Lepanthes pembertonii S.Vieira-Uribe & J.S.Moreno, 2022

Vieira-Uribe, Sebastián, Moreno, Juan Sebastián & Espinosa, Felipe, 2022, Two new species of Lepanthes (Pleurothallidinae, Orchidaceae) from the Alto de Ventanas, Colombia, Phytotaxa 567 (2), pp. 149-161 : 151-154

Lepanthes pembertonii S.Vieira-Uribe & J.S.Moreno , sp. nov. ( Figures 1–3 )

Type: — COLOMBIA. Antioquia: Municipio de Valdivia, Reserva Natural La Esperanza , 2160 m, 2 August 2017, S. Vieira 29 (holotype JAUM-Spirit!) .

Lepanthes pembertonii is most similar to L. viahoensis Luer & R.Escobar (1997: 311) , both vegetatively and in the flowers, but L. pembertonii is easily differentiated in having petals with the upper lobe narrowly triangular (vs. obliquely triangular), the lower lobe triangular (vs. oblong, oblique at the apex) and the lip transversely bilobed with flabellate lobes and with an oblong, recurved, pubescent appendix in the sinus (vs. subcordate lip with the apex broadly rounded, shortly incised, with a microscopic lobule in the sinus).

Description:— Plant epiphytic, sympodial, caespitose, sub-erect, up to 28 mm tall. Roots slender, flexuous, filiform, ca. 0.6 mm in diameter. Ramicauls slender, erect, up to 23 mm long, enclosed by 6–7 brownish, ribbed, tightly adpressed lepanthiform sheaths, the ribs and the dilated margins papillose, acuminate. Leaves abaxially purple, thickly coriaceous, narrowly ovate, with one main central vein, the apex acute, incised and tri-apiculate, up to 21.0 × 4.8 mm, the obtuse base narrowing into a petiole ca. 1 mm long. Inflorescence a congested, distichous, successively many flowered raceme up to 7 mm long, appressed to the abaxial surface of the leaf by a filiform peduncle up to 4 mm long. Floral bracts ovate, acute, covered with filiform papillae, ca. 0.7 mm long; pedicel 0.9 mm long. Ovary terete, costate, erose, ca. 0.7 mm long. Flowers with the sepals semi-hyaline, primrose, suffused with crimson near the base, petals crimson with saffron margins, lip vermilion, column magenta with a white rostellum. Sepals membranaceous, fully spread, carinate along the veins on the abaxial surface. Dorsal sepal ovate, repand, acute, 3-veined, 2.4 × 1.2 mm, connate to the lateral sepals for ca. 0.3 mm. Lateral sepals broadly ovate, oblique, crenulate, attenuate, 2-veined, 1.9 × 1.4 mm, connate for ca. 0.4 mm. Petals transversely bilobed, puberulous, 0.6 × 2.7 mm, 1-veined, with a minute rounded marginal mid-lobe, the upper lobe narrowly triangular, rounded, 1.8 mm long; the lower lobe triangular, rounded, 0.9 mm long, approximately ½ the length of the upper lobe. Lip puberulous, transversely bilobed, 0.8 × 1.1 mm when expanded, the lobes flabellate with rounded ends, with thickened external margins, erect on both sides of the column, the sub-quadrate body deeply concave, with a marginal oblong, recurved, white, pubescent appendix in the middle; adnate to the base of the column. Column obconical, 0.9 mm long, microscopically bullate, the anther apical, the stigma apical, with a minutely fimbriate rostellum. Pollinia 2, yellow, obovoid, attached to a detachable viscidium. Anther cap cucullate, white, suffused with magenta. Capsule not seen.

Distribution & Ecology: — Lepanthes pembertonii is only known from a small area in the north of the central Andes of Colombia. The type specimen was found with a few more plants of the same species growing on a single thin, moss-covered branch hanging 1.5 meters above the water of a small creek, inside a primary forest in La Esperanza Natural Reserve. This area, covered by Tropical Premontane Rainforest is particularly abundant in diversity of species of the genus Lepanthes . La Esperanza Natural Reserve is located in a very biodiverse region in the north of the central Andes of Colombia known as “Alto de Ventanas”, in the municipality of Valvidia in the Antioquia department.

Etymology: —Named to honor Robert W. Pemberton, Entomologist/Botanist, and generous donor to the expansion of the natural reserve that protects the habitat of the new species.

Taxonomic Discussion:— Lepanthes pembertonii , is both vegetatively and florally similar to L. anchicayae J.S.Moreno & S. Vieira-Uribe (2020: 100) , L. petalopteryx Luer & R.Escobar (1994:106) and L. viahoensis , all of them with small plants bearing narrowly ovate, thickly coriaceous leaves and minuscule flowers that open below the leaf blade and have membranaceous yellowish sepals, erect, puberulous petals and a blade-less, puberulous, transversely bilobed lip with the lobes erect and surrounding the column ( Figure 3 , Table 1 ).

From Lepanthes anchicayae ( Figure 3A ), it is easily separated by the narrowly triangular upper lobes of the petals (vs. ovate, oblique, with a second point midway on the inner margin) and the lip with flabellate lobes (vs. cuneate) with an oblong, recurved and pubescent appendix in the sinus (vs. no appendix). From Lepanthes petalopteryx ( Figure 3C ), it is differentiated by the leaves abaxially purple (vs. green), the petals with triangular lobes, the lower one ½ the length of the upper one (vs. equally sized lobes that are obliquely subquadrate or oblong, obliquely truncate with the inner angles shortly acuminate-obtuse, the outer angles subacute) and the lip with flabellate lobes (vs. reniform lip) with an oblong, recurved, pubescent appendix (vs. no appendix). Finally, from Lepanthes viahoensis ( Figure 3D ), the most similar species both, in plant and flower color and morphology, it is separated by having the petals with the upper lobe narrowly triangular (vs. obliquely triangular), the lower lobe triangular (vs. oblong, oblique at the apex) and the lip transversely bilobed with flabellate lobes (vs. subcordate lip) with an oblong, recurved, pubescent appendix in the sinus of the body (vs. no lip body, and a microscopic lobule in the sinus). Table 1 shows a comparative summary of differences between Lepanthes pembertonii and the already mentioned similar species.

Figures

FIGURE 1. Drawing of Lepanthes pembertonii. A. Habit. B. Flower. C. Dissected perianth. D. Lip expanded. E. Ovary, column and lip, dorsal and lateral views. Drawn by S.Vieira-Uribe from the plant that served as type.

FIGURE 2. Photos of Lepanthes pembertonii. A. Plant in habitat.B. Plant in habitat as viewed from the underside. C. Flower.Photographs by S.Vieira-Uribe from the plant that served as type.

FIGURE 3. Comparison of the flower of Lepanthes pembertonii with similar species. A. L. anchicayae. B. L. pembertonii. C. L. petalopteryx. D. L. viahoensis. Photographs by J.S. Moreno (A) and S. Vieira-Uribe (B,C,D).