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| Curcuma rangjued Saensouk & Boonma in Saensouk, Boonma & Saensouk, 2021. รางจืดขมิ้น || smujo.id/biodiv |
Abstract
Recent fieldwork to study the species diversity of the Zingiberaceae family in Thailand and preparing a revision of the Curcuma genus for the Flora of Thailand, an undescribed species of Curcuma uses as traditional medicinal for more than two decades well known in the Thai vernacular name “Rang-Jued” was found, this vernacular name is also used to call the other two medicinal plants belonging to different families which are Thunbergia laurifolia Lindl. (Acanthaceae), and Crotalaria spectabilis Roth (Fabaceae), thus some villagers are named Curcuma rangjued as “Rang-Jued-Khamin” to communicate specifically identify species in order to use correct species for each utilization. While Thunbergia laurifolia was called "Rang-Jued-Thao", which "Thao" means "vine" refers to its habit and Crotalaria spectabilis was called "Rang-Jued-Ton" which "Ton" means "stem" refers to its erect stems. After comparing this undescribed species of Curcuma with its allies species, we found that this species did not match with any existing taxa, thus described with detailed illustrations, photographs, summaries for its distribution, ecology in the name of Curcuma rangjued Saensouk & Boonma and followed by a new record of C. cordata Wall. for Thailand which in the past has been determined as a synonym of C. petiolata Roxb. but now it is back to a recognized name once again. Both species in this study were found distributed in the northern region of Thailand and belong to Curcuma subgenus Curcuma, their description along with ecology, phenology, and a revised key to 28 species of Curcuma subgenus Curcuma in Thailand are also present for facilitating identification.
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| Curcuma rangjued Saensouk & Boonma sp. nov. (A) habit, (B) front and side view of anther, (C) side view of terminal inflorescence in the leaf-sheaths, (D) dorsal corolla lobe, (E) lateral corolla lobe,(F) lateral staminode, (G) labellum, (H) epigynous glands with ovary, (I) calyx; J, bracteole; K, side view of flower. Drawn by Thawatphong Boonma. |
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| Curcuma rangjued Saensouk & Boonma sp. nov. (A) flower-top view, (B) inflorescence with flowers-top view, (C) anther -side and front view, (D) rhizome, (E) inflorescence with flowers -side view. Photographed by Thawatphong Boonma. |
Curcuma rangjued Saensouk & Boonma, sp. nov.
subgenus Curcuma
Curcuma rangjued is belonged to the subgenus Curcuma according to the presence of epigynous glands, inflorescence with coma bracts, flowers closed-form, anther spurs acuteand downward-pointed. The morphological description in having rhizome pale yellow tone internally and producing terminal inflorescence of C. rangjued make it similar to C. amada and C. sichuanensis, but differ in having non-aromatic rhizome whereas C. amada and C. sichuanensis having a smell of green mango and smell of camphor respectively. Moreover, in having leaf-adaxially sparsely hairy along the vein, peduncle long 25–37 cm long, less number of fertile bracts (7–12 per inflorescence), calyx light pale yellow, 1.64–1.75 cm long, floral tube 3.3–3.5 cm long, corolla lobes hairy at distal part and anther spurs 3–4 mm long which distinguishes C. rangjued from C. amada and C. sichuanensis (Table 1).
Etymology: The specific epithet "rangjued" is derived from Thai vernacular name of this species which means“to make the poison fade or decrease”
Surapon Saensouk, Thawatphong Boonma and Piyaporn Saensouk. 2021. A New Species and A New Record of Curcuma subgen. Curcuma (Zingiberaceae) from Northern Thailand. Biodiversitas. 22(9); 3661-3670.
