Parsimony-based phylogenetic analyses of the neotropical tribe Helieae (Gentianaceae) are presented, including 22 of the 23 genera and 60 species. This study is based on data from morphology, palynology, and seed micromorphology (127 structural characters), and DNA sequences (matK, trnL intron, ITS). Phylogenetic reconstructions based on ITS and morphology provided the greatest resolution, morphological data further helping to tentatively place several taxa for which DNA was not available (Celiantha, Lagenanthus, Rogersonanthus, Roraimaea, Senaea, Sipapoantha, Zonanthus). Celiantha, Prepusa and Senaea together appear as the sister clade to the rest of Helieae. The remainder of Helieae is largely divided into two large subclades, the Macrocarpaea subclade and the Symbolanthus subclade. The first subclade includes Macrocarpaea, sister to Chorisepalum, Tachia, and Zonanthus. Irlbachia and Neblinantha are placed as sisters to the Symbolanthus subclade, which includes Aripuana, Calolisianthus, Chelonanthus, Helia, Lagenanthus, Lehmanniella, Purdieanthus, Rogersonanthus, Roraimaea, Sipapoantha, and Symbolanthus. Generic-level polyphyly is detected in Chelonanthus and Irlbachia. Evolution of morphological characters is discussed, and new pollen and seed characters are evaluated for the first time in a combined morphological-molecular phylogenetic analysis.

A new species of Spigelia L. (Loganiaceae), Spigelia genuflexa Popovkin & Struwe, sp. n., from the Atlantic forest of northeastern Bahia, Brazil, is described, being the first reported geocarpic species in the family. During fruit maturation, the basal infructescences bend down towards the ground, depositing the fruit on the surface (and burying it in soft kinds of ground cover, e.g., moss), whereas the upper ones do so slightly but noticeably. The species is a short-lived annual apparently restricted to sandy-soil habitat of the Atlantic forest of northeastern Bahia, with variable and heterogeneous microenvironment and is known from only two restricted localities. A short review of amphi- and geocarpic species is provided. A discussion of comparative morphology within Spigelia with regards to dwarfism, indumentum, and annual habit is included. A phylogenetic parsimony and Bayesian analysis of ITS sequences from 15 Spigelia species plus 17 outgroups in Loganiaceae confirms its independent taxonomic status: on the basis of sequence similarity and phylogenetic topology it is phylogenetically distinct from all Spigelia species sequenced so far.

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As part of ongoing efforts to understand and document the flora of the southeastern United States, a number of taxonomic changes at generic, specific, and infraspecific rank are made. We also discuss and clarify the recommended taxonomy for other taxa (not requiring nomenclatural acts) and present a point of view about the practical and philosophic basis for making taxonomic changes in an allegedly well-understood flora. The genera (and families) affected are Allium (Alliaceae), Erigeron, Liatris, and Trilisa (Asteraceae), Calycanthus (Calycanthaceae), Gaylussacia (Ericaceae), Dalea and Mimosa (Fabaceae), Hydrophyllum (Hydrophyllaceae), Didymoglossum (Hymenophyllaceae), Monarda (Lamiaceae), Kosteletzkya and Sida (Malvaceae), Narthecium (Nartheciaceae), Agalinis, Melampyrum, and Orobanche/Aphyllon/Myzorrhiza (Orobanchaceae), Dichanthelium and Elymus (Poaceae), Clematis (Ranunculaceae), and Maianthemum (Ruscaceae).

A phylogenetic study and taxonomic revision of the four currently accepted species of Bartonia (Gentianaceae, subtribe Swertiinae) were conducted in order to test species boundaries and interspecific relationships. Species boundaries were examined based on measurements of key quantitative and qualitative morphological characters as given in the original descriptions. Phylogenetic analyses were performed using molecular data from the nuclear internal transcribed spacer region and chloroplast DNA (trnL intron through the trnL-F spacer), separately and combined using parsimony and Bayesian methodologies, incorporating outgroups from subtribes Swertiinae and Gentianinae. The morphological study revealed that characters of one species, B. texana, represent a subset of the morphological variation found within B. paniculata, but that B. paniculata, B. verna, and B. virginica could all be separated from one another. The molecular phylogenetic analyses all found B. texana to nest in a clade with the two recognized subspecies of B. paniculata (subsp. paniculata and subsp. iodandra), making the latter paraphyletic. Bartonia texana is here reduced to subspecific rank, as Bartonia paniculata subsp. texana. Also, the phylogenetic analyses showed strong support for a sister group relationship between B. verna and B. virginica, as opposed to between B. paniculata and B. virginica as has been previously suggested.

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Sabatia (Gentianaceae) contains ca. 20 species, distributed mainly on the U. S. A. Gulf and Atlantic Coastal Plains. Our aims were to determine 1) phylogenetic relationships among Sabatia species, 2) the time and place of Sabatia's origin and main areas of diversification, 3) relationships among sympatric species, and 4) how morphological and karyological characters evolved. We sequenced five noncoding cpDNA regions and nrITS for 30 accessions of Sabatia, Gyrandra, and Eustoma. Parsimony, likelihood, and Bayesian phylogenetic analyses were performed. Bayesian dating was done on a reduced-taxon, combined molecular dataset. The maximum clade credibility chronogram was used for ancestral area reconstruction and character optimization. Correlations between distributional, environmental and phylogenetic matrices were tested with spatial analyses. Phylogenetic analyses reveal that a Sabatia + Gyrandra clade diverged in the late Middle Miocene, with Sabatia subsequently splitting into western and eastern Gulf Coast clades during the early Late Miocene. Further diversification took place in the Late Miocene-Pliocene, with more recent range expansion. Pliocene glacial/interglacial periods could have triggered range contraction/expansion, associated with chromosomal changes. Closely related species of Sabatia tend to share both distributions and habitat types. Character optimization showed potential synapomorphies for a polymerous clade and a white-flowered clade.

These new loci will provide tools for population genetics studies, including the characterization of genetic variation in A. racemosa and other eastern North American species of Actaea.