Quercus coccinea |
Quercus ajoensis |
|
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scarlet oak |
Ajo Mountain scrub oak |
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Habit | Trees, deciduous, to 30 m; lower trunk without stubs of dead branches. | Shrubs, rarely trees, evergreen, to 2-3 m. Bark gray, scaly or furrowed. |
Bark | dark gray to dark brown, irregularly fissured with scaly ridges, inner bark orangish pink. |
|
Twigs | reddish brown, (1-)2-3.5 mm diam., glabrous. |
light brown, 1-2 mm diam., inconspicuously short stellate-pubescent or glabrate. |
Buds | brown or reddish brown, ovoid or globose, 1-1.5 mm, variously short stellate-pubescent, tomentose, or glabrate. |
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Leaves | blade elliptic to ovate or obovate, 70-160 × 80-130 mm, base obtuse to truncate, margins with 5-9 deep lobes and 18-50 awns, lobes distally expanded, sinuses usually extending more than 1/2 distance to midrib, apex acute; surfaces abaxially glabrous except for minute axillary tufts of tomentum, adaxially glossy light green, glabrous, secondary veins raised on both surfaces. |
petiole (2-)3-4 m. Leaf blade ovate to narrowly ovate or oblong, (10-)15-35(-50) × (5-)10-20(-30) mm, rather leathery, base cordate, rarely rounded, margins crispate, sometimes flat, cartilaginous, with 4-6(-8) long-attenuate, spinose-awned teeth on each side, secondary veins 5-8 on each side, whitish, apex acute or obtuse with bristly distal teeth; surfaces abaxially blue-green, waxy-glaucous, microscopically papillose, glabrous, sometimes sparsely stellate-pubescent along midrib, adaxially blue-green, glaucous, glabrous or sparingly stellate-pubescent along midrib, secondary veins raised on both surfaces. |
Acorns | biennial; cup turbinate to hemispheric, 7-13 mm high × 16.5-31.5 mm wide, covering 1/3-1/2 nut, outer surface light to dark reddish brown, glossy, glabrous to puberulent, inner surface light brown, glabrous, occasionally with ring of pubescence around scar, scales often tuberculate, base broad, glossy, margins strongly concave with tips tightly appressed, acute to attenuate; nut oblong to subglobose, 12-22 × 10-21 mm, glabrous, with 1 or more rings of fine pits at apex, scar diam. 6.5-13.5 mm. |
solitary or paired on thin axillary peduncle (5-)30-50 mm; cup shallowly cup-shaped, thin, 3-4 mm deep × 6-8(-10) mm wide, enclosing only base of nut, scales brownish, moderately tuberculate, pubescent; nut oblong to narrowly ovoid, 12-15 × 5-8 mm. |
Cotyledons | distinct. |
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Terminal | buds dark reddish brown, conic to ovoid, 4-7 mm, noticeably 5-angled in cross section, usually silvery- or tawny-pubescent distal to middle. |
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2n | = 24. |
|
Quercus coccinea |
Quercus ajoensis |
|
Phenology | Flowering spring. | Flowering in spring. |
Habitat | Poor soils, well-drained uplands, dry slopes, and ridges, occasionally on poorly drained sites | Rare to locally abundant on igneous slopes |
Elevation | 0-1500 m (0-4900 ft) | 500-1500 m (1600-4900 ft) |
Distribution |
AL; AR; CT; DC; DE; GA; IL; IN; KY; MA; MD; ME; MI; MO; NC; NH; NJ; NY; OH; PA; RI; SC; TN; VA; VT; WI; WV
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AZ; Mexico (Baja California) |
Discussion | Trees having acorns with broad, distinctly warty cups are sometimes classified as Quercus coccinea var. tuberculata Sargent. Quercus coccinea reportedly hybridizes with Q. imbricaria, Q. ilicifolia (= Q. ×robbinsii Trelease), Q. laevis, and Q. palustris (E. J. Palmer 1948) and with Q. phellos, Q. rubra, and Q. velutina (= Q. ×fontana Laughlin). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Populations of Quercus ajoensis in southern New Mexico show characteristics suggesting introgression from hybridization with Quercus toumeyi, such as increased twig and leaf pubescence and sometimes the prominent golden puberulum of the abaxial leaf surfaces. Hybrids between Q. ajoensis and both Q. turbinella and Q. gambelii (Utah) are also known. (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. Quercus |
Sibling taxa | ||
Synonyms | Q. coccinea var. tuberculata | Q. turbinella subsp. ajoensis, Q. turbinella var. ajoensis |
Name authority | Münchhausen: Hausvater 5(1): 254. (1770) | C. H. Muller: Madroño 12: 140. (1954) |
Web links |