Flora of North America species comparison

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Quercus pacifica

Quercus virginiana

Channel Island scrub oak, island scrub oak, Pacific oak

live oak, southern live oak
Habit Shrubs, rarely small trees, subevergreen, shrubs to 2 m, trees to 5 m or taller. Trees, sometimes shrubs, subevergreen, trees to 35 m, shrubs sometimes rhizomatous.
Bark

scaly on older branches and trunk.

dark brown or black, scaly.
Twigs

brownish or reddish, minutely puberulent, becoming glabrate and gray with age.

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

light or chestnut brown, ovate or globose, 2-3 × 1-2 mm.

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

scale margins glabrous or puberulent.
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 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

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.

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

distinct.

connate.

Quercus pacifica

Quercus virginiana
Phenology Flowering spring. Flowering late winter–early spring.
Habitat Chaparral, oak woodlands, margins of grasslands, understory in closed-cone pine stands Coastal plain, open evergreen woodlands, scrublands, and hummocks on loam, clay, and rarely on sand on immediate coast
Elevation 0-300 m (0-1000 ft) 0-200 m (0-700 ft)
Distribution
from FNA
CA
[WildflowerSearch map]
[BONAP county map]
from FNA
AL; FL; GA; LA; MS; NC; SC; TX; VA
[WildflowerSearch map]
[BONAP county map]
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 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. 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. 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. dumosa var. polycarpa Q. virginiana var. eximea
Name authority Nixon & C. H. Muller: Novon 4: 391. (1994) Miller: Gard. Dict. ed. 8, Quercus no. 16. (1768)
Web links 
Unless otherwise noted, all data comes from the online version of the Flora of North America, who have made most of their content available via a Creative Commons license (CC BY 4.0).



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