Quercus cornelius-mulleri |
Quercus wislizenii |
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desert scrub oak, muller oak, muller's oak |
interior live oak, Sierra live oak |
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Habit | Shrubs, evergreen or subevergreen, densely branched, 1-2(-3) m. Bark gray, scaly. | Trees or shrubs, evergreen, to 22 m. Bark nearly black, deeply furrowed with broad scaly ridges. |
Twigs | gray, yellowish, or brownish, 1-1.5 mm diam., densely tomentulose, rarely glabrate. |
brown to red-brown, 1.5-3 mm diam., glabrous or sparsely 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 circular to oblong, usually ovate, planar, 25-70 × 20-50 mm, base obtuse to cordate, margins entire or spinose with up to 16 awns, apex acute to rounded; surfaces abaxially and adaxially glabrous, veins little raised on either surface. |
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. |
biennial; cup deeply and narrowly cup-shaped or U-shaped, 9-19 mm high × 7-18 mm wide, covering 1/3-1/2(-2/3) nut, outer surface glabrous to sparsely puberulent, inner surface glabrous or pubescent on innermost 1/3, occasionally uniformly pubescent, scales acute, tips loose; nut narrowly conic or ovoid to narrowly oblong, 21-44 × 8-14 mm, glabrous, scar diam. 2.5-7.5 mm. |
Cotyledons | distinct. |
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Terminal | buds light chestnut brown to dark reddish brown, ovoid to conic, 3-9 mm, glabrous or with tuft of minute hairs at apex. |
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2n | = 24. |
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Quercus cornelius-mulleri |
Quercus wislizenii |
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Phenology | Flowering early spring. | Flowering late spring. |
Habitat | Open chaparral, pinyon and juniper woodlands, desert margins, often on loose granitic soils | Valleys, slopes, and sand chaparral |
Elevation | 1000-1800 m (3300-5900 ft) | 300-1900 m (1000-6200 ft) |
Distribution |
CA; Mexico (Baja California)
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CA
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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.) |
Shrubs with oval leaves 25-38 mm and margins entire or deeply lobed-dentate may be treated as Quercus wislizenii var. frutescens. J. M. Tucker (1993) treated Q. parvula as a distinct species, distinguished from Q. wislizenii by its larger leaves (30-90 versus 20-50 mm), by the dull, olive-green, abaxial leaf surface (versus shiny, yellow-green), and by nuts that are abruptly tapered proximal to the middle (versus gradually tapered). Tucker recognized two varieties of Quercus parvula: Q. parvula var. parvula is a shrub of 1-3 m and Q. parvula var. shrevei is a tree less than 17 m. S. K. Langer (1993) recognized a third variety, Q. parvula var. tamalpaisensis,based on several small populations on or near Mount Tamalpais, differentiated primarily by having larger leaves (50-160 × 20-60 mm) with attenuate-dentate margins. Quercus wislizenii reportedly hybridizes with Q. agrifolia and Q. kelloggii (W. B. Brophy and D. R. Parnell 1974). (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. parvula, Q. parvula var. shrevei, Q. parvula var. tamalpaisensis, Q. wislizenii var. frutescens | |
Name authority | Nixon & K. P. Steele: Madroño 28: 210. (1981) | A. de Candolle: in A. P. de Candolle and A. L. P. de Candolle, Prodr. 16(2): 67. (1864) |
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