Besleria silverstoneana O.L.Cortés, 2017

Cortés-Ceballos, Olga Lorena, Giraldo-Rodríguez, Andrés & Torres-Gonzalez, Alba Marina, 2017, Two new species of Besleria (Gesneriaceae) from the department of Valle del Cauca, Colombia, Phytotaxa 332 (2), pp. 181-188 : 185-187

Besleria silverstoneana O.L.Cortés , sp. nov., ( Figs. 2 , 3 E–H , 4 )

Type:— COLOMBIA Valle del Cauca: municipio Dagua, corregimiento San Bernardo, vía a Buenaventura, cordillera occidental, vertiente oriental, 03°30’52.0’’N, 76°37’ 27.8’’W, 1992 m, 2 March 2016, O. L. Cortés-Ceballos 259 with A. Giraldo-Rodríguez (holotype CUVC 67089!, isotypes COL! HUA! PSO! MO!).

This species differs from Besleria formosa in having 1–2-flowers (vs. flowers always solitary in B. formosa ), shorter pedicels, calyx lobes united only at the base (vs. united in the proximal half in B. formosa ) and ovate, acute, villous, entire, and unequal (vs. obovate, obtuse, sparsely strigose, crenate, and equal in B. formosa ); moreover, the flowers have pilose ovary and style, and complete annular disc (vs. ovary glabrous, style puberulous, and annular disc incomplete in B. formosa ).

Terrestrial shrub; stem erect, 1.5–2.5 m tall, terete, pubescent toward apex; branches arising from base or 10 cm above base, 0.6–3 cm diameter. Leaves opposite, decussate, members of each pair almost equal in length; petiole villous, 0.3–1 cm long; blades elliptic to oblanceolate, 4–11.5 × 1.5–3.7 cm, apex acuminate, base cuneate, margin entire, ciliate, 7–8 pairs of veins, glabrous on adaxial surface, villous along veins of abaxial surface. Inflorescence 1–2-flowered, axillary, peduncle obsolete or up to 1.2–1.5 cm long, villous, with a small bract at tip, 1–1.4 mm long; pedicel villous, 1.3–3 cm long. Calyx connate in lower 0.2–0.4 mm, lobes five, appressed to corolla, unequal, ovate, apex acuminate, margin entire and sometimes slightly serrate, ciliate, pale green, sometimes purple at base, villous on adaxial surface, pilose on abaxial surface, dorsal sepal longer than other sepals, 1.1–1.5 × 0.75–1.1 cm, other sepals 1–1.1 × 1.4–1.5 cm. Corolla orange, tube cylindrical, at angle of 45° relative to stem, ventricose ventrally, 1.7–2 cm long, constricted at throat and in the middle part, tube 5.8–6 mm wide at throat, 6.5–7 mm wide at ventricose portion, 5–6 mm wide at middle part, 5.5–5.7 mm wide at base, aperture 3.8–4 × 2.9–3 mm, slightly pilose to the apex on the outer surface, internally with glandular trichomes 1–1.7 mm long, becoming sparse toward base, limb with five unequal lobes, which are orbicular, erect or spreading, slightly pilose on the outer surface, margin ciliate and slightly revolute, three lobes two lateral and one ventral 6.4–6.5 × 6.4–6.5 mm, two dorsal lobes 3.9–4 × 3.9–4 mm. Stamens didynamous, staminode one, dorsal, filaments spiral, adnate to corolla, attached 3.3–3.5 mm above base, glabrous, anthers connivent. Ovary pilose, 2.6–2.7 × 3.9–4 mm, style pilose, 7–9 mm long, trichomes 3–6-celled, bilobed brown stigma. Disc annular, complete, glabrous. Fruit a fleshy berry, white at maturity, pilose to apex, calyx persistent.

Palynology: —Pollen grains triporate, subspheroidal (14.4–)16(–17.5) × (17–)18.5(–21) μm, P / E ratio approx. 0.86, radially symmetrical, isopolar, circular in polar view. Exine 0.9 μm thick. Pores 1.4 × 1.5 μm, apocolpe 14.7 μm long. Exine with perforate ornamentation ( Figs. 3 E–H ).

Distribution, habitat and phenology:—Known only from the type locality: Colombia, Valle del Cauca, municipio Dagua, corregimiento San Bernardo ( Fig. 4 ). Small patches of Andean forest of secondary succession, surrounded by constructions of rural housing. It grows on edge of the forest. Flowering from March to May, fruiting from April to June, according to the sampling done for this study.

Paratype:— COLOMBIA. Valle del Cauca: municipio Dagua, corregimiento San Bernardo, vía a Buenaventura , cordillera occidental, vertiente oriental, 03°30’52.0’’N, 76°37’27.8’’ W, 1992 m, 9 March 2013, A. Giraldo-Rodríguez 7961 ( HUQ!) ; loc. cit., 2 March 2016, O. L. Cortés-Ceballos 260 ( CUVC 67090 !, HUA!) .

Etymology:—The specific epithet is dedicated to Dr. Philip A. Silverstone-Sopkin, who has studied the flora of the department of Valle del Cauca, Colombia, for many years, and whose teaching has inspired many students to become botanists.

Figures

FIGURE 2. Besleria silverstoneana: A. habit; B. dorsal sepal; C. ventral sepal; D. lateral sepal; E. flower (front view); F. flower (lateral view); G. corolla inner view; H. gynoecium and disc annular. Drawn by Álvaro Vanegas.

FIGURE 3. Pollen micromorphology. A–D: Besleria physaloides. A. polar view; B. polar view (SEM); C. equatorial view (SEM); D. ornamentation (SEM). E–H: Besleria silverstoneana. E. polar view; F. polar view (SEM); G. equatorial view (SEM); H. ornamentation (SEM).

FIGURE 4. Geographical distribution of Besleria physaloides and Besleria silverstoneana in Valle del Cauca, Colombia.