Research Article |
Corresponding author: Yun-Hong Tan ( tyh@xtbg.org.cn ) Academic editor: Yu Shui
© 2018 Qiang Liu, Shi-Shun Zhou, Xiao-Hua Jin, Bo Pan, Kyaw Win Maung, Myint Zyaw, Ren Li, Rui-Chang Quan, Yun-Hong Tan.
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:
Liu Q, Zhou S-S, Jin X-H, Pan B, Maung KW, Zyaw M, Li R, Quan R-C, Tan Y-H (2018) Dendrobium naungmungense (Orchidaceae: Epidendroideae; Dendrobieae), a new species from Kachin State, Myanmar. In: Jin X-H, Shui Y-M, Tan Y-H, Kang M (Eds) Plant diversity in Southeastern Asia. PhytoKeys 94: 31-38. https://doi.org/10.3897/phytokeys.94.21337
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Dendrobium naungmungense, a new species from Naungmung, Kachin State, North Myanmar, is described and illustrated. It is morphologically similar to D. ciliatilabellum and D. vexabile, but the epichile is oblong with three long-ciliate laminae and the column wing has significant denticulation. A preliminary risk-of-extinction assessment shows that the new species should be regarded as Critically Endangered (CR) according to the IUCN Red List Categories and Criteria.
Taxonomy, risk-of-extinction assessment, Khakaborazi National Park
The orchid flora of Myanmar is highly diverse but poorly known, as a result of the past political isolation and instability of the country. The remoteness of many orchid-rich areas and the difficulties of investigation in rugged terrain have also played a role (
Dendrobium
Morphological observations of the new species were carried out based on living plants (five individuals) and dried herbarium specimens (three specimens kept in the herbaria of
Dendrobium naungmungense is similar to D. vexabile and D. ciliatilabellum, but can be distinguished by the oblong epichile with three long-ciliate laminae and the margin crisped with hairs and the margin of column wing with significant denticulation.
MYANMAR. Kachin State. Putao County, Naungmung Town, tropical forest, 500–600 m a.s.l., epiphytic on the trunk of riparian trees, 8 Apr 2017, Qiang Liu, 430 (Holotype, HITBC!).
Plant epiphytic, pendent, 30–50 cm long. Stems slender, branching from nodes, internodes covered by sheaths, yellowish, 1.4–2.8 cm long. Leaves anguste-ovate, acute to acuminate, entire, sessile, distichous, 3.0–4.2 × 4.0–5.5 mm. Inflorescence leaf-opposed, 1–2 flowered; peduncle short, sheathed at base, 0.7–0.9 cm long; sheaths membranous, overlapping, 2.5–3.0 mm long; floral bracts broadly lanceolate, three veined membranous, 3.0–4.5 × 2.0–2.5 mm. Flower fragrant, ca. 1.5 cm diameter when open, yellowish green, lip with sparsely purple stripe and spots. Dorsal sepals elliptic, 5-veined, 11.2–12.3 × 6.0–6.5 mm, acuminate; lateral sepals triangular, 5-veined, 12.0–13.5 × 8.0–8.5 mm, apex acuminate; mentum broad, ca. 3 mm. Petals lanceolate, 3-veined, 10.5–11.0 × 4.0–4.5 mm, acuminate. Lip 3-lobed with a short claw, obovate (when spread), 14.5–15.0 × 7.5–8.0 mm, lateral lobes elliptic, 6.0–6.5 × 2.6–3.1 mm, margin with hairs; mid-lobe oblong, 7.5–8.0 × 3.5–3.8 mm, margin crisped with hairs. A broad median band on the hypochile; disc with an ovoid cushion, three long-ciliate laminae extending from base to near apex of epichile. Column ca. 9.0 mm, stelidia falcate with significant denticulation. Operculum subglobose, with densely white crystalline papillate.
Dendrobium naungmungense. A Habitat B Plant C Flower D Lateral view of flower E Lateral view of labellum F Column wing G Front and lateral view of column H Abaxial and adaxial anther cap I Pollinarium J Sepals and petals K Front view of labellum. All from the type collection (Qiang Liu, 430) and drawn by Bo Pan.
A Dendrobium naungmungense (A–1 Front view of flower A–2 Lateral view of flower A–3 Labellum A–4 Front view of column A–5 Lateral view of column A–6 Column wing) B Dendrobium vexabile (B–1 Front view of flower B–2 Lateral view of flower B–3 Labellum B–4 Front view of column B–5 Lateral view of column B–6 Column wing) (Photographed by Q. Liu)
The new species is named after Naungmung, Kachin State, North of Myanmar, where it was discovered in a vast area of tropical rainforest.
Dendrobium naungmungense is only known from the type locality. It is epiphytic on the trunk of riparian trees in tropical rainforest, which is dominated by Dipterocarpus obtusifolius Teijsm. ex Miq. (Dipterocarpaceae).
MYANMAR. Kachin State. Putao County, Naungmung Town, tropical forest, 500–600 m a.s.l., epiphyte on the trunk of riparian trees, 11 Jun 2017, Hong Jiang & Qiang Liu, 17017 (YAF!) and 8 Apr 2017, Qiang Liu, 430 (HITBC!).
Dendrobium naungmungense was collected in Naungmung Town, Kachin State, Northern Myanmar. Until now, only one population, consisting of ca. 20 mature individuals, has been discovered in 3 years of continuous field investigations (2015–2017). In addition, population growth and human activities have led to serious habitat destruction and deforestation in this region. It is also illegally collected by local people due to the highly ornamental and medicinal values. Hence, according to IUCN Red List Categories and Criteria (
1 | Mentum (1 × 3 mm), epichile (7.5–8.0 mm) longer than hypochile (6.0–6.5 mm), oblong epichile with three ciliate laminae and margin crisped with dense hairs, column wing with significant denticulation | D. naungmungense |
– | Mentum (2 × 1 mm), epichile (3.5–4 mm) significantly shorter than hypochile (9–10 mm), ovate epichile without ciliate laminae and margin crisped without hairs, column wing without denticulation | 2 |
2 | Mid-lobe (2 × 2 mm), disc of lip with densely long-ciliate lamina and un-deflexed epichile | D. ciliatilabellum |
– | Mid-lobe (4 × 5 mm), disc of lip with sparsely ciliate lamina and de-flexed epichile | D. vexabile |
Morphologically, D. naungmungenseis is similar to D. vexabile and D. ciliatilabellum, which are characterised by branched stems, short inflorescences with 1 or 2 flowers, lip 3-lobed with a narrow claw and flowers yellowish green, except the lip with purple streaks or spots. However, the new species differs from D. vexabile and D. ciliatilabellum by having a wide mentum, small hypochile, oblong epichile with 3 ciliate laminae and margin crisped with dense hairs and column wing with significant denticulation. Meanwhile, D. ciliatilabellum differs from D. vexabile by having a small mid-lobe, disc of lip with densely long-ciliate laminae and un-reflexed epichile (large mid-lobe, disc of lip with sparsely ciliate lamina and reflexed epichile in D. vexabile) (
This work was financially supported by a project of the Southeast Asia Biodiversity Research Institute, Chinese Academy of Sciences (Grant No. Y4ZK111B01). We are grateful for Dr. Lang Li and Dr. Hu-Hu Meng for his kind help in the field work. We also give thanks to Mr. Bo Pan for the excellent illustrations and Prof. Richard Corlett for the linguistic modification.