Quercus engelmannii |
Quercus ilicifolia |
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Engelmann oak, Engelmann's oak |
bear oak, scrub oak |
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Habit | Trees, subevergreen, to 10 m. Bark gray or whitish, closely furrowed. | Trees or shrubs, deciduous, to 6 m. Bark dark gray, becoming shallowly fissured and scaly, inner bark pinkish. |
Twigs | light brown, 1-1.5 mm diam., densely or sparsely stellate-tomentose, soon glabrate. |
brown or yellowish brown, 1.5-3 mm diam., pubescent. |
Buds | reddish brown, subspheric to broadly ovoid, 1-2 mm, glabrous or basal scales pubescent; stipules persistent about terminal buds. |
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Leaves | blade oblong to elliptic, occasionally lanceolate or ovate, (20-)30-60(-80) × (5-)10-20(-25) mm, base cuneate to cordate, margins entire, undulate, sometimes irregularly toothed, especially toward apex, secondary veins 7-8(-10) on each side, branched, apex acute or broadly rounded; surfaces abaxially blue-green or pale green, densely and loosely glandular-tomentose, quickly glabrate or persistently floccose, especially about base of midrib, at maturity strongly glaucous, adaxially gray-green or pale green, bluish green or glaucous. |
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 | solitary or paired, subsessile or on peduncle to 5-6 mm; cup cup-shaped or shallowly cup-shaped, 8-10 mm deep × 10-15 mm wide, enclosing 1/3 nut, scales 1.5-3 mm wide, strongly and regularly tuberculate near base of cup, gray-pubescent; nut light brown, ovoid or oblong, 15-25 × 12-14 mm, glabrate or puberulent about apex. |
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 | connate. |
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Terminal | buds dark reddish brown, ovoid, 2-4.5 mm, apex puberulent. |
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2n | = 24. |
= 24. |
Quercus engelmannii |
Quercus ilicifolia |
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Phenology | Flowering in spring. | Flowering spring. |
Habitat | Oak woodlands, margins of chaparral, arroyos, slopes and bajadas | Dry, sandy soils and open rocky outcrops |
Elevation | 50-1200 m (200-3900 ft) | 0-1500 m (0-4900 ft) |
Distribution |
CA; Mexico (Baja California)
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CT; DE; MA; MD; ME; NC; NH; NJ; NY; PA; RI; VA; VT; WV
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Discussion | Quercus engelmannii is closely related to and possibly conspecific with Q. oblongifolia. The cups of Q. engelmannii are larger, deeper, and generally more tuberculate than those of Q. oblongifolia, and the scales are usually larger. Based on available samples, the nuts of Q. engelmannii are consistently larger than those of Q. oblongifolia, apparently with little, if any, overlap in diameter. Considerably more variation occurs within Q. engelmannii in leaf form, possibly reflecting introgression from other white oak species such as Q. cornelius-mulleri, Q. dumosa, and Q. durata (see treatment). On Catalina Island, Quercus engelmannii is known only from a small grove of trees. Putative hybrids between Q. engelmannii and Q. cornelius-mulleri are common in areas of contact between the two species in Riverside and San Diego counties in southern California. Such a population was the basis for Q. acutidens Torrey [Q. dumosa var. acutidens (Torrey) Wenzig]. Other names applied to those populations are Q. macdonaldii var. elegantula Greene and Q. dumosa var. elegantula (Greene) Jepson. Variable in leaf form and stature, those intermediates form extensive populations and are probably best disposed of under the name Q. ×acutidens. (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. nana | |
Name authority | Greene: Ill. W. Amer. Oaks 1: 33, plate 17. (1889) | Wangenheim: Beytr. Teut. Forstwiss., 79, plate 6, fig. 17. (1787) |
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