Flora of North America species comparison

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Quercus fusiformis

Quercus texana

escarpment live oak, live oak, plateau oak, Texas live oak

Nuttall's oak, Texas red oak
Habit Trees, sometimes shrubs, subevergreen, trees to 25 m, shrubs often forming large clonal stands. Trees, deciduous, to 25 m. Bark dark brown with flat ridges divided by shallow fissures.
Bark

dark brown or black, scaly.

Twigs

light gray, 1.5-3 mm diam., tomentulose, tomentulum often persistent in age.

red-brown to gray, 1.5-3(-3.5) mm diam., glabrous.
Buds

reddish or dark brown, subglobose or ovate, 1.5-3 mm;

scale margins glabrous or puberulent.

Leaves

blade oblong-elliptic to narrowly ovate or lanceolate, sometimes obovate, ± planar, (10-)35-90(-150) × (15-)20-40(-85) mm, base rounded to truncate or cordate, rarely cuneate, margins minutely revolute or flat, entire or irregularly 1-3 toothed on each side, teeth mucronate (rarely spinose in suckers or juveniles), secondary veins obscure, 8-10 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.

blade ovate to elliptic or obovate, 75-200 × 55-130 mm, base cuneate to almost truncate, often inequilateral, margins with 6-11 lobes and 9-24 awns, lobes oblong to distally expanded, rarely falcate, apex acute;

surfaces abaxially glabrous except for conspicuous axillary tufts of tomentum, veins raised, adaxially planar, glabrous.
Acorns

1-3, on peduncle 3-30 mm;

cup funnel-shaped, hemispheric, or deeply goblet-shaped, 8-15 mm deep × 6-12(-15) mm wide, base often constricted, scales whitish or grayish, thickened basally, keeled, acute-attenuate, tomentulose, tips reddish, glabrous or puberulent;

nut dark brown, often with light brown longitudinal stripes, subfusiform and acute to narrowly barrel-shaped, rarely distally rounded, (17-)20-30(-33) × 8-15 mm, glabrous.

biennial;

cup thin (scale bases visible on inner surface), deeply goblet-shaped with pronounced constriction at base, 10-16 mm high × 15-22 mm wide, covering 1/3-1/2 nut, outer surface glabrous to sparsely puberulent, inner surface sparsely to uniformly pubescent, scale tips appressed, acute;

nut broadly ovoid to broadly ellipsoid, 15-26 × 13-18 mm, glabrous or sparsely puberulent, scar diam. 8-13 mm, scar often orangish.
Cotyledons

connate.

Terminal

buds gray to gray-brown, ovoid, 3-7 mm, glabrous or with scales somewhat ciliate at apex.

Quercus fusiformis

Quercus texana
Phenology Flowering spring. Flowering spring.
Habitat Hills, grasslands, scrublands, open woodlands, oak-juniper woodland, and margins of thorn scrub, often on limestone or deep calcareous loams, sometimes on granular sand or gravel Flood plains and bottomlands
Elevation 0-1200 m (0-3900 ft) 0-200 m (0-700 ft)
Distribution
from FNA
OK; TX; Mexico (Coahuila, Nuevo León, and Tamaulipas)
[WildflowerSearch map]
[BONAP county map]
from FNA
AL; AR; IL; KY; LA; MO; MS; TN; TX
[WildflowerSearch map]
[BONAP county map]
Discussion

The difficulty in distinguishing Texas populations of Quercus fusiformis from Q. virginiana is reflected in a variety of taxonomic treatments, including reducing Q. fusiformis to varietal rank under Q. virginiana. The latter disposition is problematic, however, because Q. fusiformis in northeastern Mexico is amply distinct from Q. virginiana and appears to be more closely related to Q. brandegei Goldmann, an endemic of Baja California, Mexico. Thus, here we assume that the intergradation of Q. virginiana and Q. fusiformis is a result of secondary contact, and is not primary clinal variation. Under this interpretation, Q. virginiana in typical form extends into Texas only as far west as the Brazos River drainage along the coast from there to the escarpment of the Edwards Plateau; most populations elsewhere are either intermediate between the two species or show greater affinity with Q. fusiformis. On the Edwards Plateau, the live oak populations are small trees forming rhizomatous copses (shinneries) and having mostly acute acorns.

Populations of live oak on deep sands in south Texas differ from typical Quercus fusiformis in having broader, more rounded leaves, often with the secondary veins somewhat impressed abaxially, and relatively blunt, barrel-shaped acorns. These characteristics suggest introgresion from the Mexican-Central American species Q. oleoides Schlechtendal & Chamisso, which in its typical form reaches north only as far as southern Tamaulipas, Mexico. The name Q. oleoides var. quaterna C. H. Muller has been applied to what is apparently a shrub form of one of these Q. fusiformis × Q. oleoides hybrids.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

For many years the name Quercus texana was erroneously used for Q. buckleyi (L. J. Dorr and K. C. Nixon 1985). A few authors have also used the name for Q. gravesii.

Quercus nuttallii E. J. Palmer var. cachensis E. J. Palmer was described as a small-fruited form (nuts 16-18 × 12-16 mm) from specimens collected in east-central Arkansas (E. J. Palmer 1937). Noting the similarity between Q. nuttallii var. cachensis and Q. palustris, Palmer discounted the possibility of the former being of hybrid origin because (1) he had not observed Q. palustris in the type locality, and (2) the leaves and buds of the former were essentially the same as in Q. nuttallii var. nuttallii.

C. H. Muller (1942), on the other hand, argued that Quercus nuttallii was nothing more than a form [forma nuttallii (E. J. Palmer) C. H. Muller] of Q. palustris. This is a puzzling conclusion because it was based largely on the premise that Q. nuttallii occurred "...with the parent species throughout a large part of the latter's southern range (Mississippi to eastern Texas and southeastern Missouri)." The range of Q. palustris does not extend into Mississippi or eastern Texas, although its range does overlap that of Q. texana in eastern Arkansas and southeastern Missouri. E. J. Palmer (1948) and D. M. Hunt (1989) have suggested hybridization with Q. shumardii and Q. nigra, respectively. See L. J. Dorr and K. C. Nixon (1985) for an explanation of the nomenclatural confusion regarding this taxon.

(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
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. 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. tomentella, Q. toumeyi, Q. turbinella, Q. vacciniifolia, Q. vaseyana, Q. velutina, Q. viminea, Q. virginiana, Q. wislizenii
Synonyms Q. virginiana var. fusiformis Q. nuttallii, Q. rubra var. texana, Q. shumardii var. texana
Name authority Small: Bull. Torrey Bot. Club 28: 357. (1901) Buckley: Proc. Acad. Nat. Sci. Philadelphia 12: 444. (1860)
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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