Evolutionary relationships in the Asteraceae tribe Inuleae (incl. Plucheeae) evidenced by DNA sequences of ndhF; with notes on the systematic positions of some aberrant genera

The phylogenetic relationships between the tribes Inuleae sensu stricto and Plucheeae are investigated by analysis of sequence data from the cpDNA gene ndhF. The delimitation between the two tribes is elucidated, and the systematic positions of a number of genera associated with these groups, i.e. genera with either aberrant morphological characters or a debated systematic position, are clarified. Together, the Inuleae and Plucheeae form a monophyletic group in which the majority of genera of Inuleae s.str. form one clade, and all the taxa from the Plucheeae together with the genera Antiphiona, Calostephane, Geigeria, Ondetia, Pechuel-loeschea, Pegolettia, and Iphionopsis from Inuleae s.str. form another. Members of the Plucheeae are nested with genera of the Inuleae s.str., and support for the Plucheeae clade is weak. Consequently, the latter cannot be maintained and the two groups are treated as one tribe, Inuleae, with the two subtribes Inulinae and Plucheinae. The genera Asteriscus, Chrysophthalmum, Inula, Laggera, Pentanema, Pluchea, and Pulicaria are demonstrated to be non-monophyletic. Cratystylis and Iphionopsis are found to belong to the same clade as the taxa of the former Plucheeae. Caesulia is shown to be a close relative of Duhaldea and Blumea of the Inuleae-Inulinae. The genera Callilepis and Zoutpansbergia belong to the major clade of the family that includes the tribes Heliantheae sensu lato and Inuleae (incl. Plucheeae), but their exact position remains unresolved. The genus Gymnarrhena is not part of the Inuleae, but is either part of the unresolved basal complex of the paraphyletic Cichorioideae, or sister to the entire Asteroideae.     

A molecular phylogeny and generic rearrangement of the stapelioid Ceropegieae (Apocynaceae-Asclepiadoideae)

 Representatives of nearly all genera of the taxon-rich stem-succulent stapeliads and most of the few related, leafy genera were analyzed. Sequence data from two non-coding molecular markers (ITS region of nrDNA and trnT-L and trnL-F spacers as well as the trnL intron of cpDNA) support the traditional tribal affiliation of the genera, which form a monophyletic group. This monophylum breaks into a basal Neoschumannia/Anisotoma/Riocreuxia/Sisyranthus nk;clade, from which the core Ceropegieae are derived. The four Ceropegia species included are not monophyletic, and their relationship to Brachystelma changes depending on the marker studied. The stem succulent taxa fall in a number of well supported, but unresolved clades, the most prominent being the predominantly southern African clade comprising Orbea, Stapelia and some other genera. The most derived taxa of NE Africa, Duvaliandra and White-sloanea, are basal to this southern African clade. The other clades comprise the more basal genera of stem-succulent stapeliads, including the members of the Caralluma complex. Of the 17 genera accepted by Plowes for the Caralluma complex, seven are recognized: Caralluma, Apteranthes, Australluma, Boucerosia, Caudanthera, Desmidorchis and Monolluma. New combinations are proposed in 15 cases; Caralluma adscendens var. geniculata is raised to specific rank. Anomalluma is reinstated, and Pseudolithos mccoyi is transfered to it. A broadened concept for Orbea (incl. Angolluma and Orbeopsis) is recognized, but Orbeanthus is kept separate. The monotypic Ballyanthus, recently separated from Orbea, is nested within Duvalia. Piaranthus (incl. Huerniopsis) is monophyletic. The bitypic Notechidnopsis is reduced to the type species, N. tessellata, while N. columnaris is transferred to a new genus, Richtersveldia. Received February 25, 2002; accepted June 17, 2002 Published online: November 7, 2002 Address of the authors: Dr. Ulrich Meve (e-mail: ulrich.meve@uni-bayreuth.de) and Prof. Dr. Sigrid Liede (e-mail: sigrid.liede@uni-bayreuth.de), Universit?t Bayreuth, Lehrstuhl für Pflanzensystematik, Universit?tsstrasse 30, D-95440 Bayreuth, Germany.     

