Curcuma siamensis (Zingiberaceae, Zingibereae), a new species of Curcuma subgen. Ecomatae from Southeastern Thailand Curcuma siamensis (Zingiberaceae: Zingibereae), a new species of Curcuma subgen. Ecomatae from Southeastern Thailand

##plugins.themes.bootstrap3.article.main##

PIYAPORN SAENSOUK
THAWATPHONG BOONMA
SURAPON SAENSOUK

Abstract

Abstract. Saensouk P, Boonma T, Saensouk S. 2021. Curcuma siamensis (Zingiberaceae, Zingibereae), a new species of Curcuma subgen. Ecomatae from Southeastern Thailand. Biodiversitas 22: 5239-5246. 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.

##plugins.themes.bootstrap3.article.details##

References
Kew Science. 2021. World checklist of selected plant families (WCSP). http://apps.kew.org/wcsp/
Larsen K, Larsen SS. 2006. Gingers of Thailand. Queen Sirikit Botanic Garden, The Botanical Garden Organization,
Chiang Mai.
Leong-Škorni?ková J and M. Newman 2015. Gingers of Cambodia, Laos & Vietnam. Singapore Botanic Garden,
National Parks Board, Royal Botanic Garden Edinburgh
Leong-Škorni?ková J, Šida O, Záveská E, Marhold K. 2015. History of infrageneric classification, typification of supraspecific names and outstanding transfers in Curcuma (Zingiberaceae). Taxon 64(2): 362–373.
Maknoi C, Saensouk S, Saensouk P, Rakarcha S, Thammarong W. 2021. Two new species of Curcuma L.
(Zingiberaceae) from Thailand. Biodiversitas 22(9): 3910–3921.
Saensouk S, Boonma T, Saensouk P. 2021. Six new species and a new record of Curcuma L. (Zingiberaceae)
from Thailand. Biodiversitas 22(4): 1658–1685.
Sirirugsa P. 1966. The genus Curcuma L. (Zingiberaceae) in Thailand. Prince of Songkla University.
Sirirugsa P, Larsen K, Maknoi C. 2007. The Genus Curcuma L. (Zingiberaceae): Distribution and
Classification with Reference to Species Diversity in Thailand. Gardens’ Bull. Singapore 59(1&2): 203–220.
Tanaka N, Aung MM. 2019. Taxonomic studies on Zingiberaceae of Myanmar I: A new species of Curcuma
(Subgenus Ecomatae) from Myanmar. Phytotaxa 387(2): 241–248.
Tanaka N, Armstrong K, Aung MM, Naiki A. 2020. Taxonomic studies on Zingiberaceae of Myanmar II:
Curcuma stolonifera (Subgenus Ecomatae), a new species from the northwestern region.
Brittonia 72(3): 268–272.
Záveská E, Fér T, Šida O, Krak K, Marhold K, Leong-Škorni?ková J. 2012. Phylogeny of Curcuma (Zingiberaceae) based on plastid and nuclear sequences: Proposal of the new subgenus Ecomata. Taxon 61(4): 747–763.