Kathleen A. Kron

Phylogenetic Classification of Ericaceae: Molecular and Morphological Evidence

A new classification of Ericaceae is presented based on phylogenetic analyses of nuclear and chloroplast DNA sequence data, morphology, anatomy, and embryology. Eight subfamilies and 20 tribes are recognized. In this classification Epacridaceae are included as Styphelioideae and Empetraceae as tribe Empetreae within the Ericoideae. The herbaceous taxa previously recognized as Pyrolaceae and Monotropaceae by some authors are also included within Ericaceae, in the subfamily Monotropoideae. A key, morphological descriptions, and representative images are provided for all named groups. Two new combinations inKalmia (K. buxifolia andK. procumbens) are made, and three new taxa are described: Oligarrheneae, Richeeae, and Cosmelieae (all within Styphelioideae).ResumenSe presenta una clasificación nueva de las Ericaceae basada en análisis filogenéticos, empleando secuencias de ADN nuclear y de cloroplasto, morfología, anatomía y embriología. Se reconocen ocho subfamilias y 20 tribus. En esta clasificación las Epacridaceae son incluídas como Styphelioideae y las Empetraceae como la tribu Empetreae dentro de Ericoideae. Los grupos herbáceos previamente reconocidos como Pyrolaceae y Monotropaceae por algunos autores también se incluyen dentro de las Ericaceae, en la subfamilia Monotropoideae. Se dan una clave, descripciones morfológicas e imágenes representativas de todos los grupos nombrados. Se hacen dos combinaciones nuevas enKalmia (K. buxifolia yK. procumbens), y se describen tres nuevos taxones: Oligarrheneae, Richeeae y Cosmelieae (todos dentro de Styphelioideae).

Systematics of the Ericaceae, Empetraceae, Epacridaceae and related taxa based upon rbcL sequence data

The Ericaceae, Epacridaceae, and Empetraceae are usually recognized as closely related families of woody plants that share a preference for acidic soils, anthers that invert in development, and the presence of endosperm haustoria, among other characteristics. The Empetraceae are recognized as distinctive because of their often unisexual and wind-pollinated flowers. Epacridaceae are distinguished from Ericaceae by anthers that open by slits rather than pores and a primarily Australian distribution. Phylogenetic relationships of these related families are investigated using nucleotide sequences of the plastid gene rbcL. Parsimony analyses indicate a monophyletic, broadly defined Ericaceae that includes Empetraceae and Epacridaceae

rbcL Phylogeny and Character Evolution in Polygonaceae

Abstract Phylogenetic relationships within Polygonaceae, with an emphasis on Polygonum and segregate genera (e.g., Emex, Persicaria, Polygonella), are investigated using sequence data from the chloroplast gene rbcL. The results show the currently recognized subfamilies are likely not monophyletic. Polygonum as currently recognized is paraphyletic. Three strongly supported clades of Polygonum s.l. were found. Contained within these three clades of Polygonum s.l. are representatives of Atraphaxis, Bistorta, Koenigia and Persicaria. Other strongly supported clades found are Coccoloba, Eriogonum, Fagopyrum, Rumex and Triplaris. Patterns of character evolution were studied by mapping characters onto the phylogeny. A woody habit likely evolved multiple times within the family (in Atraphaxis, Koenigia, Muehlenbeckia, Polygonella and in the ancestor to the Eriogonum–Brunnichia clade). Quincuncial aestivation likely evolved early in the history of the family with four subsequent losses in the Rumex–Oxyria clade, Muehlenbeckia, the Eriogonum clade, and the Triplaris clade.

Phylogenetic relationships of Rhododendroideae (Ericaceae).

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.

Phylogenetics of Polygonaceae with an Emphasis on the Evolution of Eriogonoideae

Abstract Polygonaceae has long been recognized as a monophyletic family but the circumscription of groups within it has been in constant flux. Two groups currently recognized are the subfamilies Eriogonoideae and Polygonoideae. An analysis using three chloroplast regions (rbcL, matK, and ndhF) and increased taxon sampling of Eriogonoideae does not support this delimitation. The second intron and portions of the flanking exons of the nuclear gene LEAFY, were used to explore phylogenetic utility in Polygonaceae. The intron showed high levels of variability and was useful at low taxonomic levels, but not alignable outside of Eriogonum and allied genera. Phylogenetic analysis of data from the flanking exons of the second intron of LEAFY generally supports the major groupings found in the chloroplast analysis. A new definition of the subfamilies is proposed. Polygonoideae is restricted to what has been recognized as tribes Persicarieae, Rumiceae, and Polygoneae, with the addition of Muehlenbeckia. Eriogonoideae now includes Antigonon, Brunichia, Coccoloba, Ruprechtia, Triplaris, and Eriogonum and allied genera. The genera Eriogonum and Chorizanthe are nonmonophyletic.