Deletions in the plastid trnT–trnL intergenic spacer define clades within Cactaceae subfamily Cactoideae

 The phylogenetic distribution of two deletions, of about 350 and 250 bp respectively, within the chloroplast trnT–trnL intergenic spacer was examined. One deletion was found in all members of Cactaceae subfamily Cactoideae sampled, totaling 37 species, but not in taxa from other subfamilies or closely related families. The second was shared by a subset of Cactoideae comprising members of tribes Cereeae, Trichocereeae, and Browningieae (in part), as well as Harrisia. Close links among the former three South American tribes have been previously hypothesized. This distribution suggested that Browningieae, a tribe defined largely by shared primitive features, were not monophyletic, and that Harrisia may have been incorrectly placed outside the Browningieae–Cereeae–Trichocereeae group. Received June 12, 2001 Accepted October 26, 2001     

Tribes of Boraginoideae (Boraginaceae) and placement of Antiphytum, Echiochilon, Ogastemma and Sericostoma: A phylogenetic analysis based on atpB plastid DNA sequence data

 The genera Antiphytum, Echiochilon, Ogastemma and Sericostoma, which have been difficult to place within the tribes of the subfamily Boraginoideae (Boraginaceae), are analysed using plastid atpB sequence data. A selection of Boraginaceae genera was used to obtain a framework for the phylogenetic position of Antiphytum, Echiochilon, Ogastemma and Sericostoma. Sericostoma is found to belong within Echiochilon. The new tribe Echiochileae, Boragineae and Lithospermeae are monophyletic but the tribes Eritrichieae and Cynoglosseae are paraphyletic. The biogeography of Echiochileae (Echiochilon and Ogastemma from Africa and western Asia, and Antiphytum from America) is discussed. Received November 27, 2001; accepted March 20, 2002 Published online: November 14, 2002 ? Springer-Verlag 2002 Addresses of the authors: Elisabeth L?ngstr?m (e-mail: elisabeth.langstrom@ebc.uu.se), Department of Systematic Botany, Evolutionary Biology Centre, Uppsala University, Norbyv?gen 18D, SE-752 36 Uppsala, Sweden. Mark W. Chase, Jodrell Laboratory, Royal Botanic Gardens, Kew, TW9 3DS, UK.     

Phylogenetic analysis of a polyphyletic African genus of Caesalpinioideae (Leguminosae): Monopetalanthus Harms

 To assess the new taxonomy of Monopetalanthus proposed by Wieringa, a phylogenetic study was performed using the chloroplast trnL intron and psbA-trnH spacer, and the nuclear ITS region of the 18-26S rDNA. The phylogeny clearly indicates the polyphyletic nature of Monopetalanthus. The molecular data support the transfer of M. longiracemosus to Tetraberlinia and the newly defined Aphanocalyx, which now includes all the previous Monopetalanthus species having leaflets with a marginal vein. Our analyses do not support the monophyly of the newly described genus Bikinia, which includes four new species and six species transferred from Monopetalanthus. Bikinia occurs either as paraphyletic with Tetraberlinia (chloroplast DNA data) or as a monophyletic group that also includes the new monotypic genus Icuria sister to Tetraberlinia (ITS data). Nonetheless, the molecular phylogeny generally supports the taxonomy of Wieringa in subdividing the genus Monopetalanthus into distinct groups, none of which retains the name Monopetalanthus. Received May 28, 2001; accepted July 6, 2002 Published online: November 20, 2002 Address of the authors: G. Y. Fannie Gervais, Anne Bruneau (e-mail: bruneaua@irbv.umontreal. ca), Institut de Recherche en Biologie Végétale, Université de Montréal, 4101 Sherbrooke est, Montréal, Québec, Canada, H1X2B2.     

The tribal position of Fockea and Cibirhiza (Apocynaceae: Asclepiadoideae): evidence from pollinium structure and cpDNA sequence data

