Lepanthes oro-lojaensis Tobar & M.F.Lopez, 2021

Suarez, Francisco Tobar, Lopez, Maria Fernanda, Gavilanes, Maria Jose, Monteros, Marco Federico, Garcia, Tatiana Santander & Graham, Catherine Helen, 2021, Three new endemic species of Lepanthes (Orchidaceae, Pleurothallidinae) from the highlands of Ecuador, PhytoKeys 180, pp. 111-132 : 111

Lepanthes oro-lojaensis Tobar & M.F.Lopez sp. nov.

Figs 1 , 2 , 3a

Diagnosis.

This species is similar to Lepanthes jimburae Luer & Hirtz, but can be distinguished by the smaller plants that are less than 3 cm tall (vs. up to 4 cm tall); the shorter inflorescence that is less than 4 cm long (vs. inflorescence up to 10 cm long), the shorter dorsal sepal with a shorter sepaline tail (6.0 mm vs. 9.0 mm long), the apical lobe of the petals ovate and lower lobe triangular-oblong (vs. petals with subequal, obliquely triangular, acute lobes).

Type.

Ecuador. El Oro, Zaruma, Salvias, near Cerro de Arcos , - 3.06963333°N, - 79.478944°W, 3500 m, 28 Aug 2015, Tobar, Gálvez & Obando 1648 (holotype: QCNE; isotype: QCA) .

Epiphytic, caespitose herbs up to 3 cm tall. Roots flexuous, cylindrical 0.7 mm in diameter. Rhizome inconspicuous. Ramicaul arcuate to pendulous, 0.9-1.9 × 0.1-0.3 cm long, with 3-4 internodes, covered entirely by light brown minutely puberulent lepanthiform sheaths with a minutely pubescent, acuminate ostium. Leaves dark-green suffused with purple, arcuate 1.0-1.3 × 0.4-0.6 cm, coriaceous, elliptic, subacute to obtuse, tridentate at the apex, base cuneate, contracted into a petiole 2-4 mm long. Inflorescence racemose, one per stem, longer than the leaf, 2.0- 3.5 cm long, flexuous, producing 3-16 widely spaced, successively opening flowers; peduncle filiform, 1-3 mm long, surrounded at the base by a bract 1.5 mm long. Floral bracts sub-distichous, infundibuliform, longapiculate. Ovary 1.5 mm long, obpyramidal, slightly arcuate, irregularly keeled. Flowers ca. 12 × 4 mm; dorsal sepal red with a yellow margin, lateral sepals yellow suffused with red around the middle vein; petals with the upper lobe red and the lower one yellow, lip reddish with yellow tips, column reddish, with white and red anther. Dorsal sepal glabrous, slightly concave, ovate, ending in a decurved cauda, 3-veined, 6.0 × 2.7 mm including the cauda. Lateral sepals glabrous, with minutely denticulate margins, connate on their basal one-third, ovate, caudate, 2-veined, 5.0 × 2.0 mm. Petals, bilobate, microscopically pubescent; apical lobe ovate, rounded, lower lobe triangular-oblong, acute, ca. 3.5 × 0.9 mm. Lip bi-laminate, blades ovate, convex, subacute at the base and rounded at the apex, microscopically pubescent, covering most of the column, ca. 1.8 × 0.7 mm; the base of the lip fused to the ventral part of the column, the connectives shortly cuneate, the sinus narrowly oblong with very small, triangular, microscopically pubescent appendix. Column claviform, arcuate, markedly broaden above the middle, truncate at the apex, ca. 1.6 × 0.8 mm. Pollinarium with two ovoid pollinia, with a round, drop-like viscidium. Anther dorsal, deltate. Stigma ventral, horseshoe-shaped. Rostellum minute, apiculate. Capsule globose, 4 × 3 mm.

Distribution and habitat.

