Quercus texana |
Quercus wislizenii |
|
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Nuttall's oak, Texas red oak |
interior live oak, Sierra live oak |
|
Habit | Trees, deciduous, to 25 m. Bark dark brown with flat ridges divided by shallow fissures. | Trees or shrubs, evergreen, to 22 m. Bark nearly black, deeply furrowed with broad scaly ridges. |
Twigs | red-brown to gray, 1.5-3(-3.5) mm diam., glabrous. |
brown to red-brown, 1.5-3 mm diam., glabrous or sparsely pubescent. |
Leaves | 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. |
blade circular to oblong, usually ovate, planar, 25-70 × 20-50 mm, base obtuse to cordate, margins entire or spinose with up to 16 awns, apex acute to rounded; surfaces abaxially and adaxially glabrous, veins little raised on either surface. |
Acorns | 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. |
biennial; cup deeply and narrowly cup-shaped or U-shaped, 9-19 mm high × 7-18 mm wide, covering 1/3-1/2(-2/3) nut, outer surface glabrous to sparsely puberulent, inner surface glabrous or pubescent on innermost 1/3, occasionally uniformly pubescent, scales acute, tips loose; nut narrowly conic or ovoid to narrowly oblong, 21-44 × 8-14 mm, glabrous, scar diam. 2.5-7.5 mm. |
Terminal | buds gray to gray-brown, ovoid, 3-7 mm, glabrous or with scales somewhat ciliate at apex. |
buds light chestnut brown to dark reddish brown, ovoid to conic, 3-9 mm, glabrous or with tuft of minute hairs at apex. |
2n | = 24. |
|
Quercus texana |
Quercus wislizenii |
|
Phenology | Flowering spring. | Flowering late spring. |
Habitat | Flood plains and bottomlands | Valleys, slopes, and sand chaparral |
Elevation | 0-200 m (0-700 ft) | 300-1900 m (1000-6200 ft) |
Distribution |
AL; AR; IL; KY; LA; MO; MS; TN; TX
|
CA
|
Discussion | 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.) |
Shrubs with oval leaves 25-38 mm and margins entire or deeply lobed-dentate may be treated as Quercus wislizenii var. frutescens. J. M. Tucker (1993) treated Q. parvula as a distinct species, distinguished from Q. wislizenii by its larger leaves (30-90 versus 20-50 mm), by the dull, olive-green, abaxial leaf surface (versus shiny, yellow-green), and by nuts that are abruptly tapered proximal to the middle (versus gradually tapered). Tucker recognized two varieties of Quercus parvula: Q. parvula var. parvula is a shrub of 1-3 m and Q. parvula var. shrevei is a tree less than 17 m. S. K. Langer (1993) recognized a third variety, Q. parvula var. tamalpaisensis,based on several small populations on or near Mount Tamalpais, differentiated primarily by having larger leaves (50-160 × 20-60 mm) with attenuate-dentate margins. Quercus wislizenii reportedly hybridizes with Q. agrifolia and Q. kelloggii (W. B. Brophy and D. R. Parnell 1974). (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. Lobatae |
Sibling taxa | ||
Synonyms | Q. nuttallii, Q. rubra var. texana, Q. shumardii var. texana | Q. parvula, Q. parvula var. shrevei, Q. parvula var. tamalpaisensis, Q. wislizenii var. frutescens |
Name authority | Buckley: Proc. Acad. Nat. Sci. Philadelphia 12: 444. (1860) | A. de Candolle: in A. P. de Candolle and A. L. P. de Candolle, Prodr. 16(2): 67. (1864) |
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