The pollinium morphology of the two members of the Asclepiadoideae, tribe Fockeeae, Fockea Endl. and Cibirhiza Bruyns, has been studied in detail and compared with that of eight genera of Marsdenieae, the tribe in which Fockea and Cibirhiza were previously accommodated and thus their putative closest relatives, as well as nine genera of Asclepiadeae. Both Fockea and Cibirhiza have several morphological characteristics in common, the most important of which is the absence of well-developed caudicula, which distinguishes them from all other genera of Asclepiadoideae known. The pollinium structure of these two genera, however, differs significantly. Whereas the pollinium of Cibirhiza consists of single pollen grains and is covered by a pollinium wall, as is typical for other Asclepiadoideae, the pollinium of Fockea consists of tetrads and is not covered by a pollinium wall, a condition otherwise typical of Secamonoideae. Fockea, however, has only two pollinia per anther, as does Cibirhiza and all other Asclepiadoideae, whereas the Secamonoideae have four pollinia per anther. Sequence data from two intergenic spacers, trnT-L and trnL-F and the trnL intron of cpDNA was analyzed. The ingroup included three species of Fockea and one species of Cibirhiza. The outgroup taxa consisted of three representatives each of Periplocoideae, and Secamonoideae and 24 species of Asclepiadoideae, including representatives of all tribes, of which eight genera belong to Marsdenieae, as outgroups. The results of the DNA analysis provide strong support for Fockeeae as a monophyletic tribe, distinct from Marsdenieae and, to the rest of the Asclepiadoideae. With the exception of pollen data, all morphological and molecular evidence clearly support recognition of the tribe Fockeeae. The occurrence of two such significantly different types of pollinia structure – characters elsewhere in the family used to distinguish subfamilies – within the small tribe Fockeeae was unexpected, and can perhaps best be understood as yet another attestment to the basal position of the Fockeeae in the nascence of the Asclepiadoideae.     

Using molecular data to test the monophyly of Lallemantia in the subtribe Nepetinae (Mentheae,Lamiaceae)

Phylogenetic relationships among the species of Lallemantia and its close allies (Lamiaceae, Mentheae) were investigated using nuclear (ITS) and plastid (trnL, trnL/F, trnS/G, rpl32, and rpl32-trnL) DNA sequences. Phylogenetic results from Bayesian and parsimony analyses show that (1) Lallemantia is monophyletic, (2) Hymenocrater is nested within Nepeta, and (3) Lallemantia is more closely related to Dracocephalum than other genera in Nepetinae. Based on the molecular results, the genus Lallemantia comprises two disparate lineages, with each lineage supported by distinct morphological characters (e.g. floral structures and pollen grains).     

A light, scanning electron, and transmission electron microscopic study of pollen wall architecture in the subtribe Gnaphaliinae (Gnaphalieae, Asteraceae)

To better understand relationships within the Asteroideae, the pollen morphology and exine structure of 10 genera and 15 species of Gnaphaliinae were investigated using light, scanning electron, and transmission electron microscopy. All taxa have a Gnaphalioid pattern of exine with an evidently rough foot layer. The tectal complex consists of three main layers that differ in morphology and thickness: a tectum, a median columellar layer, and an internal interlaced sub-columellar layer. The apertural system consists of an ectoaperture, a mesoaperture, and an endoaperture, which intersect, respectively, the tectal complex, the foot layer and the upper part of the endexine, and the inner part of the endexine. On the basis of pollen characteristics, especially those of the spines, all the species examined may be gathered into two groups, one including Helichrysum foetidum, H. italicum, Plecostachys serpyllifolia, and Pseudognaphalium luteo-album and the other including the other 11 species of Gnaphaliinae now investigated. In addition, because Gnaphalieae has been proposed as sister group to several tribes and clades of Asteroideae, a comparison was made between exine pattern in the Gnaphalieae and that in its putatively related tribes. On the basis of previous phylogenetic studies and our present pollen data we suggest that either Astereae, Astereae-Anthemideae clade, or Heliantheae s.l.-Anthemideae clade are the best candidates for the sister taxon/sister group of Gnaphalieae.     

Phylogenetic relationships of New Zealand Asteraceae inferred from ITS sequences

Forty-five sequences from members of all genera of Asteraceae indigenous to New Zealand and 50 published sequences representing the tribal diversity in the family were analyzed to assess the utility of ITS sequences to resolve phylogenetic relationships. Previous studies using chloroplast DNA sequences and morphology provided support for several clades in the Asteraceae, yet the relationships among some of these were uncertain. The results from ITS analysis were largely consistent with these earlier studies. The New Zealand species are included in at least six clades, most of these corresponding to recognized tribes. Our results have also clarified the tribal affinities of a few anomalous genera. Haastia, previously aligned with the Gnaphalieae or the Astereae, is nested in the Senecioneae. Centipeda, previously included in the Astereae or Anthemideae, emerges near the Heliantheae. The relationships of Abrotanella remain unresolved. Received August 8, 2001 Accepted November 6, 2001     

A Preliminary Molecular Phylogeny of the Rhynchosporeae (Cyperaceae)

The tribe Rhynchosporeae comprises the genera Rhynchospora and Pleurostachys and has never been studied using molecular techniques. The objective of this study was to use an analysis of trnL-F sequences to evaluate the hypothesized taxonomic divisions within the Rhynchosporeae including the monophyly of the genera and the soundness of the subgenera and sections. A total of 44 ingroup species were studied, 41 of Rhynchospora representing 22 of Kükenthal’s 28 sections, and three of Pleurostachys. Five outgroup species from other genera were also included. The cladistic analysis of 50 trnL intron and trnL-F intergenic spacer sequences resulted in 16 trees and a strict consensus tree. The Rhynchosporeae form two well-supported primary clades with several well-supported smaller clades, many of which agree with previously hypothesized sections. Pleurostachys is embedded within the second primary clade.     

