Quercus vacciniifolia |
Quercus tardifolia |
|
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huckleberry oak |
lateleaf oak |
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Habit | Shrubs, low spreading to often prostrate, to 1.5 m. Twigs branching at 45° angles or less, reddish brown, 1-1.5 mm diam., flexible, glabrous to sparsely pubesent. | Trees, evergreen. |
Bark | gray, furrowed. |
|
Twigs | dark reddish brown, 1.5-2.5 mm diam., densely pubescent. |
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Leaves | blade oblong-ovate, 10-35 × 7-15 mm, flat, thin, leathery, base slightly rounded to acute, secondary veins inconspicuous, 6-8 pairs, branching at 45-60° angles, with weakly thickened cell walls, margins entire or indistinctly and irregularly mucronately toothed, apex acute or rarely obtuse; surfaces abaxially whitish green with waxy layer, glabrous or slightly pubescent with stellate hairs, adaxially dull gray-green, glabrous or sparsely pubescent with stellate hairs. |
blade broadly elliptic or obovate, widest at or distal to middle, planar, 50-100 × 20-70 mm, base cordate or occasionally rounded, margins with 3-4 lobes with shallow sinuses, 6-12 awns, apex acute or obtuse; surfaces abaxially conspicuously tomentose, primary and secondary veins raised, adaxially somewhat rugose, glabrate. |
Acorns | solitary or rarely paired; cup shallowly saucer-shaped to slightly turbinate, 3-4 mm deep × 10-15 mm wide, scales appressed, slightly embedded, moderately silvery brown-pubescent; nut ovoid, 8-17 × 5-10 mm, apex acute; nut scar to 3 mm diam. |
biennial, immature acorns in pairs, mature acorns not known. |
Terminal | buds conic, 2.5 mm, scales brown with ciliate margins. |
buds brown or reddish brown, ellipsoid or ovoid, 3.5-5.5 mm, apex hairy, scales with ciliate margins. |
Quercus vacciniifolia |
Quercus tardifolia |
|
Phenology | Flowering in early summer. | Flowering spring. |
Habitat | Dry ridges, steep slopes, and rocky areas from montane coniferous zone to near treeline | Wooded arroyos |
Elevation | 900-2800 m (3000-9200 ft) | 2000 m (6600 ft) |
Distribution |
CA; NV; OR
|
TX |
Discussion | Typical high-elevation populations in the Sierra Nevada of California can be distinguished from all shrubby forms of Quercus chrysolepis by the absence of glandular trichomes and by thin cups with small nut-attachment scars. At lower elevations in northern California and southwestern Oregon, secondary contact with Q. chrysolepis has resulted in the formation of hybrids. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Of conservation concern. Quercus tardifolia was reported from Mexico (Coahuila) (A. M. Powell 1988), but I have not seen the specimens. It should be expected in the ranges (e.g., Sierra del Carmen) adjacent to the Big Bend area. This distinctive species is apparently quite infrequent, only two small clumps being known from the Chisos Mountains (C. H. Muller 1951). Recent efforts to locate Quercus tardifolia have not been successful (M. Powell, pers. comm.). Its status is also in question; Muller and K. C. Nixon (pers. comm.) think that it might be a hybrid between Quercus gravesii and Q. hypoxantha. (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. Lobatae |
Sibling taxa | ||
Name authority | Hittell: Resources Calif. 101. (1863) — (as vaccinifolia) | C. H. Muller: Bull. Torrey Bot. Club 63: 154. (1936) |
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