Epidendrum unchogense Ocupa et E.Santiago, 2022

Ocupa-Horna, Luis, Jiménez, Marco M., Salinas, Julian Duarte, Ayala, Elizabeth Santiago & Hágsater, Eric, 2022, Two new species and a new record of Epidendrum (Orchidaceae) from the Carpish Montane Forest Regional Conservation Area, Peru, Phytotaxa 556 (3), pp. 269-280 : 274-276

Epidendrum unchogense Ocupa et E.Santiago , sp. nov. ( Figure 5 )

Type:— PERU. Huánuco: Prov. Huánuco, Distrito Churubamba, Área de Conservación Regional Bosque Montano de Carpish , bosque de Unchog, 2817 m, 07 Mar. 2022, L. Ocupa 299 (holotype: USM-Spirit!) .

Epidendrum unchogense is similar to Epidendrum llatasii Hágsater, A.G.Diaz & E.Santiago (2018: pl. 1679) but differs by the lanceolate (vs. elliptic) leaves, larger flowers, the sepals 20–23 mm long (vs. 12–15 mm long), petals 20 mm long, trullate (vs. 12.5–15 mm long), the lip entire, narrowly ovate with acute apex (vs. lip 3-lobed with truncate apex in the mid-lobe).

Description:— Epiphytic, descending, monopodial, branched herb. ca. 10 cm long. Roots ca. 2.5 mm in diameter, basal, white, fleshy, thin. Stems cane-like, terete, slightly sinuous to straight; primary stem ca. 4.5–7.9 × 0.25–0.39 cm, branches ca. 3.8–6 × 0.2–0.34 cm, new branches produced from a sub-apical node of a previous branch, progressively smaller, covered by non-foliar sheaths, 0.8–1.7 × 0.5–0.7 cm, infundibuliform, light brown to dark brown, with purple tones, ancipitose, striate, chartaceous. Leaves ca. 1.5–3.9 × 0.4–0.62 cm, 5–6 per stem, green to purplish brown, abaxially dark purplish, distributed along branches, sub-coriaceous, articulate, distichous, straight to briefly reclined, attenuate, conduplicate at base, lanceolate, channeled in central vein, margin attenuate, apex acuminate. Spathe lacking. Inflorescence ca. 5 cm long, including flowers, apical, pendulous, racemose, few-flowered; peduncle ca. 8.5 mm long, short, thin, terete; rachis ca. 3 mm long, very short. Floral bracts 3.5–5 × 2–3 mm, narrowly triangular, apex attenuate, light green or suffused with purple, membranaceous, embracing. Ovary 1.6–2.1 cm long, clavate, thin, 3-furrowed, purple-greenish and widened towards apex, forming a ventral gibbose vesicle with basal portion of column. Flowers 2 –3, simultaneous, resupinate, nutant; sepals buff-colored, with wine-red spots, petals light green, with wine-red spots below middle, lip cream tinged with wine-red spots in center, column green, wine-red at apex. Sepals free, partly spreading, slightly thickened, lanceolate, concave, 5-veined, margin entire, extended; dorsal sepal 20–22 × 5.8–6 mm, apex acute, adaxially sub-verrucose near apex; lateral sepals 21–23 × 6.5–7 mm, apex acuminate, oblique, unequal, adaxially sub-verrucose. Petals 20 × 4.8–5.3 mm, free, parallel to column, slightly convex, trullate, base long-attenuate, somewhat unequal, 3-veined, apex acute, longitudinally thickened along mid-vein, especially at half apical portion, margins slightly revolute to apical half portion. Lip 17.5 × 14 mm, attached to column, entire, narrowly ovate, deeply ovate at base, apex acute, apical half strongly recurved in natural position; bicallose; callus reniform, fleshy, wine-red, separated, forming a small cavity between them; basal sides of lip convex, microscopic, and shortly ciliated margin, giving appearance of having a bilobed apex. Column 10 × 3.5 mm, clavate, straight, widened at base, forming a ventral, gibbous vesicle with apical portion of ovary; stigma ventral, concave, covered by a viscous substance; lateral lobes of stigma thick, dark vinaceous; clinandrium-hood much reduced, margin entire. Anther 1.43 × 1.78 mm, sub-spherical, yellowish green, 4 celled. Pollinarium formed by 4 pollinia, yellow, in 2 nearly sub-equal pairs, obovoid, flattened at interfaces, caudicles attaching them in pairs, granulose; viscarium semi-liquid. Rostellum apical, slit. Nectary penetrating apical portion of pedicellate ovary, broad, smooth. Capsule not seen.

