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Engelmann oak, Engelmann's oak

live oak, southern live oak

Habit Trees, subevergreen, to 10 m. Bark gray or whitish, closely furrowed. Trees, sometimes shrubs, subevergreen, trees to 35 m, shrubs sometimes rhizomatous.
Bark

dark brown or black, scaly.

Twigs

light brown, 1-1.5 mm diam., densely or sparsely stellate-tomentose, soon glabrate.

yellowish to light gray, 1-3 mm diam., minutely puberulent or stellate-pubescent, glabrate in 2d year.

Buds

reddish brown, subspheric to broadly ovoid, 1-2 mm, glabrous or basal scales pubescent;

stipules persistent about terminal buds.

reddish or dark brown, subglobose or ovate, 1-2 mm;

scale margins glabrous or puberulent.

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 obovate to oblanceolate, sometimes orbiculate or lance-ovate, ± planar, (10-)35-90(-150) × (15-)20-40(-85) mm, base cuneate to rounded, rarely truncate or cordate, margins minutely revolute or flat, entire or irregularly 1-3-toothed on each side, teeth mucronate, secondary veins obscure, 6-9(-12) on each side, apex obtuse-rounded or acute;

surfaces abaxially whitish or glaucous, densely covered with minute, appressed, fused-stellate hairs, light green and glabrate in shade leaves, adaxially dark or light green, glossy, glabrous or with minute, scattered, stellate hairs.

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.

1-3, on peduncle (3-)10-20 mm;

cup hemispheric or deeply goblet-shaped, 8-15 mm deep × 8-15 mm wide, base often constricted;

scales whitish or grayish, proximally thickened, keeled, tomentulose, tips reddish, acute-attenuate, glabrous or puberulent;

nut dark brown, barrel-shaped, ovoid, or obcylindric, 15-20(-25) × 8-15 mm, apex rounded or blunt, glabrous.

Cotyledons

connate.

connate.

2n

= 24.

Quercus engelmannii

Quercus virginiana

Phenology Flowering in spring. Flowering late winter–early spring.
Habitat Oak woodlands, margins of chaparral, arroyos, slopes and bajadas Coastal plain, open evergreen woodlands, scrublands, and hummocks on loam, clay, and rarely on sand on immediate coast
Elevation 50-1200 m (200-3900 ft) 0-200 m (0-700 ft)
Distribution
from FNA
CA; Mexico (Baja California)
[WildflowerSearch map]
[BONAP county map]
from FNA
AL; FL; GA; LA; MS; NC; SC; TX; VA
[WildflowerSearch map]
[BONAP county map]
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 virginiana is one of the commonest and best known species in the coastal region of the southeastern United States. In the past, it was widely used for structural pieces in the manufacture of wooden ships, and large groves were actually considered a strategic resource by the federal government. Historically oil pressed from the acorns was utilized. Like other members of the live oak group (Q. minima, Q. geminata, and Q. fusiformis), Q. virginiana seedlings form swollen hypocotyls that may develop into large, starchy, underground tubers. In the past, the tubers were gathered, sliced, and fried like potatoes for human consumption. The tendency for the tree members of this group to produce rhizomatous growth and clonal shrubs in juvenile stages, and in response to damage, fire, and poor soil conditions, has led to considerable confusion in delimiting the species. This is exacerbated by considerable plasticity in leaf form. When evaluating specimens an effort should be made to sample broadly within a population. The tuberous condition mentioned above suggests that live oaks have different phases in their life history that may persist depending on the environmental conditions. This is not uncommon in other woody plants that occur in seasonally dry, fire-prone habitats of the southeastern United States.

The Houma used Quercus virginiana medicinally for healing dysentery (D. E. Moerman 1986).

Putative hybrids between Quercus virginiana and Q. minima are known, but care should be taken to avoid assigning hybrid status to clonal phases of Q. virginiana solely on the basis of habit. Hybrids with Q. fusiformis and Q. geminata are discussed under those species. Occasional putative hybrids with Q. stellata are also found, and those tend to be semi-evergreen with shallowly lobed leaves.

