Quercus pacifica |
Quercus pagoda |
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Channel Island scrub oak, island scrub oak, Pacific oak |
cherrybark oak, Texas oak |
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Habit | Shrubs, rarely small trees, subevergreen, shrubs to 2 m, trees to 5 m or taller. | Trees, deciduous, to 40 m. Bark nearly black with narrow and noticeably flaky ridges, often resembling that of wild black cherry, inner bark orange. |
Bark | scaly on older branches and trunk. |
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Twigs | brownish or reddish, minutely puberulent, becoming glabrate and gray with age. |
yellowish brown, 2-3.5 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, 90-300 × 60-160 mm, base cuneate to rounded or truncate, margins with 5-11 lobes and 10-25 awns, lobes oblong, rarely falcate, terminal lobe rarely exceeding lateral lobes in length, apex acute; surfaces abaxially pale, tomentose, adaxially glossy, 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, 3-7 mm high × 10-18 mm wide, covering 1/3-1/2 nut, outer surface puberulent, inner surface pubescent, scale tips tightly appressed, acute; nut subglobose, 9-15 × 8-16 mm, often striate, puberulent, scar diam. 5-9 mm. |
Cotyledons | distinct. |
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Terminal | buds light reddish brown, ovoid, 4-9 mm, strongly 5-angled in cross section, puberulent throughout. |
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Quercus pacifica |
Quercus pagoda |
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Phenology | Flowering spring. | Flowering spring. |
Habitat | Chaparral, oak woodlands, margins of grasslands, understory in closed-cone pine stands | Poorly drained bottoms and mesic slopes |
Elevation | 0-300 m (0-1000 ft) | 0-300 m (0-1000 ft) |
Distribution |
CA
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AL; AR; FL; GA; IL; IN; KY; LA; MO; MS; NC; OK; SC; TN; TX; VA
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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 pagoda is often treated as a variety of Q. falcata; it is quite distinctive, however, both morphologically and ecologically (S. A. Ware 1967; R. J. Jensen 1989). This species reportedly hybridizes with Q. falcata and Q. phellos (D. M. Hunt 1989). (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. falcata var. leucophylla, Q. falcata var. pagodifolia, Q. leucophylla, Q. pagodifolia |
Name authority | Nixon & C. H. Muller: Novon 4: 391. (1994) | Rafinesque: Alsogr. Amer., 23. (1838) |
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