Flora of North America species comparison

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Quercus tomentella

Quercus durata

Channel Island oak, island live oak, island oak

leather oak
Habit Trees, to 20 m. Twigs branching at 45° angles, reddish brown, 3-4 mm diam., somewhat rigid, densely tomentose, persistent into 2d year. Shrubs, evergreen, 1-2(-3) m. Bark scaly.
Twigs

gray or yellowish, 1-3 mm diam., densely or sparsely tomentulose, often with prominent, yellowish, spreading hairs.
Buds

brown or reddish brown, ovoid or globose, 1-2 mm, glabrous or puberulent.
Leaves

blade wavy or distinctly concave, oblong-lanceolate or elliptic, acuminate, (30-)70-10(-120) × 25-40 mm, leathery and brittle, base obtuse to cordate, secondary veins 8-10(-12) pairs, branching at 45-50° angles, strongly pinnate, raised abaxially, often sunken adaxially, margins often strongly revolute, with slightly thickened cell walls, entire or crenate to dentate with mucronate teeth, apex rounded or acute, mucronate;

surfaces abaxially densely tomentose with whitish nonglandular hairs, midrib pilose, adaxially glossy dark green, sparsely pubescent.

blade cupped or convex, rarely somewhat planar, (10-)15-40 × 7-15(-20) mm, base cuneate, rounded-attenuate, or truncate, margins entire or irregularly toothed, sometimes spinose, usually unevenly revolute, secondary veins 4-6 on each side, apex rounded or subacute;

surfaces abaxially densely to sparsely covered with erect, stipitate, (1-)2-4(-6)-rayed hairs 1-4 mm, felty to touch, secondary veins prominent, adaxially grayish or yellowish, with dense or scattered, semi-erect or appressed hairs, secondary veins obscure or somewhat impressed.
Acorns

solitary or rarely paired;

cup shallowly cup-shaped, 4-8 mm deep × 15-30 mm wide, scales laterally connate, appressed, deeply imbedded in tomentum, with only thin, brown, elongated apices visible, tuberculate, densely whitish brown tomentose throughout;

nut ovoid, 20-30 × 15-20 mm, apex rounded.

solitary or paired, subsessile;

cup reddish, hemispheric, deeply cup-shaped or turbinate, 4-6 mm deep × 12-18 mm wide, enclosing to 1/2 nut or more, scales reddish or yellowish, weakly to strongly tuberculate, often somewhat glandular;

nut globose, ovoid or cylindric, 15-25 × 10-25 mm, apex rounded or obtuse, persistently minute-puberulent.
Cotyledons

distinct.
Terminal

buds conic, 7-10 mm, scales brown with ciliate margins.

Quercus tomentella

Quercus durata
Phenology Flowering in spring, occasionally in fall.
Habitat Lower portions of steep canyons and occasionally ridge tops
Elevation 100-650 m (300-2100 ft)
Distribution
from FNA
CA; Mexico (Baja California and on Guadalupe Island)
[WildflowerSearch map]
[BONAP county map]
from FNA
CA
[WildflowerSearch map]
[BONAP county map]
Discussion

The insular endemic Quercus tomentella is a relict as evidenced by its widespread representation in mainland late Tertiary fossil floras. Hybridization with Q. chrysolepis is apparent on the Channel Islands: Santa Catalina, Santa Cruz, and possibly San Clemente and Anacapa. Putative hybrids have been observed in narrow zones of contact on the islands of Santa Cruz and Santa Catalina. On those islands, taxonomically distinct individuals of Q. chrysolepis occur at the highest elevations, whereas Q. tomentella generally is found in moist canyons at lower elevations. Populations of Channel Island oak are in decline because of overgrazing and poor seedling recruitment. The greatest number of populations occur on Santa Rosa Island, and those are taxonomically and genetically noteworthy because Q. chrysolepis apparently is absent from the island.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Chaparral, oak woodlands, open pine forests, on serpentine and nonserpentine soils; 150-1500 m.

Varieties 2 (2 in the flora).

