Asclepiadeae classification: evaluating the phylogenetic relationships of New World Asclepiadoideae (Apocynaceae)

Abstract

To provide an overview of New World Asclepiadoideae, we here evaluate Asclepiadeae classification by comparing the taxonomic arrangement of subtribes with a topology obtained through analyses of two plastid DNA regions (trnL intron and trnL­F intergenic spacer) for 111 species of Asclepiadoideae representing the major lineages of the subfamily. Without Jobinia, Nephradenia and Barjonia, Asclepiadeae are not monophyletic. The monotypic African genus Eustegia, with pendent pollinia, may represent the sister clade of Marsdenieae ­ Ceropegieae, the group composed of plants with erect pollinia. Metastelmatinae including African plants are also non­monophyletic, and the circumscription of the recently re­instated Cynanchinae should be studied further. Overall, Asclepiadeae are composed of three main clades. The Old World Astephaninae are the sister group of the other Asclepiadeae, which are divided into the ACTG (Asclepiadinae, Cynanchinae, Tylophorinae and Glossonematinae) and MOG (Metastelmatinae, Oxypetalinae and Gonolobinae) clades. According to this study, the New World Asclepiadoideae fall into just four clades: (1) Marsdenia (Marsdenieae), (2) Asclepias (Asclepiadinae, Asclepiadeae), (3) Cynanchum subgenus Mellichampia (Cynanchinae, Asclepiadeae), and (4) MOG, the clade comprising the majority of New World Asclepiadoideae.

Spatial analyses of the phylogenetic diversity ofMinaria(Apocynaceae): assessing priority areas for conservation in the Espinhaço Range, Brazil

“…They have glabrous branches, relatively large flowers and an elongated gynostegium, which is long-rostrate (c. 2.4 mm long) in M. volubilis. The Minaria core group has been highly supported since the first phylogenetic analyses with molecular data (Rapini et al 2003(Rapini et al , 2007Liede-Schumann et al, 2005) (Ribeiro, 2011). The clade is divided in two principal groups, one comprising six species, with axillary inflorescences, and few (usually 1 or 2) seeds per fruit, which lack coma (Fig.…”

“…It was initially discovered as a separate phylogenetic lineage based on molecular data and can be morphologically distinguished by its shrubby, erect habit and small leaves . Minaria was not supported based solely on morphology (Konno, 2005), but formed a strongly supported clade based on plastid DNA markers (Rapini et al, 2003Liede-Schumann et al, 2005). Nevertheless, at that time, only seven of the 19 species originally considered in the genus had been sampled.…”

Blepharodon crabronum (Apocynaceae: Asclepiadoideae), a new species from the pre-Cambrian serranias of eastern Bolivia

“…was excluded from the genus in these treatments, but subsequently returned to Blepharodon by Liede (1996). Molecular studies (Rapini et al 2003(Rapini et al , 2006Liede-Schumann et al 2005) have questioned the monophyly of Blepharodon as currently defined, suggesting that in future the genus may be restricted to the two species B. lineare (Decne.) Decne.…”

Xysmalobium samoritourei (Apocynaceae: Asclepiadoideae), a new species from the Guinea Highlands of West Africa

“…Despite recent interest in the phylogeny of the tribe Asclepiadeae (Rapini et al 2003;Liede-Schumann et al 2005;Goyder et al 2007), delimitation within the Asclepias L. generic complex both in Africa and in the New World remains problematic (Goyder, submitted). Until relationships are clarified, the traditional but unsatisfactory delimitation of Xysmalobium R. Br.…”