Quercus cornelius-mulleri |
Quercus emoryi |
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desert scrub oak, muller oak, muller's oak |
bellota, Emory oak, Emory's oak |
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Habit | Shrubs, evergreen or subevergreen, densely branched, 1-2(-3) m. Bark gray, scaly. | Trees or shrubs, evergreen, to 15 m. Bark dark brown to black, deeply fissured. |
Twigs | gray, yellowish, or brownish, 1-1.5 mm diam., densely tomentulose, rarely glabrate. |
dark reddish brown, 1-3 mm diam., pubescent. |
Buds | dull brown, ovoid, 2.5-3 mm, glabrous except for margins of scales. |
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Leaves | blade strongly bicolored, ovate to oblong or narrowly obovate, 15-35 ×10-20 mm, rather thick and leathery, base cuneate or attenuate-rounded, margins entire or irregularly, shallowly toothed, teeth mucronate, rarely spinose, secondary veins 6-7 on each side, apex rounded or acute; surfaces abaxially whitish, densely covered with minute, compact, appressed, (8-)10-14(-16)-rayed stellate hairs less than 0.2 mm diam. (lateral fusion of rays visible under high magnification), without glandular seriate hairs, adaxially dull, light green, grayish, or yellowish green, with scattered, appressed-stellate hairs to 0.2 mm diam. |
blade ovate to narrowly oblong to obovate, planar, 28-95 × 15-45 mm, base cordate, margins entire or spinose, with up to 13 awns, apex blunt to acute; surfaces abaxially glabrous except for tuft of tomentum on each side of midrib at base of blade, rarely completely glabrous, adaxially not rugous, glabrous or with a few hairs along midrib. |
Acorns | solitary or clustered, subsessile; cup deeply cup-shaped or turbinate, to 5-13 mm deep × 12-20 mm wide, scales whitish or cream, strongly tuberculate especially near base of cup; nut dark brown, fusiform or cylyndric, 20-30 × 10-30 mm. |
annual; cup cup-shaped, 5-7.5 mm high × 7-12 mm wide, covering 1/4-1/2 nut, outer surface pubescent to sparsely puberulent, inner surface pubescent to floccose, scale tips appressed, blunt; nut ellipsoid to oblong, 10-18 × 6-10 mm, glabrous to puberulent, especially at apex, scar diam. 3-5.5 mm. |
Cotyledons | distinct. |
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Terminal | buds reddish brown, ovoid to subconic, 2.5-6.5 mm, glabrous except for tuft of hairs at apex, occasionally hairy on distal 1/2. |
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Quercus cornelius-mulleri |
Quercus emoryi |
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Phenology | Flowering early spring. | Flowering spring. |
Habitat | Open chaparral, pinyon and juniper woodlands, desert margins, often on loose granitic soils | Foothills and slopes |
Elevation | 1000-1800 m (3300-5900 ft) | 1000-2200 m (3300-7200 ft) |
Distribution |
CA; Mexico (Baja California)
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AZ; NM; TX; n Mexico
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Discussion | Quercus cornelius-mulleri is easily distinguished from other California scrub oaks by the strongly bicolored leaves, dense minute tomentum of the abaxial leaf surface, and large acute acorns in deep tuberculate cups. Of greater difficulty are swarms of putative hybrids with Q. engelmannii, sometimes referred to as Q. ×acutidens. In Joshua Tree National Monument a lone tree and several shrubs appear to be hybrids and backcrosses between Quercus cornelius-mulleri and Q. lobata. This tree is the basis of Quercus ×munzii J. M. Tucker. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Quercus emoryi reportedly hybridizes with Q. graciliformis (= Q. ×tharpii C. H. Muller). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 3. | FNA vol. 3. |
Parent taxa | Fagaceae > Quercus > sect. Quercus | Fagaceae > Quercus > sect. Lobatae |
Sibling taxa | ||
Synonyms | Q. hastata | |
Name authority | Nixon & K. P. Steele: Madroño 28: 210. (1981) | Torrey: in W. H. Emory, Not. Milit. Reconn., 151, plate 9. (1848) |
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