Tabebuia orinocensis (Sandwith) A.H.Gentry
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Authority
Gentry, Alwyn H. 1992. Bignoniaceae--part II (Tribe Tecomeae). Fl. Neotrop. Monogr. 25: 1-370. (Published by NYBG Press)
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Family
Bignoniaceae
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Scientific Name
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Type
Type. Venezuela. Amazonas, Maguire et al. 37701 (holotype, K; isotypes, NY, US).
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Synonyms
Tabebuia insignis var. orinocensis Sandwith, Tabebuia cassinoides (Lam.) DC.
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Description
Species Description - Shrub or small tree to 8 m tall, the branchlets subterete, the surface wrinkled and somewhat angulate when dry. Leaves simple (rarely 3-foliolate in part), narrowly elliptic, the apex acute to obtuse or retuse, the base cuneate to rounded, 3-10 cm long, 1-3.4 cm wide, entire, subcoriaceous, conspicuously lepidote above and below, sometimes pilose below and along the main veins above; petiole 0.5-2 cm long, lepidote or lepidote and puberulous. Inflorescence usually a more or less terminal cyme of 2-4 flowers, the peduncle and pedicels lepidote, without young buds ccompanying the adult flowers. Flowers with campanulate calyx, irregularly 2-3-labiate, 12-17 mm long, 8-11 mm wide, lepidote, eglandular; corolla white, tubular-infundibuliform, glabrous outside, usually with scattered lepidote scales, the lobes ciliate, densely glandular-lepidote inside, scurfy puberulous in the throat, pubescent at the stamen insertion; stamens didynamous, the thecae divaricate; ovary linear-oblong, 5 mm long, 1 mm wide, lepidote; disk pulvinate. Fruit a linear-oblong capsule, subterete, acuminate, the calyx persistent, 8-14(-16) cm long, 1.3-2 cm wide, conspicuously lepidote; seeds thin, bialate, 1.4-1.7 cm long, 3.5-4 cm wide, the wings hyaline-membranaceous, sharply demarcated from the seed body.
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Discussion
Locally extremely abundant in its specialized habitat, which it shares with T. pilosa and T. uleana. Tabebuia orinocensis tends to grow in cracks in the bare laja rock or in the smallest soil pockets, while the other two species occur in larger soil accumulations. This species is closely related to T. insignis, differing in a wider capsule, longer seed wings, sometimes pubescent leaves, flowering inflorescences lacking additional minute buds, precocious flowering, and more slender dried twigs with a conspicuously wrinkled surface. Tabebuia orinocensis is somewhat variable in leaflet number and pubescence. Most individual plants are rather uniformly simple-leaved or 3-foliolate and glabrous or puberulous but all combinations of these characters sometimes occur on a single plant and all forms were represented in every population studied.
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Distribution
Endemic to the laja outcrops of the central Orinoco region around Puerto Ayacucho, Venezuela, and adjacent Colombia; 50-200 m elevation.
Colombia South America| Vichada Colombia South America| Venezuela South America| Amazonas Venezuela South America| Apure Venezuela South America| Bolívar Venezuela South America|