Some named putative hybrids are: Q. ×burnetensis Little (= Q. macrocarpa × Q. virginiana); Q. ×comptonae Sargent (= Q. lyrata × Q. virginiana); and the artificially produced hybrid, Q. ×nessiana E. J. Palmer (= Q. bicolor × Q. virginiana).

(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. Quercus
Sibling taxa
Q. acerifolia, Q. agrifolia, Q. ajoensis, Q. alba, Q. arizonica, Q. arkansana, Q. austrina, Q. berberidifolia, Q. bicolor, Q. boyntonii, Q. buckleyi, Q. carmenensis, Q. chapmanii, Q. chihuahuensis, Q. chrysolepis, Q. coccinea, Q. cornelius-mulleri, Q. depressipes, Q. douglasii, Q. dumosa, Q. durata, Q. ellipsoidalis, Q. emoryi, Q. falcata, Q. fusiformis, Q. gambelii, Q. garryana, Q. geminata, Q. georgiana, Q. graciliformis, Q. gravesii, Q. grisea, Q. havardii, Q. hemisphaerica, Q. hinckleyi, Q. hypoleucoides, Q. ilicifolia, Q. imbricaria, Q. incana, Q. inopina, Q. intricata, Q. john-tuckeri, Q. kelloggii, Q. laceyi, Q. laevis, Q. laurifolia, Q. lobata, Q. lyrata, Q. macrocarpa, Q. margarettae, Q. marilandica, Q. michauxii, Q. minima, Q. mohriana, Q. montana, Q. muehlenbergii, Q. myrtifolia, Q. nigra, Q. oblongifolia, Q. oglethorpensis, Q. pacifica, Q. pagoda, Q. palmeri, Q. palustris, Q. phellos, Q. polymorpha, Q. prinoides, Q. pumila, Q. pungens, Q. robur, Q. robusta, Q. rubra, Q. rugosa, Q. sadleriana, Q. shumardii, Q. similis, Q. sinuata, Q. stellata, Q. tardifolia, Q. texana, Q. tomentella, Q. toumeyi, Q. turbinella, Q. vacciniifolia, Q. vaseyana, Q. velutina, Q. viminea, Q. virginiana, Q. wislizenii
Q. acerifolia, Q. agrifolia, Q. ajoensis, Q. alba, Q. arizonica, Q. arkansana, Q. austrina, Q. berberidifolia, Q. bicolor, Q. boyntonii, Q. buckleyi, Q. carmenensis, Q. chapmanii, Q. chihuahuensis, Q. chrysolepis, Q. coccinea, Q. cornelius-mulleri, Q. depressipes, Q. douglasii, Q. dumosa, Q. durata, Q. ellipsoidalis, Q. emoryi, Q. engelmannii, Q. falcata, Q. fusiformis, Q. gambelii, Q. garryana, Q. geminata, Q. georgiana, Q. graciliformis, Q. gravesii, Q. grisea, Q. havardii, Q. hemisphaerica, Q. hinckleyi, Q. hypoleucoides, Q. ilicifolia, Q. imbricaria, Q. incana, Q. inopina, Q. intricata, Q. john-tuckeri, Q. kelloggii, Q. laceyi, Q. laevis, Q. laurifolia, Q. lobata, Q. lyrata, Q. macrocarpa, Q. margarettae, Q. marilandica, Q. michauxii, Q. minima, Q. mohriana, Q. montana, Q. muehlenbergii, Q. myrtifolia, Q. nigra, Q. oblongifolia, Q. oglethorpensis, Q. pacifica, Q. pagoda, Q. palmeri, Q. palustris, Q. phellos, Q. polymorpha, Q. prinoides, Q. pumila, Q. pungens, Q. robur, Q. robusta, Q. rubra, Q. rugosa, Q. sadleriana, Q. shumardii, Q. similis, Q. sinuata, Q. stellata, Q. tardifolia, Q. texana, Q. tomentella, Q. toumeyi, Q. turbinella, Q. vacciniifolia, Q. vaseyana, Q. velutina, Q. viminea, Q. wislizenii
Synonyms Q. virginiana var. eximea
Name authority Greene: Ill. W. Amer. Oaks 1: 33, plate 17. (1889) Miller: Gard. Dict. ed. 8, Quercus no. 16. (1768)
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