Epidendrum churubambense Ocupa, J.Duarte, E.Santiago et Hágsater, 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 : 271-274

Epidendrum churubambense Ocupa, J.Duarte, E.Santiago et Hágsater , sp. nov. ( Figure 3 ).

Type: — PERU. Huánuco: Prov. Huánuco, Distrito Churubamba, Área de Conservación Regional Bosque Montano de Carpish, Bosque de Unchog , 3451 m, 08 Mar. 2022, L. Ocupa 298 (holotype: USM-Spirit!) .

Similar to Epidendrum tetartociclium Collantes & Hágsater (2013: pl. 1487) but E. churubambense differs in the sepals 19.8 mm long, ovate-elliptic (vs. 25–26 mm long, elliptic), petals 16.9 × 3.5 mm, elliptic-lanceolate, pendulous and hidden behind the lateral sepals (vs. 20–25 × 8–8.5 mm, oblong-elliptic to oblong-obtrullate, spreading, slightly arching forward) mid-lobe of the lip cuneate, apex bilobed, generating a pair of sub-quadrate lobes (vs. mid-lobe with a square isthmus abruptly dilated into a pair of rounded to sub-deltoid lobes).

Description:— Lithophytic, sympodial, climbing herb, ca. 24 cm tall. Roots ca. 0.5–2 mm in diameter, distributed at base of primary pseudobulb rhizome, thin, vinaceous and white. Stems ca. 2.5–4.5 × 0.6–0.9 cm, pseudobulbous fusiform, sulcate and rugose, wine-red colored, covered by a single sheath ca. 5.5 cm long, membranaceous, acute, becoming fibrous with time, only parts present in old stems, unifoliate. Leaves ca. 6.4–8.4 × 0.9–1.2 cm, apical, narrowly lanceolate, coriaceous, articulate, spreading, medium green tinged wine-red, margin entire, apex acute. Spathe 1, ca. 1.97 cm long, tubular at base, oblong, acute, conduplicate. Inflorescence ca. 4.5 cm long, including flowers, apical, arising from developing stem, erect, racemose, shorter than leaf; peduncle ca. 3.5 cm long, terete, slender, erect; rachis ca. 3 mm long, terete. Floral bracts ca. 1 mm long, very small compared with the ovary, triangular-ovate, acuminate, embracing. Ovary 22 mm long, terete, arching, 5–sulcate. Flowers 2, simultaneous, non-resupinate, yellow green, sepals lightly tinged with brown, column green at base and white towards apex; fragrance not registered. Sepals 19.8 × 6–6.6 mm, free, ovate-elliptic, spreading, somewhat concave at middle portion, 7-veined, margin entire, apex attenuate; dorsal sepal abaxially carinate, lateral sepals oblique, slightly recurved, with low, short apical dorsal keel in the apex. Petals 16.9 × 3.5 mm, free, elliptical-lanceolate, strongly reflexed and pendent in natural position, hidden behind lateral sepals, flexuous, somewhat oblique at base, 3-veined, lateral veins few-branched, margin slightly erose, apex acute. Lip 11.5 × 13.7 mm, united to column, 3-lobed, sub-reniform in general shape, base cordate, margin entire; lateral lobes 9–10 × 6.9–7 mm, sub-orbicular, margin minutely erose; mid-lobe 3 × 5.8 mm, sub-quadrate, margin entire, apex cuneate, short, bilobed generating a pair of sub-quadrate lobes; bicallose, calli elongate, digitiform, short, fleshy, parallel; disc with 3 thickened ribs, two in front of calli and mid-rib which is slightly longer and widened at apex, fleshy, reaching apex in short mucro. Column 10 × 5.2 mm, clavate, slightly arched, thick, with pair of apical lateral wings, rounded, apex truncate, tinged green and brown to sides. Clinandrium-hood short, widely elliptic, margin entire. Anther reniform, base emarginate, apex concave, 4-celled. Rostellum apical, slit. Pollinarium formed by 4 pollinia, yellow, obovate, laterally compressed, caudicles soft and granulose, as long as pollinia; viscarium semiliquid. Nectary short, narrow, penetrating apex of pedicellate ovary. Capsule not seen.

