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| Curcuma peninsularis Saensouk, P.Saensouk, Maknoi & Boonma, in P. Saensouk, S. Saensouk, Maknoi, Setyawan et Boonma, 2024. Photographs by Thawatphong Boonma & Ornicha Chinkam. |
Abstract
The genus Curcuma L. (Zingiberaceae) is highly diverse and often exhibits similar morphological appearances, leading to frequent misidentifications that impact botanical practices, horticultural activities, and conservation efforts. This study addresses the taxonomic confusion surrounding the plant locally known as “Ploy Thaksin”, which was previously misidentified as Curcuma aurantiaca Zijp. To resolve this issue, we conducted a detailed morphological analysis and reviewed the protologues descriptions of its ally species, focusing on anther characteristics and other key features. Our findings reveal that “Ploy Thaksin” actually represents two distinct species: one correctly identified as C. aurantiaca found in lower Peninsular Thailand (Satun and Trang Provinces), and another species, characterized by calcarate anthers found in upper Peninsular Thailand which resemble C. sumatrana Miq., C. nepalensis M.Sabu, Kasaju, and S.Subedi, described here as a new species under the name “Curcuma peninsularis Saensouk, P.Saensouk, Maknoi, and Boonma” along with the details of a description, illustration, map of distribution, vernacular name, ecology, phenology, utilization, and economic value, including the proposal of a conservation status. This study clarifies previous misidentifications and underscores the importance of precise taxonomic practices for the accurate classification and conservation of Curcuma species. The results provide valuable insights for future research and horticultural applications, enhancing the understanding of Curcuma biodiversity.
Keywords: Curcuma; diversity; horticulture; new species; taxonomy; Thailand; Zingiberaceae
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| Curcuma peninsularis Saensouk, P.Saensouk, Maknoi, and Boonma sp. nov. (a) habit; (b) front view of flower; (c) top view of inflorescence; (d) clump-forming growth habit. Photographs by Ornicha Chinkam and Thawatphong Boonma. |
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| Curcuma peninsularis Saensouk, P.Saensouk, Maknoi, and Boonma sp. nov. (a) leaf apex on abaxial side with slightly reddish tinge; (b) reddish along the midrib both adaxial and abaxial side of leaves; (c) ligules; (d) rhizome and tuberous root with dissected part; (e) plants in a rubber plantation connected to a natural forest, Ranong Province, Peninsular Thailand. Photographs (a–d) by Thawatphong Boonma, (e) by Ornicha Chinkam. |
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| Curcuma peninsularis Saensouk, P.Saensouk, Maknoi, and Boonma sp. nov. (a) front and side views of anther; (b) lateral corolla lobes; (c) dorsal corolla lobe; (d) lateral staminodes; (e) labellum; (f) bracteole; (g) habits; (h) fruit with calyx; (i) ovary with epigynous glands; (j) inflorescent with flowers. Drawn by Thawatphong Boonma. |
Curcuma peninsularis Saensouk, P.Saensouk, Maknoi, and Boonma sp. nov.
Diagnosis: The new species is similar to C. sumatrana Miq but differentiated by its pale yellow rhizome (vs. C. sumatrana with a light purple and cream rhizome); 16–22 mm-long ligule (vs. c. 3 mm-long); 25–45 cm-long peduncle (vs. 4–18 cm-long); 25–42 × 10–12 cm thyrse (vs. 14–25 × 5.5–7 cm); 70–98 bracts per inflorescence (vs. 15–29); broadly obovate fertile bracts, dark red or dark reddish brown, with a pale green base (vs. ovate-elliptic, bright red, gradually becoming a yellowish cream base); 3.6–4.2 cm-long fused bracts (vs. 3.0–3.3 cm-long); 1.8–3 cm bracteole (vs. c. 1.3 cm-long); 5.3–5.8 cm-long flowers (vs. c. 6.5 cm-long); pubescent floral tube (vs. glabrous); pale yellowish, pubescent corolla lobe (vs. white, glabrous); pubescent lateral staminodes (vs. glabrous); pubescent filament (vs. glabrous); 1.5–2 mm-long anther spurs (vs. 3 mm-long).
Etymology: The specific epithet “peninsularis” denotes the species’ native habitat in the Peninsular floristic region of Thailand, underscoring its geographical distribution.
Vernacular name: “Ploy Andaman” is derived from Thai, where ‘Ploy’ means ‘gem’ or ‘jewel’ and ‘Andaman’ refers to the Andaman Sea. This name highlights the beauty and uniqueness of the species, found on the peninsular side of the Andaman Sea and the islands within it. The term emphasizes the splendid inflorescence, which is likened to a jewel of the Andaman Sea. Similarly, the vernacular name “Ploy Thaksin” merges “Ploy” with “Thaksin”, which denotes the southern region of Thailand. This name emphasizes the species’ occurrence in the southern part of the country. Both names highlight the species’ connection to specific geographic locations.
Distribution: This newly described species is currently known only from Peninsular Thailand, in the Ranong and Phang-Nga Provinces.
Habitat: Curcuma peninsularis is found at the edge of the forest, at the foot of the mountain, and in former forest areas that have been converted into rubber and palm plantations. In a nearby forest, various plants in the ginger family were observed. Notable species in these areas include Globba pendula Roxb., G. ranongensis Picheans. and Tiyaw., Kaempferia pulchra Ridl., Zingiber longibracteatum Theilade, and Z. montanum (J.Koenig) Link ex A.Dietr.
Piyaporn Saensouk, Surapon Saensouk, Charun Maknoi, Ahmad Dwi Setyawan and Thawatphong Boonma. 2024. A Horticultural Gem Unveiled: Curcuma peninsularis sp. nov. (Zingiberaceae), A New Species from Peninsular Thailand, Previously Misidentified as Curcuma aurantiaca Zijp. Horticulturae. 10(9); 950. DOI: doi.org/10.3390/horticulturae10090950
