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| Boesenbergia calcicola Boonma, Saensouk & P.Saensouk, in Boonma, S. Saensouk, P. Saensouk, Ruengrit, Srisuk, Ruannakarn et Naing, 2026. |
Abstract
Limestone karst habitats in tropical Asia support specialized and geographically restricted plant diversity, yet many areas remain incompletely explored. During botanical surveys of limestone habitats in northeastern Thailand, a distinctive, yellow-flowered population of Boesenbergia was discovered in Phu Pha Man District, Khon Kaen Province. Morphological observations were conducted on living plants in the natural population and spirit-preserved material, supplemented by comparisons with protologues, published descriptions, and herbarium material. Patterns of phenetic similarity among ten selected Boesenbergia taxa were evaluated using 32 morphological characters, Gower distance, UPGMA clustering, and principal coordinates analysis (PCoA). The population is described here as Boesenbergia calcicola Boonma, Saensouk & P.Saensouk, sp. nov. It is morphologically most comparable to B. petiolata but differs by its conspicuously exserted inflorescence, shorter bracts and flowers, distally puberulent floral tube, smaller puberulent lateral staminodes, and distinctive labellum color pattern. Phenetic analyses were used to summarize patterns of overall morphological similarity among the examined taxa. The species is currently known only from its limestone type locality at approximately 385 m a.s.l. and is provisionally assessed as Data Deficient (DD). This discovery further documents localized Boesenbergia diversity associated with limestone karst habitats in northeastern Thailand.
Keywords: Boesenbergia; karst; limestone; new species; northeastern; taxonomy; Thailand
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| Boesenbergia calcicola Boonma, Saensouk & P.Saensouk, sp. nov. (a,b) Habit in natural habitat. (c) Dissected rhizome and tuberous root. (d) Lateral view of flower. (e) Dorsal corolla lobe. (f) Lateral view of corolla lobe. (g) Lateral staminodes. (h) Calyx and ovary. (i) Floral tube and stamen with calyx and ovary. (j) Back view of anther. (k) Front view of ovary. (l) Bract. (m) Bracteole. (n) Ovary with epigynous glands. (o) Labellum, flattened under a glass plate to show its fully expanded shape. Photographs (a,b) by Mukdamas Ruengrit and (c–o) by Thawatphong Boonma. |
Boesenbergia calcicola Boonma, Saensouk & P.Saensouk
Diagnosis. Boesenbergia calcicola is morphologically similar to B. petiolata Sirirugsa in having a terminal inflorescence, lanceolate bracts, a broadly ovate to nearly orbicular labellum when flattened, and an anther crest absent, but differs by its inflorescence conspicuously exserted beyond the leafy shoot (vs. enclosed within or only shortly exserted from the upper leaf sheaths), shorter bracts, 1.5–2.5 cm long (vs. 3–4 cm long), shorter flowers, 2.0–2.5 cm long in lateral projection (vs. c. 4 cm long), a shorter calyx, 3.2–4.8 mm long (vs. c. 5 mm long), a floral tube 1.5–2.5 cm long and sparsely puberulent ...
Etymology: The specific epithet “calcicola” is derived from the Latin calx (genitive calcis), meaning “lime” or “limestone”, and -cola, meaning “dweller”, referring to the occurrence of the species on limestone substrates in Phu Pha Man District, Khon Kaen Province, northeastern Thailand.
Thawatphong Boonma, Surapon Saensouk, Piyaporn Saensouk, Mukdamas Ruengrit, Pathomthat Srisuk, Prasert Ruannakarn and Min Khant Naing. 2026. Further Botanical Exploration of Limestone Karst Habitats in Northeastern Thailand Reveals a New Yellow-Flowered Species of Boesenbergia Kuntze (Zingiberaceae). Life. 2026, 16(9), 1480; DOI: doi.org/10.3390/life16091480 [4 September 2026]
