1. Harrisella porrecta (Reichenbach f.) Fawcett & Rendle, J. Bot. 47: 266. 1909.
Aeranthus porrectus Reichenbach f., Flora 48: 279. 1865; Campylocentrum porrectum (Reichenbach f.) Rolfe; Harrisella amesiana Cogniaux; H. uniflora H. Dietrich
Plants leafless, inconspicuous. Roots numerous, silvery gray-green, 0.25–1 mm diam., covering stems. Stems erect with a few reddish brown, scarious scales, to 15 mm. Inflorescences few to many, lax racemes or panicles arising through mass of roots, 2–5 cm; floral bracts less than 1 mm. Flowers pale yellow; dorsal sepal elliptic, obovate, 2–2.5 × 1.3 mm, apex obtuse to rounded; lateral sepals obliquely elliptic-ovate, 2–2.5 × 1–1.2 mm, apex obtuse to rounded; petals ovate, obtuse, clawed, slightly smaller than sepals; lip broadly ovate, concave, 2.7–4 mm, base with short, apically expanded, scrotiform spur 1 mm wide, margins involute, apex obtuse to rounded; disc with erect tubercle; column stout, 0.25 mm; ovary subsessile, 2 mm. Capsules reddish brown when mature, ovoid, 4.5–6 mm, sparsely verruculose.
Flowering Aug--Sep. On twigs of shrubs and small trees, swamps, mesic hardwood hammocks; 0--20 m; Fla.; Mexico; West Indies; Central America (El Salvador).
Four species have been recognized in Harrisella: H. porrecta, H. filiformis (Swartz) Cogniaux, H. monteverdi (Reichenbach f.) Cogniaux, and H. uniflora Dietrich (H. Dietrich 1982). Harrisella porrecta is sometimes confused with H. filiformis (e.g., N. L. Britton et al. [1923–] 1930, vol. , part 2); a comparison of the types clearly shows that they are distinct. Harrisella filiformis and H. monteverdi are synonymous and belong to the related genus Campylocentrum (J. D. Ackerman 1995). The Cuban H. uniflora appears to be a depauperate H. porrecta. Nonetheless, the genus may not be monotypic. Mexican populations of H. porrecta do have some distinctive features and may represent at least one additional species (N. M. Warford 1997).