FIGURE 119 Tetramerium nervosum Nees, in Benth. Bot. Voy. Sulph. 148, pl. 48. 1844. Type collected at Puna, near Guayaquil, Ecuador, by Sinclair. The specific epithet alludes to the strongly nerved bracts.  Blechum angustius Nees in DC. Prodr. 11: 467. 1847. Type collected at Cartagena, Department of Bolívar, Colombia, January-February 1826, by Billberg (No. 1) (Isotype S). Cf. Leonard, Contr. U. S. Nat. Herb. 31: 63. 1951.
Branched suffrutescent herbs up to 1 meter high, the branches spreading, slender; stems subterete, pubescent to glabrate, the hairs white, spreading, up to 1 mm. long but usually shorter, sometimes disposed in two rows, the younger portions of the stems bearing numerous subpunctiform cystoliths, the bark, with age, separating into thin strips or shreds; leaf blades ovate, up to 6 cm. long and 3 cm. wide, acute to acuminate (the tip itself obtuse or acute, some- times subapiculate), subcordate or rounded at base, the upper surface sparingly hirsute with ascending straight or curved hairs about 0.5 mm. long, the costa and veins (4 or 5 pairs) rather prominent and more or less puberulous with minute appressed hairs, the lower surface sparingly hirsute to glabrate; petioles slender, up to 2.5 cm. long, pilose (the hairs spreading, up to 1 mm. long) or the channel puber- ulous; spikes terminal, up to 20 cm. long or more, 2 cm. broad, the rachis densely hirsute to glabrate; bracts rotund-ovate to ovate, up to 12 mm. long and 9 mm. wide, short-acuminate and cuspidate (the tip more or less recurved, the cusp 0.5 to 1 mm. long), rounded or abruptly contracted below the middle to a subpetiolate base, sparingly hispid- ulous, the smaller hairs intermixed with white spreading or ascending ones up to 2 mm. long, the margins strongly hispid-ciliate, the hairs jointed, white, up to 2.5 mm. long, the costa and 2 pairs of lateral veins prominent; bractlets narrowly lanceolate, about 2 mm. long and 0.5 mm. wide at base, acuminate, hispid-ciliate; calyx lobes 4, linear- lanceolate, 2 to 3 mm. long, 0.5 mm. wide at base; corolla white or purplish white, 10 mm. long, essentially glabrous, the lips about 5.5 mm. long, the upper one oblong-obovate and emarginate, the lower lip 3-lobed, the lobes oblong-obvate, 5 to 5.5 mm. long and 1.8 mm. wide, rounded at tip; capsules clavate, 5 mm. long, 1.8 mm. broad, 1.5 mm. thick, minutely hirsute, the narrowed base about 2 mm. long; seeds 4, whitish to dark brown, flattened, 1.5 mm. long and 1.2 mm. broad, strongly papillose.
Plants of this species are variable in aspect. During the earlier stages they are leafy, the bark firm, and the spikes moderately long, varying from 2 to 5 cm. in length. With age the leaves usually drop, the spikes often elongate, and the bark parts from the stem in thin shreds.
Partial to thickets or open hillsides either in dry or damp situations. Limited apparently to low altitudes. Central America to northern South America.
BOLÍVAR: La Popa, Billberg 1 (8). San Lázaro, Billberg s. n. (8). Sincé, Pennell 4026 (GH, US).
Bonda, H. H. Smith 1408 La Paz, Haught 3931 (US).
MAGDALENA: Barro Blanco, Haught 4760 (US). (GH, Ph, NY, S, US). Gaira, H. H. Smith (NY). Playa Brava, H. H. Smith 1973 (GH, Ph, NY, US). SANTANDER: Bucaramanga, Araque & Barkley 188.316 (US), 18S.321 (US).