Classification of Polemoniaceae
A phylogeny-based classification that places Polemoniaceae genera into tribes and subfamilies has been proposed that recognizes well-supported nodes from a growing body of comparative DNA sequence studies and non-cladistic consideration of morphology (Porter and Johnson, 2000). This classification is subject to revision as additional data that bear on phylogenetic branching patterns are brought forth, with an emphasis on recognizing monophyletic groups that include all descendents of a common ancestor. Driven by this philosophy, some changes to the classification of Porter and Johnson (2000) will be forthcoming as relationships in groups of questionable monophyly are addressed, and polytomies are resolved. For example, based on resolution of Acanthogilia as sister to Cobaea, Bonplandia, and Cantua, Prather et al (2000) suggested that Acanthogilia be included in subfamily Cobeaoideae. An alternative classification that reflects this same phylogenetic branching pattern could also be proposed by maintaining Cobeaoideae as circumscribed phylogenetically by Porter and Johnson (2000), and erecting a new, super subfamilial taxon that circumscribes this subfamily + Acanthogilia.
An alternative classification for Polemoniaceae based on interpretations of overall similarity has also been proposed, and revised, in recent years (Grant 1998a,b, Grant and Day 1998, Grant 2003b). This classification adheres to a broader definition of monophyly that allows paraphyletic groups, and considers phylogenetic patterns of secondary importance (Grant 2003a).
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