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| Begonia voluptuaria Lanors., Souvann. & Lamxay, in Lanorsavanh, Souvannakhoummane, Lamxay & Chanthavongsa, 2021. ສົ້ມກຸ້ງວຽງວັງ || DOI: 10.20531/tfb.2021.49.2.06 |
Abstract
Begonia cataracta and B. voluptuaria are described as new species and B. incerta is noted as a new record for Laos. Descriptions, illustrations and photographs are provided for the new species and photographs for the new record. Preliminary conservation assessments are made for the two new species which are assessed as Vulnerable and Critically Endangered respectively.
Keywords: Limestone flora, new taxa, new distribution, Cucurbitales, plant taxonomy, waterfall
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| ສົ້ມກຸ້ງແກ້ງຫຍຸຍ Begonia cataracta Souvann., Lanors. & Lamxay: A. habit; B. male flowers front view; C. male flower back view; D. female flower front view; E. female flower side view. All from Lanorsavanh & Lamxay SL2178 (type material). Photographs: S. Lanorsavanh. |
Begonia cataracta Souvann., Lanors. & Lamxay, sp. nov.
(Section Platycentrum).
Similar to Begonia rheophytica M.Hughes, but differs in having elliptic to elliptic-lanceolate leaves (vs narrowly lanceolate); lamina base obtuse (vs attenuate, sometimes unequal); 1–2-flowers per inflorescence (vs more than 5); and peduncles 6–11 cm long (vs 14–20 cm long). It is also similar to Begonia caobangensis C.I Peng & C.W.Lin but differs in having lamina base obtuse (vs attenuate); petioles terete, pilose (vs D-shaped, tomentose to glabrous); linear, ca 4 mm long (vs bracts ovate, ca 18 mm long); inflorescences 1- or 2-flowered (vs more than 5); and tepals of pistillate flowers 5, outer 4, inner 1 (vs tepals of pistillate flowers 6, outer 3, inner 3) (Table 1).
Distribution and habitat.— Known only from the type locality in Kaeng Nyui Waterfall, Nadouang Village, Vangvieng District, Vientiane Province. It is found on wet limestone rocks in mixed deciduous forest ca 400 m altitude.
Etymology.— The specific epithet ‘cataracta’ (Latin, waterfall) refers to the waterfall habitat of the species.
Vernacular.— ສົ້ມກຸ້ງແກ້ງຫຍຸຍ (Som koung kaeng nyui [Kaeng Nyui’s Begonia]).
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| ສົ້ມກຸ້ງວຽງວັງ Begonia voluptuaria Lanors., Souvann. & Lamxay: A. habit; B. male flowers front view; C. male flower side view; D. female flower front view; E. female flower side view. All from Lanorsavanh et al. SL1990 (type material). Photographs: S. Lanorsavanh. |
Begonia voluptuaria Lanors., Souvann. & Lamxay, sp. nov.
(Section Platycentrum).
Similar to Begonia dryadis Irmsch., but differs in having rhizomes globose (vs elongate); stems pilose (vs puberulous); stamens ca 50 (vs 100–160); outer pair of tepals of pistillate flowers lanceolate, strigose (vs broadly ovate, puberulous); and dorsal wing of ovary broadly falcate-linear, densely strigose,apex acute (vs dorsal wing oblong, puberulous, apex rounded). It is also similar to Begonia augustineiHemsl. but differs in having leaves lanceolate (vs ovate to broadly ovate); bracts lanceolate (vs oblong);and outer tepals of pistillate flowers lanceolate, strigose, inner tepals narrowly lanceolate (vs oblong to ovate, pilose, inner elliptic).
Distribution and habitat.— Known only from the type locality in Vangvieng District, Vientiane Province. It grows in sandy soil on limestone rocks in mixed evergreen forest ca 850 m altitude.
Etymology.— The specific epithet ‘voluptuaria’ (Latin, tourism) refers to the popularity with tourists of the area in Vangvieng district where the species grows.
Vernacular.— ສົ້ມກຸ້ງວຽງວັງ (Som koung vangvieng [Vangvieng’s Begonia]).
Soulivanh Lanorsavanh, Keooudone Souvannakhoummane, Vichith Lamxay and Khamfa Chanthavongsa. 2021. Two New Species and A New Record of Begonia (Begoniaceae) from Vangvieng Karst Limestone in central Laos. Thai Forest Bulletin (Botany). 49(2); 191-200. DOI: 10.20531/tfb.2021.49.2.06