Quercus kelloggii |
Quercus robusta |
|
---|---|---|
California black oak, Kellogg oak |
robust oak |
|
Habit | Trees, deciduous, to 25 m. Bark dark brown to black, ridges broad, irregular. | Trees, deciduous, to 13 m. Bark brown or black, roughly furrowed. |
Twigs | brown to red-brown, (1.5-)2-3.5 mm diam., glabrate. |
dark reddish brown, 1.5-2.5 mm diam., densely pubescent or glabrate. |
Leaves | blade ovate or broadly elliptic to obovate, 60-200 × 40-140 mm, base cordate to obtuse, occasionally rounded, margins with 7-11 lobes and 13-45 awns, lobes acute to distally expanded, separated by deep sinuses, apex acute; surfaces abaxially glabrous with small axillary tufts of tomentum to densely pubescent, adaxially glabrous to minutely pubescent, veins raised on both surfaces. |
blade acutely ovate to elliptic, widest at or proximal to middle, 55-120 × 20-50 mm, base cuneate to rounded or subcordate, margins with 6-8 teeth or shallow lobes with rounded sinuses, rarely entire, 1-10 awns, apex acute or attenuate; surfaces abaxially glabrous except for small axillary tufts of tomentum or pubescent along midrib, adaxially glabrous or persistently pubescent near base and along midrib. |
Acorns | biennial; cup saucer-shaped to deeply bowl-shaped, 13-27 mm high × 20-28 mm wide, covering 1/2-2/3 nut, outer surface glabrous to sparsely puberulent, inner surface 1/3 to completely pubescent, scales more than 4 mm long, attenuate or acuminate to acute, smooth, occasionally tuberculate near base of cup, tips loose, especially at margin of cup; nut oblong to broadly ellipsoid, 21-34 × 14-22 mm, puberulent, especially at apex, scar diam. 5.5-10.5 mm. |
biennial; cup deeply cup-shaped, 6-9 mm high × 8-12 mm wide, covering 1/4-1/3 nut, outer surface puberulent or glabrate, inner surface uniformly pubescent, scales tightly appressed, acute or attenuate; nut oblong to broadly ellipsoid, 10-22 × 7-10 mm, glabrate, scar diam. 3.5-4.5 mm. |
Terminal | buds chestnut brown, ovoid, 4-10 mm, glabrous or with scales ciliate on margins. |
buds glossy light brown, acutely ovoid, 4-7 mm, glabrous or pubescent on apical 1/2. |
2n | = 24. |
|
Quercus kelloggii |
Quercus robusta |
|
Phenology | Flowering late spring. | Flowering spring. |
Habitat | On slopes and valleys of hills and mountains | Moist wooded canyons in Chisos Mountains |
Elevation | 300-2400 m (1000-7900 ft) | 1500 m (4900 ft) |
Distribution |
CA; OR
|
TX |
Discussion | The abundant crops of acorns from Quercus kelloggii were at one time an important food source for Native Americans. The species reportedly hybridizes with Quercus agrifolia (= Q. ×ganderi C. B. Wolf) and Q. wislizenii (= Q. ×morehus Kellogg). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Of conservation concern. After describing this species, C. H. Muller later (1951, 1970) concluded that it represented a hybrid between Quercus emoryi and Q. gravesii. The extreme forms (e.g., the type specimens) of Q. robusta and Q. gravesii are easily differentiated, but these two taxa appear to occupy the ends of a morphologic continuum. Muller's recent view, however, is that Q. robusta deserves species status. The origin of this taxon is still worthy of study. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 3. | FNA vol. 3. |
Parent taxa | Fagaceae > Quercus > sect. Lobatae | Fagaceae > Quercus > sect. Lobatae |
Sibling taxa | ||
Synonyms | Q. californica, Q. tinctoria var. californica | |
Name authority | Newberry: Pacif. Railr. Rep. 6: 28, 89, fig. 6. (1859) | C. H. Muller: Torreya 34: 119. (1934) |
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