Lepanthes ibarrense Tobar & M.F.López, 2018

Tobar, Francisco, López, María Fernanda, Muñoz-Upegui, Dolly & Richter, Friederike, 2018, Two new species of Lepanthes (Pleurothallidinae; Orchidaceae) from Andean forest remnants in Ibarra, Ecuador, Phytotaxa 375 (3), pp. 221-228 : 222-224

Lepanthes ibarrense Tobar & M.F.López , sp. nov. ( Figs. 1A − G , 2A − C )

Type:— ECUADOR. Imbabura: Ibarra, El Sagrario, along the maintenance path of the drinking water system of La Carbonería , 3538 m, 00 35 ‘04” N, 78°59’ 4” W, Jul 2016, Tobar, Monge & Obando 1982 (holotype QCA, spirit; isotypes: HPUCESI, QCNE) .

This species is similar to L. zapatae Luer & Escobar (1994: 121) in its reduced petals with a small, rounded apicule, lip with lanceolate - oblong, papillose laminae, small, rounded appendix covered with white apical pubescence and triangular, long-attenuate, reflexed rostelum.

Epiphytic caespitose herbs up to 15 cm in height. Roots flexuous, terete, green with pink until the middle, turning white towards the apex, 0.7 mm in diameter. Rhizome inconspicuous. Stem erect to arcuate, 4.3 − 10.4 cm long, with 6 − 9 internodes, covered entirely by dark brown, puberulent, lepanthiform sheaths with a pubescent ostium on the margin, acuminate. Leaves purple or purple with green, concave 3.1 − 4.7 × 1.1 − 2.0 cm, ovate to elliptic, attenuate-acuminate and tridentate at the apex, base cuneate, contracted into a petiole 2 − 4 mm long. Inflorescence 1 − 9 per stem, shorter than the leaf, 1.8 − 3.4 cm long, growing under the leaf, racemose; peduncle filiform, surrounded at the base by a bract 3 mm long. Floral bracts sub-distichous, infundibuliform, ovate-oblong when flattened, with a small apicule. Ovary 3 mm long, ovoid, slightly arched with irregularly serrated or warty keels. Flowers ca. 15 × 6 mm; sepals reddish brown to reddish purple with yellow apex and veins, petals and lip orange to salmon turning yellow apically, petals with scattered, purple pubescence on the outer surface, column white with purple markings, anther yellowish white. Dorsal sepal glabrous, slightly concave, ovate, attenuate-acuminate, 3 − veined, carinate, 7.3 × 5.0 mm. Lateral sepals glabrous, connate in their basal third, obliquely oblong, divergent, acuminate, 2 − veined, carinate 7.7 × 3.0 mm. Petals ca. 0.8 × 1.2 mm, bilobate, with a small rounded apicule, sparsely papillose, upper lobe triangular-oblong, contracted near the apex, obtuse; lower lobe obliquely triangular-oblong, subacute to rounded. Lip bilobate, blade lanceolate-oblong, papillose, joined at the base, partially covering the column, divergent above the middle and overlapping apically below the column, truncate basally and apically rounded, 2.8 × 1.7 mm; base of the lip fused to the ventral part of the column, ending in a small, rounded reddish orange appendix with white apical pubescence. Column slightly arched, clavate, truncate apically. Pollinarium with two yellow pollinia, narrowly obovate, united basally with a round, drop-like viscidium. Stigma apical, broad, round, flat. Rostellum triangular, long-attenuate, reflexed.

Distribution and habitat: — Lepanthes ibarrense is known only from the type locality, a small remnant of evergreen montane forest (“bosque siempreverde montano alto del norte de la cordillera oriental de los Andes” (BsAn01); (Ministerio del Ambiente de Ecuador 2013) located east of Ibarra, in the foothills of the northern Andean Cordillera. This species is strictly epiphytic on the bases of trunks and lower branches of trees of Clethra sp. and Weinmannia sp. It grows sympatrically with other Lepanthes species, such as L. conchilabia Luer & Hirtz (1998: 102) , L. cyrtostele Luer & Hirtz (1998: 102-103) and L. obandoi Tobar & M.F.Lopez , the last described below.

Conservation status: —The species may eventually be found within the Cayambe-Coca National Park. However, so far only a small population of no more than six individuals is known from a restricted area less than 5 km 2. This species faces great pressure due to the advance of the agricultural frontier and extraction of wood mainly for firewood. These factors suggest that the species should be considered as threatened.

Eponymy: —Named after the city of Ibarra, in the surroundings of which is located the forest where the species was discovered.

Discussion: —This species is similar to L. zapatae from Colombia. The main differences are that L. zapatae has pink flowers with red veins (vs reddish brown to purple flowers with yellow veins), lip with narrowly oblong, minutely pubescent blades (vs. lanceolate-oblong, papillose), a tiny appendix (vs. small rounded) and a small apically obtuse rostellum (vs. prominent, triangular, long-attenuate).

Figures

FIGURE 1. Lepanthes ibarrense. (A). Habit. (B). Flower. (C). Dissected sepals and petals. (D). Dorsal view of the lip and column. (E). Dorsal view of the spread-out lip without the column. (F). Lateral view of the ovary, lip and column. (G). Polinarium. Drawn by F. Tobar from the holotype, Tobar et al. 1982.

FIGURE 2. Lepanthes ibarrense. (A). Plant growing in its natural habitat. (B). Front view of the flower. (C). Detail of bottom-side view. Photograph by F. Tobar from the plant that provide the holotype, Tobar et al. 1982.