MCCAULEY, ROSS A.* AND HARVEY E. BALLARD. Department of Environmental and Plant Biology, Ohio University, Athens, OH 45701. - Systematics, biogeography, and evolutionary trends in the North American species of Froelichia (Amaranthaceae).
As it is currently circumscribed, Froelichia Moench. is a genus
of 15-20 species of annual and perennial herbs and shrubs which
inhabit dry plains and coastal areas of the tropical and subtropical
western hemisphere and temperate North America. This group is closely
related to Gomphrena (Globe Amaranth) and Alternanthera
(Chaff Flower), both planted ornamentally in North America. As a
portion of a full generic revision of this group, the identity and
distribution of the North American species are considered using a
series of morphological and molecular datasets. Preliminary analysis
suggests there are four distinct species, F. interrupta (L.)
Moq. in central and northern Mexico, F. arizonica Thornber ex
Standley in northern Mexico and the American Southwest, F.
gracilis (Hooker) Moq. native to Texas and now naturalized over a
wide range, and F. floridana (Nutt.) Moq., a species exhibiting
wide varietal variation in regions of the Great Plains and
southeastern United States. Evidence is also presented for the
recognition of F. floridana var. pallescens Moq., a form
from central Florida described by Moquin-Tandon in 1849 but not
recognized by later authors.
Key words: Amaranthaceae, Froelichia, North American Flora, Systematics