Odontochilus putaoensis X.H.Jin, L.A.Ye & A.T.Mu, PhytoKeys

Odontochilus putaoensis X.H.Jin, L.A.Ye & A.T.Mu, PhytoKeys View in CoL 103: 20. 2018. Type: MYANMAR, Kachin state, Putao township, Hponkanrazi Wildlife Sanctuary, X. H. Jin et al. PT- ET 959 (PE, n.v.). Fig. 1 View Fig

Vernacular name: (pu tao chi chun lan in Mandarin).

Terrestrial herbs, autotrophic, 18–60 cm long. Rhizomes creeping, cylindric, fleshy. Roots fibrous, arising from rhizome nodes. Stems ascending, terete, pubescent, 2–7-leaved, internodes 1.5–3.5 cm long. Leaves alternate, laminae ovate-lanceolate or ovate-elliptic, 2.5–9.7 × 2.5–4.2 cm, base cuneate, margins entire, apex acute, glabrous, dark green; petiole like base plus tubular sheath 1–4 cm long. Inflorescence erect, terminal, racemose, 12–16- flowered; peduncles c. 4 cm long, pubescent, reddish-brown, with several sterile bracts; rachis c. 7.5 cm long, pubescent. Pedicelled ovary cylindric, twisted, sparsely pubescent. Floral bracts ovate lanceolate, c. 0.8–1.2 × 0.4 cm, shorter or nearly as long as pedicelled ovary, apex long acuminate, membranous, abaxially pubescent, reddish brown. Flowers resupinate. Sepals separate. Dorsal sepal forming a hood with petals, ovate to orbicular, 6– 7.5 × 3–4 mm, apex acute, abaxially pubescent, dark greenish brown to reddish brown. Lateral sepals elliptic, oblique, 8–9 × 4–5 mm, apex acute, abaxially pubescent, dark greenish brown to reddish brown. Petals obliquely ovate-falcate, 5–7.5 × 3–4 mm, apex acute, membranous, glabrous, white or white tinted with reddish brown. Labellum Tshaped, curled up, 10–12 mm long, light yellow or white; hypochile sub globose, bi-saccate, 1.2–2 mm in diam., with central septum and a pair of lamellar calli which apically emarginate; mesochile 4–5 mm long, with pair of pectinate flanges, each flange with two or three narrow filaments, one broad tooth, narrow filaments 1.5–4 mm long, broad blade-like or triangular tooth, 1–3 mm long; epichile bi-lobed, lobes erect, diverging at obtuse angle to each other, elliptic, concave, 5–5.5 × 2–3 mm, margins entire, apex obtuse. Column stout, c. 1 mm long, ventrally with pair of lamellate appendages; appendages nearly axe-shaped, c. 1 × 1 mm; rostellum bifid, c. 3 mm long, apex twisted; anther acuminate in front, c. 4 mm long, apex twisted; pollinia two, clavate or obovate-clavate, c. 4 mm long; stigma lobes confluent.

Flowering & fruiting: Flowering from October to December. The plants found in Myanmar flowered in October ( Aung et al., 2018), and the population recorded from Laos flowered in December ( Lanorsavanh et al., 2019). In China, we observed the flowers at the beginning of November, but they were fading, thus we assume that the population we found also started to flower in October. Fruit not seen.

Habitat: Plants were found growing in damp places in evergreen broad leaved forests, in association with other Orchidaceae such as Anoectochilus roxburghii (Wall.) Lindl. and Zeuxine nervosa (Wall. ex Lindl.) Benth. ex Trimen , at an elevation of about 1100 m.

Distribution: China, Laosand Myanmar.

Specimen examined: CHINA, Yunnan, Malipo , c. 1130 m, 03.11.2019, H. Z . Tian & M . Sun 20191103039 ( HSNU00079857 About HSNU ) .

Conservation status: Including the site in Malipo County, China, three populations of this species have been discovered so far. The first population being in the Hponkanrazi Wildlife Sanctuary in Putao township, Myanmar, which was reported to contain c. 200 mature individuals ( Aung et al., 2018). The second population was found in Laos in Phou Chom Voy Provincial Protected Area with 15 mature individuals ( Lanorsavanh et al., 2019). The population found in Malipo County, China, comprised around 20 mature individuals and is located outside the protected area and in close vicinity of a village. Hence, the known overall population size comprised of around 235 mature individuals. However, owing to such a disjunct distribution range, the species is likely to occur in similar habitats in intervening regions. To ascertain this, extensive fieldwork is needed. Due to these limitations, the species is assessed as Data Deficient [DD] following the IUCN guidelines ( IUCN, 2019).

Notes: The individuals from China and Laos both have milky white lips ( Lanorsavanh et al., 2019), whereas the ones from Myanmar have light yellow lips. The plants we observed and the ones reported from Laos were found at the end of the flowering period, whereas the ones in Myanmar were in full bloom, hence this variation may be a result of the maturity state of the flowers. Most species of Odontochilus have white lips with pale green or yellow pectinate flanges, some others have yellow lips, such as O. lanceolatus (Lindl.) Blume and O. clarkei Hook. f.. Therefore, it is unclear whether the variable lip colours of O. putaoensis may be attributable to intraspecific genetic variation, different microhabitat conditions and/or different stages of maturity of the flowers. More studies are required here.