Epidendrum, Linnaeus (1763:, 1347

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 × inauditum Zambrano & Hágsater, nothosp. nov. Figs. 4–6

Planta haec Epidendrum puniceoluteum Pinheiro & Barros (2006: 247–250) similis sed sepalo dorsali oblanceolato-elliptico, petalis ellipticis, labelo 4-tuberculato differt.

Type:— ECUADOR. El Oro: Cantón Piñas, sector Quebrada Oscura , vía a Moromoro , 1000 m, 12 August 2019, Zambrano B . 2408a (holotype, QCNE; isotype, QCNE) .

Hybrid formula: Epidendrum laciniatum Zambrano & Hágsater × Epidendrum calanthum Rchb. f. & Warsz. in Reichenbach (1854: 111).

Terrestrial, sympodial, caespitose herb, to 150 cm tall including the inflorescence. Roots 1.5–2.0 mm in diameter, from the base of the stems, fleshy, flexuous, white. Stems 20–120 × 0.4–0.6 cm, cane-like, terete, erect, the lower half covered by 5–7 tubular, imbricated, persistent, chartaceous, gray non-foliar sheaths. Leaves 5.5–11.0 × 1.6–3.3 cm, 6–15 distributed along the apical half of the stem, fleshy, coriaceous, distichous, oblong-lanceolate, obtuse, oblique to slightly bilobed at the apex, channeled at the base; sheaths 1.5–3.6 × 0.4–0.6 cm, longitudinally striated, tubular, persistent, chartaceous. Inflorescence up to 60 cm long, apical, erect, racemose; peduncle 15–50 × 0.2–0.3 cm, terete, covered by chartaceous bracts 55–65 × 2–3 mm, conduplicate, persistent; rachis 3–4 × 0.2 cm, terete. Floral bracts 2–9 × 1–2 mm, much shorter than the ovary, acuminate, persistent, scarious, amplexicaul. Flowers numerous, nonresupinate, 6–15, successive, several open at the same time, with floral buds in various stages of development, the sepals, petals and lip red-orange, lateral apices of the column, calli and mid-rib yellow, the yellow color spilling over to the disc, turning totally red when old, the anther yellow-red; no fragrance perceived. Sepals extended, margin entire, 7-veined, slightly reticulate; dorsal sepal 10–11 × 4.0– 4.5 mm, oblanceolate-elliptic, acute, short apiculate; lateral sepals 10–11 × 4.5–5.0 mm, obliquely oblanceolate, acute, short apiculate, dorsally carinate. Petals 10–11 × 4.5–5.0 mm, extended, elliptic, acute to obtuse, margin somewhat undulate, 3-veined, with the lateral veins branched. Lip 10– 11 × 11–13 mm, slightly fleshy, deeply 3-lobed, fused to the column, cordate at the base; 4-callose, the calli digitiform, in two superimposed pairs, one adnate to the lip, another sub-erect at a 30° angle, with a thickened, short mid-rib that extends to the distal end of the isthmus of the mid-lobe of the lip; lateral lobes 5.0–6.0 × 6.0–7.0 mm, trapezoid, distally laciniate; mid-lobe 6.0–6.8 × 7.0–9.0 mm, flabellate from a short obtrapezoid isthmus at the base, apical half deeply bilobed, the lobes divergent, oblong, distally laciniate, with a minute mucro in the apical sinus. Column 6.0–7.5 × 1.6–2.0 mm, short, terete, with a digitiform, rounded lateral wings extending on each side, slightly divergent; clinandrium-hood reduced, covering only the base of the anther, margin erose-denticulate; stigma ventral, concave, covered by a viscous substance; rostellum apical, laminar, slit; nectary long, penetrating about half the ovary, minutely papillose. Ovary 25.0–36.0 × 1.5–1.8 mm, arching, terete, longitudinal sulcate. Anther 1.5 × 1.0 mm, dorsal, ovate, glandular-papillose. Pollinarium 1 mm long, formed by 4 pollinia, yellow, obovoid, sub-equal, caudicles imbricated, granulose; viscidium semi-liquid. Capsule not seen.

Distribution and habitat: — Epidendrum × inauditum is a rare natural hybrid known only from El Oro province, in southwestern Ecuador ( Fig. 6 ). It has been registered in two reduced areas (road to Libertad and on the way Moromoro-Machala) growing as a terrestrial on the organic matter and moss at 1000–1100 m in elevation.An additional unvouchered specimen was observed near the ranger station at Buenaventura reserve.

Phenology: —In cultivation, E. × inauditum flowered from April to November.

Etymology: —The specific epithet is from the Latin inauditus “new or unknown”, referring to this new and rare natural hybrid plant in the field.

Additional material examined: — El Oro: Cantón Piñas, Piñas, sector Libertad , 1000 m, 12 November 2007, Zambrano 392 ( QCNE; AMO-digital voucher). Piñas: Moromoro, Monos, 1047 m, en remanente de bosque siempre verde premontano Catamayo-Alamor, 22 August 2015, Tobar 1528 (AMO-digital voucher) .

