Phylogeny and evolution of morphological characters in tribe Chamaedoreeae (Arecaceae)

Abstract

Within the palm family, molecular analyses have resulted in a need to re­evaluate characters previously considered useful to establish hypotheses of relationships among groups. Recent phylogenetic analyses of tribe Chamaedoreeae have shown that characters traditionally used as strong indicators of relationship, such as presence of solitary flowers and dioecy, are homoplasious within this tribe. In the largest genus, Chamaedorea, published molecular analyses recover well­supported groups not previously proposed based on morphological characters and at the same time resolve some of the current subgenera as polyphyletic. In this study we further explore the phylogenetic relationships in Chamaedoreeae and search for morphological synapomorphies for the monophyletic groups recovered. Phylogenetic analyses of morphological, nuclear (PRK, RPB2), and plastid (matK, ndhF, trnD­trnT, rps16 intron, trnL­trnF) data are performed and morphological characters are subsequently optimized on the resulting topologies. Although most of the morphological characters included are highly homoplasious, the inclusion of morphological characters in the phylogenetic analyses improves the resolution within Chamaedoreeae, particularly among species of Chamaedorea. With the exception of Synechanthus and Wendlandiella, all the genera and subgenera in Chamaedoreeae are defined by a combination of homoplasious characters, none of which is unique within the tribe. Two of the seven subgenera of Chamaedorea included in our analyses, C. subg. Eleutheropetalum and subg. Stephanostachys, are supported as monophyletic with a number of morphological synapomorphies also used in the original descriptions of these subgenera. Some morphological characters not used in the traditional subgeneric classification of Chamaedorea, such as leaf sheath structure and pistillode, gynoecium and filament connation, though homoplasious, are resolved as synapomorphies and, therefore, potentially useful when defining subgenera within this genus.

BeyondGenera Palmarum: progress and prospects in palm systematics

“…and Synechanthus H.Wendl., which is sister to Wendlandiella Dammer, with Hyophorbe Gaertn. sister to all remaining Chamaedoreeae (Cuenca et al ., , ; Baker et al ., ). A recent study of tribe Iriarteeae confirms the monophyly of all five accepted genera, and finds strong support for a clade of Iriartea Ruiz & Pav.…”

“…The phylogenetics of several arecoid tribes have been studied in depth since GP2. There is much conflict between phylogenetic hypotheses for intergeneric relationships in Chamaedoreeae (Asmussen et al ., ; Thomas et al ., ; Cuenca & Asmussen‐Lange, ; Cuenca, Asmussen‐Lange & Borchsenius, ; Baker et al ., , ; Cuenca, Dransfield & Asmussen‐Lange, ). However, the studies with the densest data and taxon sampling offer moderate to strong support for a clade comprising Chamaedorea Willd., Gaussia H.Wendl.…”

Comparison of Floral Structure and Ontogeny in Monoecious and Dioecious Species of the Palm Tribe Chamaedoreeae (Arecaceae; Arecoideae)

“…This study focuses on two members of the tribe Chamaedoreeae, belonging to the almost entirely monoecious subfamily Arecoideae (Asmussen et al 2000(Asmussen et al , 2006Asmussen and Chase 2001;Lewis and Doyle 2002). The tribe Chamaedoreeae has been resolved as monophyletic in several phylogenetic analyses using both morphological and molecular data (Thomas et al 2006;Cuenca and Asmussen 2007;Cuenca et al 2008Cuenca et al , 2009. The key synapomorphy that defines the tribe is the arrangement of flowers in distinctive clusters called acervuli (Cuenca et al 2009).…”

“…The tribe Chamaedoreeae has been resolved as monophyletic in several phylogenetic analyses using both morphological and molecular data (Thomas et al 2006;Cuenca and Asmussen 2007;Cuenca et al 2008Cuenca et al , 2009. The key synapomorphy that defines the tribe is the arrangement of flowers in distinctive clusters called acervuli (Cuenca et al 2009). These structures are considered to be a reversed cincinnus adnate to the rachilla (Uhl and Moore 1978;Uhl and Dransfield 1987;Ortega and Stauffer 2011).…”

“…These two features have been considered important when inferring the evolutionary relationships among the genera of the tribe. Nevertheless, recent studies have suggested that transitions to solitary flowers and dioecy have each occurred more than once within the tribe (Thomas et al 2006;Cuenca and Asmussen 2007;Cuenca et al 2009).…”