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| Chlorohiptage vietnamensis T.V.Do, T.A.Le & R.F.Almeida, in Do, Lu, Le, Lam, Trinh, Deguine, Hoang et Almeida, 2024. |
Abstract
Background and aims – Vietnam is one of the leading diversity centres for Asian Malpighiaceae, comprising 24 accepted species and three native genera (i.e. Aspidopterys, Hiptage, and Tristellateia). During recent fieldwork towards completing the taxonomic revision of Malpighiaceae for the Flora of Vietnam, we have collected specimens from two populations that could not be placed in any of the three native genera of this family. We performed morphological and molecular phylogenetic studies to test the generic placement of those specimens.
Material and methods – We sampled 27 genera (including the Asian Acridocarpus, Aspidopterys, Brachylophon, Hiptage, Stigmaphyllon, and Tristellateia, out of a total of 75) of Malpighiaceae representing all phylogenetic clades comprising paleotropical lineages (i.e. acridocarpoids, bunchosioids, tetrapteroids, malpighioids, and stigmaphylloids), the unusual specimen recently collected in Vietnam, and the two genera of Elatinaceae as outgroups. Maximum Likelihood analysis was carried out based on a molecular matrix alignment of the internal transcribed spacer marker (ITS). Comprehensive morphological analyses were also carried out based on the collected specimens and additional herbarium specimens.
Key results – Our molecular phylogeny strongly supported the unusual specimen from Vietnam placed as sister to Hiptage in the tetrapteroid clade. Key morphological traits differing these Vietnamese specimens from Hiptage were identified related to the floral bud imbrication, shape, colour, posture of sepals and petals, length of stamen filaments, number of styles, and shape of mericarps, allowing the proposition of a new monospecific genus.
Conclusions – Chlorohiptage vietnamensis is proposed as a new monospecific genus closely related to Hiptage but differing in several key morphological traits. A complete morphological description is provided alongside photographic illustrations and notes on its conservation, distribution, ecology, etymology, and taxonomy. Additionally, an updated identification key to the genera of the tetrapteroid clade is provided.
Keywords: Asia, Hiptage, Malpighiales, systematics, taxonomy, tetrapteroid
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| Comparison of morphological traits of Chlorohiptage T.V.Do, T.A.Le & R.F.Almeida, gen. nov. with Hiptage and Aspidopterys. A–D. Chlorohiptage. A. Leaves with two basal glands. B. Close up of a thyrse. C. A flower without petals showing the androecium and gynoecium structure and eglandular calyx. D. Close up of a mericarp. E–H. Hiptage benghalensis (L.) Kurz. E. Leaves with two basal glands and marginal glands. F. Close up of a thyrse showing glandular calyces. G. Flower showing the androecium and gynoecium structure and petal with fimbriate margins. H. Close up of mericarp. I–K Aspidopterys tomentosa (Blume) A.Juss. I. Leaves eglandular. J. Floral bud showing eglandular calyx. K. Flower showing the androecium and gynoecium structure and petals with margin entire. L. Shape of mericarp. Photographed and designed by Truong Van Do, Anh Tuan Le, and Rafael Felipe de Almeida. |
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| Photographic plate of Chlorohiptage vietnamensis T.V.Do, T.A.Le & R.F.Almeida, sp. nov. A. Leaves with two basal glands (indicated by red arrows). B. Close up of a thyrse. C. Open flower. D. Shape of petals. E. Flower without petals showing the androecium and gynoecium structure and the eglandular calyx. F. Close up of a 3-styled gynoecium. G–I. Close up of the androecium structure. J. Immature mericarp. K. Shape of the mature mericarp. Photographed and designed by Truong Van Do, Anh Tuan Le, and Rafael Felipe de Almeida (scale bars 1 mm). |
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| Photos of Chlorohiptage vietnamensis T.V.Do, T.A.Le & R.F.Almeida, sp. nov. from the original population in the natural habitat. A. Habitat. B. Habit. C. Branch bearing thyrses. D. Close up of a thyrse. E. Branch bearing mature mericarps. Photographed and designed by Truong Van Do and Anh Tuan Le. |
Chlorohiptage T.V.Do, T.A.Le & R.F.Almeida, gen. nov.
Chlorohiptage vietnamensis T.V.Do, T.A.Le & R.F.Almeida, sp. nov.
Diagnosis: Distinguished from Hiptage by its floral buds valvate (vs imbricate), petals pale-green to yellowish-green (vs white to yellow) with margins erose and velutine (vs dentate to fimbriate and glabrous), stamens 9 long + 1 short (vs 9 short + 1 long), styles 3 (vs 1-2), shorter than filaments of the stamens (vs longer than filaments of the stamens), mericarps with 1 lateral wing, 3-lobed (vs 3 free lateral wings).
Etymology: The name Chlorohiptage is the combination of the Greek words “chlorós” (= green) and “hiptamai” (= to fly), referring to the unique green flowers of this Hiptage look-alike new genus.
Notes: Chlorohiptage is endemic to open subtropical broad-leaved evergreen forests and limestone-steeped mountains in Central Vietnam at ca 100–250 m.
Chlorohiptage vietnamensis T.V.Do, T.A.Le & R.F.Almeida, sp. nov.
Truong Van Do, Ngan Thi Lu, Anh Tuan Le, Mai Xuan Thi Lam, Xuan Thi Trinh, Jean-Philippe Deguine, Thao Thi Hoang and Rafael Felipe de Almeida. 2024. Chlorohiptage (Tetrapteroids, Malpighiaceae), A distinct New Genus endemic to Vietnam based on morphological and molecular data. Plant Ecology and Evolution. 157(2): 125-136. DOI: 10.5091/plecevo.115623