Cohniella macrocebolleta Cetzal & Carnevali, 2013

Cohniella macrocebolleta Cetzal & Carnevali View in CoL , sp. nov. —TYPE: VENEZUELA. Sucre: vecindades de la ciudad de Carúpano, aprox. 10 40 0 12 00 N, 63 13 0 48 00 W, 50 –100 m, epífita colectada originalmente por Agustín Prieto; flores recogidas en una exposición de orquídeas en Maracay, 22 May 2007, Carnevali 7220 (holotype: VEN!; isotypes: AMES!, CICY!, MO!) .

Cohniella macrocebolleta is similar to C. cebolleta but differs by its conspicuously larger flowers (31–36 mm vs. 18–25 mm diameter in C. cebolleta ), the lateral lobes of labellum are shorter or about as long as wide (7–8 + 7.5–12.0 mm vs. as long than wide, 5– 6 + 4–5 mm in C. cebolleta ), the lateral margins of the platform of the callus is ear-like, and its central portion has two small, globose teeth, apparently attached to the proximal teeth (vs. absent in C. cebolleta ).

Epiphytic erect herbs, shortly creeping to cespitose; rhizome short, thin, brittle; roots 1–2 mm thick, white; pseudobulbs 9–11 + 9–11 mm, subspherical to broadly ovoid, totally enclosed by 3 imbricate sheaths 5–11 + 1.5–4.0 cm upon spreading, eventually deciduous; leaves (30-)37–59(–90) + 0.5 –0.9 cm, terete, thickly fleshy-coriaceous, dark green; inflorescences solitary, born at the base of the pseudobulbs, 88–89(–155) cm long, a 10–20-flowered panicle with 2–6 branches, 6–14 cm long, the branches 5–7-flowered; peduncle and rachis dark green tinged with purple; peduncle terete, erect to arching, 3.5 –4.0 mm thick, with 7–9 remotely bracted internodes, peduncle bracts 12–15 + 10–11 mm, the basalmost longest, oblanceolate, acuminate, tubular; bracts subtending the lateral branches 7–9 + 2–4 mm, elliptic, acuminate; floral bracts 2–4 + 1.0– 2.5 mm, narrowly elliptic, acuminate; flowers resupinate, large for the genus, 31–36 mm diameter, with widely opening perianth segments and the petals and sepals somewhat reflexed, greenish yellow with reddish-brown or red-purple spots; ovary with pedicel 18–27 mm long, of which 5–10 mm correspond to the ovary, this 2 mm thick; sepals basally clawed, the claw 1/5–1/6 of sepal total length, spreading or somewhat reflexed, dorsal sepal 9.0 –10.5 + 7–9 mm, rounded or obovate, apically obtuse and minutely apiculate, concave in the upper half, the claw 1.0– 1.5 mm wide; lateral sepals 9–12 + 6–8 mm, partially fused at the base, then free, similar to dorsal, but apically acute; petals 11–13 + 5–6 mm, oblong, somewhat oblique, the apex rounded, somewhat reflexed in natural position; labellum bright yellow, deeply 3-lobed, 19–23 mm long from the base to the apex of the central lobe, (20-) 22–24 mm wide across the apices of the lateral lobes, the lateral lobes in the same plane as the central lobe and +/– perpendicular to it; central lobe 14–16 + 18–24 mm, spathulate to transversely elliptic or rounded, apically circular, conspicuously emarginated, 4.0– 4.5 mm deeply, with overlapping lobes, basally produced into an isthmus, 2–4 + 1.5 –3.5 mm; lateral lobes 7–8 + 7.5–12.0 mm, erect-patent, oblong to rounded, apically truncate-rounded, somewhat reflexed in natural position, the upper and lower margins flat to rounded; disc 5.5–6.0 + 5–6 mm, yellow with reddish spots at the base, subrectangular; the disc bearing a well-developed callus, 4.5–5.0 + 3.0 – 3.2 mm, yellow or white with reddish spots, consisting of an elevated, +/– flat, rectangular platform, 2–3 + 1.7–2.0 mm, the platform in its central portion has two small, divergent, globose teeth, apparently attached to the proximal teeth, the lateral margins ear-shaped; proximally with two lateral, larger teeth that are conical, divergent and pointing upward, 2.0 –2.5 + 2 mm; distally with two small lateral teeth that are broadly conical, 1.2–2.1 + 0.8–1.0 mm; the central tooth or keel laterally compressed, 3–3 + 2–3 mm; the basal portion of the callus with conspicuous lateral extensions, conical, yellow with reddish spots; column 3.5 –5.5 + 2.8–3.0 mm, yellow with red-brown spots at the base, the ventral face in the same plane as the labellum lobes, tabula infrastigmatica longitudinally channelled, stigmatic surface 2.5 + 2.5mm, rounded; column wings yellow, ovate or asymmetrically bilobed, proximal lobe 1.0– 1.2 + 1–3 mm, distal lobe 1 + 1.5 –2.0 mm; anther cap 2.8 + 1.8 mm, operculate, obovate; pollinarium typical for the genus, ca. 1.5 mm long, tegula spathulate, 0.8 + 0.5 mm at the subtruncate apex; viscidium disc-like, small, pollinia 0.6–1.0 mm long, yellow. Figures 7 View FIG , 8A View FIG .

