Molecular evidence for a Mediterranean origin of the Macaronesian endemic genus Argyranthemum (Asteraceae)

The internal transcribed spacers (ITS) of nuclear ribosomal DNA were sequenced for 52 species from 32 genera and eight subtribes of Anthemideae. Phylogenetic analyses of ITS data generated trees that are largely incongruent with the recent classification of Anthemideae; most of the subtribes examined are not resolved as monophyletic. However, ITS trees are congruent with morphological, isozyme, phytochemical, and chloroplast DNA (cpDNA) restriction site data in supporting a Mediterranean origin for Argyranthemum, the largest endemic genus of the Atlantic oceanic islands. A combined analysis of ITS sequences and cpDNA restriction sites indicates that Argyranthemum is sister to the other three genera of Chrysantheminae (i.e., Chrysanthemum, Heteranthemis, and Ismelia). Times of divergence of Argyranthemum inferred from the ITS sequences ranged between 0.26 and 2.1 million years ago (mya) and are lower than values previously reported from isozyme and cpDNA data (1.5-3.0 mya). It is likely that rate heterogeneity of the ITS sequences in the Anthemideae accounts for the low divergence-time estimates. Comparison of data for 20 species in Argyranthemum and Chrysantheminae indicates that the cpDNA restriction site approach provided much more phylogenetic information than ITS sequences. Thus, restriction site analyses of the entire chloroplast genome remain a valuable approach for studying recently derived island plants.     

Origin and evolution of endemic plants of the Bonin (Ogasawara) Islands

The Bonin Islands are typical oceanic islands, located at the western part of the North Pacific Ocean and approximately 1,000 km south of mainland Japan. This archipelago consists of about 20 small islands. Although floristic diversity is low due to the small area and limited environmental diversity, the Bonin Islands harbor unique endemic flora as in other well-known oceanic islands. This paper presents a brief summary of the results obtained from recent studies on the endemic flora of the Bonin Islands. The results are reviewed in relation to the four stages of the evolution of endemic flora in the oceanic islands; migration, establishment, enlargement and diversification. The ancestors of the flora originated mostly from tropical and subtropical Southeast Asia or mainland Japan by rare events of long distance dispersal. The proportion of bird-dispersed species is relatively high as for other oceanic islands. Genetic data sets obtained from allozyme variation in some endemic species suggest that migration occurred several million years ago and genetic diversity is correlated with current population size. At the time of establishment, self-compatible plants are expected to have an advantage. However, the percentage of dioecious plants is relatively high. This is partly due to evolutionary changes from hermaphroditic ancestors to dioecy which occurred in two genera in the Bonin Islands. In addition, there are some examples of evolutionary changes from herbaceous ancestors to woody endemics. Adaptive radiation is found in some genera, although the number of congeneric endemic species is less than five. Studies of allozyme variation inPittosporum, Symplocos andCrepidiastrum showed that genetic identity is generally very high between congeneric species in spite of their distinct morphologies. This result suggests that divergence of these species occurred rather recently and distinct morphological differences are based on a limited number of genetic changes.     

A phylogeny of Thermopsideae (Leguminosae: Papilionoideae) inferred from nuclear ribosomal internal transcribed spacer (ITS) sequences

Based on nuclear ribosomal DNA internal transcribed spacer (ITS) sequences, Thermopsideae is phylogenetically studied within a genistoid background. Analysis reveals that the tribe is not supported as a monophyletic group. Some species of Sophora s.s are nested within it. The central Asian desert Ammopiptanthus forms an isolated clade but is relatively remote to other Thermopsideae members. Piptanthus , Anagyris , Baptisia , and Thermopsis are clustered together into a robust clade. We hence propose that the tribe could either be reduced to just the four 'core genera' with Ammopiptanthus excluded, or, as an alternative, that Thermopsideae could become part of a new Sophoreae s.s. if it is re-circumscribed in the future. Both Piptanthus and Baptisia appear as monophyletic. The genus Anagyris is closer to some east Asian Thermopsis species than to Piptanthus . The east Asian and North American disjunct Thermopsis is not monophyletic. The ITS results suggest a geographical division between the Old World and New World Thermopsis . The east Asian species are clustered with Piptanthus and Anagyris , whereas the North American species are allied to Baptisia . Nonetheless, the only two north-eastern east Asian native Thermopsis species appear to be more related to the North American group than to the east Asian one. The related biogeographical significance has therefore been additionally discussed.  © 2006 The Linnean Society of London, Botanical Journal of the Linnean Society , 2006, 151 , 365–373.     

