SMALL, RANDALL L. Dept. of Botany, University of Tennessee, Knoxville, TN 37996. - Morphological and genetic variation in Hibiscus sect. Muenchhusia (Malvaceae).
The Rose Mallows (Hibiscus sect. Muenchhusia, Malvaceae)
as currently circumscribed include five species: Hibiscus
coccineus, H. dasycalyx, H. grandiflorus, H.
laevis, and H. moscheutos. Further, H. moscheutos
includes up to four subspecies, although the most recent taxonomic
treatment recognizes only two (H. moscheutos subsp.
moscheutos and H. moscheutos subsp. lasiocarpos).
Previously published experimental hybridization studies as well as
morphological data suggest that these species are divided into two
natural groups: (1) H. grandiflorus and H. moscheutos;
and (2) H. coccineus, H. dasycalyx, and H.
laevis. Beyond these inferences, however, phylogenetic
relationships among these species and their relationship to other
Hibiscus species are unknown. Further, the number of subspecies
of H. moscheutos that are recognized varies in different
treatments and the suite of morphological characters that distinguish
them is highly variable. Phylogenetic analyses of molecular data (both
chloroplast and nuclear DNA sequences) are being conducted to
elucidate relationships among the species of Hibiscus sect.
Muenchhusia, and to discover their relationship to other
Hibiscus species. Additionally, analyses of morphological and
genetic variation within and among populations of those taxa referred
to H. moscheutos are being conducted to determine how many
unique biological entities exist within this taxon.
Key words: Hibiscus, Malvaceae, systematics