Etymology— The specific epithet refers to the Cohniella cebolleta -like flowers that are, however, considerably larger. In horticultural circles, this species was known as the “tetraploid Oncidium cebolleta of eastern Venezuela ” under the untested assumption that these populations were polyploid members of the latter.

Distribution and Ecology— Cohniella macrocebolleta is endemic to eastern Venezuela in the states of Bolívar, Delta Amacuro, and Sucre. In Bolívar and Delta Amacuro, it grows on trees on the banks of the Orinoco River and in riparian forests of the Orinoco Delta; in Sucre it grows in savanna woodlands with deciduous hardwoods, and xeric vegetation on rocky outcrops of cliffs at elevations of 0– 90 m. It is to be expected in portions of Anzoátegui, Guárico, and Monagas states and may also occur in neighboring Guyana.

Diagnostic Characters— Cohniella macrocebolleta is similar to C. cebolleta but differs by its conspicuously larger flowers (31–36 mm vs. 18–25 mm diameter in C. cebolleta ). Furthermore, the lateral lobes of labellum are shorter or about as long as wide (7 –8 + 7.5–12.0 mm) as opposed to C. cebolleta where they are longer than wide (5–6 + 4–5 mm). This feature often becomes apparent only after flattening of the structures since in natural position they may be somewhat reflexed. The lateral margins of the platform of the callus are ear-like, and its central portion has two small, globose teeth, apparently attached to the proximal teeth (vs. absent in other species). The distribution range of this species is essentially disjunct with other member of the genus but it may be found to overlap with that of C. cebolleta in the northern part of its range and with C. ultrajectina in the southern part.

Range of Variation— Cohniella macrocebolleta is generally homogeneous in its vegetative and floral morphology. As far as we can ascertain, it seems to vary only in the color (bright red to reddish brown) and size and density of the spots of the petals and sepals. The spots may be many and small or large, separated or confluent.

Taxonomic Comment— Herbarium specimens of Cohniella macrocebolleta were previously identified as Oncidium sprucei (= C. sprucei ) or O. cebolleta (= C. cebolleta ). With the first species it was confused due to its similar floral size, whereas with the second species by general floral appearance and also due to the former broad circumscription of C. cebolleta .

Additional Material Examined— VENEZUELA. Bolívar: Ciudad Bolívar and vicinity, on the Orinoco, 200 ft, 27 Feb 1921, Bailey & Bailey 1350 (AMES!, NY!); upper part of west-facing wooded slopes, E. of Miamo, Altiplanicie Nuria, 8 Jan 1961, Steyermark 88257 (NY!, VEN!); Dto. Heres, Campamento Guri, Jan-Feb 1984, Fernández 952 ( PORT!); Mpio. Sucre, Río Caura, 7 N, 64 55 0 W, 70 m, Fernández & Sanoja 5152 (MO!, PORT!). Delta Amacuro: Mpio. Antonio Díaz, Isla Tobejuba, barra litoral antigua, cercana a caño Kamotaina, 23 Feb 2003, González et al. 1 ( PORT!); Mpio. Antonio Díaz, Isla Curiapo, entre caños Obaruvaca y Naguabanoco, 8 31 0 N, 61 04 0 W, Feb 1987, Fernández 3820 (MO!, NY!, PORT!); Río Manamo, Vuelta Triste, 20 Feb 1911, Bond et al. 164 (AMES!, PH!).