Monographs Details: Tabebuia orinocensis (Sandwith) A.H.Gentry
Authority: Maguire, Bassett. 1978. The botany of the Guayana Highland--part X. Mem. New York Bot. Gard. 29: 1-288.
Discussion:2. Tabebuia orinocensis (Sandwith) A. Gentry, comb et stat nov
Tabebuia insignis var orinocensis Sandw., Mem. N. Y. Bot. Gard. 9: 364. 1957. Type. Venezuela, Amazonas, Bassett Maguire et al 37701 (K, N Y, US).
Sandwith described this taxon as a mere variety of T. insignis with reservadon. He noted its sometimes pubescent smaller leaves or leaflets and its wider capsule and longer seed wings as distinguishing this plant from other variedes of T. insignis. I have studied this plant in the field and seen sixteen addidonal collecdons besides those cited by Sandwith. All his characters hold up and several addidonal disdnguishing characters exist. While I can discover no differences between the flowers of this plant and T. insignis, the inflorescences do differ: Inflorescences of T. insignis (all varieties) nearly always have several minute buds in addidon to large buds and flowers; minute buds are never present in flowering inflorescences of T. orinocensis. Tabebuia orinocensis flowers precociously while mostly deciduous and the flowers are always borne on leafless branches; evergreen T. insignis always has leaves on the flowering branches. The twigs of the two also differ: In T. orinocensis they are more slender when dried and have a conspicuously wrinkled surface while in T. insignis they are thicker and inconspicuously or not at all wrinkled. Finally the fruit of T. orinocensis is shorter as well as wider than that of T. insignis var insignis (T. insignis var monophylla also has a relatively short fruit). I deem these characters sufficient, in conjunction with its welldefined Central Orinoco range and laja outcrop habitat, to elevate T. orinocensis to specific rank.
Tabebuia orinocensis is one of the commonest and most characteristic species of the laja outcrops of the Central Orinoco region. Individual plants are somewhat variable in leaflet number and presence or absence of leaf pubescence but clearly constitute a single taxonomic entity. Although most plants are rather uniformly simple-leaved or 3-foliolate and consistently glabrous or puberulous, all combinations of these characters sometimes occur on a single plant and all forms were represented in every population examined.