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| Wrightia vietnamensis Hazell & D.J.Middleton, in Hazell, Baines, Nguyen, Francis et Middleton, 2023. |
Summary
A new species of Wrightia (Apocynaceae) from Vietnam, Wrightia vietnamensis Hazell & D.J.Middleton, is described and illustrated. Seed was collected on a Vietnamese led international collaborative expedition and grown on in the Temperate House at the Royal Botanic Gardens, Kew. When it matured and flowered, it was found to be an undescribed species. The species is currently only known from one karst limestone locality. This restricted distribution conforms to regional patterns of speciation and endemism in the genus whereby species restricted to karst limestone have very restricted distributions and those found on other soil types have wider distributions.
Key Words: Bat Dai Son, karst limestone, taxonomy.
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| Wrightia vietnamensis. A habit; B twig and base of leaf; C twig showing opposite leaves and terminal inflorescence; D dissected flower; E corona; F synorganisation of gynoecium and androecium; G anthers from the front and back; H pistil. Drawn by Jessica Frances. |
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| Wrightia vietnamensis. A habitat; B bark; C habit and flower; D fruit. photos: A, D Richard Baines; B, C Emily Hazell. |
Wrightia vietnamensis Hazell & D.J.Middleton, sp. nov.
RECOGNITION. Similar to Wrightia kwangtungensis Tsiang in its antepetalous corona lobes toothed at the apex and having free carpels but differs in its glabrous inflorescence (pubescent in W. kwangtungensis), usually longer sepals ((2 –) 3.6 – 5.5 mm long in W. vietnamensis, c. 2 mm in W. kwangtungensis), shorter alternipetalous corona lobes (2 – 3 mm long in W. vietnamensis, c. 5.2 mm long in W. kwangtungensis).
DISTRIBUTION. Vietnam. Ha Giang Province: Bat Dai Son, 766 m.
HABITAT. Temperate and humid montane hillside, in wet, thin soil with high humus content over karst limestone. The surrounding vegetation is characterised by Rhododendron, Callicarpa and Trichosanthes spp.
ETYMOLOGY. The species is named after the country in which it was first collected.
Emily C. Hazell, Richard A. Baines, Van Dzu Nguyen, Jessica V. Francis and David J. Middleton. 2023. Wrightia vietnamensis (Apocynaceae), A New Species from Vietnam. Kew Bulletin. DOI: 10.1007/s12225-023-10133-9
