31. ROENTGENIA Urb., Ber. Deutsch. Bot. Ges. 34: 747. 1916.

Lianas, the branchlets terete to subtetragonal, without interpetiolar glandular fields; pseudostipules minutely foliaceous or absent. Leaves 2-foliolate, sometimes with a minutely trifid tendril. Inflorescence a racemose panicle or a terminal or axillary raceme. Calyx cupular, subtruncate to slightly lobed, ± lepidote; corolla white with purple splotches or lines inside throat, tubular-funnel-shaped, lepidote outside. Anthers glabrous, the thecae straight, divaricate. Ovary linear-oblong, lepidote; ovules 2-seriate in each locule. Fruit a linear capsule, strongly flattened, the valves parallel to the septum, the midline inconspicuous. Seeds flat, 2-winged, the wings thin, brownish, inconspicuously demarcated from seed body.

Venezuela, Guyana, Suriname, French Guiana, Amazonian Brazil; 2 species, 1 in Venezuela.

Roentgenia sordida (Bureau & K. Schum.) Sprague & Sandwith, Bull. Misc. Inform. 1932: 91. 1932. -Arrabidaea sordida Bureau & K. Schum. in Mart., Fl. Bras. 8(2): 30. 1896.

Liana. Nonflooded evergreen lowland forests, 100-200 m; Delta Amacuro (Serranía de Imataca), Bolívar (lower Río Caura, lower Río Paragua). Guyana, Suriname, French Guiana, Amazonian Brazil. Fig. 409.

This species looks rather like Cydista but differs in having a minutely trifid tendril and nectariferous disk.


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