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* Premise of the study: Taxonomic groups have often been recognized on the basis of geographic distinctions rather than accurately representing evolutionary relationships. This has been particularly true for temperate and tropical members from the same family. Polygonaceae exemplifies this problem, wherein the woody tropical genera were segregated from temperate members of the family and placed in the subfamily Polygonoideae as two tribes: Triplarideae and Coccolobeae. Modern phylogenetic studies, especially when inferred from many lines of evidence, can elucidate more probable hypotheses of relationships. This study builds on previous work in the family and aims to test the traditional classification of the tropical woody taxa, which have been understudied and undersampled compared to their temperate relatives. * Methods: A phylogenetic study was undertaken with expanded sampling of the tropical genera with data from five plastid markers (psbA-trnH, psal-accD, marK, ndhF, and rbcL), nuclear ribosomal DNA (ITS) and morphology. * Key results: Results support the placement of nine of 12 genera of the Triplarideae and Coccolobeae within Eriogonoideae, in which these genera form a paraphyletic assemblage giving rise to Eriogoneae. The remaining woody tropical genera excluded from Eriogonoideae occur in the paleotropics. * Conclusions: Traditional characters used to delimit Coccolobeac and Triplarideae are not useful for defining monophyletic groups. The six-tepal condition is derived from the five-tepal condition, and unisexual flowers have arisen multiple times in different sexual systems. Ruminate endosperm has arisen multiple times in the family, suggesting this character is highly plastic. Key words: Coccoloba; Eriogonoideae; ochrea; phylogeny; Polygonaceae; ruminate endosperm. doi: 10.3732/ajb.1000022

The blueberry tribe (Vaccinieae) is a large and morphologically diverse group that is widespread in the temperate and tropical zones of most continents. The greatest species diversity is in the tropics, where Vaccinieae are a major component of montane cloud forests. Generic limits are poorly understood, and many of the characters traditionally used fail to adequately distinguish among taxa. This study analyzed sequence data from the chloroplast matK gene and the nrITS region for 93 species of Vaccinieae, representing 28 genera, and 16 sections (of the ~33 currently recognized) of Vaccinium. Results indicated that, in general, traditional generic circumscriptions were not corroborated, but several well-supported clades were found: an Andean clade (including at least some members of 18 of the 23 Neotropical genera sampled), a Meso-American/Caribbean clade, an East Malesian clade (including the Old World taxa Paphia and Dimorphanthera), an Agapetes clade comprised of some Asian Vaccinium and Agapetes, and a Bracteata-Oarianthe clade (Vaccinium spp.). This study is the first to address phylogenetic relationships among members of Vaccinieae on a worldwide basis and the results indicate that the large genus Vaccinium is not monophyletic, but likely represents a grade group out of which several more specialized clades evolved. Key words: blueberries; Ericaceae; matK; nrITS; tropics; Vaccinieae; Vaccinium.

The Rhododendroideae are usually recognized as a subfamily within Ericaceae. This group has been considered primitive (i.e., occupying the ancestral or basal position relative to all other Ericaceae) due to the occurrence of separate petals in several taxa, deciduous corollas, and septicidally dehiscent capsules. Previous molecular studies using rbcL and nr18s sequences have indicated that Rhododendroideae may be paraphyletic and cladistically derived (i.e., the relative position in the geneology of Ericaceae is not basal). The matK sequences of 42 taxa from traditional Rhododendroideae and potentially related clades were obtained via standard gene amplication and double-stranded dideoxy sequencing. Phylogenetic analyses of these sequences using Actinidia chinensis as the outgroup indicate that the Rhododendroideae are paraphyletic. Trees obtained in the analyses indicate an expanded rhododendroid clade that includes four major subclades - empetroid, rhodo, ericoid, and phyllodocoid. The ericoid clade is sister to the phyllodocoid clade and the empetroid clade is sister to the rhodo clade. Relationships within the clades are generally well resolved except within the rhodo clade where matK data indicate that Rhododendron is probably paraphyletic. Daboecia and Calluna are included within the ericoid clade; Erica is paraphyletic. Cassiope lies outside the rhododendroid clade. The relationships indicated by the matK data suggest that sympetalous flowers are likely plesiomorphic within rhododendroids. Key words: empetroid; ericoid; matK; Rhododendroideae.

