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| Argyreia collinsiae subsp. megabracteata Traiperm & Srisombat, Srisombat, Chitchak, Rattanakrajang, Stewart et Traiperm,. 2024. DOI: 10.7717/peerj.18294 |
Abstract
Argyreia Lour. is a speciose genus in the Convolvulaceae. However, the genus contains several problematic species complexes due to their morphological similarity. In this study, we aimed to resolve the Argyreia collinsiae complex, which consists of four similar operational taxonomic units (OTUs), i.e., A. collinsiae (Craib) Na Songkhla & Traiperm, A. dokmaihom Traiperm & Staples, A. versicolor (Kerr) Staples & Traiperm, and a peculiar OTU typically known as the large-bract morphotype of A. collinsiae. Following morphological comparison and phenetic analysis, all four OTUs were found to be distinct. However, the large-bract morphotype of A. collinsiae was confirmed to be more closely related to the original morphotype of A. collinsiae than to the other two species. Species distribution modeling (SDM) was then conducted for both morphotypes of A. collinsiae, revealing different geographical ranges of suitable habitat for each. In conclusion, the large-bract morphotype of A. collinsiae was described in this study as a new subspecies, A. collinsiae subsp. megabracteata Traiperm & Srisombat, subsp. nov., based on morphological differences and separate geographic range. We also provide here an identification key, description, detailed illustrations, distribution data, and ecological notes of the new subspecies. An updated description of A. versicolor and an assessment of its conservation status were also prepared since the original description was based solely on dried herbarium specimens and lacks key details.
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Original A. collinsiae morphotype, Argyreia collinsiae subsp. megabracteata Traiperm & Srisombat, subsp. nov., A. dokmaihom and A. versicolor |
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| Macro and micro morphology of the four studied Argyreia OTUs. Original A. collinsiae morphotype (A, E, I, M: Y. Sirichamorn (2018) 10; Q, U: P. Rattanakrajang et al. 143), large-bract A. collinsiae morphotype (B, F, J, N, R, V: P. Hassa 17), A. dokmaihom (C, G, K, O: Staples et al. 1546; S, W: P. Rattanakrajang et al. 137) and A. versicolor (D, H, L, P: A. Jirabanjongjit et al. 08; T, X: P. Traiperm et al. 630). Non-glandular trichomes (Y, Z, AA, AB) consisted of simple straight non-glandular trichomes (Y-Z, AB), and non-glandular trichomes with bicellular-branched apical cells (AA). Glandular trichomes (AC-AF) consisted of short-stalked glandular trichomes (AC-AF), and long-stalked glandular trichomes (AF). Photos by N. Chitchak (AA, AF), P. Hassa (R, V: P. Hassa 17), P. Rattanakrajang (S, T, W, X: P. Rattanakrajang et al. 137, P. Traiperm et al. 630), P. Srisombat (Y-Z, AB-AE) and W. Inta (Q, U: P. Rattanakrajang et al. 143). Red arrowhead indicates non-glandular trichome on the abaxial surface of the mid-petaline band. Abbreviations: ap, apical cell; bc, bicellular-branched apical cell; ls, long-stalked glandular trichome; ss, short-stalked glandular trichome; st, stalk. |
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| Argyreia collinsiae subsp. megabracteata Traiperm & Srisombat, subsp. nov. Plant habit (A), inflorescence (B), and fruits (C). Photos by N. Chitchak; (A, B) P. Traiperm et al. 625 and (C) P. Srisombat 05. |
Argyreia collinsiae (Craib) Na Songkhla & Traiperm,
Thai Forest Bull., Bot. 33: 42. 2005
Subsp. megabracteata Traiperm & Srisombat, subsp. nov.
Distribution: Thailand (Northeastern and Eastern).
Habitat: Dry deciduous forest, mixed evergreen-deciduous forest, canal bank, roadside, and rice fields
Etymology: The epithet ‘megabracteata’ is derived from prominent bracts larger than the original mophotype.
Poompat Srisombat, Natthaphong Chitchak, Pantamith Rattanakrajang, Alyssa B. Stewart and Paweena Traiperm. 2024. The Argyreia collinsiae Species Complex (Convolvulaceae): Phenetic Analysis and Geographic Distribution reveal Subspecies New to Science. PeerJ. 12:e18294. DOI: doi.org/10.7717/peerj.18294