Phylogenetic and biosystematic relationships in four highly disjunct polyploid complexes in the subgenera Ceterach and Phyllitis in Asplenium (Aspleniaceae)

Phylogenetic studies using DNA sequences of two chloroplast regions, rbcL and trnL-F, demonstrate that the proposed genus Ceterach is a small clade within the large genus Asplenium, and sister to the Phyllitis clade. The Ceterach clade is characterised by irregular anastomosing veins and often densely scaled leaf blades. Its taxonomic status as a group nested within Asplenium is confirmed, and it is accepted here as a subgenus with seven species. The Ceterach clade comprises four lineages that correspond to disjunct polyploid complexes: the A. aureum clade forming a polyploid complex (4×, 6×, 8×) in Macaronesia, the A. ceterach clade forming a polyploid complex (2×, 4×, 6×) in the Mediterranean Basin, the A. paucivenosum clade (4×, 6×) in central Asia, and the A. dalhousiae clade (2×) with a disjunct distribution in the Himalaya, Yemen and Eritrea, and southwestern North America. Asplenium paucivenosum is sister to all other members of the Ceterach clade, whereas A. dalhousiae is sister to the A. aureum clade that includes tetraploid A. aureum, hexaploid A. lolegnamense, and octoploid A. parvifolium. Asplenium ceterach and its variations – including the hexaploid A. ceterach subsp. mediterraneum subsp. nov. first described below – form a monophyletic unit, sister to a clade consisting of A. aureum and A. dalhousiae. Asplenium cordatum from Africa and A. haugthonii from the isolated atlantic island of St. Helena are not members of the Ceterach clade, which suggests that leaf blades with dense indumenta have evolved at least twice within asplenioid ferns. The allotetraploid species A. hybridum has the chloroplast DNA from A. ceterach, and therefore the latter species is the maternal ancestor of the former. The other parent of this hybrid species is A. sagittatum that is nested within the sister clade of Ceterach, the Phyllitis clade comprising A. sagittatum and A. scolopendrium. The findings suggest that the current distribution of Ceterach is either the result of long-distance dispersal or represents fragmented relicts of a previously more widely distributed species.     

Molecular phylogenetics of the subtribeGentianinae (Gentianaceae) inferred from the sequences of internal transcribed spacers (ITS) of nuclear ribosomal DNA

The internal transcribed spacer (ITS) regions of 18S–25S nuclear ribosomal DNA from representatives of 23 species of the subtribeGentianinae and one outgroup species (Centaurium capitatum) were analyzed by polymerase chain reaction amplification and direct DNA sequencing. Within the taxa analyzed, the length of the ITS1 region varied from 221 to 233 bp, ITS2 from 226 to 234 bp. Of the aligned sequences of 497 positions, 151 sites involved gaps or nucleotide ambiguity, 133 were invariable and 213 showed divergence. In pairwise comparisons among the taxa of the subtribeGentianinae and the outgroup, sequence divergence ranged from 1.3% to 34.1% in ITS1, from 0 to 28.1% in ITS2 and from 0.6% to 27.5% in combined ITS1 and ITS2. Phylogenetic trees generated from ITS sequences were highly resolutive and principally concordant with morphological classifications for the major phylogenetic divisions in the subtribe. An ancient divergence leading to two evolutionary lines was suggested in the subtribe by both DNA sequence and morphological data. One line encompasses the generaGentiana, Crawfurdia andTripterospermum, morphologically characterized by their glands on the base of ovary and their plicate corolla, while the other line involves all other members of the subcribe surveyed, characterized by their epipetalous glands and simple corolla without plicae.Megacodon, with glands on the base of ovary but without plicae on its corolla, was revealed to be more related to the latter group than to the former.Comastoma, Gentianella andGentianopsis were shown to be well-defined monophyletic genera.Pterygocalyx showed much closer affinity toGentianopsis than to any other genus. Some conflictions were detected in the genusSwertia.     