Phylogenetic relationships within the blueberry tribe (Vaccinieae, Ericaceae) based on sequence data from MatK and nuclear ribosomal its regions, with comments on the placement of Satyria

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.

Circumscription of Ericaceae (Ericales) as determined by preliminary cladistic analyses based on morphological, anatomical, and embryological features

Cladistic analyses of selected taxa of Ericaceae (and potential relatives) suggest that the family, as traditionally circumscribed, is paraphyletic. The traditionally recognized groups, Monotropaceae, Pyrolaceae, Epacridaceae, and Empetraceae, are nested within the cladistic structure of Ericaceae, and it seems reasonable to expand the circumscription of the latter. Preliminary analyses suggest thatActinidia (Actinidiaceae) likely is cladistically basal within Ericales, withCyrilla (Cyrillaceae) andClethra (Clethraceae) positioned, respectively, as second and first outgroups to Ericaceae. Generic relationships within Ericaceae are highly unresolved due to extensive homoplasy, butEnkianthus appears to be the sister group of the remaining ericad genera. The current division of the family into five subfamilies, i.e., Rhododendroideae, Ericoideae, Vaccinioideae, Pyroloideae, and Monotropoideae, very likely is not in accordance with phylogenetic relationships.

Phylogenetic Relationships of European and African Ericas

The genus Erica (Ericeae, Ericoideae, Ericaceae) occurs in Europe, the Middle East, and Africa. Southern Africa has the largest number of species, especially at the southern tip of the continent. This narrow north‐south distribution is unique in the Ericaceae and has fueled speculation about the origin of Erica species. Phylogenetic relationships among selected species of Erica were investigated in order to determine whether the origin of this genus lies in Europe or Africa. Three regions of DNA, one from the nuclear genome (nrITS) and two from the chloroplast (rbcL‐atpB spacer and matK), were selected as sources of molecular data because of their previously demonstrated utility within the Ericaceae. Parsimony analysis indicates a monophyletic group of African taxa derived from within the European taxa. Erica arborea has a broad geographic range occurring in both Europe and Africa and is sister to the African clade, indicating that the common ancestor of both E. arborea and the Cape African taxa was also widespread across both continents. This common ancestor probably expanded its range into Africa after the establishment of the connection between Europe and Africa during the mid‐Miocene.

A Large‐Scale Phylogeny of Polygonaceae Based on Molecular Data

Few studies have addressed the evolutionary relationships within Polygonaceae from a global perspective. The convoluted taxonomic history of Polygonaceae is a major barrier to understanding evolution in this group, and only portions of it have been included in systematic treatments. Phylogenetic studies have been limited in both taxon sampling and amount of data. Our objective is to identify clades within Polygonaceae and to provide a global estimate of phylogenetic relationships in this morphologically diverse and geographically widespread group. We include a total of 75 species representing approximately 40 of the 55 named genera in the family. We use three chloroplast regions (rbcL, matK, and ndhF) and the ribosomal internal transcribed spacer to understand the phylogenetic relationships in Polygonaceae. Maximum parsimony and maximum likelihood are used to analyze the data. Symmeria is the sister group to remaining Polygonaceae sampled, and there is strong support for this placement. Afrobrunnichia branches next but has only moderate support. Two large clades comprise Polygonaceae, generally corresponding to those found in previous molecular analyses. Circumscription of most of the currently recognized subgroups within Polygonaceae did not agree with clades identified in the total data analyses, with the exception of Rumiceae Dum.

Hawaiian Blueberries and Their Relatives—A Phylogenetic Analysis of Vaccinium Sections Macropelma, Myrtillus, and Hemimyrtillus (Ericaceae)

Abstract Phylogenetic relationships among Vaccinium sections Macropelma, Myrtillus, and Hemimyrtillus have been the subject of much debate. These taxa have been proposed as close relatives and they share, along with sect. Oxycoccoides, the character of buds covered by two partially fused prophylls. However, the monophyly of these sections has not been assessed and hypotheses about evolutionary relationships have not been tested using a cladistic framework. While most investigators agree that the Hawaiian taxa from sect. Macropelma represent a monophyletic group, the phylogenetic position of the Polynesian V. cereum has been the subject of much discussion. Molecular data from the nrITS and the chloroplast genes matK and ndhF for 52 species of Vaccinieae were used in a phylogenetic analysis to assess the monophyly of these sections and to determine their phylogenetic position in tribe Vaccinieae. Hawaiian representatives from sect. Macropelma form a monophyletic group that is derived from within sect. Myrtillus. However, the Polynesian V. cereum is likely of hybrid origin. The Myrtillus + Macropelma clade is sister to a clade that includes sections Oxycoccoides and Praestantia, and the two Asian representatives from sect. Hemimyrtillus. The Tethyan clade from sect. Hemimyrtillus is sister to the rest of tribe Vaccinieae. Communicating Editor: Aaron Liston