Reinstating Palaeotropical genera of Convolvulaceae: Argyreia, Stictocardia, Turbina and Astripomoea (tribe Ipomoeeae, subtribe Argyreiineae)

Simões A.R.G.*, Shimpale V.B., Rattanakrajang P., Traiperm P., Kagame S.P., Huerta-Ramos G., Goray S., Gowda V., Nayi T., Moreira A.L.C., Barbosa J.C.J., More, S.S., Paixão C.P., Atta-Adjei P., Williams B.D. & L.A. Eserman

Published on : 31-Dec-2024

DOI : https://dx.doi.org/10.22244/rheedea.2024.34.05.15

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Abstract

Ipomoeeae, the most diverse tribe inConvolvulaceae, contains 815 species, nearly half ofthe species diversity of the family. Its largest genus,Ipomoea, is morphologically highly variable and hasrepeatedly been demonstrated to be polyphyletic, withseveral Palaeotropical genera nested within it. A genericreclassification of the tribe is, however, still lagging dueto the sizeable task of sequencing and morphologicallycharacterising the 815 species, and an intricacy relatedto the type species of Ipomoea, which could lead to amajor nomenclatural destabilisation - especially in theNeotropical region, where the greatest diversity of Ipomoeais concentrated. Previous researchers, while makinggood progress in molecular studies of Ipomoeeae, haveopted to consolidate all the previously recognised generaof Ipomoeeae into an even broader, morphologicallyambiguous, Ipomoea.This resulted in 206 nomenclaturalchanges, of whichonly 5 Neotropical taxa, and theremaining 201 African, Asian, Australian, or Malagasy taxa; therefore, with the greatest impact on species and genera from the Eastern Hemisphere. We suggest that tribe Ipomoeeae is better understood as a collection of smaller, morphologically distinguishable clades rather than a single expanded genus, morphologically more challenging to circumscribe, with greater benefits also for species conservation, as species of genus Ipomoea tend to be negatively perceived as weeds in the Eastern Hemisphere. As the nomenclatural blockage to re-classifying this complex group has now been resolved, with the proposal of a new type species, we propose the reinstatement of the most clearly delimited and phylogenetically distinct, Palaeotropical genera of the tribe - Argyreia, Astripomoea, Turbina and Stictocardia. As these genera are widely recognised (e.g. in herbarium collections, local Floras, and databases), this will allow to minimise nomenclatural disruption caused by the proposed transfer into Ipomoea, before it becomes more widely implemented, and thus mitigating the impact of these name changes on biodiversity monitoring, conservation, horticulture, or citizen science. This will also be a contribution for an improved classification of tribe Ipomoeeae, for which an integrative and more equitable approach, with the contribution of taxonomists from the Eastern Hemisphere, and further sampling in this region, will be pillar.