Comments: — Epidendrum × inauditum belongs to the Schistochilum group and may be recognized by the redorange, non-resupinate flowers, elliptic petals with the margins somewhat undulate, and the lip with digitiform calli, in two superimposed pairs, and trapezoid lateral lobes and a flabellate mid-lobe. The natural hybrid is very rare since it has only been seen, photographed or collected a few times in a narrow area. The putative parent species are E. lacinatum and E. calanthum ; which occur sympatrically on the road to Moromoro and Libertad and bloom in the same season. Epidendrum lacinatum differs from the hybrid in the orange flowers (vs. red-orange), lanceolate-elliptic dorsal sepal (vs. oblanceolate-elliptic), oblanceolate petals (vs. elliptic), and a lip with callus formed by 5 unequal tubercles (vs. digitiform, in two superimposed pairs, with a thickened, short mid-rib not reaching the isthmus of the mid-lobe). Epidendrum calanthum ( Fig. 7 ) can be distinguished by the resupinate flowers (vs. non-resupinate), pink flowers (vs. red-orange), marginally erose petals (vs. marginally undulate), and a bicallose lip with a longer, central mid-rib (vs. 4-callose, with a short mid-rib not reaching the isthmus of the mid-lobe of the lip). To be noted, E. laciniatum has non-resupinate flowers with a complex callus and seems to have dominated in color and position over the resupinate E. calanthum . There is no evidence of the hybrid being fertile and reproducing or producing introgression with either of the parent species.

Similar hybrids are not known from the Andean region. The color and non-resupinate flowers are reminiscent of the Brazilian E. puniceoluteum . That species is distinguished from E. × inauditum by the larger sepals (11.3–18.0 mm vs. 10–11 mm long), the lip with a calli digitiform, entire (vs. digitiform, in two superimposed pairs), the sub-quadrate to sub-flabelliform lateral lobes (vs. trapezoid), and a mid-lobe formed by a sub-oblong isthmus in the basal half (vs. flabellate, formed by a obtrapezoid isthmus in the basal half) (Hágsater 2019). Another similar species is Epidendrum cryptopateras Hágsater & Courtinard (2019 : pl. 1715) from Martinique, which can be distinguished by the oblonglanceolate dorsal sepal (vs. oblanceolate-elliptic), the lip with a callus laminar, semi-elliptic (vs. digitiform, in two superimposed pairs), and a mid-lobe formed by a quadrate isthmus in the basal half (vs. flabellate, formed by an obtrapezoid isthmus). The natural hybrid between E. cryptopateras and Epidendrum secundum Jacquin (1760: 29) is Epidendrum × elongatum Jacquin (1791: 260), whose both parent species have non-resupinate flowers, but the former has two calli and mid-rib, whereas E. secundum has a complex callus. The resulting hybrid with pink flowers, which turns orange when aging, back-crossed with both parents and thus E.× elongatum has a range of callus forms and dominates the populations on the islands of Martinique and Guadeloupe, the parents being very rare and nearly extinct ( Hágsater & Santiago 2019).

Epidendrum × obrienianum Rolfe (1888: 770–771), a commonly cultivated artificial hybrid, differs in its crimsonred flowers (vs. red-orange), oblong-lanceolate petals (vs. elliptic), lip with a calli digitiform, entire (vs. digitiform, in two superimposed pairs), and a mid-lobe formed by a sub-quadrate isthmus in the basal half (vs. flabellate, formed by an obtrapezoid isthmus) ( Hágsater & Cisneros 2019). The Peruvian Epidendrum reflexilobum Schweinfurth (1943: 112–113) differs in the oblong leaves (vs. oblong-lanceolate), red flowers (vs. red-orange), ovate-elliptic dorsal sepal (vs. oblanceolate-elliptic), petals oblanceolate or cuneate-spathulate (vs. elliptic), lip with callus complex, formed by 3– 5 straight, parallel ribs (vs. digitiform), obliquely ovate lateral lobes (vs. trapezoid), obcuneate mid-lobe (vs. flabellate), and the column with an entire clinandrium-hood (vs. erose-denticulate) (Hágsater 2020b: pl. 1835). Epidendrum × pinheiroi Hágsater (2020a: pl. 1787) is a common natural hybrid between E. puniceoluteum and E. fulgens Brongniart (1834 : pl. 43) from the coast of SE Brazil. It can be distinguished by its red flowers with lip orange and red dots (vs. red-orange, without dots), rhombic-spathulate petals (vs. elliptic), and a mid-lobe formed by a sub-quadrate isthmus in the basal half (vs. flabellate, formed by an obtrapezoid isthmus). In this case both parents have non-resupinate flowers, with two calli and a mid-rib, as the hybrid does.

Figures

FIGURE 4. Epidendrum × inauditum Zambrano & 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 5. Epidendrum × inauditum Zambrano & 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. F. Detail of the callus, frontal and 3/4 view. G. Anther cap and pollinarium. Plate by B.J. Zambrano based on the plant that served as type.

FIGURE 6. Known locality of Epidendrum × inauditum in southwestern Ecuador. Map by B.J. Zambrano.

FIGURE 7. Epidendrum calanthum Rchb.f. & Warsz. A. Habit. B. Flower, 3/4 view. C. Perianth dissection. D. Ovary and column, lateral view. E. Detail of the column, lateral view. F. Detail of the callus, frontal view. G. Anther cap and pollinarium. Plate by B.J. Zambrano based on Zambrano B. 2408.