Quercus palmeri |
Quercus tardifolia |
|
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Palmer oak, Palmer's oak |
lateleaf oak |
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Habit | Trees, evergreen. | |
Bark | gray, furrowed. |
|
Twigs | dark reddish brown, 1.5-2.5 mm diam., densely pubescent. |
|
Leaves | blade suborbiculate, elliptic to round-ovate, 20-30(-50) × 20-40 mm, crisped, leathery and brittle, base obtuse to strongly subcordate, secondary veins 5-8(-12) pairs, each terminating in spine, basal pairs recurving, others branching at 45° angles, raised abaxially, margins spinose-dentate to occasionally entire, with highly thickened cell walls, spines cartilaginous, (1-)1.5-2 mm, apex broadly rounded or subacute, spinose; surfaces abaxially glaucous with waxy layer, often obscured by golden brown glandular hairs, adaxially grayish dark green, scurfy with fasciculate erect and twisting 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 turbinate to saucer-shaped, margins involute, often irregular, 7-10 mm deep × 10-25(-35) mm wide, scales appressed, embedded, often appearing laterally connate into concentric rings with only tip of scale visible, tuberculate, densely golden-tomentose throughout; nut oblong to fusiform, 20-30 × 10-15 mm, apex acute. |
biennial, immature acorns in pairs, mature acorns not known. |
Small | trees and shrubs, to 2-3 m. Twigs rigid, divaricately branched at 65-90° angles, reddish brown, 1.5-3 mm diam., pubescent, sparsely so in 2d year. |
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Terminal | buds ovoid, 1-1.5 mm, apex rounded, glabrous. |
buds brown or reddish brown, ellipsoid or ovoid, 3.5-5.5 mm, apex hairy, scales with ciliate margins. |
Quercus palmeri |
Quercus tardifolia |
|
Phenology | Flowering in spring. | Flowering spring. |
Habitat | Disjunct in canyons, mountain washes, dry thickets, and margins of chapparal communities | Wooded arroyos |
Elevation | 700-1800 m (2300-5900 ft) | 2000 m (6600 ft) |
Distribution |
AZ; CA; Mexico (n Baja California)
|
TX |
Discussion | Populations of Quercus palmeri are often small and may exist as single clones. The disjunct populations of California and Baja California are consistent morphologically. In Arizona populations, individuals tend to have flatter leaves bearing fewer teeth; this distinction is not constant, however. Morphologically aberrant populations identified as Q. palmeri in eastern Arizona (Chiracahua, Huachuca, and Santa Catalina mountains) and southwestern New Mexico are most likely the result of introgression from Q. palmeri to Q. chrysolepis (J. M. Tucker and H. S. Haskell 1960). Those populations tend to be intermediate in overall morphology, but all lack the diagnostic trichomes and biochemical markers of Q. palmeri; they are best classified as Q. chrysolepis affinity Q. palmeri. (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 | ||
Synonyms | Q. dunnii | |
Name authority | Engelmann: in S. Watson, Bot. California 2: 97. (1880) | C. H. Muller: Bull. Torrey Bot. Club 63: 154. (1936) |
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