Echinosepala truncata Pupulin, L.Álvarez & Bogarín, 2022

Pupulin, F., Álvarez-Alcázar, L. & Bogarín, D., 2022, A just overtime discovery: another new species of Echinosepala (Orchidaceae) from Costa Rica, Blumea 67 (2), pp. 109-112 : 109-111

Echinosepala truncata Pupulin, L.Álvarez & Bogarín , sp. nov. — Fig. 1 , 2a

Species resembling Echinosepala tomentosa (Luer) Pridgeon & M.W.Chase in the habit and the shape and size of the flower, but easily distinguished by the sparsely lanate ovary,obovate synsepal, spathulate and apically rounded petals, and rectangular, apically truncate lip (see also Discussion). — Type: L. Álvarez 288 , T. M. Jeffery , M. López Morales & J. Ortiz García (holo JBL), Costa Rica, Puntarenas, Osa, Piedras Blancas , Santa Cecilia , trails West of the property Lomas del Sierpe , Reserva Forestal Golfo Dulce, N8.7625 W83.2857, 100 m, wet tropical forest, mature secondary vegetation, 10 Apr. 2020 .

Etymology. From the Latin truncatus, ‘truncate, having the end cut off’, in reference to the apex of the lip.

Epiphytic, caespitose, erect herb up to 22 cm tall. Roots slen- der, quite stiff, 1–2 mm diam. Ramicauls slender, erect, terete, thicker in the distal portion, 2.5–9.5 cm long, homoblastic, composed of c. 3 internodes different in length, the lower one much shorter (to 1–1.3 cm long), completely enclosed by 4, loosely tubular-inflated, ancipitous, apically obliquely truncate, greenish sheaths, the youngest with purple spots, increasing in size toward the upper one, 0.8–6.5 by 0.7–1.5 cm, glumaceous when young, becoming dry-papyraceous with age and breaking longitudinally into long fibres, eventually disintegrating when old. Leaf erect, thinly coriaceous, narrowly elliptic to subligulate, 8.4–12.4 by 1.4–2.4 cm, apex acute, tip minutely emarginate, the margins slightly revolute, the base cuneate, conduplicate, sessile, the midvein strongly protruding abaxially and several lateral veins faintly visible on both sides. Inflorescence a fascicle of single, successive flowers at the apex of the ramicaul; the peduncle terete, suberect, microscopically sparsely pubescent, 4–6 mm long, subtended by a papyraceous, whitish, obliquely truncate spathe, c. 15 mm long. Floral bract papyraceous, broadly obovate, apex obliquely subobtuse, c. 8 by 5 mm, sparsely covered with short and soft spines. Pedicel teretesubclavate, c. 2.5 mm long, sparsely warty; ovary completely 5 mm 3 mm covered by the bract, linear-subclavate, c. 1 mm long, sparsely lanate-hirsute. Flowers bilabiate, ringent, externally densely tomentose, the sepals light greenish yellow, semi-transparentfenestrate at the base, boldly blotched with a dark purple in the basal two thirds, the apex of the dorsal sepal yellow, the apex of the synsepal finely dotted with blackish purple to become almost solid purple; the petals light greenish yellow, blotched with dark purple; the lip densely spotted and blotched with blackish purple on a pale yellow background, the lateral lobes yellow, finely spotted with purple, the rear apex of the callus yellow; the column pale greenish yellow, blotched with purple. Dorsal sepal narrowly oblong, apex obtuse, 7.5–8 by c. 3.5 mm, 5-veined, adaxially tomentose. Lateral sepals connate into a narrowly obovate-oblong, apically rounded, shortly excise synsepal, c. 9 by 5 mm, each half 4-veined, the free apices broadly obtuse, adaxially tomentose. Petals fleshy, spathulate, c. 4 by 1.7 mm, apex rounded, thickened, 3-veined. Lip 3-lobed, rectangular from a small, transversely rectangular, thin, rosehyaline claw, c. 4 by 2 mm (c. 3.7 mm across the lateral lobes), the base subtruncate with 2 retrorse auricles; the apical lobe truncate, with a pair of intramarginal, thick, introrse keels running toward the apex; lateral lobes narrowly triangular-uncinate, erect, the apex introrse, c. 2 mm long; disc with a horseshoeshaped, channelled pseudoglenion at the base, running into a groove which extends close to the lip apex. Column straight to arcuate, semiterete, clavate, c. 3.8 mm long, with narrow, rectangular stigmatic wings above the middle, the foot less than 1 mm long. Anther cap hemispherical, cucullate, with a fimbriate crest, 2-celled. Pollinia 2, ovoid, flattened, on a short, broad, elliptic-obreniform, minutely bilobed caudicle.

Distribution — Known only from the Península de Osa in the southern Pacific region of Costa Rica.

Habitat & Ecology — An epiphyte in mature secondary and disturbed primary vegetation in tropical wet forest of southeastern Costa Rica, at c. 100 m elevation. Individuals of the new species were found on fallen branches (possibly develop- ing high in the tree or crown), along with several other orchid species. Flowering: July to September.

Note — Echinosepala truncata is characterized by the small plant habit and small flower size, the sparsely lanate ovary, the narrowly obovate, rounded synsepal, the spathulate petals, rounded at apex, and the rectangular, truncate lip provided with a pseudoglenion extending in front into a groove running to the tip of the lip.

Figures

Fig. 1 Echinosepala truncata Pupulin, L.Álvarez & Bogarín. a. Habit; b. flower; c. dissected perianth; d. lip, front with lateral lobes spread, front with lateral lobes in natural position and side view; e. column and lip, lateral view; f. anther cap and pollinarium. — Drawn by D. Solano Ulate from the holotype.

Fig. 2 Flower morphology of a. Echinosepala truncata; b. E. tomentosa (from a. Álvarez 288, b. Bogarín 12945; all JBL). — Photos by F. Pupulin.