Restrepia santanderensis N. Gut. & K. Gil-Amaya

Morales, Nicolás Gutiérrez, Moreno, Juan Sebastián, Karremans, Adam P. & Gil-Amaya, Karen, 2023, Restrepia santanderensis (Orchidaceae: Pleurothallidinae), a new species from the western slope of the eastern Andes in Colombia, Phytotaxa 598 (4), pp. 293-300 : 294-299

Restrepia santanderensis N. Gut. & K. Gil-Amaya , sp nov. ( Figures. 1 , 2 , 3C, 3D )

Type: — COLOMBIA. Santander: La Belleza, Vereda Berlin , 1950 m, January 2016, flowering under cultivation in January 2020, M. Calderón et al. 191 (holotype: JBB!) .

Restrepia santanderensis is similar to R. mendozae Luer (1996: 157) , but can be distinguished by the sheaths of the ramicauls completely brown-dotted (vs. only lowermost sheath dotted), the sepals partially spreading, yellow with vinaceous stripes in the synsepal (vs. sepals completely spreading, yellow with purple spots), the dorsal sepal prostrate (vs. dorsal sepal erect), the synsepal with trichomes along the veins on the adaxial surface (vs. synsepal glabrous), the straight petals (vs. decurved petals), and the lip yellow with intense rose at base (vs. entirely yellow with purple spots).

Description:— Plant epiphytic, caespitose, occasionally prolific, erect to sub-erect, up to 24 cm tall. Roots slender, flexuous, ca. 1 mm in diameter. Ramicauls erect, 2–13 cm long, enclosed by 5–6, whitish, brown-spotted, papery, loose, imbricating, oblique, laterally compressed, acute sheaths, the uppermost prominent, extended as long as the pedicel, acuminate. Leaves erect, elliptical-ovate, coriaceous, sub-acute, minutely tri-denticulate, 4.5–11.2 × 2.2–4.3 cm, the base cuneate contracted into a short, twisted petiole. Inflorescence up to 3.9 cm, emerging without an annulus 5–9 mm below the apex of the ramicaul, with a solitary yellow flower, produced successively in a fascicle behind the leaf, in a slender, sub-erect, 2.0– 2.7 cm long peduncle, subtended by a tubular, oblique spathe, 9.2–9.9 mm long, floral bract translucent, oblique, slightly inflated, apiculate, to 6.9 mm long, enclosing the short, stout pedicel, 1.0– 1.3 mm long, with a filament 2.8–3.5 mm long. Ovary slightly arcuate, lightly costate, 4.7–6.17 mm long. Flowers resupinate, intermediate-sized, to 2.5 cm long. Sepals pale yellow, membranous, not completely spreading, the dorsal sepal free, narrowly ovate and slightly concave below the lower third, 5-veined, contracted into a long tail above the lower third, with the apex clavate-thickened, 1 mm thick at the apex, 17.0– 22.6 mm long, 1.91–2.56 mm wide above the base, the lateral sepals somewhat striped in vinaceous near the margins of the basal third, each 7-veined, connate ca. 19.0– 21.8 mm into a narrowly oblong, slightly concave at base, bifid, subacute lamina, with glandular trichomes in the middle region and in the apex of the adaxial surface, along the veins, 22–25 mm long, 7.35–7.8 mm wide. Petals translucent yellow, slender, narrowly linear-triangular, membranous, 3-veined, the margins minutely serrate near the base, attenuated above the middle, the apex clavate-thickened, 11.0– 11.6 mm long, 1.0– 1.2 mm wide above the base. Lip yellow, vinaceous along the veins, the base intense rose and white, rectangular, 3-veined, truncated, 3-veined, 7.6– 10.9 mm long, 2.3–3.6 mm wide, the base a slightly concave, with erect margins, the sides with a translucent, uncinate process or cirrhi, ca. 1.4–1.8 mm long, each with a minute tooth at the base, the lip with a pair of low calli extending forward from the base of near the middle, the base connected to the column-foot by a white, rigid, cylindrical neck, the apical portion microscopically verrucose. Column greenish-white, the basal half slender, clavate, the margins of the apical half irregular, marked with intense yellow, 4.6–6.1 mm long, the base pedestal-like with a pair of longitudinal, minutely papillose calli, ending in a pair of light orange, obtuse points, the anther and stigma ventral, the stigma subcuneiform. Anther cap incumbent, deciduous, whitish. Pollinia four, ovoid, in two pairs, united by a viscidium. Capsule dehiscent, ca. 1.5 cm long

Distribution and Ecology: — Restrepia santanderensis occurs in a small area the eastern Andes of Colombia. The specimen that served as type was found in 2016 in the municipality of La Belleza, Santander, near to the top of the waterfall called “El chorro de la Humareda” ( Figure 4 ). The plant was found growing epiphytically, partially exposed to direct sunlight, at around four meters above the ground, on an isolated tree among pastures, not so far from the edge of the forest. Other orchid species in the area were Pleurothallis furcifera Luer (1976: 108) , Maxillaria carrilloi Christenson (2013: 174) , Epidendrum cupreum F. Lehmann. & Kraenzl (1899: 476) and Epidendrum fusagasugaense E. Parra, Hágsater & L. Sánchez (2013: 69) . A short expedition in May of 2022 failed to recover more individuals of the new species, plantations of Solanum quitoense Lam (1794: 16) , “lulo”, were introduced in recent years, and the tree where the original specimen was collected was not found. However, the steep walls of the canyon that receives the “Peña Bonita” river, which falls for more than 220 meters into a waterfall, has a well-preserved forest remnant in a gradient of elevation of 1,700 to 1,900 m, and may host a population of Restrepia santanderensis .

