Rusbya taxifolia Britton, Bull. Torrey Bot. Cl. 20: 68.  1893.  Type.  Bolivia.  Dept. La Paz:  Yungas, 1250 m, Rusby 2692 (holotype, NY;  isotype: US).

    Epiphytic shrub, branches swollen at the nodes and distinctly marked by leaf scars, glabrous;  bud scales subulate, persistent.  Leaves alternate, evergreen, coriaceous, crowded, linear-oblong, 20-30 x ca. 2 mm, base cuneate, apex rounded or slightly emarginate, glabrous, margin entire and slightly thickened;  venation 1-nerved, the midrib impressed above and plane beneath, continuing to apex;  petiole canaliculate, less than 1 mm long.  Inflorescences sparse, axillary, solitary, with 1 flower;  bracts at base of inflorescence inconspicuous, ovate, ciliate, ca. 0.6 x 0.2 mm;  pedicel 10-12 mm long;  bracteoles basal, deciduous, oblong-ovate, acute, ciliate, ca. 0.8 mm long.  Flowers 5-merous, without odor;  aestivation valvate;  calyx continuous with pedicel;  hypanthium obconical or campanulate, narrowly 5-angled, rugose, ca. 3 mm long;  limb suberect, ca. 2 mm long including lobes;  lobes elongate-triangular, ca. 1.5 x 1.3 mm, with prominent midnerve;  sinuses acute;  corolla cylindric-urceolate, 8-9 mm long and ca. 4 mm diam., narrowing to 2 mm diam. at throat, glabrous, the lobes reflexed, oblong, subacute, ca. 1.5 x 1 mm;  stamens 10, nearly equalling corolla, alternately unequal, ca. 7 mm and 7.2 mm long;  filaments distinct, alternately unequal, ca. 1.5 mm and 2.5 mm long, pubescent at margins, lacking spurs, shorter than anthers;  anthers alternately unequal, basifixed, without disintegration tissue;  thecae alternately unequal, ca. 3 mm and 2.7 mm long, smooth to very slightly granular;  tubules equal, ca. 3.4 mm long, broad, dehiscing by elongate clefts more than half the length;  pollen without viscin threads;  ovary inferior;  style filiform, nearly equalling corolla, ca. 7.5 mm long;  nectariferous disc not seen.  Fruit not seen.

    Distribution.  Endemic to Bolivia and known only from two collections.  Rare and endangered.