Liparis sessilis Damian , Salazar & Rimarachin, 2020

Damian, Alexander, Salazar, Gerardo A. & Rimarachin, Leyda, 2020, A new species and a new record of Liparis sect. Decumbentes (Malaxidinae, Orchidaceae) from Peru, PhytoKeys 146, pp. 37-46 : 37

Liparis sessilis Damian, Salazar & Rimarachin sp. nov. Figs 1A, E , 2

Type.

Peru. Amazonas; Bagua Grande, Bosque Berlín-“ plot Higueron", UTM 17 M 0786059, 9346365, 2300 m a.s.l. March 9, 2016, L. Rimarachín LR 517 (holotype: UFV, isotype: HUT).

Similar to Liparis brachystalix Rchb.f. but differing in having sessile leaves (vs. distinctly petiolate) and ovate-elliptic labellum with truncate base (vs. obovate-oblong to pandurate labellum with cordate to sagittate base).

Description.

Terrestrial or epiphyte, long-creeping herb. Stem elongate, decumbent, laterally compressed, green, 2 mm in diameter, up to 35 cm. Leaves distichous, sessile, ovate, acute, with a narrow base clasping the stem, the margins undulate, 3-veined, 2.5-3.5 cm long and 1-1.5 cm wide. Inflorescence terminal, erect, racemose, producing many (up to 20) flowers in succession, peduncle terete in cross-section, provided with conspicuous glandular trichomes up to 6 mm long. Floral bracts pale greenish, narrowly triangular, margins undulate, 7-8 mm long and 2 mm wide. Ovary terete, with longitudinal keels, pale greenish, to 8 mm long including the pedicel. Flowers resupinate, widely spreading, sepals, petals and column pale greenish, labellum green, darker towards the center on the basal one-third. Dorsal sepal lanceolate, apex convex, broadly triangular, obtuse, margins revolute, 1-veined, 6-7.5 mm long and 1-1.5 mm wide. Lateral sepals lanceolate, slightly oblique, broadly rounded, margins revolute, 1-veined, 8 mm long, 2 mm wide. Petals linear, truncate with a rounded mucro, margins irregular, revolute, 1-veined, 7.5 mm long, 1 mm wide. Labellum ovate-elliptic, apex obtuse, upper lateral margins irregularly erose, 11-veined, 10-12 mm long, 4-5 mm wide, ecallose, with a squarish fovea above the base, medially with two low ridges converging up to three-quarters of the lamina. Column short, stout, 1.7 mm long; anther cucullate, 2-celled. Pollinia 2, obovate. Fruit unknown.

Etymology.

The specific epithet refers to the distinctive sessile leaves of the species.

Distribution and ecology.

This species inhabits the cloud forests around the river Utcubamba in the province of the same name in the district of Bagua Grande. This area is known as "El Higuerón” and is legally administered by the Rafael Cotrina family. This family, together with that of the third author, are conducting research and conservation programs about the yellow-tailed woolly monkey Lagothrix flavicauda Humbolldt and its habitat in the PCA BF. Flowers have been recorded in March and April.

Liparis sessilis inhabits the understory rich in mosses, rocks and old stems of Anthurium Schott and Psychotria L. species. Also, this species has been using Palicourea shrubs as its phorophyte and can reach up to 2 m above ground. The roots of Liparis sessilis are poorly developed and the stems turn white or brownish as the younger parts of the plant grow. According to recent observations ( Rimarachín pers. obs.), the population of this species is small. Indeed, it has only been found in a degraded area and in two other zones of primary forest. The species has been propagated from cuttings and is currently being grown in the PCA BF.

Comments.

Among the four species belonging to Liparis sect. Decumbentes , L. sessilis is most similar to L. brachystalix , which differs in having petiolate leaves and different labellum morphology. Liparis sessilis is easily distinguished from other members of its section by the features indicated in the key and in Table 1 .

Figures

Figure 1. Flowers (A-D) and portions of stem with leaves (E-H) of the species of Liparis sect. Decumbentes A, E Liparis sessilis B, F Liparis brachystalix C, G Liparis laticuneata D, H Liparis crispifolia. Photographs: A L. Rimarachin, B L. Egoavil, C, E, G A. Damian, D A. Hirtz, F G. Salazar. H E. Santiago. Scale bar: 1 cm.

Figure 2. Liparis sessilis Damian, Salazar & Rimarachin A habit B lateral view of flower C inflorescence, D dissected perianth E column in ventral view with anther. Drawn by Alexander Damian from the type L. Rimarachin LR 517.