The phylogeny of Lens (Leguminosae): new insight from ITS sequence analysis

 Lens includes L. culinaris subsp. culinaris (the cultivated lentil) and several wild species distributed from the Mediterranean region to western Asia. We compared sequence variation in the ITS region among species of Lens in an effort to end persisting uncertainty regarding the phylogeny of the genus. The parsimony analysis revealed a single minimum-length tree with a topology congruent with patterns derived by previous studies of nuclear and chloroplast DNA RFLPs. The basal and highly divergent status of the L. nigricans clade is depicted, and the progenitor-derivative relationship between L. culinaris subsp. orientalis and L. culinaris subsp. culinaris is reaffirmed. Resolution in the tree was improved by combining the ITS data set with a pre-existing set of chloroplast DNA restriction site data obtained from the same group of samples. Received May 8, 2000 Accepted October 26, 2001     

Molecular approach to the phylogeny and systematics of Cytisus (Leguminosae) and related genera based on nucleotide sequences of nrDNA (ITS region) and cpDNA (trnL-trnF intergenic spacer)

 Phylogenetic relationships of Cytisus and allied genera (Argyrocytisus, Calicotome, Chamaecytisus, Cytisophyllum, and Spartocytisus) were assessed by analysis of sequences of the nrDNA internal transcribed spacer (ITS) and the cpDNA trnL-trnF intergenic spacer. Genera of the Genista-group (Chamaespartium, Echinospartum, Genista, Pterospartum, Spartium, Teline and Ulex) were included to check the position of Cytisus species transferred to Teline. The tree obtained by combining both sets of data indicates that the Genista and Cytisus groups form two separate clades. Cytisus heterochrous and C. tribracteolatus are more closely related to the Cytisus-group, thus their transfer to Teline is not supported by molecular data. Cytisus fontanesii (syn. Chronanthos biflorus) groups with Cytisophyllum sessilifolium and Cytisus heterochrous within the Cytisus-group. Similarly, Argyrocytisus battandieri falls within the Cytisus-group as a well differentiated taxon. All these taxa seem to have early diverged from the Cytisus-group. Their taxonomic rank should be reconsidered to better reflect their phylogenetic separation from Cytisus. On the contrary, Chamaecytisus proliferus and Spartocytisus supranubius enter in the main core of Cytisus, and they should better be included in sections of Cytisus (sect. Tubocytisus and Oreosparton, respectively). Sect. Spartopsis is not monophyletic and the position of several species, currently included in this section, deserves reevaluation: C. arboreus aggregate is closely related to C. villosus (sect. Cytisus) and to Calicotome; C. striatus is closely related to Cytisus sect. Alburnoides; and the position of C. commutatus (incl. C. ingramii) remains unclear. The relationships and positioning of several minor taxa (C. transiens, C. megalanthus, and C. maurus) are also discussed. Received November 22, 2001; accepted March 16, 2002 Published online: October 14, 2002 Addresses of the authors: Paloma Cubas (e-mail: cubas@farm.ucm.es) and Cristina Pardo (e-mail: cpardo@farm.ucm.es), Departamento de Biología Vegetal II, Facultad de Farmacia, Universidad Complutense, E-28040 Madrid, Spain. Hikmat Tahiri Faculté des Sciences, Université Mohammed V, BP 1014 Rabat, Morocco (e-mail: tahiri@ fsr.ac.ma).     

Karyological evolution and molecular phylogeny in Macaronesian dendroid spurges (Euphorbia subsect. Pachycladae)

 Euphorbia subsect. Pachycladae is a taxon of primarily Macaronesian distribution, defined by morphological and biogeographical criteria. On the basis of morphological data, it is a heterogeneous group within which at least three complexes of species can be distinguished. To ascertain whether it is a natural group and discover its phylogenetic relations, we performed a cladistic analysis of the sequences of ribosomal nuclear DNA and a karyological study. The results of the two studies are concordant and show that the sub-section is polyphyletic and includes three different groups. The first monophyletic group is made up of the Macaronesian endemics E. atropurpurea complex and E. lamarckii complex, which form a polytomy with E. dendroides as the basal species. The lauroid species E. longifolia and E. stygiana represent the second monophyletic group, which derive from Mediterranean forms of E. sect. Helioscopia Dumort. Both species are paleopolyploid (2n=44) with highly symmetrical karyotypes. Finally, E. balsamifera, with a Canarian, African and Arabian distribution, remains isolated in a basal position. Its karyotype, with 2n=20 chromosomes, differs from the Macaronesian model and displays analogies with African cactiform spurges. On the basis of the results, some hypotheses are formulated about speciation processes in the three groups. Received March 3, 2001 Accepted October 28, 2001     

