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| Curcuma siamensis Saensouk & Boonma in Saensouk, Boonma & Saensouk, 2021. |
Abstract.
Curcuma siamensis Saensouk & Boonma sp. nov. (Zingiberaceae: Zingibereae) belonging to the genus Curcuma subgenus Ecomatae, as herein described and illustrated discovered in Chachoengsao Province, Southeastern Thailand during our exploration of Zingiberaceae family in Thailand and in preparation for the revision of the genus Curcuma for the Flora of Thailand project. It is similar to Curcuma rangsimae Boonma & Saensouk in having terminal inflorescences between the leaf-sheaths, emerging at the basal of the pseudo-stem, lacking coma bract, yellow flowers, presence of epigynous glands, and anther spurs make this plant most similar to, which are also distributed in this nearby area too. But differ in having leaves narrowly elliptic, narrower and shorter in size 18–36 × 6–8.5 cm, upper midrib reddish; thyrse shorter and smaller (5–6.5 cm long, 4–5 cm in diam.); peduncle glabrous; bracts per inflorescence 10–15 in number, fused almost only at base; corolla lobes white, longer and narrower 17–18.3 × 6–7.8 mm; staminodes uniquely obovate-rhombic; labellum ovate-trullate; filament 4.4–4.5 mm long; anther longer c. 8 mm long, spurs pointing outward in front view, with anther crest apex retuse (vs. C. rangsimae having leaves narrowly elliptic to oblanceolate, 40–70 × 12–20 cm, upper midrib green; thyrse 12–20 cm long, 7.8–9.5 cm in diam.; peduncle pilose; 25–48 in number, connate 1/4 to 1/3 at base; corolla lobes light pale yellow, 15–17 × 9–12 mm; staminodes asymmetrical trullate–ovate; labellum ovate; filament 6–7 mm long; anther 6.3–6.9 mm long, spurs pointing downward in from view, with anther crest apex rounded). Based on the results of the morphological comparison and examination of all allied species in the same genus were found to be inconsistent with any species, especially in the subgenus Ecomatae. A comprehensive description, illustration, photographs, ecology, etymology, distribution and a revised key to 21species of Curcuma subgenus Ecomatae in Thailand are provided.
Keywords: Curcuma rangsimae, C. cotuana, Chachoengsao, Flora of Thailand, taxonomy, Zingiberales
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| Curcuma siamensis Saensouk & Boonma sp. nov. (A) habit, (B) side view of terminal inflorescence in the leaf-sheaths, (C) dorsalcorolla lobe, (D) lateral corolla lobes,(E) staminodes, (F) labellum, (G) bract, (H) bracteole, (I) calyx with ovary, (J) epigynous glands with ovary, (K) side and front view of anther. Drawn by Thawatphong Boonma |
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| Curcuma siamensis Saensouk & Boonma sp. nov. (A) Natural habitat in oblique-top view, C. siamensis (red midrib) grows near C. harmandii Gagnep., (B) plants with inflorescence and flowers in oblique-top view, (C) inflorescence with flowers in side view, (D) flower-front view, (E) anther-side and front view. Photographs A–D by N. Wannaphirun; E by Thawatphong Boonma |
Curcuma siamensis Saensouk & Boonma sp. nov.
Subgen. Ecomatae
The new species is similar to C. rangsimae Boonma & Saensouk. but differ in having leaves narrowly elliptic, narrower and shorter in size 18–36 × 6–8.5 cm, upper midrib reddish; thyrse shorter and smaller (5–6.5 cm long, 4–5 cm in diam.); peduncle glabrous; bracts per inflorescence 10–15 in number, fused almost only at base; corolla lobes white, longer and narrower 17–18.3 × 6–7.8 mm; staminodes uniquely obovate-rhombic; labellum ovate-trullate; filament 4.4–4.5 mm long; anther longer c. 8 mm long, spurs pointing outward in front view, with anther crest apex retuse (vs. C. rangsimae having leaves narrowly elliptic to oblanceolate, 40–70 × 12–20 cm, upper midrib green; thyrse 12–20 cm long, 7.8–9.5 cm in diam.; peduncle pilose; 25–48 in number, connate 1/4 to 1/3 at base; corolla lobes light pale yellow, 15–17 × 9–12 mm; staminodes asymmetrical trullate-ovate; labellum ovate; filament 6–7 mm long; anther 6.3–6.9 mm long, spurs pointing downward in from view, with anther crest apex rounded).
Etymology: The specific epithet “siamensis” is named from the former name of Thailand, refers to the geographical origin of this new species.
"ขมิ้นสยาม" "สุวรรณพนม" "มหาอุดมเหลืองนวล"
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| Distribution map of Curcuma siamensis Saensouk & Boonma sp. nov. and its allies. Abbreviations in the map are the floristic region after the "Flora of Thailand" project which N: Northern; NE: Northeastern; SW: Southwestern; C: Central; E: East; SE: Southeastern; and PEN:Peninsular. |
Saensouk P, Boonma T, Saensouk S. 2021. Curcuma siamensis (Zingiberaceae, Zingibereae), A New Species of Curcuma subgen. Ecomatae from Southeastern Thailand. Biodiversitas. 22(12); 5239-5246. DOI: 10.13057/biodiv/d221201 smujo.id/biodiv/article/view/9607
