Epidendrum viridium Zambrano, Hágsater & Solano, 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 viridium Zambrano, Hágsater & Solano , sp. nov. Figs. 23–25

Species haec Epidendrum rigidum similis sed sepalo dorsali oblongo-ovato, petalis oblongis, 3-nervia, labello oblongo-obovato differt. Type:— ECUADOR. El Oro: Cantón Piñas, Capiro sector Conchicola , 669 m, 21 September 2015, Zambrano B . 1700 (holotype, QCNE;

isotype, QCNE-spirit).

Epiphytic, erect, sympodial, rhizomatous herb, up to 17 cm tall including the inflorescence. Roots 1–2 mm in diameter, emerging from the base of the stems, fleshy, flexuous, white. Rhizome 2.0– 3.5 cm long between adjacent stems, abbreviated, terete, with 3–4 internodes, covered by imbricate, chartaceous, persistent sheaths. Stems 60 × 3.5–4.0 mm, cane-like, terete at the base but then laterally compressed towards the apex, erect, the lower part covered by 2–3 laterally compressed, persistent, chartaceous, gray-green non-foliar sheaths. Leaves 6.5–7.5 × 1.5–1.7 cm, 2–3 distributed along the apical half of the stem, fleshy, coriaceous, distichous, articulate with the sheaths, narrowly oblong-elliptic, obtuse, emarginated, channeled at the base; sheaths 0.8–1.4 × 0.4–0.5 cm, longitudinal striated, persistent, chartaceous. Inflorescence up to 11.0 cm long, arising from the apex of the mature stem, erect, simple, distichous; peduncle 30–32 mm long, laterally compressed, covered by chartaceous bracts 15–16 × 5–6 mm, conduplicate, persistent; rachis 6.0–8.0 cm long, laterally compressed; floral bracts 8–11 × 5–7 mm, as long as the ovary, longitudinally striated when dry, laterally compressed, obtuse, persistent, scarious, with a prominent dorsal keel. Flowers 3–7, successive, 1–3- open at the same time, small, non-resupinate, with the lip always oriented towards the apex of the rachis, producing a camphorated-lemon odor at night, the sepals, petals and lip light green turning yellow-green when old, callus green, column light green, anther cream suffused with green. Sepals fleshy, margins entire, slightly revolute; dorsal sepal 8.2–8.5 × 3.0– 3.7 mm, partly spreading, oblong-ovate, obtuse, 9-veined; lateral sepals 8.5–9.5 × 3.8–4.2 mm, slightly reflexed, obliquely oblong-ovate, obtuse, carinate dorsally, 10-veined. Petals 8.0–8.3 × 1.5–1.7 mm, fleshy, somewhat reflexed, narrowly oblong, obtuse, margin entire, 3-veined. Lip 6.0–6.6 × 5.0– 5.5 mm, entire, fleshy, slightly porrect, arched, fused to the column, oblong-obovate, rounded, marginally entire, slightly cordate at the base, 10-veined, with the lateral veins branched; with a transverse entire callus at the base, the sides slightly thickened, the middle truncate with a small hollow to each side, with a narrow, low rounded mid-rib not running the entire length to the lip, with a smaller, shorter rib on each side. Column 3.8–4.4 × 2.4–2.6 mm, short, straight, terete, apex truncate, with a rounded wing on each side next to the lip; clinandrium-hood prominent, forming a mid-lobe, separate from the sides, margin erose, covering the anther; stigma ventral, concave, covered by a viscous substance; rostellum apical, laminar; nectary penetrating about half of the ovary, constricted at the height of the perianth, unornamented. Ovary 12.0–12.5 × 3.2–3.5 mm, arching, terete, prominently inflated ventrally, unornamented. Anther 1.0 × 0.9 mm, dorsal, ovate-triangular, 4-celled, glandular-papillose; pollinarium 1 mm long, formed by 4 pollinia, yellow, sub-equal, obovate, laterally compressed, wax-like, caudicles granulose; viscidium semi-liquid. Capsule not seen.