Origin and evolution of the endemic genera of Gonosperminae (Asteraceae: Anthemideae) from the Canary Islands: evidence from nucleotide sequences of the internal transcribed spacers of the nuclear ribosomal DNA

The Gonosperminae (Asteraceae) are composed of three genera endemic to the Canary Islands (GONOSPERMUM: Less., and LUGOA: DC.) and southern Africa (INULANTHERA: K?llersj?), and they are considered an example of a floristic link between these two regions. Phylogenetic analyses of ITS sequences reveal that the Canarian genera are not sister to INULANTHERA: and do not support the monophyly of the Gonosperminae. These results, coupled with previous phylogenetic studies of other groups, suggest that many of the putative biogeographic links between Macaronesia and southeast Africa need to be evaluated by rigorous phylogenetic analyses. INULANTHERA: forms part of the basal southern African radiation of the Anthemideae, and therefore it is closely related to other taxa from this region. Maximum likelihood and weighted parsimony analyses support a monophyletic group in the Canary Islands, that includes LUGOA:, Gonospermum, and three TANACETUM: species endemic to the island of Gran Canaria. Bootstrap support for the monophyly of this Canarian group is weak, and it collapses in the strict consensus tree based on unweighted parsimony. LUGOA: is nested within Gonospermum, and both interisland colonization among the western islands of La Gomera, El Hierro, La Palma and Tenerife, and radiation on the central island of Gran Canaria have been the major patterns of species diversification for these Canarian endemics.     

Phylogeny of Rubus (rosaceae) based on nuclear ribosomal DNA internal transcribed spacer region sequences

We used nuclear ribosomal DNA internal transcribed spacer region (ITS 1 - 5.8S - ITS 2; ITS) sequences to generate the first phylogeny of Rubus based on a large, molecular data set. We sampled 57 taxa including 20 species of subgenus Rubus (blackberries), one to seven species from each of the remaining 11 subgenera, and the monotypic and closely related Dalibarda. In Rubus, ITS sequences are most informative among subgenera, and variability is low between closely related species. Parsimony analysis indicates that Rubus plus Dalibarda form a strongly supported clade, and D. repens may nest within Rubus. Of the subgenera with more than one species sampled, only subgenus Orobatus appears monophyletic. Three large clades are strongly supported: one contains all sampled species of nine of the 12 subgenera; another includes extreme Southern Hemisphere species of subgenera Comaropsis, Dalibarda, and Lampobatus; and a third clade consists of subgenus Rubus plus R. alpinus of subgenus Lampobatus. Rubus ursinus appears to be a hybrid between a close relative of R. macraei (subgenus Idaeobatus, raspberries) and an unidentified subgenus Rubus species. ITS sequences are generally consistent with biogeography and ploidy, but traditionally important morphological characters, such as stem armature and leaf type, appear to have limited phylogenetic value in Rubus.     

Phylogeny ofCyclamen L. (Primulaceae): Evidence from morphology and sequence data from the internal transcribed spacers of nuclear ribosomal DNA

A molecular phylogenetic study of the genusCyclamen L. (Primulaceae) has been undertaken, based on sequence data from the 5.8S gene in the ribosomal nuclear DNA and its flanking internal transcribed spacers ITS1 and ITS2. Sequence data from 15 species ofCyclamen and seven outgroup taxa selected from Primulaceae and Myrsinaceae were analyzed phylogenetically. A second analysis based on a combined morphological and molecular dataset was performed to evaluate earlier hypotheses of character evolution in the genus. The results indicate that four monophyletic subgroups may be recognized in the genus, viz.Cyclamen, Psilanthum Schwarz,Eucosme Schwarz andGyrophoebe Schwarz. Each of the four subgenera is diagnosed by distinct basic chromosome number, as well as by morphological and molecular characteristics.     

