Epidendrum chrisii-sharoniae L.Valenz. & E.Santiago, 2022

Gamarra, Luis Valenzuela & Ayala, Elizabeth Santiago, 2022, A new species of Epidendrum (Laeliinae: Orchidaceae), in the Yanachaga Chemillen National Park, Pasco-Peru, Phytotaxa 543 (2), pp. 163-169 : 163-168

Epidendrum chrisii-sharoniae L.Valenz. & E.Santiago , sp. nov. Figs. 1–4 .

Type:— PERU. Pasco, Oxapampa Province, Huancabamba District, Peasant Community of Santa Barbara , Yanachaga Chemillen National Park ; high montane sclerophyllous forest, on white sand, 3200 m, 10°20’17.45”S 075°38’22.72”W, 8 August 2020; L. Valenzuela, T. Aronson, R. Zehnder, M. Cantalicio 38574 (holotype HOXA ; isotypes USM, MO ).

Epidendrum chrisii-sharoniae is similar to Epidendrum cyclotylosum Hágsater (2004: 7 (4), pl. 730) but has a strictly erect inflorescence with 7–18, non-resupinate, deep violet to atropurpureous flowers (vs. an arching inflorescence with 13–20 resupinate, pale brown-red flowers), a larger lip (7.0–8.0 × 7.0–9.0 vs. 3.0–4.0 x 3.5–4.7 mm) with the mid-lobe sub-quadrate (vs. semi-orbicular), and laminar, erect calli (vs. a single, sub-orbicular callus, slightly concave and striated at the base).

Epiphytic, sub-caespitose, sympodial herb, 20–35 cm tall. Roots 1.5–2.0 mm basal, thick, fleshy, white. Stems 12–18 × 0.4–0.7 cm, cane like, erect, arising from a middle internode of previous stem, terete towards the base below first leaf, laterally compressed towards apex. Leaves 4–8, distributed along apical half of stem; sheaths 2.0–2.5 × 0.6–1.0 cm, tubular, laterally compressed, striated; blade 4.5–7.5 × 0.7–1.0 cm, dark green tinged purple above, lighter green beneath, oblonglanceolate, obtuse, apex apiculate, margin entire. Spathes 2–3, 2.5–4.0 × 0.7–1.0 cm, covering entire peduncle, tubular, ancipitose, conduplicate, narrow, acute, and finely striated. Inflorescence 8.0– 9.5 cm long, apical, racemose, erect; peduncle 3.5–5.5 cm long, erect, laterally flattened, not ornamented; rachis 4.0- 4.5 cm long, terete, slightly flexuous. Floral bracts 4.0–8.0 × 2.0– 2.5 mm, as long as the ovary, gradually shorter towards apex of inflorescence, triangular, acuminate. Ovary 7–8 × 1–2 mm, terete, thin at base, progressively wider towards the apex, not inflated, glabrous, furrowed towards apex. Flowers 7–18, simultaneous, non-resupinate; deep violet to atropurpureous, apices of sepals, clinandrium, anther, calli and disc of lip more or less yellow-green; fragrance none perceived. Sepals free, obovate-oblong, acuminate, spreading; dorsal sepal 10–12 × 2.3–3.4 mm, reflexed, 5-veined; lateral sepals 13.0 × 3.0– 4.2 mm, partly spreading, 7-veined, twisting basally so that adaxial side faces upward, strongly keeled. Petals 10–11 × 0.7–1.6 mm, reflexed, linear-oblanceolate, falcate, apex truncate-rounded, 1-veined, spreading. Lip 7.0–8.0 × 7.0–9.0 mm, adnate to the column, cordate at base, 3-lobed, fleshy, slightly concave; bicallose, calli laminar, erect, leaning towards mid-line and producing a channel effect at entrance of cuniculus in young flowers, gradually leaning laterally as the flower ages, prolonged at apex to form a obovoid disc covering most of mid-lobe of lip and nearly reaching end of mid-lobe, center slightly striated; lateral lobes 3.8–4.0 × 3.0– 3.2 mm, dolabriform, trapezoidal, ornamented with a sinuous thickened lamina at base ending near calli and parallel to them, margins erose, posterior margin involute; mid-lobe 5 × 4 mm, sub-quadrate, wider towards truncate apex, margin somewhat erose. Column 7.0–7.2 × 2.0–3.0 mm, slightly dilated towards apex, apex with a wide obtuse tooth on each side. Clinandrium reduced, margin entire. Anther 1.2 × 0.9 mm, yellow, sub-spherical, blunt keel in front, 4-celled. Pollinia 4, sub-equal, obovoid, caudicles almost as long as pollinia, viscarium semi-liquid. Rostellum , apical, cleft; lateral lobes of the stigma small, occupying 1/4 of the length of the stigmatic cavity, occupying about half depth of column and nearly entire width. Nectary shallow and wide, penetrating as far as perianth, end rounded, unornamented.

