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

Fig. 8

Type material.

Peru. Amazonas: Prov. Bongara, Distr. Yambrasbamba, camino a la Perla del Imaza, 1886 m, 17 Jul. 2022, J. P. Arista, J. D. Edquén, E. Hágsater, E. Santiago, G. A. Salazar, E. Yrigoín, L. I. Cabrera & K. Edquen 272 (holotype: KUELAP!).

Diagnosis.

Similar to Epidendrum freireanum Hágsater & E.Santiago, but the plants are smaller, 3.6-10 cm tall (vs. plants 10-40 cm tall), the leaves 1.1-3.6 cm long (vs. leaves 3.7-7.0 cm long), the ovary 10 mm long, sigmoid, with a prominent ventral vesicle, inflated in the middle (vs. ovary 6 mm, straight, not inflated), the sepals 5.5 mm long (vs. sepals 10 mm long), and the flowers pale green with a red-brown tinge on the tepals (vs. flowers purple brown with lip and apex of column ivory white).

Description.

Epiphytic, monopodial, branching, erect herb, ca. 10 cm tall, with new stems produced from upper internodes of previous stem. Roots ca. 2 mm in diameter, from base of primary stem only, fleshy, thick. Stems 2-4 × 0.1-0.25 cm, simple, cane-like, produced from sub-apical internodes of previous stem, sometimes two from same stem, thin, laterally compressed, erect, straight or slightly arched upward, base covered by sheaths 1-10 mm long, tubular, non-foliar. Leaves 2-3, aggregate toward apex of stem, alternate, articulate, coriaceous, slightly conduplicate; sheaths 7-8 × 1.2-2.5 mm, tubular, minutely striated, red; blade 1.1-3.6 × 0.25-0.5 cm, lanceolate, acute, minutely apiculate, margin entire, spreading. Spathe lacking. Inflorescence ca. 2 cm long, apical, racemose, few-flowered; peduncle 1 cm long, sub-terete, rachis 0.3 cm long. Floral bracts 1.5-2.8 mm long, much shorter than ovary, triangular, long acuminate, embracing. Flowers 3, simultaneous, non-resupinate, tepals pale green turning yellow tinged red brown ventrally, dorsally red brown, lip and column pale green to yellow, concolor; fragrance not registered. Ovary 10 mm long, sigmoid, with a prominent ventral vesicle inflated toward middle and involving 2/3 of ovary length, verrucose. Sepals free, 3-veined, dorsally verrucose, margins entire, spreading; dorsal sepal 5.5 × 2.0 mm, reflexed, oblong, obtuse; lateral sepals 5.5. × 2.5 mm, partly spreading, narrowly obovate, oblique, obtuse, minutely apiculate. Petals 5 × 1 mm free, spreading, oblong, obtuse, 1-veined, margins entire, spreading. Lip 3.0-3.3 × 5.5 mm, totally united to column, 3-lobed, cordate at base; bicallose, calli spherical, widely spaced, disc with a single mid-rib, thickened and reaching apical sinus; lateral lobes 1.3-1.7 × 2.2-2.4 mm, dolabriform with apical margin fimbriate; mid-lobe 1.5 × 2.3 mm, rectangular apex slightly emarginate. Column 4.5-5.0 mm long, thin, straight. Clinandrium hood short, margin entire. Cuniculus penetrating 2/3 of ovary, inflated in middle of ovary, forming an elongate prominent vesicle, unornamented. Anther reniform, 4-celled. Pollinia 4, obovoid, laterally compressed. Rostellum apical, slit; viscarium semi-liquid. Lateral lobes of stigma prominent, half as along as stigmatic cavity. Ovary 10 mm long including pedicel, sigmoid, with a prominent ventral vesicle inflated toward middle and involving 2/3 of ovary length, verrucose, furrowed. Capsule not seen.

Distribution.

Presently known only from the type from northern Peru, department of Amazonas, eastern range of the Andes around the ACPPB, at 1886 m.

Habitat and ecology.

Epiphytic in relict wet montane forest.

Phenology.

Flowering in July.

Taxonomic notes.

Epidendrum imazaense belongs to the Fruticetorum Group, which is characterized by the monopodial, branching habit, the few-leaved stems, flattened above, the erect to arching racemose to pluri-racemose inflorescence producing new racemes from the same peduncle in successive years, the flowers generally non-resupinate, and the 3-lobed lip with the distal margins of the lateral lobes dentate to shortly fimbriate. The new species is recognized by the short inflorescences, nearly sessile, with 3 non-resupinate flowers, yellow tepals, ventrally tinged red-brown, dorsally red-brown; lip and column pale green, concolor, the sepals 5.5 mm long, dorsally verrucose and the ovary sigmoid with a prominent, elongate vesicle in the middle of the ovary. Epidendrum freireanum has purple leaves and stems, smaller flowers, the sepals being 10 mm long, the sepals, petals and basal half of column vinaceous to purple-brown, apical half of column and the lip ivory white, immaculate, and the lip with a single wide mid-rib. Epidendrum fruticetorum Schltr. (see Cisneros and Hágsater in Hágsater and Santiago 2019: t. 1721) is similar but larger in habit and flowers, the sepals are 14 mm long, the flowers are green, the lip with 3 narrow parallel ribs is pale green and the column green. Bennett and Christenson (1995a: t. 247) misidentified their plate of Epidendrum fruticetorum as E. odontospathum Schltr.

Etymology.

In reference to the Imaza river, whose basin includes the Pampa del Burro. This river is a tributary of the Chiriacu river, an affluent of the Marañón river.

Figures

Figure 8. Epidendrum imazaense from Arista et al. 272 A habit B flower C dissected perianth D inflorescence at apex of stem E longitudinal section of flower F column and ovary apex from below (left) and above (right) G anther from below (up) and above (down), and pollinarium (Photographs by J. D. Edquen; plate prepared by X. Alcantara).