Research Article |
Corresponding author: Sahut Chantanaorrapint ( sahut.c@psu.ac.th ) Academic editor: Yasen Mutafchiev
© 2021 Janejaree Inuthai, Sahut Chantanaorrapint, Manop Poopath, Naiyana Tetsana, Wittawat Kiewbang, Somran Suddee.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Inuthai J, Chantanaorrapint S, Poopath M, Tetsana N, Kiewbang W, Suddee S (2021) Corybas papillatus (Orchidaceae), a new orchid species from peninsular Thailand. PhytoKeys 183: 1-7. https://doi.org/10.3897/phytokeys.183.71167
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A new species, Corybas papillatus, is described and illustrated from peninsular Thailand. The new species is easily recognized through a combination of the following characters: the purplish flower, the rounded apex of the dorsal sepal, the outer surface of dorsal sepal covered with irregular papillae in the upper half, the lateral sepals adnate laterally at the base to the connate petals, the V-shaped throat, the labellum bearing short hairs, dentate to erose labellum margins, and well-developed conical spurs. A key to the species of Corybas in Thailand is presented.
Helmet orchid, Khao Luang National Park, montane forest, Thai-Malay Peninsula
Corybas Salisb. is a genus of terrestrial orchids comprising about 120 species, and is widely distributed from India, South China, peninsular Thailand, the Malesian region, to New Zealand and the Western Pacific Islands (
During a recent visit to Khao Luang Mountain, Khao Luang National Park, by staff of BKF herbarium, an interesting taxon of the genus Corybas was collected with a unique combination of characters that did not match any of the known species. It is therefore described here as a species new to science.
This study is based on material collected during July 2018 from Khao Luang National Park, Nakhon Si Thammarat province, southern Thailand. Specimens were preserved in alcohol (70% ethanol) and deposited in BKF herbarium. Morphological characters were studied using a stereo microscope Olympus SZX7 and the distinctive characters of the species were illustrated with the aid of an Olympus drawing tube. Measurements were taken from spirit material. The specimen details were compared in detail with original drawings and descriptions given in the protologues of Corybas species in the Malaysian region (e.g.
Similar to Corybas villosus J. Dransf. & Gord. Sm., but differs in the absence of dorsal sepal keel and the lateral sepals adnate laterally at the base to the connate petals.
Thailand. Nakhon Si Thammarat province, Khao Luang National Park, near summit of Khao Luang Mt., 08°29'36.8"N, 099°43'38.9"E, ca. 1,700 m alt., 4 July 2018, M. Poopath, N. Tetsana, W. Kiewbang, C. Hemrat & S. Jirakorn 2201 (holotype BKF!, spirit material).
Small terrestrial herb with underground tubers. Tubers globose or ovoid, fleshy, 3–4 mm diam. Stem erect, whitish-green, 5–12 mm long, 1–1.5 mm diam., with a basal sheath; stolon whitish, hairy, up to 2 cm long, 1–1.2 mm diam. Foliage leaf sessile, cordate, long acuminate at apex, glabrous, 6–10 mm long, 6–8 mm wide at the widest point, flat, only slightly undulate along margin, pale green with paler veins, the veins scarcely conspicuous. Inflorescence one-flowered, terminal; bract pale green, lanceolate-triangular, long acuminate, 5–6 mm long, recurved. Flower dark purple. Dorsal sepal purplish, erect below, then strongly curved above, hooded and clasping labellum throughout its length, spathulate, ca. 15 mm long, 8–10 mm wide, rounded at apex, apical margins denticulate, abaxial (dorsal) surface bearing irregular papillae in the upper half. Lateral sepals greenish-white, linear-triangular to antenna-like, ca. 25 mm long, laterally adnate to the petals in the basal ca. 1 mm. Petals greenish-white, connate at the base for ca. 1 mm, free above, similar to lateral sepals but shorter, ca. 22 mm long. Labellum differentiated into 2 parts, erect in basal half and strongly reflexed above, ca. 17 mm long in total length; the basal half with margins strongly inrolled throughout, and forming a tube with the dorsal sepal, ca. 7 mm long; the upper half reflexed and expanded, orbicular, ca. 10 mm diam., margin erose, reddish-purple excepted for a white zone just below the margins; mouth of throat very deeply V-shaped; adaxial surface bearing short hairs; spurs 2, divergent, conical, ca. 3 mm long. Column very short, ca. 1.5 mm long; stigma rounded, ca. 0.5 mm diam.; anther erect, smooth; pollinia not seen. Ovary green, glabrous, ca. 2 mm long. Capsule (immature) erect, ellipsoid or fusiform, 5–7 mm long, 2.5–3 mm diam. Seed not seen.
Flowering and fruiting observed in July.
The new species was found growing amongst bryophytes (Fig.
Corybas papillatus is only known from the type locality (Fig.
The specific epithet ‘papillatus’ alludes to occurrence of irregular papillae in upper portion of abaxial (dorsal) surface of dorsal sepal.
We consider it likely that if a formal assessment were performed, this species would be categorized as Critically Endangered (CR (D)) based on a preliminary risk of extinction assessment using the IUCN red list categories and criteria (
Corybas papillatus Inuthai, Chantanaorr. & Suddee A whole plant with flower and tubers B plant with immature flower C mature flower, lateral view D plant with immature fruit E floral bract, F, G dorsal sepal F ventral view G lateral view H lateral sepals and petals I labellum J, K column, J lateral view, K front view. Drawn by J. Inuthai.
Corybas papillatus is most similar to C. villosus, which is endemic to Peninsular Malaysia (
Corybas papillatus might be confused with C. ridleyanus Schltr., another endemic to Peninsular Malaysia (
Together with the recent discovery of a new species and new records of orchids from peninsular Thailand, especially in the Nakorn Si Thammarat mountain range (e.g.
There are now three species of Corybas known from Thailand. A key to distinguish these is given below.
1 | Lateral sepals and petals free at base; spurs inconspicuous, broad and poorly developed | C. geminigibbus |
– | Lateral sepals adnate laterally to the connate petals at base; spurs well-developed, conical, slightly oblique to divergent | 2 |
2 | Flowers pink, dorsal sepal as long as the lateral sepals, acute at apex; central portion of labellum bearing a callus | C. ecarinatus |
– | Flowers purplish, dorsal sepal shorter than the lateral sepals, rounded at apex; central portion of labellum hairy without a callus | C. papillatus |
We would like to thank the staff of BKF, C. Hemrat and S. Jirakorn for their help in the field; and A. Schuiteman (K) for his useful comments relating to this new species. We would also like to thank anonymous reviewers for their valuable comments and suggestions to improve the manuscript. This work was supported by the Prince of Songkla University annual government expenditure under the Plant Genetic Conservation Project Year 2018 (no. SCI600107S) under the Royal initiative of Her Royal Highness Princess Maha Chakri Sirindhorn.