JENKINS, PHILIP D. Herbarium, 113 Shantz, University of Arizona, Tucson, AZ 85721. - Systematics of Browallia Linnaeus (Solanaceae, Cestroideae), inferences from morphological data.
Browallia Linnaeus (Solanaceae, Cestroideae) is native to the
New World tropics and subtropics. Taxonomists first grouped
Browallia and morphologically similar genera within the
Salpiglossideae, which were considered advanced in Solanaceae because
of their derived characters. Recent evidence indicates that
Salpiglossideae is paraphyletic within the subfamily Cestroideae and
perhaps Cestroideae is primitive in Solanaceae, and that
Browallia seems more closely allied with the large, widespread
genus Cestrum. Morphological evidence, analyzed
phylogenetically and using multivariate techniques, implies that there
are five species of Browallia. The generic boundaries of
Browallia and the monotypic sister group Streptosolen
jamesonii (Bentham) Miers are doubtful. Streptosolen,
erected out of Browallia in 1850, is here resubmerged. The
species recognized are Browallia acutiloba Segástegui & Díos,
B. americana Linnaeus, B. eludens R. K. Van Devender &
P. Jenkins, B. jamesonii Bentham, and B. speciosa
Hooker. Four Browallia have limited distributions: three in
the South American Andes and one disjunct in southwestern North
America. The fifth, Browallia americana, is widespread and
introduced throughout the tropics of the New and Old Worlds. It
exhibits variable characters in the Andes of Peru, but less so
elsewhere, especially where it is likely introduced. Morphological
evidence suggests that the origin of the group is Andean, and that the
genus is diverging, but that diversification does not warrant
recognition of all the species previously described. Browallia
eludens, with its disjunct range, poses interesting questions
about the biogeographical history of the group. It has a more
northern range where seasonally freezing temperatures occur. It
appears to be a seasonal ephemeral with larger seeds than the tropical
Browallia, that the seeds are viable for a number of years, and
that the plants may be largely autogamous.
Key words: Browallia, phylogenetics, Solanaceae