28. Quercus texana Buckley, Proc. Acad. Nat. Sci. Philadelphia. 12: 444. 1860.
Texas red oak, Nuttall's oak
Quercus nuttallii E. J. Palmer; Q. rubra Linnaeus var. texana (Buckley) Buckley
Trees , deciduous, to 25 m. Bark dark brown with flat ridges divided by shallow fissures. Twigs red-brown to gray, 1.5-3(-3.5) mm diam., glabrous. Terminal buds gray to gray-brown, ovoid, 3-7 mm, glabrous or with scales somewhat ciliate at apex. Leaves: petiole 20-50 mm, glabrous. Leaf 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 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.
Flowering spring. Flood plains and bottomlands; 0-200 m; Ala., Ark., Ill., Ky., La., Miss., Mo., Tenn., Tex.
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.