Iliamna is a temperate North American mallow with eight
species, seven of which are classified as rare or endangered. They
occupy a range of habitats from streamsides at high elevations to arid
hillsides. Cytological and morphological evidence has indicated a
close relationship between Iliamna Greene, Malacothamnus
Greene, and Phymosia Hamilton to form the Malacothamnus
alliance. Malacothamnus is located in California and northern
Baja California with an additional species in Chile. Phymosia
is found in the Bahamas, southern Mexico, and Guatemala. In habit,
species in Iliamna are herbaceous to small shrubs,
Malacothamnus shrubs, and Phymosia small trees. All are
distinctive in their non-reticulate dehiscent fruits and have showy
flowers. Much hybridization has been reported within
Malacothamnus and is suspected to occur in Iliamna. The
internal transcribed spacer (ITS) of nuclear ribosomal DNA was used to
develop a phylogeny for the Malacothamnus alliance. Parsimony was used
to develop a phylogenetic tree by random stepwise addition with 100
replicates. Robustness of the phylogeny was tested using decay,
bootstrap, and jackknife analyses. The results indicate that
Iliamna is paraphyletic and closely allied to
Malacothamnus. The phylogeny and biogeographic history of the
Malacothmnus alliance will be discussed.
Key words: Iliamna, ITS, Malacothamnus, Malvaceae, Phymosia