Epidendrum ochrostachyum Hagsater , E.Santiago, J.P.Arista & Edquen, 2023

Arista, Jessy Patricia, Hagsater, Eric, Santiago, Elizabeth, Edquen, Jose D., Pariente, Eli, Oliva, Manuel & Salazar, Gerardo A., 2023, New and noteworthy species of the genus Epidendrum (Orchidaceae, Laeliinae) from the Area de Conservacion Privada La Pampa del Burro, Amazonas, Peru, PhytoKeys 227, pp. 43-87 : 43

Epidendrum ochrostachyum Hagsater, E.Santiago, J.P.Arista & Edquen sp. nov.

Fig. 10

Type material.

Peru. Amazonas: Prov. Bongará, Distr. Yambrasbamba, Perla del Imaza, Río Rojo, Pampa del Burro, 1839 m, 25 Aug. 2021, J. P. Arista, J. D. Edquén, E. Yrigoín & L. Iliquín 79 (holotype: KUELAP!).

Diagnosis.

Similar to Epidendrum bangii Rolfe but differs by the shorter lateral sepals, 13 mm long, spreading, ovate-elliptic, the apex obtuse (vs. lateral sepals 16-18 mm long, slightly reflexed, obliquely ovate, with the apex acuminate), the shorter petals, 10 mm long, oblanceolate, apex obtuse (vs. petals 13-15 mm long, linear, apex acuminate), the floral bracts 8-13 mm long, nearly as long as the ovary (vs. floral bracts 11-22 mm long, longer than the ovary), and the column with a pair of truncate wings (vs. column with a pair of rounded wings).

Description.

Terrestrial, monopodial, branching, erect herb, ca. 66 cm tall including inflorescence. Roots 1.0-2.5 mm in diameter, basal, scarce, fleshy. Stems cane-like, erect, straight, scarcely branching sub-apically, primary stem 54 × 0.6 cm, branches 7 × 0.3 cm; base covered by sheaths 6-30 mm long, tubular, non-foliar, scarious. Leaves 9 on primary stem, 3-5 on branches, distributed throughout the stems, articulate, slightly conduplicate, spreading, coriaceous, rigid, medium green on both sides, margins red-brown; sheaths 0.5-5.0 × 0.3-0.6 cm, tubular, minutely striated, rugose, red; blade 2.5-12 × 0.6-2 cm, lanceolate, acute, margin entire, spreading. Spathe lacking. Inflorescence 12 cm long on primary stem, ca. 6 cm long from branches, apical, racemose, erect, laxly few-flowered; peduncle 1.2 cm long, terete, without bracts, red-brown; rachis 5-11 cm long. Floral bracts 8-13 × 5-7 mm, nearly as long as ovary, widely ovate, sub-acuminate, oblique, embracing. Flowers up to 15, successive, non-resupinate, fleshy, ochre-yellow to olive green, sometimes tinged orange, dorsal surface of sepals red-brown to wine-brown, lip yellow; fragrance not registered. Sepals free, spreading, ovate to ovate-elliptic, obtuse, minutely apiculate, 3-veined, margins entire, spreading; dorsal sepals 12 × 5 mm, lateral sepals 13 × 7 mm. Petals 10 × 3 mm, free, spreading, oblanceolate, obtuse, 1-veined, margin entire, spreading. Lip 8 × 10 mm, united to column, entire, widely cordiform, base deeply cordate, apex acute, embracing apex of column in natural position; ecallose, strongly pubescent in front of stigmatic cavity. Column 8 mm long, thick, apex bidentate, with a pair of truncate wings. Clinandrium hood reduced, margin entire. Anther ovoid, apex acute, 4-celled. Pollinia 4, obovoid, laterally compressed; caudicles soft and granulose. Rostellum apical, slit; viscarium semi-liquid. Lateral lobes of stigma small, ¼ length of stigmatic cavity. Cuniculus shallow, without penetrating pedicellate ovary, strongly pubescent in front of stigmatic cavity. Ovary 8-9 mm long, terete, thick, furrowed. Capsule not seen.

