Curcuma roseobracteata sp. nov. (Zingiberaceae), a new species from Thailand and distribution notes on the recently described C. suraponii Boonma

PIYAPORN SAENSOUK (Diversity of Family Zingiberaceae and Vascular Plant for Its Applications Research Unit, Department of Biology, Faculty of Science, Mahasarakham University. Kantarawichai District, Maha Sarakham 44150, Thailand)
SURAPON SAENSOUK (Diversity of family Zingiberaceae and Vascular Plant for Its Applications Research Unit, Walai Rukhavej Botanical Research Institute, Mahasarakham University. Kantarawichai District, Maha Sarakham 44150, Thailand)
CHARUN MAKNOI (Romklao Botanic Garden, The Botanical Garden Organization. Phitsanulok 65170, Thailand)
DANH DUC NGUYEN (Institute of Innovation in Pharmaceutical and Healthcare Food, Thu Dau Mot University. 6 Tran Van On, Phu Hoa Ward, Thu Dau Mot City, Vietnam)
THAWATPHONG BOONMA (Brio Botanical Research Garden. 53 M. 5 Phikun-ok, Ban Na, Nakhon Nayok 26110, Thailand)

Biodiversitas Journal of Biological Diversity
Vol. 25 No. 8 (2024)

Abstract. Saensouk P, Saensouk S, Maknoi C, Nguyen DD, Boonma T. 2024. Curcuma roseobracteata sp. nov. (Zingiberaceae), a new species from Thailand and distribution notes on the recently described C. suraponii Boonma. Biodiversitas 25: 3368-3375. Curcuma roseobracteata P. Saensouk, Saensouk, Maknoi & Boonma sp. nov., a newly identified species within the Curcuma subgenus Curcuma of the Zingiberaceae family, has been found in the northern and southwestern floristic regions of Thailand, distributed in Mae Hong Son, Tak, and Kanchanaburi Provinces. This new species shares similarities with C. rubrobracteata Škorni?ková, M. Sabu & Prasanthkumar, and C. suraponii Boonma, but differentiated by its lemon yellow rhizome; leaves base broadly cuneate to rounded, or cordate, abaxial surface with scattered hairs; thyrse oblong ovoid; fertile bracts obovate, rose pink with a pale green base; coma bracts inconspicuous, with 1-4 in number; bracteoles apex rounded with short mucronate; filament c. 3 × 6 mm; anther c. 8.5 × 3.5 mm; epigynous glands c. 4.5 mm long; ovary 2.5-3 × 2.5 mm. The new taxon is formally described here, detailing its morphological characteristics, vernacular name, ecology, phenology, and distribution, which includes updates on the presence of C. suraponii, previously recorded only in Tak Province, but now also observed in Mae Hong Son Province. The study includes an IUCN conservation assessment based on recent collections and presents a revised taxonomic key to differentiate the new species from its relatives.