Specimens examined:— PERU. San Martin, Rioja Province, Pardo Miguel Naranjos District, Venceremos locality, shrubby thicket in Humid Montane Forest , 2108 m, 5°38’57.94”S 077°44’51.39”W, Alto Mayo Protection Forest , 15 October 2021, J. Edquen O. 5249 (KUELAP) .

Etymology:—Honoring botanists Christopher and Sharon Davidson, who have supported botanical research and fieldwork by Missouri Botanical Garden in Peru.

Ecology:—The new species is only known from two localities in Peru. The first is the Yanachaga Chemillen National Park, near to Santa Barbara Peasant community, located in the buffer zone of the natural protected area, in the Pasco region, Oxapampa province, Huancabamba in the central jungle of Peru ( Fig. 4A ). The second one corresponds to Venceremos locality in the San Martin region in the North of Peru ( Fig. 4B ). Only a few individuals were found forming small colonies on the branches of several tree species such as Escallonia myrtilloides L.f. (in Linnaeus 1782: 756) ( Escalloniaceae ), Saracha punctata Ruiz & Pav. (1799: 42) (Solanaceae) and Symplocos nana Brand (1901: 76) (Symplocaceae) , within a high montane sclerophyllous forest between 2100–3600 m elevation ( Fig. 1 ). The species blooms between the months of July and October.

Epidendrum chrisii-sharoniae belongs to the ‘Pergracile Group’ and the ‘Rhodoides Subgroup’ (Hágsater: 2004: pl. 730), which is characterized by the caespitose habit, the racemose inflorescence with narrow, parallel-sided spathes, the flowers with a wide, rounded mid-lobe and a large fleshy disc. The new species is recognized by the 4–8, oblong-lanceolate leaves, 2–3 spathes covering the whole length of the peduncle of the inflorescence, the flowers that are simultaneous, atropurpureous with the apices of sepals, clinandrium, anther, calli and disc of the lip yellowish-green, the sepals that are 10–12 mm long, the petals 10–11 × 0.7–1.6 mm and linear-oblanceolate, the lip with the apex truncate, provided of an obovoid disc covering most of the mid-lobe ( Figs. 2–3 ). Epidendrum cyclotylosum has 2–5, narrowly oblong-elliptic leaves, 2 spathes about half as long as the peduncle, and the petals are linear oblanceolate, 4.8–5.5 × 1.0– 1.2 mm.

Figures

FIGURE 1. Habitat. A: High montane forest between 3200–3600 m; B: Sclerophyllous Forest on white sand; C: Characteristic tree species, Escallonia myrtilloides, whose twisted branches and trunks are home to epiphytic plants, including the new species; D: Flowering stems of Epidendrum chrisii-sharoniae (Photographs by L. Valenzuela).

FIGURE 2. Illustration of Epidendrum chrisii-sharoniae. A: Plant habit; B: Old flower, front view; C: Dissected perianth of young flower; D: Ovary and column, longitudinal section; E: Anther; F: Pollinia (Drawings by L. Valenzuela from the type).

FIGURE 3. Lankester Composite Digital Plate (LCDP) of Epidendrum chrisii-sharoniae. A: Plant habit; B: Inflorescence; C: Old flower, front, and side view; D: Dissected perianth of young flower; E: Ovary and column, longitudinal section; F: Anther (Photographs by L. Valenzuela from the type).

FIGURE 4. Distribution map of Epidendrum chrisii-sharoniae, A: Yanachaga Chemillen National Park, Pasco. B: Altomayo Protection Forest, San Martín, to North of Peru. Prepared by L. Valenzuela.