Quercus pacifica |
Quercus ilicifolia |
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Channel Island scrub oak, island scrub oak, Pacific oak |
bear oak, scrub oak |
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Habit | Shrubs, rarely small trees, subevergreen, shrubs to 2 m, trees to 5 m or taller. | Trees or shrubs, deciduous, to 6 m. Bark dark gray, becoming shallowly fissured and scaly, inner bark pinkish. |
Bark | scaly on older branches and trunk. |
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Twigs | brownish or reddish, minutely puberulent, becoming glabrate and gray with age. |
brown or yellowish brown, 1.5-3 mm diam., pubescent. |
Buds | light or chestnut brown, ovate or globose, 2-3 × 1-2 mm. |
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Leaves | blade obovate or oblong, planar to moderately convex or undulate, 15-40 × 7-20(-40) mm, base cuneate or rounded, attenuate-decurrent along petiole, margins minutely cartilaginous, entire or with 1-5 irregular teeth on each side, secondary veins obscure, 1-5 on each side, apex blunt or rounded, occasionally subacute with mucronate tip; surfaces abaxially waxy, glandular, with scattered minute, flat, appressed, ± 8-rayed stellate hairs, not obscuring surface, adaxially green, glossy, glabrate or with minute, scattered, stellate hairs. |
blade ovate to elliptic or obovate, 50-120 × 30-90 mm, base cuneate to obtuse, margins with 3-7 acute lobes separated by shallow sinuses and 5-14 awns, apex acute; surfaces abaxially pale green to gray, tomentose, adaxially glossy dark green, glabrous, secondary veins raised on both surfaces. |
Acorns | paired or solitary in leaf axil, subsessile, rarely pedunculate in teratological forms; cup hemispheric to turbinate, to 15 mm deep × 20 mm wide, enclosing only 1/4-1/2 nut, scales moderately to heavily tuberculate, irregularly formed; nut light brown, acute-cylindric or fusiform, tapered, (15-)20-30 × (6-)9-15 m, apex acute, glabrate. |
biennial; cup saucer-shaped to cup-shaped, 5-9 mm high × 10.5-17 mm wide, covering 1/4-1/3(-1/2) nut, outer surface puberulent, inner surface pubescent, scale tips tightly appressed, acute; nut ovoid to subglobose, 9.5-16 × 8-11 mm, striate, puberulent, scar diam. 4.8-7 mm. |
Cotyledons | distinct. |
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Terminal | buds dark reddish brown, ovoid, 2-4.5 mm, apex puberulent. |
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2n | = 24. |
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Quercus pacifica |
Quercus ilicifolia |
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Phenology | Flowering spring. | Flowering spring. |
Habitat | Chaparral, oak woodlands, margins of grasslands, understory in closed-cone pine stands | Dry, sandy soils and open rocky outcrops |
Elevation | 0-300 m (0-1000 ft) | 0-1500 m (0-4900 ft) |
Distribution |
CA
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CT; DE; MA; MD; ME; NC; NH; NJ; NY; PA; RI; VA; VT; WV
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Discussion | Of conservation concern. Quercus pacifica is endemic on three of the California Channel Islands: Santa Cruz, Santa Catalina, and Santa Rosa. It is not known from the mainland, but it bears a superficial similarity to some of the tree forms that are putative hybrids between Q. engelmannii and Q. cornelius-mulleri in San Diego County. The latter populations, sometimes treated as Q. ×acutidens, differ in having much greater variability in leaf shape; thicker, more leathery leaves; denser abaxial leaf vestiture; much smaller hairs, having more than 10 rays; and variable levels of connation of cotyledons (always distinct in Q. pacifica). Quercus pacifica appears to be most closely related to Q. douglasii, whether by direct descent or by introgression with another species no longer extant on the islands. Quercus ×macdonaldii Greene (as a species) [= Quercus dumosa var. macdonaldii (Greene) Jepson] is a stabilized hybrid complex between Quercus pacifica and Q. lobata Née. The plants tend to be small to moderate trees with leaves that resemble those of Q. lobata; the leaves are much more shallowly lobed and always less than two-thirds the distance from the margin to the midrib. Quercus ×macdonaldii is known from Santa Rosa, Santa Cruz, and Santa Catalina islands. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Quercus ilicifolia reportedly hybridizes with Q. coccinea, Q. falcata, Q. imbricaria, Q. marilandica, Q. phellos, Q. rubra, and Q. velutina. The Iroquois considered Quercus ilicifolia very helpful in treating gynecological problems (D. E. Moerman 1986). (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. dumosa var. polycarpa | Q. nana |
Name authority | Nixon & C. H. Muller: Novon 4: 391. (1994) | Wangenheim: Beytr. Teut. Forstwiss., 79, plate 6, fig. 17. (1787) |
Web links |