Pteroglossa acalcarata Damián & Salazar, 2017

Damián, Alexander & Salazar, Gerardo A., 2017, A New Species And First Record Of The Genus Pteroglossa (Orchidaceae: Spiranthinae) From Peru, Phytotaxa 311 (3), pp. 235-244 : 240

Pteroglossa acalcarata Damián & Salazar , sp. nov. ( Fig. 2 , 3 )

Similar to Pteroglossa macrantha (Rchb.f.) Schltr. , differing on the pubescent petals, the narrower labellum with inconspicuous laterals lobes, which are free (i.e.not adherent to the sides of the column), and lack of a spur.

TYPE:— PERU. Cusco: Provincia de Calca, Distrito de Yanatile, 3 km from Santiago valley, 1,400 m, 8 January 2015, A. Damián & U.

Huaycho 200 (Holotype MOL!).

Terrestrial herb to 37 cm in height including the inflorescence. Roots fleshy, cylindrical, lanuginose. Leaves absent at flowering time, not seen. Inflorescence ca. 16 cm long, with 5–9 flowers, pubescent; scape terete, partially covered by 5–7 tubular, acute bracts; raceme congested; floral bracts 27–32 × 4–5.5 mm, prominent, green, sparsely pubescent, especially at the margins, slightly concave, ovate, acuminate. Flowers resupinate, fleshy, greenish-white with yellow veins. Sepals densely pubescent outside; dorsal sepal 27–30 × 4–5 mm, slightly spreading, adherent to the petals on its proximal one third, densely pubescent outside, lanceolate, acuminate, margins entire, apex recurved. Lateral sepals 30–37 × 4.5 mm, densely pubescent outside, elliptic-lanceolate, acuminate, margins entire. Petals 25–30 × 2.8–4 mm, shortly pubescent, margins entire, falcate, acuminate, connivent at apex with the dorsal sepal. Labellum 22.5–28 × 3.5–5 mm, obscurely three-lobed, free, pubescent throughout, especially at apex, free from the column sides, midlobe ovate, acute, lateral lobes broadly rounded. Column 14–16 × 5 mm, semiterete, stout, pubescent, the base extended into a long column foot adnate obliquely to the ovary apex; clinandrium with membranaceous margins enclosing the basal portion of the anther; anther thick, massive, ovate, long-acute, with filament completely adnate; pollinarium 12 × 2 mm, formed by 2 deeply cleft, narrowly clavate granular pollinia, with a ventral-apical, oval, black viscidium; rostellum remnant narrowly triangular, stiff, stigma shaped like an inverted “ U,” i.e. bilobed towards its base. Ovary 20–22 mm long, 5 mm in diameter, densely pubescent. Capsule not seen.

Distribution and habitat: — Pteroglossa acalcarata is known only from the eastern slope of the Peruvian Andes on the hills of Yanatile-Cusco, Peru. It inhabits in woody-shrubby semi-deciduous fields at about 1,400 m elevation.

Conservation status: —Only two distant populations of this species have been recorded. A recent visit to one of the collection sites (May 2015) revealed extensive deforestation triggered by the need to clear land for coffee plantations. In fact, we failed to locate any additional individuals of P. acalcarata there at that visit. According to the IUCN Red List Categories and Criteria ( IUCN 2010), P. acalcarata would qualify as Critically Endangered CR (criteria B1a, B1b(i)). However, further field studies are required to attain an objective assessment of its conservation status.

Phenology: —Flowering in January (rainy season).

Etymology: —The specific epithet refers to the absence of a spur or mentum, which otherwise is a conspicuous feature of most genera of the Stenorrhynchos clade, including all other species of Pteroglossa (Salazar 2003, Buzatto et al. 2014).

Comments:— The genus Pteroglossa was cited for Peru by Brako & Zarucchi (1993), as Eltroplectris roseoalba Reichenbach (1854: 11) Hamer & Garay (1974: 160) . However, we have been unable to find verifiable Peruvian material of P. roseoalba and, as far as we know, P. acalcarata represents the first vouchered species of Pteroglossa in this country.

Figures

FIGURE 2. Pteroglossa acalcarata Damian & Salazar. A. Inflorescence. B. Flower in lateral and frontal view. C. Ventral view of gynostemium and pollinia. Scale bars, 2 cm (A); 1 cm (B); 2 mm (C). Representative species of Pteroglossa. D. Pteroglossa macrantha (Argentina, Flachsland s.n.). E. Pteroglossa roseoalba (El Salvador, Salazar 6023). F. Pteroglossa glazioviana (Argentina, Radins s.n.). Photographers: Alexander Damian (A–C), Eduardo Flachsland (D), Rolando Jiménez-Machorro (E) and José Antonio Radins (F). Abbreviations: co, column; ds, dorsal sepal; fb, floral bract; l, labellum; ls, lateral sepals; ov, ovary; p, petals; po, pollinium; st, stigma; vi, viscidium.

FIGURE 3. Pteroglossa acalcarata Damian & Salazar. A. Habit. B. Flower C. Dissected perianth. D. Column and anther, lateral view. E. Column, ventral and dorsal view. F. Anther and pollinarium. Drawn by Alexander Damián from the type (A. Damián & U. Huaycho 0200).