(Discussion copyrighted by Flora of North America; reprinted with permission.)
Key
1. Leaf blade adaxially grayish stellate, usually deeply cupped, growth compact; leaves densely crowded on twigs; serpentine soils, Santa Barbara County and northward.
var. durata
1. Leaf blade adaxially greenish, glabrate or essentially so, rarely deeply cupped, usually moderately cupped or subplanar, growth open, scraggly; leaves not densely crowded; nonserpentine soils, Los Angeles County.
var. gabrielensis
Source FNA vol. 3. FNA vol. 3.
Parent taxa Fagaceae > Quercus > sect. Protobalanus Fagaceae > Quercus > sect. Quercus
Sibling taxa
Q. acerifolia, Q. agrifolia, Q. ajoensis, Q. alba, Q. arizonica, Q. arkansana, Q. austrina, Q. berberidifolia, Q. bicolor, Q. boyntonii, Q. buckleyi, Q. carmenensis, Q. chapmanii, Q. chihuahuensis, Q. chrysolepis, Q. coccinea, Q. cornelius-mulleri, Q. depressipes, Q. douglasii, Q. dumosa, Q. durata, Q. ellipsoidalis, Q. emoryi, Q. engelmannii, Q. falcata, Q. fusiformis, Q. gambelii, Q. garryana, Q. geminata, Q. georgiana, Q. graciliformis, Q. gravesii, Q. grisea, Q. havardii, Q. hemisphaerica, Q. hinckleyi, Q. hypoleucoides, Q. ilicifolia, Q. imbricaria, Q. incana, Q. inopina, Q. intricata, Q. john-tuckeri, Q. kelloggii, Q. laceyi, Q. laevis, Q. laurifolia, Q. lobata, Q. lyrata, Q. macrocarpa, Q. margarettae, Q. marilandica, Q. michauxii, Q. minima, Q. mohriana, Q. montana, Q. muehlenbergii, Q. myrtifolia, Q. nigra, Q. oblongifolia, Q. oglethorpensis, Q. pacifica, Q. pagoda, Q. palmeri, Q. palustris, Q. phellos, Q. polymorpha, Q. prinoides, Q. pumila, Q. pungens, Q. robur, Q. robusta, Q. rubra, Q. rugosa, Q. sadleriana, Q. shumardii, Q. similis, Q. sinuata, Q. stellata, Q. tardifolia, Q. texana, Q. toumeyi, Q. turbinella, Q. vacciniifolia, Q. vaseyana, Q. velutina, Q. viminea, Q. virginiana, Q. wislizenii
Q. acerifolia, Q. agrifolia, Q. ajoensis, Q. alba, Q. arizonica, Q. arkansana, Q. austrina, Q. berberidifolia, Q. bicolor, Q. boyntonii, Q. buckleyi, Q. carmenensis, Q. chapmanii, Q. chihuahuensis, Q. chrysolepis, Q. coccinea, Q. cornelius-mulleri, Q. depressipes, Q. douglasii, Q. dumosa, Q. ellipsoidalis, Q. emoryi, Q. engelmannii, Q. falcata, Q. fusiformis, Q. gambelii, Q. garryana, Q. geminata, Q. georgiana, Q. graciliformis, Q. gravesii, Q. grisea, Q. havardii, Q. hemisphaerica, Q. hinckleyi, Q. hypoleucoides, Q. ilicifolia, Q. imbricaria, Q. incana, Q. inopina, Q. intricata, Q. john-tuckeri, Q. kelloggii, Q. laceyi, Q. laevis, Q. laurifolia, Q. lobata, Q. lyrata, Q. macrocarpa, Q. margarettae, Q. marilandica, Q. michauxii, Q. minima, Q. mohriana, Q. montana, Q. muehlenbergii, Q. myrtifolia, Q. nigra, Q. oblongifolia, Q. oglethorpensis, Q. pacifica, Q. pagoda, Q. palmeri, Q. palustris, Q. phellos, Q. polymorpha, Q. prinoides, Q. pumila, Q. pungens, Q. robur, Q. robusta, Q. rubra, Q. rugosa, Q. sadleriana, Q. shumardii, Q. similis, Q. sinuata, Q. stellata, Q. tardifolia, Q. texana, Q. tomentella, Q. toumeyi, Q. turbinella, Q. vacciniifolia, Q. vaseyana, Q. velutina, Q. viminea, Q. virginiana, Q. wislizenii
Subordinate taxa
Q. durata var. durata, Q. durata var. gabrielensis
Synonyms Q. dumosa var. bullata, Q. dumosa var. revoluta
Name authority Engelmann: Trans. Acad. Sci. St. Louis, 3: 393. (1877) Jepson: Fl. Calif. 1(2): 356. (1909)
Web links 
Unless otherwise noted, all data comes from the online version of the Flora of North America, who have made most of their content available via a Creative Commons license (CC BY 4.0).



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