Phylogeny and classification of Rosaceae

Phylogenetic relationships among 88 genera of Rosaceae were investigated using nucleotide sequence data from six nuclear (18S, gbssi1, gbssi2, ITS, pgip, and ppo) and four chloroplast (matK, ndhF, rbcL, and trnL-trnF) regions, separately and in various combinations, with parsimony and likelihood-based Bayesian approaches. The results were used to examine evolution of non-molecular characters and to develop a new phylogenetically based infrafamilial classification. As in previous molecular phylogenetic analyses of the family, we found strong support for monophyly of groups corresponding closely to many previously recognized tribes and subfamilies, but no previous classification was entirely supported, and relationships among the strongly supported clades were weakly resolved and/or conflicted between some data sets. We recognize three subfamilies in Rosaceae: Rosoideae, including Filipendula, Rubus, Rosa, and three tribes; Dryadoideae, comprising the four actinorhizal genera; and Spiraeoideae, comprising Lyonothamnus and seven tribes. All genera previously assigned to Amygdaloideae and Maloideae are included in Spiraeoideae. Three supertribes, one in Rosoideae and two in Spiraeoideae, are recognized.     

A worldwide phylogenetic classification of the Poaceae (Gramineae) III: An update

We present an updated worldwide phylogenetic classification of Poaceae with 11 783 species in 12 subfamilies, 7 supertribes, 54 tribes, 5 super subtribes, 109 subtribes, and 789 accepted genera. The subfamilies (in descending order based on the number of species) are Pooideae with 4126 species in 219 genera, 15 tribes, and 34 subtribes; Panicoideae with 3325 species in 242 genera, 14 tribes, and 24 subtribes; Bambusoideae with 1698 species in 136 genera, 3 tribes, and 19 subtribes; Chloridoideae with 1603 species in 121 genera, 5 tribes, and 30 subtribes; Aristidoideae with 367 species in three generaand one tribe; Danthonioideae with 292 species in 19 generaand 1 tribe; Micrairoideae with 192 species in nine generaand three tribes; Oryzoideae with 117 species in 19 genera, 4 tribes, and 2 subtribes; Arundinoideae with 36 species in 14 genera and 3 tribes; Pharoideae with 12 species in three generaand one tribe; Puelioideae with 11 species in two generaand two tribes; and the Anomochlooideae with four species in two generaand two tribes. Two new tribes and 22 new or resurrected subtribes are recognized. Forty-five new (28) and resurrected (17) genera are accepted, and 24 previously accepted genera are placed in synonymy. We also provide an updated list of all accepted genera including common synonyms, genus authors, number of species in each accepted genus, and subfamily affiliation. We propose Locajonoa, a new name and rank with a new combination, L. coerulescens. The following seven new combinations are made in Lorenzochloa: L. bomanii, L. henrardiana, L. mucronata, L. obtusa, L. orurensis, L. rigidiseta, and L. venusta.     

Phylogenetic analysis of Stylosanthes (Fabaceae) based on the internal transcribed spacer region (ITS) of nuclear ribosomal DNA

