Epidendrum marioi Zambrano & Hágsater, 2021

Romero, Bosco Javier Zambrano, Hágsater, Eric & Solano, Rodolfo, 2021, Miscellaneous of new species in Epidendrum (Orchidaceae) from southwestern Ecuador, Phytotaxa 511 (2), pp. 111-114 : 111-114

Epidendrum marioi Zambrano & Hágsater , sp. nov. Figs. 14–16

Species haec Epidendrum macuchiense Hágsater & Santiago (2015 : pl. 1537) similis sed inflorescentia arcuata, sepala 3-nervia, petalis linear-oblanceolatis, labello trilobato, lobis lateralibus sub-orbiculatis, columna breviora differt.

Type:— ECUADOR. El Oro: Cantón Pasaje, cuesta a Chilla , 1275 m, 03 May 2017, Zambrano B . 1905 (holotype, QCNE; isotype, QCNE) .

Epiphytic, erect, sympodial herb, 25 cm tall. Roots 1.0– 1.5 mm in diameter, emerging from the base of the primary stem, fleshy, flexuous, white. Stems up to 15 × 0.4–0.6 cm, cane-like, terete, erect to slightly curved, new stem produced from a middle or sub-apical internode of the previous stem, the lower part covered by 5–8 tubular, imbricated, persistent, chartaceous, gray-brown non-foliar sheaths. Leaves 2.5–8.5 × 1.2–2.0 cm, 2–6 distributed along the apical half of the stem, slightly coriaceous, distichous, sessile, oblong-elliptic, acute; sheaths 0.5–1.3 × 0.4–0.5 cm, longitudinally striated, tubular, persistent, chartaceous. Inflorescence apical from the mature stem, arching, a simultaneously flowered raceme; peduncle 6–10 × 2.0– 2.3 mm, terete, covered by a chartaceous bract 7–11 × 2.3–2.5 mm, conduplicate, persistent; rachis 30–40 × 2 mm, terete, sinuous; floral bracts 3.0– 7.5 mm long, acute, persistent, scarious. Flowers small, resupinate, the sepals and petals green or green-brown, sometimes suffused with purple dorsally, lip green to green-brown, the calli light green, column light green or green suffused with brown at the apex, anther green or cream. Sepals partly spreading, fleshy, slightly translucent, concave, margin entire, 3-veined, with the lateral veins branched, slightly reticulated; dorsal sepal 10.0–10.5 × 3.8–4.5 mm, oblanceolate-elliptic, acute; lateral sepals 11.5–12.0 × 5.2–5.8 mm, obliquely oblanceolate-elliptic, acute, apiculate, carinate dorsally. Petals 10.0–10.5 × 1.4–1.6 mm, partly spreading, fleshy, parallel to the dorsal sepal, linear-oblanceolate, sub-acute, slightly arched to parallel with the margin of the dorsal sepal, margin entire, 1-veined, with branches on both sides. Lip 10.0–10.8 × 16.0– 16.7 mm, fleshy, 3- lobed, fused to the column, deeply cordate at the base; bicallose, the calli small, divergent, elliptic-ovate, rounded, disc with a prominent, thickened mid-rib reaching the apical sinus; lateral lobes 8.0–8.5 × 6.2–6.6 mm, obliquely and widely sub-orbicular, rounded, margin entire; mid-lobe 2.3–2.9 × 5.5–6.0 mm, smaller than the lateral lobes, bilobate, emarginate, forming a wide sinus. Column 7.0–7.7 × 3.5–4.0 mm, short, terete, progressively widening apically, apex forming a wide lobe on each side; clinandrium-hood much reduced, margin entire; stigma ventral, short, concave, covered by a viscous substance; rostellum apical, laminar, slit; nectary penetrating one-third of the ovary, unornamented. Ovary 15–16 × 2.0– 2.2 mm, slightly arching, terete, furrowed ventrally, thickened along the apical third. Anther 2 × 2 mm, dorsal, ovate, acute, glandular-papillose, 4-celled; pollinarium 1.3 mm long, formed by 4 pollinia, yellow, sub-equal, widely elliptic, laterally compressed, the inside surface of each pair flat, waxy, caudicles granulose. Capsule not seen.

Distribution and habitat: — Epidendrum marioi is known from El Oro province ( Fig. 16 ), in remnant forest disturbed by human activities (cuesta a Chilla). The plant grows as an epiphyte on branches of shrub of Euphorbia and Myrcianthes Berg (1856: 315) species at 1275–1672 m in elevation.

Phenology: —In cultivation E. marioi flowered between April and June.

Etymology: —The specific epithet is named after Mario Aguilar Atiencie, orchid grower from Marcabelí, Ecuador, who contributed to the discovery of this species.

Additional material examined:— ECUADOR. El Oro: Cantón Chilla, Loma de Valsa , 1672 m, 09 June 2018, Zambrano B . 2308 (QCNE).

Comments: — Epidendrum marioi belongs to the Incomptum group, and is recognized by the oblong-elliptic leaves, green to green-brown flowers, linear-oblanceolate, 1-veined petals, and lip with lateral lobes obliquely and widely sub-orbicular and scarcely emarginated mid-lobe. The most similar species are the Ecuadorian E. macuchiense , E. homoion Hágsater & Dodson (1993: pl. 145), and E. oenochromum Hágsater & Dodson (2004: pl. 768). Epidendrum macuchiense can be distinguished from E. marioi by the narrowly, lanceolate leaves (vs. oblong-elliptic), 5-veined dorsal sepal (vs. 3-veined), petals with one vein that is bifurcate near the middle (vs. one vein with two lateral branches), lip with transverse-elliptic lateral lobes (vs. sub-orbicular), and longer column (10 mm vs. 7.0– 7.7 mm long). Epidendrum homoion differs in the elliptic dorsal sepal (vs. oblanceolate-elliptic), obtrullate petals (vs. linear-oblanceolate), and the larger lip (14–16 × 26–28 mm vs. 10.0–10.8 × 16.0– 16.7 mm), with a deeply emarginate apex (vs. scarcely emarginate). Epidendrum oenochromum differs in the narrower leaves (0.6–0.8 mm vs. 1.2–2.0 cm wide), burgundy-red flowers (vs. green to green-brown), oblong, 3-veined petals (vs. linear-oblanceolate, 1-veined), and mid-lobe 1/3 the length of the lateral lobes (vs. ½ the length of the lateral lobes).

Figures

FIGURE 14. Epidendrum marioi Zambrano & Hágsater. A. Habit. B. Flower, lateral view. C. Perianth dissection. D. Ovary and column, lateral view. E. Detail of the column, lateral and ventral view. Drawn by B.J. Zambrano based on the plant that served as type.

FIGURE 15. Epidendrum marioi Zambrano & Hágsater. A. Habit. B. Apex of the leaf. C. Detail of the inflorescence. D. Perianth dissection. E. Ovary, column, lateral view, and detail of the column, lateral and ventral view. F. Anther cap and pollinarium. Plate by B.J. Zambrano based on the plant that served as type.

FIGURE 16. Known locality of Epidendrum marioi in southwestern Ecuador. Map by B.J. Zambrano.