little 1980).
"P. muricata is quite variable in terms of morphological, genetic, geographical, physiological, ecological and chemical characteristics. Research by Millar (1983, 1986) and Lloyd (1975) has attested to a steep cline within the species. Pinus muricata is divided into four varieties [not all validly published; see taxonomic notes, above]: muricata, borealis, remorata, and cedrosensis. The differences between the varieties are based on tree size, foliage, bark, and cones. Millar (1983) states that in northern California, a continuous population extends 180 kilometers from Ft. Ross to Ft. Bragg with several morphological and biochemical characteristics changing abruptly at Sea Ranch (27 km north of Ft. Ross). The northern population is called the blue strain (due to the blue colored cast to the foliage) and the southern population is called the green strain (due to deep green foliage). The differences in the strains are related to stomatal anatomy, waxiness of needles, monoterpene composition, allozymes, and the flowering phenology. It is thought that the evolution of these different strains is due to population biogeographic movement and adaptation to unique soils. Millar (1986) felt that sufficient allozymic variation exists to encourage isozyme analysis for further genetic studies with Bishop pine" (Trees of California website, http://biology.fullerton.edu/courses/biol_445/web/, now defunct).
The northern 'blue' trees, probably distinct at subspecific rank or even a separate species, are without a scientific name; Axelrod's [invalid] var. borealis was described from Salt Point, Sonoma Co., about 20 km south of the southernmost 'blue' trees at Sea Ranch, on the Coast Hwy at the Annapolis road junction. They have proved impossible to hybridise with the typical 'green' trees in controlled experiments. (Millar 1983, 1986; Millar and Critchfield 1988; Millar et al. 1988).
The northern 'blue' trees have shown promise as a potential timber tree in Britain and New Zealand, with growth rates of up to 2m/year when young even on very poor sandy soils.
In its native range, this species is a principal host for the dwarf mistletoe Arceuthobium littorum (Hawksworth and Wiens 1996).
Don, D. 1836. Descriptions of five new species of the genus Pinus discovered by Dr. Coulter in California. Trans. Linn. Soc. London 17:439-444.
Hoover, R.F. 1966. Miscellaneous new names for California plants. Leafl. West. Bot. 10: 337-338.
Millar, C.I. 1983. A steep cline in Pinus muricata. Evolution 37: 311-319.
Millar, C.I. 1986. The Californian closed-cone pines; a taxonomic history and review. Taxon 35: 657-670.
Millar, C.I. and W.B. Critchfield. 1988. Crossability and relationships of Bishop Pine. Madroño 35: 39-53.
Millar, C.I., S.H. Strauss, M.T. Conkle and R.D. Westfall. 1988. Allozyme differentiation and biosystematics of the Californian closed-cone pines. Systematic Botany 13: 351-370.
This page co-edited with M.P. Frankis, 1999.03.
Millar, C.I. 1985. Inheritance of allozyme variants in Bishop pine (Pinus muricata D. Don). Biochemical Genetics 23(11/12):933-946.
Last Modified 2012-11-23