Multilocus Phylogenetics of New World Milkweed Vines (Apocynaceae, Asclepiadoideae, Gonolobinae)

Evolution on the backbone: Apocynaceae phylogenomics and new perspectives on growth forms, flowers, and fruits

“…It has been shown that climbing and vining species readily give rise to self‐supporting descendent lineages (e.g., Wagner et al., ), and that the gain and loss of secondary growth is highly labile with lineage‐specific rates (Beaulieu et al., ). Such shifts have been documented previously at various phylogenetic depths in Apocynaceae (Lahaye et al., ; Livshultz et al., ; Joubert et al., ; McDonnell et al., ). It is noteworthy that we found the rate of change from herbaceousness to woodiness to be far greater than the reverse (Table ), reflecting the retention of woodiness through the slow diversification of rauvolfioid lineages and the numerous reversions to woodiness across the rapidly diversifying APSA clade (including reversals from subshrubs and other basally woody forms to trees and shrubs; Appendix S13).…”

“…Apocynaceae are typical of many angiosperm clades that are ancestrally tropical, woody, and with self‐supporting growth forms, and which have given rise to subtropical and temperate radiations of twining and herbaceous species (Raunkiaer, ; Stebbins, ; Takhtajan, ; reviewed by McDonnell et al., ). It has been shown that climbing and vining species readily give rise to self‐supporting descendent lineages (e.g., Wagner et al., ), and that the gain and loss of secondary growth is highly labile with lineage‐specific rates (Beaulieu et al., ).…”

“…(), including style differentiation, ovary fusion, fruit type, and seed morphology. At the subtribal level, evolution of corolla form (McDonnell et al., ) and fruit ornamentation (Krings et al., ; McDonnell et al., ) have been analyzed in Gonolobinae. For example, McDonnell et al.…”

“…For example, McDonnell et al. () showed high lability in the gain and loss of a corolla tube. Comparable studies in other families are rare and have reached conflicting conclusions.…”

“…Vegetative traits are less often studied in Apocynaceae, but growth form evolution was analyzed in the APSA clade (Livshultz et al., ), in Secamonoideae (Lahaye et al., ), and Gonolobinae (McDonnell et al., ). In each case, twining was shown to be derived from self‐supporting growth forms with subsequent reversals.…”