Quercus tomentella |
Quercus lyrata |
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Channel Island oak, island live oak, island oak |
overcup oak |
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Habit | Trees, to 20 m. Twigs branching at 45° angles, reddish brown, 3-4 mm diam., somewhat rigid, densely tomentose, persistent into 2d year. | Trees, deciduous, to 20 m. Bark light gray, tinged with red, with thick plates underlying scales. |
Twigs | grayish or reddish, (2-)3(-4) mm diam., villous, soon glabrate. |
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Buds | 3 mm, gray-puberulent. |
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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 obovate or broadly obovate, 100-160(-200) × 50-100(-120) mm, base narrowly cuneate to acute, margins moderately to deeply lobed, lobes somewhat to sharply angular or spatulate, often with 2-3 teeth, sinuses nearly to midrib, secondary veins arched, divergent, (3-)5-7 on each side, apex broadly rounded or ovate; surfaces abaxially light green or somewhat glaucous, tomentose, tomentum persisting or soon falling, adaxially dark green or dull gray, sparsely puberulent to glabrate. |
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. |
1-2 on axillary peduncles to 40 mm; cup goblet-shaped, burlike, or spheroid, 15-20 mm deep × 20-30 mm wide, usually completely enclosing nut or merely apex visible, rarely enclosing only 1/2 nut, orifice smaller than nut diameter, often splitting irregularly at maturity, scales closely appressed, especially about margin, laterally connate, broadly triangular, keeled-tuberculate, finely grayish tomentose; nut light brown or grayish, ovoid-ellipsoid or oblong, (15-)25-50 × (10-)20-40 mm, finely puberulent or floccose. |
Cotyledons | distinct. |
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Terminal | buds conic, 7-10 mm, scales brown with ciliate margins. |
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Quercus tomentella |
Quercus lyrata |
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Phenology | Flowering in spring, occasionally in fall. | Flowering spring. |
Habitat | Lower portions of steep canyons and occasionally ridge tops | Bottoms, lowlands, wet forest, streamside forests, swamp forests, periodically inundated areas |
Elevation | 100-650 m (300-2100 ft) | 0-200 m (0-700 ft) |
Distribution |
CA; Mexico (Baja California and on Guadalupe Island)
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AL; AR; DE; FL; GA; IA; IL; IN; KY; LA; MD; MO; MS; NC; NJ; OK; SC; TN; TX; VA
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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.) |
The large acorns with hardened cups that enclose all or most of the nut are diagnostic. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 3. | FNA vol. 3. |
Parent taxa | Fagaceae > Quercus > sect. Protobalanus | Fagaceae > Quercus > sect. Quercus |
Sibling taxa | ||
Synonyms | Q. bicolor var. lyrata | |
Name authority | Engelmann: Trans. Acad. Sci. St. Louis, 3: 393. (1877) | Walter: Fl. Carol., 235. (1788) |
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