This is virtually unknown east of the Mississippi River, except in s. Ill. and sw. Ind., where it may intergrade with pallida (FNA 3). There are erroneous reports from Ky., apparently based on misidentified pallida, but a few colls. from CALL (MUR), HARD (KY), MCRA and elsewhere (M) do appear somewhat intermediate. C. texana differs in the more rusty-brown color of its peltate scales; also, its petioles and rachises are relatively glabrous, without concentrations of hairs near leaflet insertions, as found in pallida. These two species, plus C. myristicaeformis (Mich.f.) Ell. (and perhaps some C. floridana Sarg.) may form a natural group, with following differences from glabra and its close allies (W): well-developed leaves with 5-9 leaflets but mostly 7 (versus 3-7, rarely 9); lower surface of spring leaflets densely lepidote with 4-lobed, irregular, and round peltate scales, giving the undersurface a reflective, silvery-tan, rusty-brown, or bronze sheen (versus slightly to densely lepidote with irregular and round peltate scales, 4-lobed peltate scales uncommon or absent); buds up to 10 mm (versus 15 mm) and predominantly lepidote (versus predominantly pubescent or perhaps lepidote); nuts usually with narrow wings (versus usually none). However, it has been suggested that they originate from hybridization between subgenera Apocarya and Eucarya (perhaps as independant events), and that continued hybridization may blur boundaries between species in some cases; note also that keys vary much among major sources (e.g. FNA 3 versus W). From an initial molecular study with only one sample per species, it appears that diversification of Carya in North America has been relatively rapid, within the past 10 million years, and most indicated dichotomies remain poorly resolved (Zhang et al 2013).