Xyris witsenioides

Primary tabs

Xyris witsenioides


Densely cespitose, smooth perennial, (12-)20-60 cm high; stems elongate-ascending, much-branched from base, branches enfolded by tightly imbricate rows of leaves and old sheath bases, forming stiff plates (the whole forming dense domes or cushions). Leaves mostly ascending, 5-20 cm, sheath eciliate, fully as long as blade, keeled, mostly castaneous, apically with a triangularerect ligule of 1-2 mm, blade flattened, 1-3(-4) mm wide, sometimes falciform, margin thin, smooth or scaberulous-papillose, rarely ciliolate, surface finely but strongly multiveined surface. Scapes distally subterete to slightly compressed and oval or oblong-elliptic, 0.7-1 mm wide, ribless or with 1 (-2 or more) ribs, these smooth or scaberulous (rarely ciliolate); spikes ellipsoid to obovoid, 0.7-1.4 cm long, olive-brown or red-brown, bracts in a spiral, thin, without evident dorsal area, several empty ones, the lowest small, grading into flowering ones, these oblong to obovate, low-carinate and rounded at apex, lacerate with age. Lateral sepals free, subequilateral, ca. 5-7 mm, obtuse, keel subentire to ciliate, lacerate with age; petals broadly obovate to suborbicular, 3-6 mm; staminodes bearded; anthers 1.5-1.7 mm. Capsule 3.5-4 mm, placentation axile, valves with complete septa; seeds fusiform, ca. 1-1.3 mm, amber.


Bolivar present, S Amazonas present, SE Guyana present, Southern America: Venezuela (Venezuela present), contiguous high-altitude Brazil present
S Amazonas and Bolivar, Venezuela E to SE Guyana and in contiguous high-altitude Brazil.


F. Oliver 1887: p. 285. – In: Trans. Linn. Soc. London: pl. 50, fig. 915


Perhaps the most distinctive of the Guiana Xyris in habit, on the basis of placentation and leaf appearing to be one of the primitive mem- bers and part of a complex of species best represented along the tepuis of southern Venezuela.