The Mimulus moschatus Alliance (Phrymaceae): Molecular and Morphological Phylogenetics and their Conservation Implications

The Mimulus moschatus alliance consists of 13 morphologically similar species, the majority of which have been considered for conservation protection. Phylogenetic analyses of four rapidly evolving molecular DNA regions (ITS, ETS, trnL-F, and rpl16) and a morphological data set under several optimality criteria reveal that the M. moschatus alliance is composed of three geographically defined clades: the Sierra Nevada Clade (M. floribundus, M. norrisii, and M. dudleyi), the Snake River Clade (M. hymenophyllus, M. ampliatus, and M. patulus), and the Columbia River Clade (M. washingtonensis and M. jungermannioides). The relationships within and among the clades are well resolved. Numerous instances of morphological homoplasy among the clades are inferred, including three independent origins of the autogamous mating system. Although nearly half of the morphological characters are highly homoplasious, the inclusion of morphological data in the combined maximum parsimony and Bayesian analyses improves topological resolution and branch support. The phylogenetic results support the specific recognition of three rare taxa (M. ampliatus, M. patulus, and M. dudleyi), previously synonymized with more widespread species. A key to the species within the M. moschatus alliance is provided.