Arcytophyllum lavarum K. Schum. ex Standl.

Arcytophyllum lavarum K. Schumann; (Donn. Smith, Enum. PI
Guat. 5: 36, as synonym. 1899) Standley, Contr. U. S. Nat.
Herb. 18: 127. 1916.
Mallostoma lavarum Donn. Smith, Enum. PI. Guat. 5: 36; hyponym. 1899.
Much branched rigid shrub, 1-2.5 dm. high, glabrous except upon the corollas, the branches dark brownish-gray, the branchlets sharply angulate, brown, densely leafy; stipules triangular or ovate, 1.5 mm. long or shorter, coriaceous, dentate or laciniate; leaf-blades broadly ovate or ovate-oblong, 4-6 mm. long, 2-3 mm. wide, abruptly contracted at the base into a very short petiole, rounded or very obtuse at the apex, lustrous above, paler beneath, the costa very broad and prominent beneath; flowers crowded in small dense terminal cymes, the pedicels stout, 2 mm. long or shorter; hypanthium at anthesis less than 1 mm. long; calyx-lobes broadly ovate, obtuse or acute, much longer than the hypanthium, with 1 or more setae between each pair; corolla salverform, 4-5 mm. long, glabrous outside, the tube thick, the lobes ovate, obtuse, shorter than the tube, whitevillous within; capsule subglobose, 1.5-2 mm. long, three fourths inferior; seeds about 0.8 mm. long, oval to orbicular, concavo-convex, coarsely punctate, black.
Type locality: On bare rock slopes at the summit of Chiriqui Volcano, Panama, at an altitude of 3,374 meters.
Distribution: Summits of the highest mountains of Costa Rica and Panama.