Quercus ellipsoidalis |
Quercus oblongifolia |
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Hill's oak, Jack oak, northern pin oak |
Mexican blue oak, Sonoran blue oak |
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Habit | Trees, deciduous, to 20 m; lower trunk often with stubs of dead branches. | Trees, evergreen, to 10 m. Bark gray or whitish, closely furrowed. |
Bark | dark gray-brown, shallowly fissured, inner bark orangish. |
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Twigs | dark reddish brown, (1-)1.5-3 mm diam., glabrous. |
light brown, 1-1.5 mm diam., densely or sparsely stellate-tomentose, soon glabrate. |
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 elliptic, 70-130 × 50-100 mm, base obtuse to truncate, margins with 5-7 deep lobes and 15-55 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. |
blade oblong to elliptic, occasionally lanceolate or ovate, (20-)30-60(-80) × (5-)10-25(-30) 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 densely and loosely glandular-tomentose, quickly glabrate or persistently floccose, especially about base of midrib, at maturity strongly glaucous, adaxially dull pale green, bluish green, or glaucous, sparsely stellate-tomentose, quickly glabrate. |
Acorns | biennial; cup narrowly turbinate to deeply cup-shaped, 6-11 mm high × 10-19 mm wide, covering 1/3-1/2 nut, outer surface reddish brown, puberulent, inner surface light brown, glabrous, rarely with ring of pubescence around scar, scales with straight or slightly concave margins, tips tightly appressed, obtuse or acute; nut ellipsoid to ovoid, rarely subglobose, 10-20 × 9-15 mm, occasionally striate, glabrous, occasionally with 1 or more faint rings of fine pits at apex, scar diam. 4-8 mm. |
solitary or paired, subsessile or on peduncle 4-12 mm; cup cup-shaped, about 6-8(-13) mm deep × 10-13 mm wide, enclosing ca. 1/3 nut, scales to 1-1.5 mm wide, moderately, regularly tuberculate near base of cup, gray-pubescent; nut light brown, ovoid or oblong, 12-17(-19) × (7-)10-12 mm, glabrate or puberulent about apex. |
Cotyledons | connate. |
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Terminal | buds dark reddish brown, ovoid, 3-5 mm, often conspicuously 5-angled in cross section, usually silvery- or tawny-pubescent toward apex. |
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Quercus ellipsoidalis |
Quercus oblongifolia |
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Phenology | Flowering spring. | Flowering in spring. |
Habitat | Dry sandy sites, rarely on moderately mesic slopes or uplands | Common in high grasslands and midelevation woodlands, mesas, and canyons |
Elevation | 150-500 m (500-1600 ft) | 1300-1650 m (4300-5400 ft) |
Distribution |
IA; IL; IN; MI; MN; OH; WI; ON
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AZ; NM; TX; Mexico (Baja California South, Sonora, Chihuahua, and Coahuila)
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Discussion | In many treatments (e.g., E. G. Voss 1972+, vol. 2), Quercus ellipsoidalis is included in Q. coccinea. Variation in fruit morphology has led to recognition of several formae (W. Trelease 1919; see also R. J. Jensen 1986) and one variety (Q. ellipsoidalis var. kaposianensis, based on specimens from St. Paul, Minnesota, in which the cup tightly encloses the nut for two-thirds its length at maturity). Quercus ellipsoidalis reportedly hybridizes with Q. rubra and Q. velutina. The Menominee used Quercus ellipsoidalis medicinally to treat suppressed menses caused by cold (D. E. Moerman 1986). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Source | FNA vol. 3. | FNA vol. 3. |
Parent taxa | Fagaceae > Quercus > sect. Lobatae | Fagaceae > Quercus > sect. Quercus |
Sibling taxa | ||
Synonyms | Q. ellipsoidalis var. kaposianensis | |
Name authority | E. J. Hill: Bot. Gaz. 27: 204, plates 2, 3. (1899) | Torrey: in L. Sitgreaves, Rep. Exped. Zuni Colorado Rivers, 173, plate 19. (1853) |
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