Molecular evidence for the polyphyly of Olearia (Astereae: Asteraceae)

 Analyses of ITS sequences for 49 species of Olearia, including representatives from all currently recognised intergeneric sections, and 43 species from 23 other genera of Astereae, rooted on eight sequences from Anthemideae, provide no support for the monophyly of this large and morphologically diverse Australasian genus. Eighteen separate lineages of Olearia are recognised, including seven robust groups. Three of these groups and another eight species are placed within a primary clade incorporating representatives of Achnophora, Aster, Brachyscome, Calotis, Camptacra, Erigeron, Felicia, Grangea, Kippistia, Lagenifera, Minuria, Oritrophium, Peripleura, Podocoma, Remya, Solidago, Tetramolopium and Vittadinia. The remaining four groups and three individual species lie within a sister clade that also includes Celmisia, Chiliotrichum, Damnamenia, Pleurophyllum and Pachystegia. Relationships within each primary clade are poorly resolved. There is some congruence between this molecular estimate of the phylogeny and the distribution of types of abaxial leaf-hair, which is the basis of the present sectional classification of Olearia, but all states appear to have arisen more than once within the tribe. It is concluded that those species placed within the second primary clade should be removed from the genus, but the extent to which species placed within the first primary clade constitute a monophyletic group can only be resolved with further sequence data. Received November 12, 2001; accepted April 29, 2002 Published online: November 22, 2002 Addresses of authors: Edward W. Cross, Centre for Plant Biodiversity Research, CSIRO, GPO Box 1600, Canberra, ACT 2601, Australia (E-mail: ed.cross@csiro.au); Christopher J . Quinn, Royal Botanic Gardens, Mrs Macquaries Rd., Sydney, NSW 2000, Australia; Steven J. Wagstaff, Landcare Research, PO Box 69, Lincoln 8152, New Zealand.     

Cladistic and phenetic analysis of relationships in Vicia subgenus Vicia (Fabaceae) by morphology and isozymes

 Variation of 80 multistate morphological characters and isozymes encoded by 13 loci among 23 vetch species of the type subgenus of the genus Vicia in comparison with V. dumetorum, V. pisiformis and V. sylvatica of the subgenus Cracca is described and analyzed with cladistic parsimony and phenetic neighbour-joining methods by using two different ways of coding. Morphological analyses showed the subgenus Vicia monophyletic and revealed subgroups in a general agreement with traditionally recognized sections, except showing V. faba nested within section Narbonensis and ambiguity in the position of V. lathyroides and V. bithynica. Parsimony analysis of orthozymes as presence/absence characters revealed in the subgenus two basic monophyletic clades: 1) V. faba and three species of the section Peregrinae, V. michauxii, V. aintabensis and V. peregrina, in one subclade linked with species of the Narbonensis and Hyperchusa sections together with V. pisiformis of subgenus Cracca in a second subclade; 2) species belonging to sections Vicia, Sepium, Pseudolathyrus and Lathyroides together with V. sylvatica of the subgenus Cracca. Neighbour-joining analysis of orthozymes revealed the same two basic groups, differing only in the relative position of some species in subclusters. Both isozyme analyses showed paraphyly of the subgenera Vicia and Cracca. Parsimony analysis of orthozymes as character states of isozymes yielded a largely unresolved strict consensus cladogram of 209 most parsimonious trees, and reweighting of characters failed to produce a stable tree. Phylogenetic congruence and discordance among morphological and isozyme analyses, coding ways, homoplasy and weighting of characters are discussed. Received November 20, 2001 Accepted January 31, 2002     

Chromosome and breeding system evolution of the genus Mercurialis (Euphorbiaceae): implications of ITS molecular phylogeny