Additional specimens examined.

Peru. Amazonas: Prov. Bongará, Distr. Yambrasbamba, La Perla Vieja, Pampa del Burro , 1880 m, 22 Aug. 2021, Arista et al. 12 (KUELAP!); ibid. loc., 1850 m, 22 Aug. 2021, Arista et al. 61 (KUELAP!); Jumbilla-Molinopampa, 2500-2900 m, 6 Nov. 2012, van der Werff 25206 (HOXA! USM!) .

Other records.

Peru. Amazonas: Prov. Bongará, Distr. Florida, Pomachapanda, 2300-2500 m, 8 Nov. 2010, Dalström 3178, digital image (AMO!); Bosque Protector Alto Nieva, 2184 m, 17 Mar. 2019, Hágsater 16077, digital image (AMO!); San Martín: Prov. Rioja, Distr. Pardo Miguel Naranjos, Sector Venceremos, 1959 m, 23 Feb. 2017, Edquén 2019, digital images (AMO!); ibid. loc., 1715 m, 21 Feb. 2017, Edquén 2020, digital images (AMO!); ibid. loc., 1730 m, 22 Feb. 2017, Edquén 2021, digital images (AMO!); ibid. loc., 1975 m, 20 Feb. 2017, Edquén 2022, digital images (AMO!); ibid. loc., 1918 m, 6 Nov. 2015, Edquén 2023, digital images (AMO!).

Distribution.

Known only from northern Peru, on the border between the departments of Amazonas and San Martín, growing at 1715-2500 m.

Habitat end ecology.

Terrestrial, on road bank, in white sand with abundant organic matter 10 cm deep, in low forest.

Phenology.

Flowering in August to March.

Taxonomic notes.

Epidendrum ochrostachyum belongs to the Macrostachyum Group, which is characterized by the monopodial plants with sub-apical branching, the rugose leaf sheaths, the large leaves, generally spreading, the erect racemose inflorescence, the fleshy flowers generally green to black (ripe olive colored), as well as yellow to pink to purple, with an entire, conduplicate, generally ecallose lip embracing the column, and the cuniculus pubescent to papillose in front of the stigmatic cavity and at least at the base of the lip. The species is recognized by the small plant (up to 66 cm tall), leaves 2.5-12 × 0.6-2 cm, lanceolate, acute, the inflorescence of primary stem with up to 15 flowers, the floral bracts nearly as long as the ovary, the flowers ochre-yellow to olive green, sometimes tinged orange, dorsal surface of sepals red-brown to wine-brown, lip yellow, the lateral sepals 13 mm long, spreading, petals oblanceolate, obtuse, the lip deeply cordiform, acute, and the column with a pair of truncate wings. Epidendrum bangii is vegetatively similar, but the floral bracts are longer than the ovary, the flowers are purple, the lateral sepals 16-18 mm long, the petals are linear, acuminate, the lip is cordiform, and the column has a pair of rounded apical wings. Epidendrum odontostachyum Hágsater & E.Santiago has larger plants, ca 1 m tall, leaves 6-8 × 0.6-1.6 cm, linear-lanceolate, the inflorescence up to 20 cm long, the flowers dark green with the lip purple-green, the petals 12 × 1.5 mm, slightly reflexed, and the floral bracts triangular and acuminate.

Etymology.

From the ochre color of the flowers, from the Greek ὠχρός, and σταχυς, from the Greek spike, in reference to the Macrostachyum Group to which the species belongs.

Figures

Figure 10. Epidendrum ochrostachyum from Arista et al. 79 A habit B flower C dissected perianth D inflorescence at apex of stem E longitudinal section of flower F column and ovary-pedicel from below (left) and side (right) G anther from above (up) and below (down), and pollinarium (Photographs by J. D. Edquen; plate prepared by A. Cisneros).