Etymology: —Named for the Department of Santander, Colombia, where the species was discovered.

Additional material examined (paratype): — COLOMBIA. Santander: La Belleza, Vereda Berlin , 1950 m, January 2016, flowered under cultivation in January 2023, N. Gutiérrez & J. de Jesus 241 (JBB!) .

Taxonomic Discussion: — Restrepia santanderensis ( Figures. 1 , 2 , 3C, 3D ) can be distinguished from other species in the genus by the ramicauls covered by densely brown-spotted sheaths, the elongate uppermost sheath extending as long as the pedicel, the short inflorescences with intermediate-sized, partially spreading, yellow flowers, the elongate, prostrate dorsal sepal, the synsepal with trichomes along the veins on the adaxial surface, and the rectangular lip, truncate at the apex, with intense rose at base and microscopically verrucose.

The most similar species morphologically are R. flosculata Luer (1982: 127) ( Figure 3A ), from Valle del Cauca department in Colombia and northwestern Ecuador, a species that present various color forms, dotted or stripped in purple to orange ( Luer 1996), and R. mendozae ( Figure 3B ) known from southeastern Ecuador ( Luer 1996), with pale yellow flowers dotted in dark purple. They all share the overall similar size, shape of the leaves, the short-pedunculate inflorescence, and the pale yellow, intermediate to small-sized flowers.

The flowers of R. flosculata may have a similar color pattern to that of R. santanderensis . However, in R. flosculata , only the basal sheaths of the ramicauls are brown-dotted (vs. all sheaths brown-dotted), the uppermost sheath is oblique, acute (vs. elongate, acuminate), the sepals are shorter, to 14 mm long (vs. sepals to 25 mm long), the dorsal sepal is narrowly triangular below the middle, attenuate above (vs. dorsal sepal narrowly ovate below the lower third, contracted into a tail above), with a notoriously glabrous, obovate synsepal (vs. synsepal with evident trichomes, oblong), decurved petals (vs. straight petals), and a broadly oblong lip with retuse apex (vs. rectangular lip with truncate apex).

In R. mendozae the shapes and size of sepals and petals are very similar to that of R. santanderensis , but only the lowermost sheath is brown-dotted. In addition, the sepals are spreading, yellow with purple dots (vs. partially spreading sepals, yellow with vinaceous strips in the synsepal), the dorsal sepal is erect (vs. prostrate), the synsepal is glabrous (vs. synsepal with evident trichomes), the petals are decurved (vs. straight), and the lip is entirely yellow, with dark purple spots (vs. yellow with intense rose at the base and vinaceous, longitudinal stripes).

The arrangement of the trichomes along the veins of the synsepal in R. santanderensis , matches Millner & Baldwin’s (2016) description of the papillae in R. brachypus , following the stripes of the synsepal. This as ‘false nectar guides’, part of the non-rewarding pollination strategy that is supposed to occur in the genus Restrepia .

Figures

FIGURE 1. Illustration of Restrepia santanderensis, A. Habit. B. Flower. C. Dissected perianth with magnified trichomes of the synsepal. D. Lip, column, ovary, floral bract in lateral view. E. Lip, lateral and adaxial view. F. Column in ventral view, without the anther G. Anther cap and pollinaria. Illustration by Nicolás Gutiérrez Morales and Sebastián Moreno from the holotype.

FIGURE 2. Lankester composite dissection plate (LCDP) of Restrepia santanderensis. A. Habit. B. Flower. C. Dissected perianth with magnified trichomes of the synsepal. D. Lip and column, lateral view. E. Lip, adaxial view. F. Column in ventral view. Photographs by Nicolás Gutiérrez Morales, from the holotype.

FIGURE 3. Restrepia santanderensis N. Gutiérrez & K. Gil-Amaya, and similar morphological species. A. R. flosculata. B. R. mendozae. C. R. santanderensis. D. Capsules of R. santanderensis. Photographs byAndreas Key (A), Joost Riksen (B) from cultivated specimens and Nicolás Gutiérrez Morales (C, D) from the paratype.

FIGURE 4. View of the Restrepia santanderensis habitat in the western slope of the eastern Andes in Colombia, near to the top of “La Humareda” waterfall, in La Belleza (Santander) municipality.