Pleurothallis vide-vallis Karremans & J.E.Jiménez, 2018

Karremans, Adam P. & Jiménez, José Esteban, 2018, Pleurothallis hawkingii and Pleurothallis vide-vallis (Orchidaceae; Epidendroideae), two new species from Cordillera de Guanacaste in Costa Rica, Phytotaxa 349 (2), pp. 185-191 : 189-190

Pleurothallis vide-vallis Karremans & J.E.Jiménez , sp. nov. ( Fig. 3 )

Type:— COSTA RICA. Guanacaste:Bagaces, Fortuna, Zona Protectora Volcán Miravalles, cumbre del volcán sobre sendero, 10°44’47.07”N 85°09’07.97”W, 1929 m, 17 de diciembre 2014, Calderón & Jiménez 96 (holotype: JBL-spirit!).

Pleurothallis vide-vallis is closely related to P. hawkingii , but it can be easily distinguished by its elliptic synsepal (vs. oblong), broader elliptic (vs. oblong) petals, apically recurved lip (vs. horizontal) that is longer, narrower and thinner (3.4–3.6 × 1.3–1.5 mm vs. 2.6–2.8 × 1.6–1.8 mm) and a lip lacking raised margins with a callus higher at the base bearing a raised glenion (vs. raised margins, lacking a raised basal callus).

Epiphytic, erect herbs, up to 20 cm tall. Roots flexuous, thin, 0.5–1.0 mm diameter, densely almost fasciculate. Ramicauls erect, up to 8–14 cm long, covered by tubular sheaths tightly adpressed and close to the base, up to 5 cm long. Leaves horizontal or nearly so, sessile, acuminate, 7.0–11.0 × 2.5–3.0 cm, deeply cordate. Inflorescence a fascicle of simultaneously open flowers, 3–6 at a time, subtended by a spathaceous bract 1–2 cm long; pedicels terete, 5–6 mm long, pale green. Ovary sub-clavate, 4–5 mm long, green. Flowers pale yellow, diversely suffused with pink, to solid pink; dorsal sepal slightly concave, elliptic, obtuse, 5-veined, 12.0–12.5 × 5.0–6.0 mm; lateral sepals connate in a weakly concave synsepal, oblong, sub-acute, 6-veined, with the 2-central veins fused near the apex, 12.0–13.0 × 5.5–6.0 mm; petals elliptic, oblique, acute, 6.5–7.0 × 2.3–2.5 mm; lip pale yellow, whitish basally, lanceolate to narrowly panduriform, sigmoid, acute, shortly apiculate, 3.4–3.6 × 1.3–1.5 mm, minutely papillose, with a callus raised at the base, bearing a raised glenion, basally hinged to the column foot; column straight, transversely subrectangular, with a column foot, 2.0.–2.3 × 1.9–2.1 mm; anther and stigma apical; anther cap ovate, cucullate, acute at the base, bilobed at the apex, 2-celled, ca. 0.6 × 0.4 mm; pollinia 2, narrowly ovate-pyriform, 0.6 mm long, connected to a round viscidium. Fruits and seeds not seen.

Etymology:—From the Latin, videre, to see, and vallis, valley, referring to the Miravalles Volcano, which in Spanish means overlooking the valleys.

Phenology:—Flowering in August and December, probably also in between.

Distribution:—Endemic to Costa Rica, where it is known from the Miravalles Volcano in the Cordillera de Guanacaste of northern Costa Rica.

Habitat and ecology:—Growing in primary forest at about 2000 m.

Notes:— Pleurothallis vide-vallis belongs to P. sect. Macrophyllae-Fasciculatae ( Luer 2005) and can be recognised by the fascicled inflorescence of numerous simultaneous flowers and the broad petals, rare features in this species-rich group. It is similar to Pleurothallis bothros ( Fig. 4 ) but distinguished by its non-spreading, the flowers pale yellow, diversely suffused with pink, to solid pink (vs. greenish), the elliptic and oblique petals (vs. oblong and straight), the lanceolate to narrowly panduriform, sigmoid, acute, ca. 3.8 × 1.4 mm (vs. ovate, recurved and obtuse, 3.5 × 2.5 mm). Pleurothallis hawkingii , described in this paper, is highly similar, but the two species conspicuously differ in the labellum. Pleurothallis vide-vallis has a generally similar distribution, but P. hawkingii grows at higher elevations ( Fig. 5 ).

Figures

FIGURE 3. Pleurothallis vide-vallis. A. Habit. B. Inflorescence. C. Flower. D. Dissected perianth. E. Ovary, column and lip, lateral view. F. Column lateral and dorsal view. G.Anther cap and pollinarium. Based on type specimen Calderón & Jiménez 96 (JBL-spirit). Lankester Composite Digital Plate (LCDP) by APK.

FIGURE 4. Flower comparison. A. Pleurothallis bothros. B. Pleurothallis hawkingii. C. Pleurothallis vide-vallis. Photographs by APK and JEJ.

FIGURE 5. Distribution of Pleurothallis hawkingii and P. vide-vallis in the Cordillera de Guanacaste, Costa Rica.