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 | Curcuma achrae Saensouk & Boonma,
in Saensouk, Boonma & Saensouk, 2022. photos by Thawatphong Boonma |
Abstract Curcuma achrae Saensouk & Boonma, a new species of Curcuma subgenus Ecomata (Zingiberaceae) from Nakhon Nayok province, Central Thailand is described and illustrated along with photographs, notes on its distribution and habitat. A revised identification key to 68 species of the genus Curcuma in Thailand is also presented.
Keywords: Curcuma flaviflora, C. xanthella, Nakhon Nayok province, Taxonomy.
 | Curcuma achrae Saensouk & Boonma:
a. Habit–oblique top view; b. Flower–side view; c. Lateral staminodes; d. Labellum; e. Flower– front view; f. Stamen–side view; g. Dorsal corolla lobe; h. Lateral corolla lobes; i. Floral tube with ovary, calyx, and front view of stamen; j. Bract; k. Bracteole; l. Calyx; m. Ovary with epigynous glands; n. Inflorescence with flowers, rhizome, and tuberous roots
(from T. Boonma 24; drawn by Thawatphong Boonma). |
 | Curcuma achrae Saensouk & Boonma:
a. Plants in natural habitat; b. Pseudostem–top view; c. Pseudostem–side view; d. Distal part of sheathing bract–side view; e. Young inflorescence–side view; f. Anthesis in natural habitat
(a–c in September 2019; d in late April 2020; f. e & f in late March 2020, 2021 respectively; photos by Thawatphong Boonma). |
 | Curcuma achrae Saensouk & Boonma:
a. Flower, (upper row) dorsal corolla lobe and lateral corolla lobes, (lower row) two lateral staminodes, labellum, calyx, cross-section of flower, ovary with epigynous glands, bracteole, flower bud, and bract; b. Reddish V-shaped patch at base of staminode; c. Stamen–side, oblique side, front and back view; d. Inflorescence with rhizome, spike varied in sizes and colours–side view; e. Inflorescence–oblique top view; f. Close up flower–front view
(photos by Thawatphong Boonma). |
Curcuma achrae Saensouk & Boonma, sp. nov.
Similar to Curcuma xanthella Škornik. but differs. C. achrae having pubescent petioles (vs. glabrous), green with a reddish tinge (vs. green); adaxially sparsely hairy leaves with fine hairs along the midrib (vs. glabrous on both surfaces); fertile bracts connate in the lower 1/7 (vs. connate in the lower 1/4), apex mucronate (vs. narrowly acute); base of labellum white, middle and apical part golden yellow, with embossed two golden yellow median band running along the midrib from tip to base and divided into two Y-shaped patches at base (vs. base of labellum white to light yellow, middle and apical part warm yellow, with two yellow-orange swollen bars running across the center); staminodes irregularly ovate, apex acute, golden yellow gradually fades to pale yellow at base, with reddish V-shaped or triangle patch at base of staminodes (vs. staminodes irregularly oblong, apex obtuse, bright warm yellow without red patch); anther appear almost straight (vs. anther appear as L-shaped), spurs c. 3 mm long (vs. spurs c. 6 mm long), crest 3–4 mm long with apex acute to rounded or slightly truncate (vs. crest not obvious).
Habitat: Occurring at elevations of 60–152 m, growing in sandy loam soil at the boundary, close to the watercourse, in semi-open area in a deciduous forest.
Distribution: Curcuma achrae is known from the southwestern part of the Sankamphaeng mountain range in Mueang Nakhon Nayok district, Nakhon Nayok province, Central Thailand (Fig. 4).
Etymology: The specific epithet “achrae” is chosen to honour Assistant Professor Dr. Achra Thammathaworn (botanist of Khonkaen University), who is a specialist in botany and teacher of many Thai botanists. Vernacular name: Khamin Thong -- ขมิ้นทอง.
Surapon Saensouk, Thawatphong Boonma and Piyaporn Surapon Saensouk. 2022. Curcuma achrae (Zingiberaceae), A New Species from Central Thailand. Rheedea. 32(1); 30-45. DOI: 10.22244/rheedea.2022.32.01.03
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