Molecular phylogeny of Osmanthus(Oleaceae)based on non-coding chloroplast and nuclear ribosomal internal transcribed spacer regions

The phylogenetic relationships of Osmanthus Lour.were investigated using the nuclear ribosomal internal transcribed spacer(ITS)regions and non-coding chloroplast regions(psbA-trnH,trnL-F).The two datasets support the conclusion that Osmanthus is polyphyletic.with some species of the subtribe Oleinae nested within Osmanthus.Osmanthus didymopetalus P S.Green is nested within the clade formed by species of section Osmanthus in two trees.Osmanthus attenuatus P.S.Green.O.Funnanensis P.S.Green,and O gracilinervis R.L.Lu of traditional section Osmanthus are clearly divergent from other accessions,and do not form a monophyletic group with other Osmanthus accessions.Osmanthus marginatus Hemsl.is embedded in the clade formed by species of section Osmanthus in the ITS tree.In cpDNA trees all species of section Osmanthus are placed in the large clade and all species of section Leiolea formed a group.The taxonomic incongruence among trees for ITS and cpDNA indicate hybridization.as introgression may have occurred among some species of sections Osmanthus and Leiolea.Phylogeny of Osmanthus is discussed in light of molecular and morphological data,and a revised infrageneric classification with three sections(Leiolea,Siphosmanthu,and Osmanthus)is presented.The section Linocieroides is abandoned and united with section Osmanthus.     

A phylogeny of Apiaceae tribe Scandiceae: evidence from nuclear ribosomal DNA internal transcribed spacer sequences

The evolutionary relationships among members of Apiaceae (Umbelliferae) tribe Scandiceae and representatives of all major lineages of Apioideae (including putatively allied Caucalideae) identified in earlier molecular studies were inferred from nucleotide sequence variation in the internal transcribed spacer regions (ITS1 and ITS2) of nuclear ribosomal DNA. In all, 134 accessions representing 18 genera commonly treated in Scandiceae were analyzed. Phylogenies estimated using maximum parsimony and distance methods were generally similar and suggest that: (1) Scandiceae form a well-supported clade, consisting of the genera Anthriscus, Athamanta (in part), Balansaea, Chaerophyllum, Conopodium, Geocaryum, Kozlovia, Krasnovia, Myrrhis, Myrrhoides, Neoconopodium, Osmorhiza, Scandix, Sphallerocarpus, and Tinguarra; (2) Athamanta is polyphyletic, with A. della-cellae allied with Daucus and A. macedonica placed close to Pimpinella; and (3) Rhabdosciadium and Grammosciadium find affinity with the Aegopodium group of umbellifers, whereas the placement of the monotypic Molopospermum cannot be inferred because of its high sequence divergence. The genus Bubon has been restored with two new combinations, B. macedonicum subsp. albanicum and B. macedonicum subsp. arachnoideum. Scandiceae arise within paraphyletic Caucalideae, the latter comprising two major lineages whose relationships to Scandiceae are not clear. Therefore, a broad treatment of Scandiceae is proposed, with subtribes Scandicinae, Daucinae, and Torilidinae (the latter two representing the Daucus and Torilis subgroups, respectively, of recent molecular systematic investigations).     

a molecular phylogeny of apiaceae subfamily Apioideae: evidence from nuclear ribosomal DNA internal transcribed spacer sequences