Lepanthes oro-lojaensis is known from a single locality on the border between El Oro and Loja provinces (Fig. 4 ). The species was collected in a small patch of scrubs, growing on Berberis lutea Ruiz & Pav. (Fig. 5 ), which is a representative species of the evergreen forest formation (BsSn01) according to Ministerio del Ambiente del Ecuador (2013). This type of vegetation is found in sites protected from the wind and desiccation, such as glacial valleys, ravines or under large blocks of rock, which allow them to maintain a higher humidity than the surrounding vegetation and favors the presence of some epiphytes ( Sierra et al. 1999).

Phenology.

The species was collected in bloom in August and had inflorescences in different stages of development, which suggests that the flowering period may be much broader.

Etymology.

The specific epithet refers to the provinces of El Oro and Loja, since this species was discovered at their border.

Preliminary conservation status.

Lepanthes oro-lojaensis , is known only from the type location, and only two mature individuals were observed. After its discovery in 2015, two additional visits were conducted to explore surrounding areas but it was not possible to find more plants. However, it was evident that the original habitat is under strong pressure due to cattle ranching, the collection of remaining shrubs as firewood and a rapid transformation and fragmentation of the surrounding landscape due to fires and exotic species plantations such as Pinus radiata D.Don ( Penafiel et al. 2018). Therefore, its small population size, area of occupancy of four km2, as well as its habitat restriction and degradation of its unique location allow us to apply criteria B of the IUCN (2012) Red List. The species is preliminarily assessed as Critically Endangered (CR) B2a+b(ii,iii,v) given that it is known from a single location where its area of occupancy, habitat quality, and number of mature individuals are probably declining.

Discussion.

Morphologically, the most similar species is Lepanthes jimburae (Fig. 3b ) from the southeastern slopes of the Ecuadorian Andes. From that species, L. oro-lojaensis differs in the smaller plants, the dorsal sepal attenuate into a shorter decurved cauda, the lateral sepals with minutely denticulate margins and petals with the upper lobe ovate, with rounded apex and lower lobe triangular-oblong. The new species is also similar to L. corkyae (Fig. 3c ) and L. schizix (Fig. 3d ), both occurring on the western slopes of the northern Ecuador and from which it differs in the red to reddish with yellow dorsal sepals, yellow lateral sepals suffused with red around the mid-vein (vs. orange to red brown sepals in L. corkyae and purple flower in L Lepanthes schizix ), lateral sepals in L. oro-lojaensis are minutely denticulate in the margin, are no denticulate in L. corkyae and minutely ciliate in L. schizix . In Both L. corkyae and L. schizix the lip blade are glabrous (vs. microscopically pubescent L. oro-lojaensis ) and, lip blades are oblong in L. corkyae and L. oro-lojaensis and lunate in L. schizix .

Figures

Figure 1. Lepanthes oro-lojaensis A habit B flower C dissected sepal and petals D anther dorsal and ventral view E polinarium F dorsal view of the spread-out lip with dorsal view of the column G dorsal view of the spread-out lip without the column H lateral view of the ovary, lip and column. Drawn by F. Tobar & S. Tobar from the plant that served as type (Tobar et al 1648).

Figure 2. Lepanthes oro-lojaensis A plant growing in its natural habitat B front view of the flower C detail of the lepanthiform sheat D detail of lip and petals E anther dorsal view F anther ventral view G polinarium. Photograph by F. Tobar from the plant that served as type (Tobar et al. 1648).

Figure 3. Comparison with the most similar species to Lepanthes oro-lojaensis Tobar & M. F. Lopez A Lepanthes oro-lojaensis B Lepanthes jimburae C Lepanthes corkyae D Lepanthes schizix. Photographs by F. Tobar.

Figure 4. Geographical distribution of the three new species of Lepanthes microprsartima Tobar & M. J. Gavil. (black hexagon, three collections), Lepanthes caranqui Tobar & Monteros (black triangle, two collections) and Lepanthes oro-lojaensis Tobar & M. F. Lopez (black pentagon, one collection).

Figure 5. Landscape near to Cerro de Arcos, where Lepanthes oro-lojaensis was collected, in El Oro Province A natural vegetation remnants B areas where Pinus have been planted.