Quercus wislizenii

A. de Candolle

in A. P. de Candolle and A. L. P. de Candolle, Prodr. 16(2): 67. 1864.

Common names: Sierra live oak interior live oak
EndemicIllustrated
Synonyms: Quercus parvula Greene Quercus parvula var. shrevei (C. H. Muller) Nixon Quercus parvula var. tamalpaisensis S. K. Langer Quercus wislizenii var. frutescens Engelmann
Treatment appears in FNA Volume 3.

Trees or shrubs, evergreen, to 22 m. Bark nearly black, deeply furrowed with broad scaly ridges. Twigs brown to red-brown, 1.5-3 mm diam., glabrous or sparsely pubescent. Terminal buds light chestnut brown to dark reddish brown, ovoid to conic, 3-9 mm, glabrous or with tuft of minute hairs at apex. Leaves: petiole 3-20 mm, glabrous or sparsely pubescent. Leaf 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 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. 2n = 24.


Phenology: Flowering late spring.
Habitat: Valleys, slopes, and sand chaparral
Elevation: 300-1900 m

Discussion

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).

Selected References

None.

Lower Taxa

None.
... more about "Quercus wislizenii"
Kevin C. Nixon +
A. de Candolle +
Sierra live oak +  and interior live oak +
300-1900 m +
Valleys, slopes, and sand chaparral +
Flowering late spring. +
in A. P. de Candolle and A. L. P. de Candolle, Prodr. +
Endemic +  and Illustrated +
Quercus parvula +, Quercus parvula var. shrevei +, Quercus parvula var. tamalpaisensis +  and Quercus wislizenii var. frutescens +
Quercus wislizenii +
Quercus sect. Lobatae +
species +