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| Didymocarpus middletonii Souvann., Soulad. & Tagane
in Souvannakhoummane, Souladeth, Tagane, et al., 2019.
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Abstract
Didymocarpus middletonii Souvann., Soulad. & Tagane, a new species of Gesneriaceae from Nam Kading National Protected Area, is described and illustrated. The new species is morphologically similar to Didymocarpus brevicalyx, D. formosus and D. puhoatensis but distinguished from the three by its fewer-flowered inflorescence, longer pedicel, and urceolate and multicellular eglandular hairy calyx. Based on the latest IUCN criteria, Didymocarpus middletonii is proposed to be Critically Endangered (CR). Our record of Didymocarpus represents a new genus record for the flora of Laos.
Keywords: Biodiversity, Didymocarpus brevicalyx, Didymocarpus formosus, Didymocarpus puhoatensis, Indochina, Laos, new taxa, taxonomy.
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| Fig. 1. Didymocarpus middletonii Souvann., Soulad. & Tagane. A, Habit; B, abaxial surface of lamina; C, inflorescence with flower (lateral view); D, flower (top view); E, dissected corolla, showing stamens and staminodes; F, multicellular glandular and eglandular hairs on pedicel; G, calyx and pistil; H, fertile stamens. Scale bars: A, 4 cm; B, 3 cm; C–E and G, 1 cm; F and H, 4 mm.
Drawn by K. Souvannakhoummane from Tagane et al. L1198 (FOF).
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| Fig. 2. Didymocarpus middletonii Souvann., Soulad. & Tagane in the type locality. A, Habit; B, abaxial surface of lamina; C, flower (front view); D, flower (lateral view). Scale bars: A, 4 cm; B–D, 1 cm.
Photographed by S. Tagane on 29 June 2017.
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Didymocarpus middletonii Souvann., Soulad. & Tagane, sp. nov.
Didymocarpus middletonii is similar to Didymocarpus brevicalyx Nangngam & D.J.Middleton, Didymocarpus formosus Nangngam & D.J.Middleton from Thailand and Didymocarpus puhoatensis X.Hong & F.Wen from Vietnam but differs from these three in having an urceolate calyx (versus campanulate) and a smaller corolla (c.3.4 cm long versus longer than 4.5 cm).
– Type: Laos, Nam Kading National Protected Area, Bolikhamxai Province, ..., 665 m elevation, 29 vi 2017, Tagane, S., Souladeth, P., Okabe, N., Yang, C.-J. L1198 [fl.] (holo FOF; iso E, HNL, P).
Distribution. Laos, Bolikhamxai Province (so far known only from the type locality).
Habitat and ecology. Didymocarpus middletonii grows on shaded rocks, along a stream in semi-evergreen forest. Given that most of the individuals seen during our field survey had flower buds, the species should be in full bloom in July.
Etymology. The specific epithet honours Dr David Middleton (Singapore Botanic Gardens), from whom we received the most generous advice regarding this new species.
Vernacular name. ດອກລຳໂພງຫີນສີມ່ວງ [Dok Lam Phong Hin Si Mouang (meaning: limestone purple funnel flower)].
K. Souvannakhoummane, P. Souladeth, S. Tagane, C.-J. Yang. and T. Yahara. 2019. Nam Kading National Protected Area VI: Didymocarpus middletonii (Gesneriaceae), A New Species from Limestone. Edinburgh Journal of Botany. DOI: 10.1017/S0960428618000264