 Phylogenetic relationships in Stylosanthes are inferred by DNA sequence analysis of the ITS region (ITS1–5.8S–ITS2) of the nuclear ribosomal DNA in 119 specimens, representing 36 species of Stylosanthes and 7 species of the outgroup genera Arachis and Chapmannia. In all examined specimens of any particular diploid and (allo)polyploid species, only a single ITS sequence type was observed. This allowed us to identify a parental genome donor for some of the polyploids. In several diploid and polyploid species, different specimens contained a different ITS sequence. Some of these sequence types were present in more than one species. Parsimony analysis yielded several well-supported clades that agree largely with analyses of the chloroplast trnL intron and partially with the current sectional classification. Discordances between the nuclear and cpDNA analyses are explained by a process of allopolyploidization with inheritance of the cpDNA of one parent and fixation of the ITS sequences of the other. S. viscosa has been an important genome donor in this process of speciation by allopolyploidy. Received August 14, 2001; accepted March 4, 2002 Published online: November 14, 2002 Addresses of the authors: Jacqueline Vander Stappen, Steven Van Campenhout and Guido Volckaert (E-mail: guido.volckaert@agr.kuleuven.ac.be), Katholieke Universiteit Leuven, Laboratory of Gene Technology, Kasteelpark Arenberg 21, B-3001 Leuven, Belgium. Jan De Laet, American Museum of Natural History, Division of Invertebrate Zoology, Central Park West at 79th Street, New York 10024–5192, USA. Susana Gama-López, Universidad Nacional Autónoma de México, Unidad de Biología, Tecnología y Protipos (UBIPRO), FES-Iztacala, Laboratorio de Recursos Naturales, Av. de Los Barrios S/N, Colonia Los Reyes Iztacala, Municipio Tlalnepantla, Estado de México, C.P. 54090, México. Present address: Apartado Postal 154, Cto. Parque No. 3, C.P. 53102, México.     

The complex history of the genus Ilex L. (Aquifoliaceae): evidence from the comparison of plastid and nuclear DNA sequences and from fossil data

 A plastid phylogeny of the genus Ilex based on three different loci (the atpB-rbcL spacer, trnL-trnF and rbcL) is compared with its nuclear phylogeny based on two different loci (the ribosomal ITS and the 5S RNA spacer). These two sets of molecular data are then compared to geographical and temporal data from the fossil record. The plastid phylogeny is strongly correlated with the geographic distribution of extant species. However, the nuclear phylogeny is strongly incongruent with the plastid phylogeny, suggesting frequent interlineage hybridizations. Moreover, the comparison of the ribosomal ITS tree and the 5S RNA spacer tree indicates also possible lineage sorting. Particularly interesting is the finding of two different Ilex lineages in the plastid American clade showing different biogeographic patterns in South America. One of them has a simple North American/South American biogeographical relationship. The other has complex biogeographical relationships, some species showing direct Asian/South American biogeographical relationships. During its history, the genus Ilex probably experienced frequent lineage sorting and interlineage hybridization with subsequent nuclear or cytoplasmic introgression, making the study of its history very complex. Received September 24, 2001; accepted August 19, 2002 Published online: November 28, 2002 Addresses of the authors: Jean-Fran?ois Manen (e-mail: manen@cjb.ville-ge.ch), Yamama Naciri-Graven, Conservatoire et Jardin Botaniques, Impératrice 1, CH-1292 Chambésy/Genève, Switzerland. Michael C. Boulter, Palaeobiology Research Unit, University of East London, Romford Road, London E15 4LZ, UK.     

CHROMOSOME NUMBERS IN COMPOSITAE. X.

Reports of 126 new counts are recorded for 9 tribes of Compositae, including reports for 45 genera and 102 species. Six genera, Psilocarphus (n = 14). Relhania (n = 7), Rutidosis (n = 9), Chaetanthera (n = 14), Hecastocleis (n = 8), and Hesperomannia (n = 10), and 41 species were previously unreported.     

Phylogenetic Relationships and the Radiation of Sigmodontine Rodents in South America: Evidence from Cytochrome b

Phylogenetic relationships among South American sigmodontine rodents were examined based on the complete sequence for the mitochondrial cytochrome b gene [1140 base pairs (bp)] for 66 species and between 759 and 1140 bp for an additional 19 species. Thirty-eight South American genera were represented, coming from eight of nine tribes. Outgroups included the North American murid rodents Peromyscus, Reithrodontomys, Scotinomys, and Neotoma, the Old World murine rodents Mus and Rattus, and the geomyoid genera Thomomys, Geomys, Dipodomys, and Perognathus as the most distant outgroup. The South American sigmodontines were supported as a monophyletic lineage. Within this radiation several clear-cut suprageneric groupings were identified. Many of the currently recognized tribal groupings of genera were found fairly consistently, although not always with high levels of bootstrap support. The various tribes could not be linked hierarchically with any confidence. In addition, several genera stand out as unique entities, without any apparent close relatives. The overall pattern suggests a rapid radiation of the sigmodontines in South America, followed by differentiation at the tribal and generic levels.     