Distribution and ecology: — Epidendrum churubambense is only known from an area located within the Unchog Montane Forest, in the Carpish Montane Forest Regional Conservation Area, located in Churubamba District, Huánuco Department, at around 3451 m ( Figure 2 ), forming part of the western slope of the central branch of the Andes Mountains. This new species grows as a lithophyte on high rocks eroded by rain and wind, directly exposed to sunlight and high humidity, product of dense mists. Epidendrum churubambense grows sympatric with other orchid species such as Maxillaria haemathodes ( Ruiz & Pavón 1798: 240) Garay (1962: 528) , Maxillaria rotundilabia C. Schweinfurth (1944: 232) and Elleanthus aurantiacus ( Lindley 1845: 149) Reichenbach (1863: 482) . This species was observed flowering in March, at the beginning of the rainy season in that department.

Etymology: —In reference to the District of Churubamba in the Department of Huánuco, where the species has been collected.

Additional specimens examined: — PERU. Huánuco: Prov. Huánuco, Distrito Chinchao, caserío San Pedro de Carpish , alrededor del túnel de Carpish, 2732 m, 12 Feb 2003, H. Beltrán 5181 (USM!); Pachitea, Distrito Umari, comunidad campesina de San Marcos, 2800 m, 3 Mar 2010, H. Beltrán 6668 (USM!) .

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

Taxonomic discussion: — Epidendrum churubambense belongs to the Saxicola group (Hágsater et al. 2019) characterized by the pseudobulbous stems, the caespitose or scandent habit, the prominent spathaceous bract apically rounded, the few-flowered, erect inflorescence, the flowers purple or yellow, and the surface of the vegetative structures often rugose. The new species is recognized by the sepals and petals green-brown, lip yellow, the sepals 19.8 mm long, acuminate, the petals 16.9 mm long, elliptic-lanceolate, pendulous and hidden behind the lateral sepals, the lip 3- lobed, mid-lobe cuneate, apex bilobed, generating a pair of subquadrate lobes; disc with three, fleshy ribs, the mid-rib elongate to the apical sinus, the apex apiculate, slightly revolute. It is similar to E. tetartociclium Collantes & Hágsater (2013: pl. 1487) has sepals light green to creamy green, translucent to somewhat opaque, petals and lip creamy green to citrine-yellow, the mid-lobe light green, translucent to slightly opaque, the sepals 25–26 mm long, elliptic, the petals 20–25 × 8–8.5 mm, oblong-elliptic to oblong-obtrullate, spreading, slightly arching forward; the lateral lobes shaped like a quarter circle, and the mid-lobe with the apex retuse forming a pair of rounded to sub-deltoid lobules. Other related species such as E. monzonense Kraenzlin (1905: 88) which has the roots distributed throughout the rhizome, the leaves 6–9 × 1.5–2 mm, broadly-elliptic, apex sub-bilobed, the sepals brown, 15 × 5 mm, acute, oblong, and the lip yellow, margin erosive, median lobe small, sub-rectangular. Epidendrum herreranum C. Schweinfurth (1943: 350) which has perianth brown-reddish and the inner segments yellow, the sepals 19–20 mm long, ovate-elliptic, the petals 19 × 11 mm, rhombic-spatulate, slightly oblique, the lip with lateral lobes obliquely semi-orbicular with the forward margin truncate, and the mid-lobe obovate flabellate with the apex retuse with a pair of sub-orbicular lobules. Epidendrum acjanacoense Hágsater, E.Santiago & J.Duarte (2020) has purple-brown flowers, the sepals 14–16 mm long, elliptic, the petals 15 × 6.4 mm, obovate-elliptic, the lip 12 × 17.5 mm, the lateral lobes sub-orbicular, the midlobe sub-quadrate, apex bilobulate, short with a small apiculus in the sinus ( Table 1 , Figure 4 ).

Figures

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

FIGURE 3. Lankester Composite Digital Plate of Epidendrum churubambense Ocupa, J.Duarte, E.Santiago & Hágsater. A. Habit. B. Flower. C. Dissected perianth. D. Lip, column and ovary, lateral view. E. Column, lateral and ventral view. F.Anther cap and pollinarium. Prepared by L. Ocupa Horna from the holotype.

FIGURE 4. Species of Saxicola group similarto Epidendrum churubambense. A.Epidendrum churubambense Ocupa,J.Duarte, E.Santiago & Hágsater. B. Epidendrum tetartociclium Collantes & Hágsater. C. Epidendrum acjanacoense Hágsater, E.Santiago & J.Duarte. D. Epidendrum herreranum C.Schweinf. Photographs by: L. Ocupa (A) (L. Ocupa 298 [USM]); B. Collantes (B (R. Suarez & G. Alegría 006 ex B. Collantes 903 [USM]), D (C. Vargas 2755 [CUZ])); R. Jiménez (C) (A. Cano 3364 [USM]).