Phylogenetic relationships among 40 New World and Old World members of Apiaceae subfamily Apioideae, representing seven of the eight tribes and eight of the ten subtribes commonly recognized in the subfamily, were inferred from nucleotide sequence variation in the internal transcribed spacer (ITS) regions of 18-26S nuclear ribosomal DNA. Although the sequences are alignable, with only 11% of sites excluded from the analyses because of alignment ambiguity, divergence values in pairwise comparisons of unambiguous positions among all taxa were high and ranged from 0.5 to 33.2% of nucleotides in ITS 1 and from 0 to 33.2% of nucleotides in ITS 2. Average sequence divergence across both spacer regions was 18.4% of nucleotides. Phylogenies derived from ITS sequences estimated using neighbor-joining analysis of substitution rates, and maximum likelihood and parsimony methods give trees of essentially similar topology and indicate that: (1) there is little support for any existing system of classification of the subfamily that is based largely on morphological and anatomical features of the mericarp; (2) there is a major phylogenetic division within the subfamily, with one clade comprising the genus Smyrnium and those taxa belonging to Drude's tribes Dauceae, Scandiceae, and Laserpitieae and the other clade comprising all other examined taxa; and (3) the genera Arracacia, Coaxana, Coulterophytum, Enantiophylla, Myrrhidendron, Prionosciadium, and Rhodosciadium, all endemic to Mexico and Central America, comprise a clade but their relationships to other New World taxa are equivocal. A phylogeny derived from parsimony analysis of chloroplast DNA rpoC1 intron sequences is consistent with, but considerably less resolved than, relationships derived from these ITS regions. This study affirms that ITS sequences are useful for phylogenetic inference among closely related members of Apioideae but, owing to high rates of nucleotide substitution, are less useful in resolving relationships among the more ancestral nodes of the phylogeny.     

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.     

Phylogeny and biogeography of Allium (Amaryllidaceae: Allieae) based on nuclear ribosomal internal transcribed spacer and chloroplast rps16 sequences, focusing on the inclusion of species endemic to China

Background and Aims

The genus Allium comprises more than 800 species, placing it among the largest monocotyledonous genera. It is a variable group that is spread widely across the Holarctic region. Previous studies of Allium have been useful in identifying and assessing its evolutionary lineages. However, there are still many gaps in our knowledge of infrageneric taxonomy and evolution of Allium. Further understanding of its phylogeny and biogeography will be achieved only through continued phylogenetic studies, especially of those species endemic to China that have often been excluded from previous analyses. Earlier molecular studies have shown that Chinese Allium is not monophyletic, so the goal of the present study was to infer the phylogeny and biogeography of Allium and to provide a classification of Chinese Allium by placement of Chinese species in the context of the entire phylogeny.

Methods

Phylogenetic studies were based on sequence data of the nuclear ribosomal internal transcribed spacer (ITS) and chloroplast rps16 intron, analysed using parsimony and Bayesian approaches. Biogeographical patterns were conducted using statistical dispersal–vicariance analysis (S-DIVA).

Key Results

Phylogenetic analyses indicate that Allium is monophyletic and consists of three major clades. Optimal reconstructions have favoured the ancestors of Amerallium, Anguinum, Vvedenskya, Porphyroprason and Melanocrommyum as originating in eastern Asia.

Conclusions

Phylogenetic analyses reveal that Allium is monophyletic but that some subgenera are not. The large genetic distances imply that Allium is of ancient origin. Molecular data suggest that its evolution proceeded along three separate evolutionary lines. S-DIVA indicates that the ancestor of Amerallium, Anguinum, Vvedenskya, Porphyroprason and Melanocrommyum originated from eastern Asia and underwent different biogeographical pathways. A taxonomic synopsis of Chinese Allium at sectional level is given, which divides Chinese Allium into 13 subgenera and 34 sections.     

Phylogenetic inferences in Antennaria (Asteraceae: Gnaphalieae: Cassiniinae) based on sequences from Nuclear Ribosomal DNA internal transcribed spacers (ITS)