Genetic diversity of dodder (<Emphasis Type="Italic">Cuscuta</Emphasis> spp.) collected from commercial cranberry production as revealed in the<Emphasis Type="Italic">trn</Emphasis>L (UAA) intron

Swamp dodder (Cuscuta gronovii) is a parasitic plant detrimental to cranberries. Observation of emergence of dodder seeds collected from a cultivated cranberry bog in Massachusetts revealed 2 or more peak emergence times during 4 consecutive growing seasons. Molecular methods were used to investigate genetic variation among the emerging dodder seedlings. On emergence, dodder seedlings were collected and analyzed for DNA sequence diversity in thetrnL (UAA) intron, a noncoding region of chloroplast DNA. DNA sequence analysis of 87 seedlings collected during the 1999 and 2000 growing seasons revealed the presence of 2 dodder ecotypes, designated A and B. Comparative DNA sequence analysis indicated that in thetrnL (UAA) intron, the sequence of ecotype A is identical to that ofCuscuta gronovii, whereas the sequence of ecotype B is closest to that ofCuscuta attenuata (99.3% sequence identity; 293 bases considered). ABg/II restriction enzyme cut site was identified that distinguished between thetrnL (UAA) introns of ecotypes A and B. Restriction fragment length polymorphism (RFLP) was used to analyze the sequences of 100 seedlings collected during the growing seasons of 2001 and 2002. Only 10 of the 187 samples were ecotype A, all of which emerged on or before May 7 in the growing seasons. Therefore, the predominant dodder haplotype found in this study may be a close relative ofC. attenuata and notC. gronovii, the common species found in cranberry bogs.     

Genetic evidence for hybridization between the native Spartina maritima and the introduced Spartina alterniflora (Poaceae) in South-West France: Spartina × neyrautii re-examined

 Spartina alterniflora, a perennial grass native to the North American Atlantic coast, was introduced during the 19th century in western Europe (Southern England and western France) where it hybridized with the native Spartina maritima. In England, the sterile hybrid S. × townsendii gave rise by chromosome doubling to the highly fertile allopolyploid Spartina anglica, which has now invaded many salt marshes and estuaries in western Europe, and has been introduced in several continents. In South-West France, another sterile hybrid was discovered in 1892 in the Bidassoa Estuary, and named Spartina × neyrautii. According to their morphology, some authors suggested that S. × neyrautii and S. × townsendii result from reciprocal crosses. During the 20th century, the hybridization site was severely disturbed, and surviving of S. × neyrautii was questioned. In this paper, various Spartina populations are investigated in the Basque region (France and Spain), and compared to the hybrid taxa formed in England (S. × townsendii and S. anglica). The samples were analyzed using molecular fingerprinting (RAPD and ISSR) and Chloroplast DNA sequence (trnL-trnT spacer, trnL intron and trnL-trnF spacer). In the Bidassoa estuary, a hybrid isolated clone has been found, that displays additive species-specific nuclear markers of S. maritima and S. alterniflora, and that is subsequently considered as a surviving clone of S. × neyrautii. The molecular analyses indicate that S. × neyrautii and S. × townsendii share the same maternal (S. alterniflora), and paternal (S. maritima) parental species, but also that the two independent hybridization events have involved different parental (nuclear) genotypes in England and in South-West France. Received July 12, 2002; accepted October 4, 2002 Published online: March 20, 2003     

Molecular phylogeny and biogeography of Erithalis (Rubiaceae), an endemic of the Caribbean Basin

 Erithalis consists of 8–10 species endemic to the Caribbean Basin. DNA sequences of chloroplast (trnF-trnL) and nuclear non-coding spacers (ITS and ETS) indicate that Erithalis is monophyletic. ETS was the most informative marker, resolving some interspecific relationships. Analyses of the combined data revealed two weakly supported clades: one composed of E. fruticosa and E. nk;harrisii, and a sister clade of the remaining species. Since fossil records indicate the presence of Erithalis-like pollen from the Eocene Gatuncillo Formation of Panama, it is possible that an initial colonization may have been from Central America. Through trans-oceanic dispersal, most likely by birds, Erithalis colonized the Caribbean islands. Some of the inter-island colonizations were accompanied by speciation and low molecular divergence, supporting a recent radiation across these islands. Received October 3, 2001; accepted March 4, 2002 Published online: November 7, 2002 Address of the authors: Vivian Negrón-Ortiz (e-mail: negronv@muohio.edu), Linda E. Watson, Department of Botany, Miami University, Oxford, Ohio 45056, USA.