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

Fig. 14.

Type material.

Peru. Amazonas: Prov. Bongará, Distr. Yambrasbamba, camino a la Perla del Imaza, 1842 m, 15 Jul. 2022, J. P. Arista, J. D. Edquén, E. Hágsater, E. Santiago, G. A. Salazar, E. Yrigoín, L. I. Cabrera & K. Edquen 278 (holotype: KUELAP!).

Diagnosis.

Similar to Epidendrum croceoserpens Hágsater & Salas-Guerr. but the plants much smaller, up to 2.5 cm tall (vs. plants 9 cm tall), the leaves 0.8-1.2 cm long, orbicular, 4-7 forming a rosette (vs. leaves 3.5-5.6 cm long, 1-3, lanceolate), the flowers 7, ochre-yellow, with sparse red dots (vs. flowers 3-6, orange, turning pink with age), and the lip ovate-triangular, acute (vs. lip widely cordiform, base sub-cordate, apex short apiculate, margin erose-crenulate).

Description.

Epiphytic, sympodial, caespitose herb 1.8-2.5 cm tall, forming a small mat. Roots 2 mm in diameter, basal, fleshy, thin, white. Stems 0.6-1.0 × 0.8 cm, thickened, forming a pseudobulb, globose, compact, homoblastic, medium green, somewhat coppery, completely covered by several sheaths 5-6 mm long, non-foliar, somewhat striated when dry, light brown. Leaves 4-6, forming a rosette at apex of pseudobulb, sessile; leaves 0.8-1.2 × 0.65-0.9 cm, orbicular, apex rounded, minutely apiculate, apical margin denticulate, spreading, fleshy thickened, succulent, surface strongly rugose, adaxially dark green, margin red-brown, abaxially red-purple, margins brownish black. Spathe lacking. Inflorescence apical, sessile, racemose, densely few-flowered, not surpassing leaves. Floral bracts 4 mm long, prominent, somewhat longer than ovary, widely triangular, acute, embracing. Flowers up to 7, simultaneous, upright, ochre-yellow with sparse red dots; fragrance not detected. Sepals partly spreading, free, 3-veined, acute, margins entire, spreading; dorsal sepal 3.5-4 × 1.6-1.7 mm, narrowly triangular; lateral sepals 5.0-5.8 × 2.4-2.5 mm, ovate triangular, oblique, apiculate. Petals 3.0-3.2 × 1 mm, free, partly spreading, oblong-lanceolate, 1-veined, obtuse, margin entire, spreading. Lip 3.0-3.2 × 3.0-3.1 mm, totally united to column, entire, ovate-triangular, acute, base truncate, margins entire, spreading: ecallose and without ribs on disc. Column 2.2 mm long, thick, slightly arched, forming a 120° angle with apex of ovary. Clinandrium hood short, margin erose. Anther sub-reniform, base and apex truncate, 4-celled, cream colored with center brown and rugose. Pollinia 4, lenticular; caudicles soft and granulose, longer than pollinia. Rostellum apical, slit; viscarium semi-liquid. Lateral lobes of stigma large, about half length of stigmatic cavity. Cuniculus shallow, without penetrating ovary, very wide in column, unornamented. Ovary 3.0-3.5 mm long including pedicel, terete, not inflated, furrowed. Capsule not seen.

Distribution.

Presently known only from the type. Peru, Amazonas: Prov. Bongará, Distr. Yambrasbamba, camino a la Perla del Imaza, at 1842 m.

Habitat and ecology.

Epiphytic in an isolated Inga sp. tree amidst a pasture for cattle grazing, near remnants of wet montane forest. In the crown of the tree with several individuals on branches below the leaves of the tree.

Phenology.

Flowering in July-August.

Taxonomic notes.

Epidendrum rosulatum belongs to the Kaloptenix Group, Serpens Subgroup, characterized by the aggregate, globose pseudobulbs with fleshy-coriaceous leaves, and a sessile inflorescence, and one or few fleshy, compact, stellate flowers, often burgundy red in color, and the lip entire, more or less cordiform. The new species is recognized for having very small plants, up to 2.5 cm tall, globose pseudobulbs, 4-6 apical, leaves forming a rosette around the inflorescence, the leaves orbicular tinged purple red with the margins brown black, the inflorescence of up to 7 flowers, ochre with some red dots, lateral sepals 5.0-5.8 mm long and the lip 3.0-3.2 × 3.0-3.1 mm, ovate-triangular, acute. Epidendrum croceoserpens has 1-3 leaves per pseudobulb, the leaves lanceolate, to 5.1 cm long, green above, underside vinaceous, margin minutely erose; flowers 3-6, facing upwards, orange, turning somewhat pink with age, petals 4.2 mm long, ovate, and lip with a low wide mid-rib. Epidendrum citroserpens Hágsater, Cisneros & J.Duarte has 2 leaves per pseudobulb, a 2-3 flowered inflorescence, the flowers yellowish green, a cordiform lip, short apiculate, the disc with a thick mid-rib, and a column about 5 mm long. Epidendrum breviyacuriense Hágsater, H.Medina & J.Duarte has a single apical leaf, ovate, 4 simultaneous, reddish violet flowers, petals 5.0 × 1.5 mm, margin somewhat erose, the lip widely cordiform, margin irregularly dentate-erose, and disc with a thin mid-rib from the base to the middle of the disc.

Etymology.

From the Botanical Latin rosulatus, rosette (a circular cluster of leaves) shaped, in reference to the distinctive rosette formed by the leaves, which is a rare trait in the genus.

Figures

Figure 14. Epidendrum rosulatum from Arista et al. 278 A habit; the inset shows a slightly enlarged portion of the leaf underside B flower C dissected perianth D top view of inflorescence and leaves E longitudinal section of flower F column and ovary apex from below G anther from below (up) and above (down), and pollinarium (Photographs by J. D. Edquen; plate prepared by X. Alcantara).