Distribution and ecology: — Epidendrum unchogense is a rare species known presently only from a small area located on the western slope of the central branch of the Andes, in Churubamba District, Huánuco Department ( Figure 2 ). The type specimen was recorded in a small area within the Unchog Montane Forest, in the southern part of the Carpish Montane Forest Regional Conservation Area, growing as an epiphyte on branches of Miconia monzoniensis Cogniaux (1908: 140) (Melastomataceae) , between 2663–2817 m altitude, along the trail on the way to Ñaupamarca. This species was observed flowering in March, at the beginning of the rainy season in that department.

Etymology: —The specific epithet is named in honor of the montane forest of Unchog, where this unusual Epidendrum was found.

Conservation status: —DD. Data deficient. This species is currently known only from the Carpish Montane Forest Regional Conservation Area, central Peru.

Taxonomic discussion: — Epidendrum unchogense belongs to the Soratae subgroup of the Scabrum group ( Santiago & Hágsater 2007: pl. 988) which is characterized by the branching habit starting on a monopodial, primary stem, infundibuliform, rugose leaf-sheaths, lanceolate, aristate, obtuse, acute to subacute leaves, a racemose subcapitate inflorescence on a short, thin peduncle, and the bicallose lip. The new species can be easily recognized by the leaves lanceolate, acuminate apex, the laxly, three-flowered inflorescence, the sepals 20–23 mm long, the petals trullate in the apical half and long attenuate at the base, parallel to the column, the lip entire, narrowly ovate with the apex acute and strongly revolute and a gibbous ventral vesicle, formed between the column and the ovary. It is similar to E. llatasii Hágsater, A.G.Diaz & E.Santiago (2018: pl. 1679), described from northern Peru but recently recorded for the San Pablo de Pillao district of Huánuco (Dalström 3675, digital images, AMO!), has greenish-yellow, concolorous flowers, sepals 12–15 mm long, petals linear with rounded apex and the lip incipiently 3-lobed with the lobe transversely rectangular and the apex truncate strongly revolute. Other related species such as E. carpishense Hágsater, D.Trujillo & E.Santiago (2009: pl. 1215) has 3–4 creamy yellow flowers, concolorous, the sepals 4.5–5 mm long, the petals linear-filiform and the lip reniform. The shape of the callus and revolute apices of the lip of E. unchogense are slightly reminiscent of E. labrychilum Hágsater, Edquén & E.Santiago (2019: pl. 1730) recorded from northern Peru, in San Martín Department, but that species has smaller flowers (sepals 9 mm long) and filiform petals 8 × 0.3 mm, in addition to the lip is 3-lobed with the median lobe short and incipient ( Table 2 , Figure 6 ).

Figures

FIGURE 2. Distribution map of new species and new record of Epidendrum. Prepared by L. Ocupa Horna.

FIGURE 5. Lankester Composite Digital Plate of Epidendrum unchogense Ocupa et E.Santiago. A. Habit. B. Flower. C. Dissected perianth. D. Lip, column and ovary, lateral view and longitudinal section. E. Column, lateral and ventral view. F. Lip, ventral and extended view. G. Anther cap and pollinarium. Prepared by L. Ocupa Horna from holotype.

FIGURE 6. Species of Soratae subgroup, Scabrum group, similar to Epidendrum unchogense. A. Epidendrum unchugense Ocupa & E.Santiago. B. Epidendrum llatasii Hágsater, A.G.Diaz & E.Santiago. C. Epidendrum carpishense Hágsater, D.Trujillo & E.Santiago. D. Epidendrum labrychilum Hágsater, Edquén & E.Santiago. Photographs by: L. Ocupa (A) (L. Ocupa 299 [USM]); A. G. Díaz (B) (A. Díaz 83 [HUT]); D. Trujillo (C) (D. Trujillo 78 [HURP]); J. Edquén (D) (J. Edquén 400 [HURP]).