Lecanorchis sarawakensis Suetsugu & Naiki, 2018

Suetsugu, Kenji, Yiing, Ling Chea, Naiki, Akiyo, Tagane, Shuichiro, Takeuchi, Yayoi, Toyama, Hironori & Yahara, Tetsukazu, 2018, Lecanorchis sarawakensis (Orchidaceae, Vanilloideae), a new mycoheterotrophic species from Sarawak, Borneo, Phytotaxa 338 (1), pp. 135-139 : 135-136

Lecanorchis sarawakensis Suetsugu & Naiki , sp. nov. ( Figs. 1 & 2 ).

Type: — MALAYSIA. Sarawak: Bukit Pantu near Rumah Aying, Sebauh Sub-District, Bintulu Division, elev. 156 m, 03°17’10.37”N,

113°47’16.03”E, 27 Jan 2017, Tagane S., Okabe N., Kawakubo A., Naiki A., Takeuchi Y. SWK4060 (holotype: SAR! in the spirit collection!). Lecanorchis sarawakensis is similar to L. betung-kerihunensis but can be distinguished by the dense, filamentous white hairs on its lip.

Terrestrial, mycoheterotrophic herbs. Inflorescence ca. 30 cm tall, solitary or branched (usually once), stem blackish when dry, glabrous, ca. 1 mm in diam., with several membranous scale-like sheaths along the stem. Roots not seen. Rachis 1.0 cm long, densely bearing ca. 5 flowers. Floral bracts triangular, 1.5–2.0 mm long, apex acute, glabrous. Pedicellate ovary ascending, ca. 20 mm long, pale pinkish purple, glabrous, with a calyculus at the top; calyculus 1.0 mm high, thin, margin irregularly denticulate, warty on abaxial surface. Flowers hardly opening, slightly downwards pointing, pale olive-brown to pale purple. Dorsal sepal oblong to oblanceolate, 21.0–22.0 × 3.7 mm, nearly equal width from the base to upper 1/2 of the length, widest at ca. 1/4 of the length from the tip, margin entire. Lateral sepals oblong to oblanceolate, 21.0–22.0 × 3.4 mm, nearly equally wide from the base to lower 1/3 of its length, widest at ca. 1/3 of the length from the tip, margin entire. Petals lanceolate, ca. 21.0 × 3.6 mm, widest at ca. 1/3 of its length from the tip, margin entire. Lip trilobed, adnate to about one half the length of the column from the base, 21.0–22.0 × 10.0 mm when flattened, 5.0 mm wide in fresh flowers; lateral lobes exceeding the column length, with fine serrations along the margins; midlobe round to subquadrate, 3.8 × 6.9 mm when fattened; disc covered with a dense mass of white filamentous hairs. Column 15.0–16.0 mm long, slightly curved, fused with lip more than 2/3 of its length, ventrally glabrous; stelidia semicircular-trapezoid with an incision, edges oblique to column. Anther cap white, 1.5 mm wide. Capsule not seen.

Distribution and phenology: — Lecanorchis sarawakensis is currently known only from a single population with fewer than ten flowering individuals.

Notes: — Lecanorchis sarawakensis is similar to L. betung-kerihunensis in having relatively large flowers (sepals ca. 20 mm long) and pale olive-brown to pale purple sepals. However, these two species are distinguished by lip morphology. First, the midlobe of the lip is more recurved in L. sarawakensis . Second, hairs on the lip of L. sarawakensis are much denser than those of L. betung-kerihunensis . Third, hairs of L. sarawakensis are white and filamentous, whereas those of L. betung-kerihunensis are lemon yellow and a mixture of filamentous and dentate, ribbon-like ones. Finally, the column wing of L. sarawakensis has an incision with edges oblique to the column, whereas that of L. betung-kerihunensis is entire with edges parallel to the column ( Tsukaya & Okada 2013). Lecanorchis sarawakensis is somewhat similar to L. multiflora in having a recurved midlobe of the lip and dense white hair on the lip. However, it can be distinguished by its shorter rachis (up to 1.5 cm long in L. sarawakensis vs. up to 7 cm long in L. multiflora ), the size of flowers (sepals 21.0–22.0 mm long in L. sarawakensis vs. 9.5–11.0 mm in L. multiflora ) and no calli below the base of the lip midlobe ( Smith 1918, Seidenfaden 1978, Tsukaya & Okada 2013).

Figures

FIGURE 1. Lecanorchis sarawakensis in the type locality. A. Habit. B. Flower, side view. C. Flower, front view.

FIGURE 2. Lecanorchis sarawakensis.A. Flowering plant. B. Flower and pedicellate ovary. C. Flower, front view. D–E. Lip and column. F. Dorsal sepal. G. Lateral sepal. H. Lateral petal. I. Flattened lip. J. Column. K. Anther cap. L. Anterior portion of column. Scale bars:A = 1 cm, B–I = 5 mm, K–L = 1 mm. Materials from Tagane et al. SWK4060 (SAR). Drawn by Kumi Hamasaki.