Citation for Study 13806
Costea M., Garcia I., Docksteder K., & Stefanovic S. 2013. More problems despite bigger flowers: systematics of Cuscuta tinctoria clade (subgenus Grammica, Convolvulaceae) with description of six new species. Systematic Botany, .
- Costea M.
- Garcia I.
- Docksteder K.
- Stefanovic S. (submitter) +1-905-569-4271
Cuscuta tinctoria clade, the second largest infrageneric group of subg. Grammica, includes 14 species with Mexico and adjacent regions as a center of diversity, but also two species found in Australia presumably as a result of a long-distance dispersal event. Flowers, pollen, and stigmas are among the largest in Cuscuta, and plants are xenogamous or facultatively xenogamous. Perhaps more than in other major clades of subg. Grammica, the convergent evolution of some important morphological characters, for example of the calyx and gynoecium/capsule, has obscured identity of some species and has hindered previous efforts to determine their limits. Basic morphology, scanning electron microscopy and sequence data from the nuclear internal transcribed spacer (ITS) and the plastid trnL-F region were used to reconstruct the phylogeny, gain a better understanding of the evolutionary history, and determine species boundaries. Overall, species were grouped in five subclades. Based on their morphological and molecular similarly, C. tinctoria, C. aurea, and C. floribunda represent one single species. The latter two species were retained as a variety of the former, C. tinctoria var. aurea and var. floribunda, respectively. Our results also show that in their currently accepted delimitation C. rugosiceps and C. tinctoria are polyphyletic, the former including one new species, C. volcanica, and the latter two new species, C. timida and C. tolteca. In addition, three other new species are described: two that have multicellular protuberances on the calyx and/or corolla lobes, C. iguanella and C. insolita, and one with broader that long calyx lobes, C. montana. A taxonomic treatment with an identification key, descriptions, and illustrations is provided.
Australia, Cuscuta, dodders, evolution, floristics, geographical distribution, host range, ITS, morphology, Mexico, new species, North and Central America, parasitic, phenology, phylogeny, taxonomy, trnL-F
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