Epidendrum oroense Zambrano, E.Santiago & 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 oroense Zambrano, E.Santiago & Hágsater , sp. nov. Figs. 17–19

Species haec Epidendrum aureoglobiflorum Hágsater & Dodson (2004: pl. 709) similis sed sepalo dorsali oblongo-lanceolato, petalis ellipticis, 3-nervia, labello saccato, bi-pustulato differt.

Type:— ECUADOR. El Oro: Cantón Portovelo, parroquia Morales, sector El Nudillo, 1962 m, 20 August 2018, Zambrano B. 2364 (holotype, QCNE; isotype, QCNE-spirit) .

Epiphytic, erect, sympodial herb, up to 30 cm tall. Roots 2–3 mm in diameter, from the base of the main stem or rarely from a sub-apical stem, fleshy, flexuous, white. Stems up to 10 × 0.15–0.2 cm, cane-like, terete, erect, new stems produced from sub-apical internodes of the previous stem, covered by 3–6 tubular, imbricated, persistent, chartaceous, gray-brown non-foliar sheaths. Leaves 1.7–5.0 × 0.4–0.6 cm, 2–7 distributed along the apical half of the stem, subcoriaceous, distichous, narrowly lanceolate, obliquely bilobed, mucronate at the apex, channeled at the base; sheaths 0.5–1.5 × 0.15–0.2 cm, longitudinally striated, tubular, persistent, chartaceous. Inflorescence apical, racemose, shorter than the apical leaf, arching; peduncle 4–5 × 0.8–1.0 mm, terete, pustulate, enclosed at the base by a chartaceous bract 3.0–3.5 × 0.7–0.8 mm, triangular-lanceolate, acuminate, persistent; rachis 4–5 × 0.7–0.8 mm, terete, pustulate; floral bracts 3.0–5.0 mm long, triangular-lanceolate, acuminate, embracing. Flowers 5–8, 2-open at the same time, with floral buds in various stages of development, resupinate, the sepals, petals and lip light green or green-brown, column light green, the anther green-cream colored; no fragrance perceived. Sepals membranous, translucent, scarcely pustulate on the adaxial surface, margin entire, 3-veined; dorsal sepal 7.0–7.5 × 2.5–2.7 mm, oblong-lanceolate, acute; lateral sepals 8.0–8.5 × 2.8–3.0 mm, slightly concave, obliquely lanceolate, shortly acuminate, somewhat involute towards the apex. Petals 7.5–8.0 × 2.3–2.5 mm, partly spreading, the lower margin obliquely fused to the column almost half of their length, translucent, elliptic, acute, oblique, margin entire, 3-veined. Lip 5.0–5.3 × 5.8–6.5 mm, united only to the base of the column and slightly embracing its apex, entire, base saccate, ovate, translucent, 7-veined, with lateral veins branched, with a pair of minute pustules on the lateral inside, where it is united to the column, apex truncate, shortly apiculate, crenate along the margin; ecallose. Column 4.0–4.5 × 2.0– 2.2 mm, short, straight, with a pair of rounded wings at the apex ventrally; clinandrium-hood short, margin entire; stigma ventral, concave, smooth; rostellum apical, slit; nectary shallow, without penetrating the ovary, forming a wide cavity, unornamented. Ovary 8–9 × 0.8–0.9 mm, pustulate, slightly arching, terete, longitudinally sulcate. Anther 0.7 × 1.3 mm, dorsal, reniform, glandular-papillose; pollinarium 0.5 mm long, formed by 4 pollinia, light yellow, sub-equal, elliptic, laterally compressed, the inner side of each pair flat, caudicles granulose. Capsule 8.0–14.0 × 7.0 mm, elliptic, with a persistent perianth.

Distribution and habitat: — Epidendrum oroense is only known from one locality (El Nudillo) in El Oro province ( Fig. 19 ). The plant grows as an epiphyte on branches of shrubs of Miconia species at around 1900–2000 m in elevation.

Phenology: —In cultivation E. oroense flowered and fructifies between January and March.

Etymology: —In reference to the province El Oro, Ecuador, where the species was originally collected.

Additional material examined:— ECUADOR. El Oro: Cantón Portovelo, parroquia Morales, sector El Nudillo, 1962 m, 20 August 2018, Zambrano B . s.n. (QCNE).

Comments: — Epidendrum oroense belongs to the Diothonea group, and is distinguished by the light green to green-brown flowers with green pustules on the adaxial surface, oblong-lanceolate sepals with an acute to acuminate apex, and saccate lip with a pair of minute, lateral pustules, and truncate, shortly apiculate apex. The most similar species is the Ecuadorian E. aureoglobiflorum , which can be distinguished by the yellow-green flowers (vs. light green to green-brown), elliptic sepals with an obtuse apex (vs. oblong-lanceolate, with an acute to acuminate apex), and nonsaccate lip with a widely mucronate apex (vs. saccate, with an apex slightly truncate, shortly apiculate). Saccate lips are rare in Epidendrum and are usually considered a distinguishing feature of Scaphyglottis Poeppig & Endlicher (1836: 58) . Another species with a saccate lip is the Colombian Epidendrum saccatum Hágsater (2001: pl. 483), which belong to the unrelated Elleanthoides group ( Hágsater & Salazar 1993). It differs in its erose-dentate leaf margins (vs. entire), elliptic dorsal sepal (vs. oblong-lanceolate), 1-veined petals (vs. 3-veined), and broader ovate lip (vs. ovate).

Figures

FIGURE 17. Epidendrum oroense Zambrano, E.Santiago & Hágsater. A. Habit. B. Flower, frontal 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 18. Epidendrum oroense Zambrano, E.Santiago & Hágsater. A. Habit. B. Apex of the leaf. C. Detail of the inflorescence. D. Perianth dissection. E. Ovary and column, lateral view. F. Detail of the column and lip, lateral and ventral view. G. Anther cap and pollinarium. Plate by B.J. Zambrano based on the plant that served as type.

FIGURE 19. Known locality of Epidendrum oroense in southwestern Ecuador. Map by B.J. Zambrano.