Hybridization and introgression have been suggested by previous workers as important factors in the southeastern azaleas. However, because of high levels of intraspecific variation and lack of intensi of this phenomenon has been difficult. We investigated a population of azaleas on Stone Mountain, Ge Rhododendron flammeum, R. canescens, and their interspecific hybrids. After analysis of chloroplast of extensive localized cytoplasmic introgression into R. flammeum. Many individuals in the sample po morphologically indistinguishable from R. flammeum possess the chloroplast genome of R. canescens. T some of the observed variation in some populations of R. flammeum may be due to past introgression

Macleania and Psammisia are two genera of blueberries found primarily at higher elevations throughout the Neotropical cordillera. These genera have been considered closely related to each other and distinct from other tropical Vaccinieae based on features of the androecium. As part of a revision of these taxa, a molecular systematic study was performed using nuclear ribosomal internal transcribed spacer (nrITS) and the chloroplast gene matK for 29 species of Macleania and Psammisia (i.e., about 30% of the taxa currently recognized within the genera) and selected Vaccinieae. Analyses of the combined data indicate that most of the taxa currently within Macleania and Psammisa form a clade. (Exceptions to this are Macleania megabracteata and Psammisia urichiana which consistently fall outside the group.) However, branch lengths are very short at the base of this clade and therefore bootstrap support for the group is below 50%. Macleania and Psammisia are both paraphyletic in this study. The results indicate that Macleania is, for the most part, derived from within Psammisia. Psammisia dolichipoda and Ps. sodiroi are indicated as sister and this relationship has strong bootstrap support. These two species represent the 'globosa' subgroup within Psammisia. However, the results of this study do not support any of the other species groups suggested in previous studies for either Macleania or Psammisia. This study suggests that Macleania and Psammisia are closely related but that neither is monophyletic as currently recognized. Further resolution of species relationships is likely to require a more variable data source. Larger scale analyses based on combined analysis of matK, ITS and the chloroplast trnT-L spacer indicate that Macleania and Psammisia fall within a large clade that includes other Neotropical genera such as Satyria and Sphyrospermum.

Phylogenetic relationships within the Andromedeae and closely related taxa were investigated by means of cladistic analyses based on phenotypic (morphology, anatomy, chromosome number, and secondary chemistry) and molecular (rbcL and matK nucleotide sequences) characters. An analysis based on combined molecular and phenotypic characters indicates that the tribe is composed of two major clades - the Gaultheria group (incl. Andromeda, Chamaedaphne, Diplycosia, Gaultheria, Leucothoe, Pernettya, Tepuia, and Zenobia) and the Lyonia group (incl. Agarista, Craibiodendron, Lyonia, and Pieris). Andromedeae are shown to be paraphyletic in all analyses because the Vaccinieae link with some or all of the genera of the Gaultheria group. Oxydendrum is sister to the clade containing the Vaccinieae, Gaultheria group, and Lyonia group. The monophyly of Agarista, Lyonia, Pieris, and Gaultheria (incl. Pernettya) is supported, while that of Leucothoe is problematic. The close relationship of Andromeda and Zenobia is novel and was strongly supported in the molecular (but not morphological) analyses. Diplycosia, Tepuia, Gaultheria, and Pernettya form a well-supported clade, which can be diagnosed by the presence of fleshy calyx lobes and methyl salicylate. Recognition of Andromedeae is not reflective of our understanding of geneological relationships and should be abandoned; the Lyonia group is formally recognized at the tribal level. Key words: Andromedeae; Ericaceae; Lyonieae; matK; molecular systematics; rbcL.