The phylogenetic relationships among sexually reproducing species of Antennaria (Asteraceae) are poorly understood. An earlier cladistic analysis based on morphology did not fully resolve the phylogeny of these taxa and therefore a different approach using molecular data was explored. The internal transcribed spacer regions (ITS-1 and ITS-2) of nuclear ribosomal DNA were sequenced for 30 species of Antennaria and one species from each of the outgroup genera Anaphalis, Ewartia, Leontopodium, and Pseudognaphalium. The ITS-1 sequence in Antennaria ranged from 253 to 260 base pairs (bp) in length, and the proportion of nucleotide differences between pairs of species of Antennaria ranged from 1 to 14%. For ITS-2, the divergence between pairs of species of Antennaria ranged from 0 to 8%. ITS-2 is shorter than ITS-1, ranging from 213 to 219 bp. Phylogenetic analysis indicates that, relative to the outgroups included, Antennaria is a well-supported monophyletic group. Based on the genera surveyed, Leontopodium appears to be the sister genus of Antennaria. The general topology of the molecular trees agrees with that based on previous morphological analyses and indicates that Antennaria is composed of six clades of equal rank, corresponding to the traditionally recognized informal groups, the Geyeriae, Argenteae, Arcuatae, Dimorphae, Pulcherrimae, and Catipes. Sequence and morphological data indicate that the Alpinae and Dioicae are unnatural, polyphyletic units that should be abandoned and redefined as the monophyletic Catipes group. Phylogenetic analysis of ITS sequences also suggests the dissociation of A. stenophylla from the Dimorphae, where it is traditionally placed, and its affiliation with the Argenteae, as well as the placement of A. arcuata in its own group.     

基于ITS序列探讨山茶属金花茶组的系统发育关系

测定了分布于我国的 2 2个山茶属金花茶组的种或变种的nrDNAITS区序列 ,它们的序列长度在 476～ 496之间。GC含量都超过了 70 % ,应用Kimura2 模型计算了序列间的分化程度 ,构建了最大简约树、邻接树和最大似然树 ,分析结果表明 :( 1 )淡黄金花茶、毛籽金花茶、陇瑞金花茶、弄岗金花茶、大样金花茶和凹脉金花茶的关系较近 ;( 2 )小瓣金花茶、小花金花茶、薄叶金花茶、多瓣金花茶、夏石金花茶和龙州金花茶的关系较近。ITS区序列分析结果与AFLP分析结果相近     

Recolonization and radiation in Larix (Pinaceae): evidence from nuclear ribosomal DNA paralogues

Gene paralogy frequently causes the conflict between gene tree and species tree, but sometimes the coexistence of a few paralogous copies could provide more markers for tracing the phylogeographical process of some organisms. In the present study, nrDNA ITS paralogues were cloned from all but one species of Larix, an Eocene genus having two sections, Larix and Multiserialis, with a huge circumboreal distribution and an Eastern Asia-Western North America disjunction, respectively. A total of 96 distinct clones, excluding five putative pseudogenes or recombinants, were obtained and used in the gene genealogy analysis. The clones from all Eurasian species of section Larix are mixed together, suggesting that recolonization and recent morphological differentiation could have played important roles in the evolution of this section. In contrast, the species diversification of the Eurasian section Multiserialis may result from radiation in the east Himalayas and its vicinity, considering extensive nrDNA founder effects in this group. Our study also suggests that the distribution pattern analysis of members of multiple gene family would be very useful in tracking the evolutionary history of some taxa with recent origin or rapid radiation that cannot be resolved by other molecular markers.     

Phylogeny of the Macaronesian endemic Crambe section Dendrocrambe (Brassicaceae) based on internal transcribed spacer sequences of nuclear ribosomal DNA

The 14 species of Crambe L. sect. Dendrocrambe DC. (Brassicaceae) form a monophyletic group endemic to the Canary and Madeira archipelagos. Both parsimony and maximum likelihood analyses of sequence data from the two internal transcribed spacer regions of nuclear ribosomal DNA were used to estimate phylogenetic relationships within this section. These analyses support the monophyly of three major clades. No clade is restricted to a single island, and therefore it appears that inter-island colonization has been the main avenue for speciation in these two archipelagos. The two species endemic to Fuerteventura (C. sventenii) and Madeira (C. fruticosa) comprise a clade, providing the first evidence for a floristic link between the Eastern Canary Islands and the archipelago of Madeira. Both maximum likelihood and weighted parsimony analyses show that this clade is sister to the two other clades, although bootstrap support for this relationship is weak. Parsimony optimizations of ecological zones and island distribution suggest a colonization route from the low-altitude areas of the lowland scrub toward the high-elevation areas of the laurel and pine forests. In addition, Tenerife is likely the ancestral island for species endemic to the five westernmost islands of Gran Canaria, La Gomera, El Hierro, La Palma, and Tenerife.