Liparis listeroides Schltr., Repert. Spec. Nov. Regni Veg. Beih. 33: 143 (1924).
Medium sized, slender, erect terrestrial or epiphytic plant, up to 18 cm high, rhizome very short, roots wiry, more or less hairy. Pseudobulbs stem-like, thin, erect, fleshy, enveloped by thin grey striate sheaths overlapping each other, with two leaves at the apex (rarely 3), older growths retaining their leaves, up to 13 cm, c. 5 mm diam. Leaves sub-opposite, erectly spreading to sub-erect, oval or elliptic-lanceolate, acute, base rounded or wedge-shaped, sessile or on a short petiole, fairly leathery and glossy, pale green becoming darker with age, 3.5 – 7.3 × 1.5 – 3.0 cm. Inflorescence erect, up to 15 cm long and almost as long as the pseudobulbs, sub-laxly 5 – 15-flowered. Peduncle almost as long as the raceme, slightly ridged, with two to three sheaths c. 5 × 3 mm. Rachis successive flowering, up to 9 cm long. Floral bracts erectly spreading, acuminate, about 1/3 – ½ the length of the pedicellate ovary, c. 4 × 2 mm. Flowers small to medium in size 8 – 11 × 6.5 – 7 mm, greenish-yellow becoming more yellow with age, the disk of the lip darker viridian green, lip generally appears darker in herbarium material. Pedicel and ovary glabrous, slender, a little ridged, 8 – 12 × 0.7 – 3 mm. Dorsal sepal reflexed (often remaining in herbarium material), narrowly lanceolate almost tubular, somewhat obtuse, base subcordate to auriculate, 5.5 – 8.0 × 1.1 – 1.5 mm. Lateral sepals folded beneath the lip, semi-oval, obtuse, 5.0 – 6.0 × 2.5 – 3.9 mm. Petals reflexed, linear almost tubular, subacute, slightly narrowing towards the base, 5.5 – 8.3 × 0.5 – 0.8 mm. Lip slightly curved, shortly auriculate at base, expanded into an obcordate blade sometimes covered by small viscous droplets in living plants, with two simple central veins and two branched lateral ones, the margins curved, the front margin a little denticulate-undulate, subtruncate or emarginated with a bicornate or 2-horned callus at the base which can be up 1.4 mm long, 4.5 – 7.1 × 5.0 – 6.9 mm. Column slightly curved, up to 5 × 1.5 mm, somewhat angular wings. Anther with a short, obtuse beak, c. 1.0 × 1.1 mm. Pollinia 2 pairs, oval c. 0.5 × 0.6 mm.
The plant resembles a medium-sized Listera R.Br. in its habit (Schlechter 1924: 143). Listera, in turn, was named for Dr Martin Lister (c. 1638 – 1712), English physician and naturalist.
Distinguished by its long stem with two somewhat leathery oval-lanceolate leaves at the top. Its lip is entire, slightly indented on the anterior margin and rounded with a distinct two-horned callus at the base. Its anther is slightly beaked. It is a very variable species both in shape of the lip and that of the two calli on the lip which can be more or less united or separate and up to 1.4 mm long, parallel or slanting. In herbarium specimens, the lip of the flowers often appear considerably darker and denser than the rest of the floral segments.
Moss forest, evergreen forest in undergrowth, in shade, moss and lichen-covered trees. Altitude: 1040 – 1600 m.
Flowering in January to April.
This species is slightly variable as to the form of the labellum and its 2 basal calluses, more or less joined or separated.
As given for the genus.
Endemic to Madagascar
Flora of Madagascar: vascular plants: 49th family, Orchids / by H. Perrier de La Bathie; published under the auspices of the government of Madagascar and under the direction of H. Humbert; English revision and translation by Steven D. Beckman; Malaxideae (Orchidaceae) in Madagascar, the Mascarenes, Seychelles and Comoro Islands Kew Bulletin volume 75, Article number: 1 (2020)
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