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| Stemona namkhunensis Chatan & Promprom, in Promprom et Chatan, 2021. |
Abstract
Stemona namkhunensis Chatan & Promprom, a new species from the East of Thailand, is described and illustrated. It is morphologically similar to S. collinsiae Craib but clearly differs in the characteristic of the petiole, lamina, tepal, stamen, pistil, simple and pedunculated flower, and lacking bract. A morphological description, distribution, ecology, etymology, vernacular name, preliminary conservation status, and photographs are provided. A key to species of the erect species in Thailand is presented.
Keyword: Erect species, new species, Stemona collinsiae, taxonomy, Ubon Ratchathani Province
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| Stemona namkhunensis Chatan & Promprom. A. & B. Flowers, C. & D. tepals (adaxial and abaxial sides, respectively), E. Androeciym, F. and G. stamens (adaxial and abaxial sides, respectively), H. Gynoecium, I. Young fruit. Photos by: Wilawan Promprom. |
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| Stemona namkhunensis Chatan & Promprom sp. nov. A. Habits and Habit in the field, B. Habit in the author‘s home garden, C. Roots. Photos by: Wilawan Promprom. |
Stemona namkhunensis Chatan & Promprom, sp. nov.
Diagnosis: The most similar species of Stemona namkhunensis Chatan & Promprom is S. collinsiae Craib because they share similar morphological characters, including erect and glabrous herb, alternate leaves, long tepal (more than 15 mm long), inner tepals larger than outer tepals, and the absence of thecal appendage.
It differs from S. collinsiae Craib in having distinctly pulvinate petiole (vs. indistinct one), wider lamina with slightly fewer in a number of the vein (vs. smaller one with somewhat greater in number), Simple flower with no bract, and always with long peduncle (vs. inflorescence with bracts and peduncle, sometimes sessile inflorescence present near stem base), slightly narrower tepal, i.e., width and length ratio 1: 3.33–4.25 (vs. slightly wider one, i.e., width and length ratio 1: 2.0–3.6). Narrowly lanceolate to slightly linear stamen, ovate-cylindrical ovary, conspicuous stigma with retuse apex with two groups of hair ((vs. narrowly lanceolate stamen and ovate
ovary with inconspicuous and glabrous stigma).
Etymology: The epithet refers to Nam Khun District,
Ubon Ratchathani Province, where the type was collected.
Vernacular name: Non Tai Yak Phum - หนอนตายหยากพุ่ม
Wilawan Promprom and Wannachai Chatan. 2021. Stemona namkhunensis (Stemonaceae), A New Species from Eastern Thailand. Taiwania. 66(3); 332 - 336. DOI: 10.6165/tai.2021.66.332
