Yerba Puerto Rico De Cueva

Gesneria citrina Urban

Gesneria citrina Urban, Symb. Ant. 1:477, 1900.—Britt. & Wils., Sci. Surv. P.R. & V.I. 6:205, 1925.

Subshrubs: stems woody at the base, pendent or decumbent, to 1 m long, 2–5 mm thick, bark of young stems reddish to brown, becoming brown to gray, glabrescent, apex slightly resinous, lenticels sometimes erumpent, elongated, white to brown; pith reddish; branches from the stem base, rarely in upper leaf axils, internodes 0.1–1.0 cm long, leaf scars swollen.

Leaves alternate, petiolate or sessile, persistent: petioles terete to subsulcate, 0–1.0 cm long, 1–2 mm in diameter, red to gray-brown, sparsely pubescent with glandular or eglandular trichomes or glabrous; blades obovate or spathulate, 1.2–5.9 cm long, 0.5–2.9 cm wide, coriaceous, plane, base cuneate, margin ciliate to glabrescent, serrate to dentate toward apex, apex acute to obtuse, adaxial surface dark green, glabrous, glossy, abaxial surface

lighter green, becoming white when dry, glabrous, occasionally with a few appressed trichomes along the midvein, glossy, veins sometimes reddish-brown, prominent, dried leaves with exfoliating epidermis.

Inflorescences 1– to 4 (-∞)-flowered: peduncles very short, 1–2 mm long, flattened to terete, about 1 mm wide, red, glandular-pubescent, occasionally resinous; bracts 2–4, linear, 1–3 mm long, less than 1 mm wide, red, resinous; pedicels terete, arcuate, 2.8–6.3 cm long, about 1 mm in diameter, red, sparsely pilose; floral tube shortly turbinate, 2 mm long, 2–3 mm in diameter at anthesis, green to red, sparsely pilose to glabrous, resinous; calyx lobes 5, connate for 1–2 mm at base, each narrowly triangular, 2–3 mm long, 1.0–1.5 mm wide at the base, apex acute to acuminate, reddish or green, sparsely pilose, veins 3, prominent, inner surface with short glandular trichomes; corolla tube, curved, nearly cylindrical, 1.6–2.1 cm long, 3 mm wide at the sometimes reddish base, widening to 7 mm at the slightly (Figure 16i) ventricose middle, then narrower toward the oblique mouth where 5 mm wide, outside orange-yellow to bright yellow, densely puberulent, inside lighter yellow, glabrous, limb 5-lobed, erect, each lobe semiorbiculate, glabrous, yellow or sometimes reddish, margin subentire, often ciliate, upper lobes 1 mm long, 2 mm

wide, lateral lobes 3 mm long, 2.5 mm wide, basal lobe 2.5 mm long, 2.5 mm wide; stamens 4, adnate to the base of the corolla tube for less than 1 mm, not exserted, filaments linear, straight, 1.6–1.9 cm long, less than 1 mm in diameter, yellow or white, glabrous, anthers rectangular, 1.5 mm long, 1 mm wide, yellow to red on back, coherent in two pairs by their apices, pollen grains isopolar, with size small to medium (18.8–25.6 μm long at the polar axis, 12.3–16.0 μm wide at the equatorial axis), with a nearly circular amb, tricolpate, colpi 20 μm long, less than 1 μm wide, apocolpia rounded to acute, prolate, sexine reticulate, heterobrochate, lumina 0.1–1.0 μm across, larger near the equatorial axis, muri about 0.5 μm across; ovary inferior, disc annular, 1.5 mm long, green, puberulent with glandular trichomes, style straight except curved at apex, to 2.3 cm long, white, glabrous, stigma clavate, papillate.

Capsule broadly turbinate, becoming a splash cup, 3–5 mm long, ca 6 mm in diameter, gray-brown, glabrescent, glossy, costae 5–10, prominent; seeds narrowly fusiform, less than 1 mm long, tawny.

TYPE-COLLECTION.—Prope Utuado, Puerto Rico, P. Sintenis 6590 (S, lectotype, Figure 53b; BM, BP, BR, C, E, F, G, GH, GOET, K, L, LD, M, MO, NY, P, UCWI, US, W, Z, isolectotypes).

CHROMOSOME NUMBER.—n = 14 (Lee, 1966).

DISTRIBUTION AND ECOLOGY.—Known from limestone cliffs in the hills of north-central Puerto Rico (Figure 55) at about 200–325 m elevation, Gesneria citrina has been collected in flower during the months of February, March, May, August to November in the field. In the greenhouse it flowers in May and October. The corolla tube appears to be adapted for pollination by hummingbirds (Chlorostilbon maugaeus or Orthorhynchus cristatus).

SPECIMENS EXAMINED.—PUERTO RICO: Quebradillas, 22 November 1913, F. Stevens & W. Hess 5163 (NY); Lares, 325 m, 24 October 1943, F. Sargent 3235 (US); near the Arecibo Ionospheric Observatory on P. R. Hwy 625 about 15 km S of Arecibo, 27 August 1970, L. Skog & J. Skog 1716 (BH, E, K, US); Esperanza, ⅜ mi along path toward the left just before the entrance to Cornell Radar in Esperanza south of Arecibo, ca 800 ft, 12 February 1965, T. Talpey 28 (BH, US); Arecibo radar station, 27 February 1965, T. Talpey 41 (BH, US); cliffs, Arecibo, 31 May 1935, F. Sargent 703 (US); base of cliff between Arecibo and Utuado, 8 February 1924, N. Britton & E. Britton 7976 (GH, NY, PH, US); prope Utuado in sylva primaeva montis Cerro Hueco ad Cayuco, 25 March 1887, P. Sintenis 6590 (S, lectotype of Gesneria citrina Urban; BM, BP, BR, C, E, F 2 sheets, G 5 sheets, GH GOET, K, L, LD, M, MO, NY, P, UCWI, US, W, Z, isolectotypes); Barceloneta, S of Florida, 250 m, 23 August 1963, H. McKee 10616 (K, P, US); near Florida on route 140, 27 September 1967, R. Wagner 1233 (A); Río Piedras, Ciales, 17 August

1903, J. Johnston 974 (NY, US). LOCALITY UNKNOWN: Río Arriba, Forest Reserve, I. Velez 1606 (NY). CULTIVATED: Cornell University, G-888, 5 October 1969, L. Skog 1408 (BH), 23 May 1966, M. Stone 130 (BH).