Distribution and habitat: — Epidendrum viridium is only known from El Oro province in southwestern Ecuador ( Fig. 25 ). The plant grows as an epiphyte on branches of Ficus species at 650–1100 m in elevation.

Phenology: —In cultivation E. viridium flowered between December and March.

Etymology: —The specific epithet is derived from the Latin viridi- “green”, in reference to the color of the plant and flowers.

Additional material examined:— ECUADOR. El Oro: Cantón Piñas, Capiro sector Conchicola , 650 m, 21 September 2015, Zambrano B. s.n. ( QCNE). Entre Piñas y Zaruma, 1100 m, Tobar s.n., (AMO-digital voucher) .

Comments: — Epidendrum viridium belongs to the Spathiger group, and can be recognized by the 2–3 leaves per stem, narrowly oblong-elliptic leaves, narrowly oblong, 3-veined petals and oblong-obovate, rounded lip, with an entire callus with short parallel ribs. The most similar species is E. rigidum , which differs in the shorter plants (12 cm vs. 17 cm tall), with 5–7 leaves per stem (vs. 2–3 leaves per stem), a shorter inflorescence (5–6 cm vs. 11.0 cm long), an elliptic dorsal sepal (vs. oblong-ovate), shorter petals (5.0 mm vs. 8.0– 8.3 mm long), and an ovate, bicallose lip (vs. oblong-obovate, with an entire callus). Another similar species is E. cardiophorum , which can be distinguished by its larger plants (35 cm vs. up to 17 cm tall), narrowly elliptic leaves (vs. narrowly oblong-elliptic), an ovate-elliptic dorsal sepal (vs. oblong-ovate), 5-veined petals (vs. 3-veined), and an ovate-cordiform lip (vs. oblong-obovate).

The Colombian E. beatricis differs in the ochre colored flowers turning orange with age (vs. green, turned yellowgreen when old), that are odor-less (vs. producing a camphorated-lemon odor at night), 5-veined dorsal sepal (vs. 9-veined), narrower petals (1.2 mm vs. 1.5–1.7 mm wide), and a sub-rectangular-ovoid, bicallose lip (vs. oblongobovate, with an entire callus). Epidendrum angustisegmentum can be distinguished by its elliptic leaves (vs. narrowly oblong-elliptic), ovate dorsal sepal (vs. oblong-ovate), linear-oblanceolate petals (vs. narrowly oblong), and an ovate, bicallose lip with a central mid-rib (vs. oblong-obovate, with an entire callus and three fleshy, short, low ribs). Finally, E. viridi-ochraceum , described herein, differs in the obtuse-mucronate leaves (vs. emarginate), ochre-orange flowers (vs. green, turning yellow-green when old), oblong-elliptic dorsal sepal (vs. oblong-ovate), linear-oblanceolate petals (vs. narrowly oblong), and an obovate-pandurate, acute lip with three fleshy, parallel, low ribs, the mid-rib running down the entire lip to the apex (vs. oblong-obovate, rounded, with short ribs, the mid-rib not running the entire length of the lip).

A photograph of this species, based on Tobar s.n. (AMO-digital voucher), was erroneously labeled E. beatricis in Hágsater & Santiago (2019). Table 1 shows a comparative summary of the morphological features that distinguish E. viridi-ochraceum and E. viridium from morphologically similar species in the Spathiger group.

Figures

FIGURE 23. Epidendrum viridium Zambrano, Hágsater & Solano. 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 24. Epidendrum viridium Zambrano, Hágsater & Solano. A. Habit. B. Apex of the leaf. C. Flower, lateral view. D. Perianth dissection. E. Ovary and column, lateral view. F. Detail of the column, lateral and ventral view. G. Anther cap and pollinarium. Plate by B.J. Zambrano based on the plant that served as type.

FIGURE 25. Known locality of Epidendrum viridium in southwestern Ecuador. Map by B.J. Zambrano.