The Chenopodiaceae and Amaranthaceae are closely related families
consisting of about 174 genera and 2,050 species of world-wide
distribution. The Chen-Am alliance is ecologically important and also
contains a number of economically important crop and weedy species.
The alliance is further noted for C4 photosynthesis as well for
adaptations to xeric and saline environments. The Chen-Ams
traditionally have been considered allied based on a shared core
floral formula, as well as morphological, anatomical, chemical, and
molecular data. Despite their importance, the phylogeny of the
Chen-Ams has not been investigated. We report here a preliminary
analysis of the phylogeny of the Chen-Am alliance based on plastid
ndhF gene sequences. All currently recognized subfamilies and tribes
(except the Polycnemoideae) were sampled including over 15 genera.
Parsimony analysis of ndhF strongly supports a monophyletic Chen-Am
alliance. Based on sampling to date, the Chenopodiaceae as currently
circumscribed is paraphyletic, and the Amaranthaceae is potentially
polyphyletic.
Key words: Amaranthaceae, Chenopodiaceae