 The internal transcribed spacers (ITS1 and ITS2) of nuclear ribosomal DNA were amplified and sequenced from 19 samples representing all species of the genus Mercurialis and two outgroup species, Ricinus communis and Acalypha hispida. The length of ITS1 in the ingroups ranged from 223 to 246 bp and ITS2 from 210 to 218 bp. Sequence divergence between pairs of species ranged from 1.15% to 25.88% among the ingroup species in the combined data of ITS1 and ITS2. Heuristic phylogenetic analyses using Fitch parsimony on the combined data of ITS1 and ITS2 with gaps treated as missing generated 45 equally parsimonious trees. The strict consensus tree was principally concordant with morphological classification. Within the genus, the ITS sequences recognised two main infrageneric clades: the M. perennis complex including three Eurasian stoloniferous species (M.␣leiocarpa, M. ovata and M. perennis) and the western Mediterranean group including eight both annual and perennial species. Of the western Mediterranean clade, the annual and perennial species grouped respectively into two different groups, and the annual life form is revealed as a synapomorphic character derived from perennial, whereas in the Eurasian clade ITS phylogeny suggested M. leiocarpa as basal clade sister to M.␣perennis and M. ovata. ITS phylogeny failed to resolve the relationships among the different cytotypes of M. ovata and M. perennis. ITS phylogeny also suggested rapid karyotypic evolution for the genus. The karyotypic divergence among the perennial species of western Mediterranean region did not corroborate the nucleotide sequence divergence among the species. Optimisation of chromosome numbers onto the ITS phylogeny suggested x=8 to be the ancestral basic chromosome number of the genus. ITS phylogeny confirmed that the androdioecy of M. ambigua is derived from dioecy. The nucleotide heterozygosity and additivity in ITS sequences clearly confirm the interspecific hybridisation in the genus Mercurialis. Received December 22, 2001; accepted May 21, 2002?Published online: November 14, 2002 Address of the authors: Martin Kr?henbühl, Yong-Ming Yuan (correspondence) and Philippe Küpfer, Institut de Botanique, Laboratoire de botanique évolutive, Université de Neuchatel, Emile-Argand 11, CH-2007 Neuchatel, Suisse. (e-mail: yong-ming.yuan@unine.ch)     

The phylogeny of Patrinieae sensu Graebner (Valerianaceae) revisited: additional evidence from ndhF sequence data

 DNA sequences of both 5′ and 3′ regions of the plastid ndhF gene were generated in order to study the position of Patrinia and Nardostachys, to check the potential paraphyletic nature of Patrinieae, and to evaluate the possible link between the tribe and Linnaeaceae. Parsimony analysis showed very strong support for Patrinia as sister to all members of Valerianaceae (including Nardostachys) and indicated the paraphyletic nature of the tribe Patrinieae. Additionally, trees were constructed from available rbcL data separately and supplemented with ndhF sequences. Topologies of these combined cladograms are in agreement with the ndhF phylogeny, suggesting that the traditionally circumscribed Patrinieae can no longer be recognized but must be considered as part of a basal grade in Valerianaceae. Parsimony analysis based on a morphological data set supported a monophyletic Patrinieae; combination with the molecular data showed a paraphyletic Patrinieae. Furthermore, the possible link between Patrinieae and Linnaeaceae is evaluated. Received July 12, 2001 Accepted February 25, 2002     

Systematics of the Dactylorhiza euxina/incarnata/maculata polyploid complex (Orchidaceae) in Turkey: evidence from allozyme data

 Material of Dactylorhiza were sampled from 49 localities in Turkey and investigated for allozyme variation at ten loci (nine enzyme systems). Among diploids, the Anatolian D. osmanica and D. umbrosa were allozymically variable, but not distinct from each other or from D. incarnata. Dactylorhiza saccifera contained the same alleles as the European D. fuchsii. Dactylorhiza iberica and D. euxina were distinct from each other and the other diploids. On basis of allozyme patterns three distinct allotetraploid genotypes were distinguished, and each of them could be treated as a separate species. Dactylorhiza nieschalkiorum is similar to European allotetraploids, and may have arisen from hybridization between D. incarnata s.l. and D. saccifera. Dactylorhiza urvilleana may have arisen from parents related to present-day D. saccifera and D. euxina, but it also contains additional alleles that have not been found in any of the diploids investigated. A third allotetraploid known from four populations in the Ardahan and Kars provinces of north-eastern Turkey combines the allozyme patterns found in material of D. incarnata s.l. from the same area with those from D. euxina. It is here described for the first time as D. armeniaca. Received November 14, 2000 Accepted June 20, 2001     

Contribution to the taxonomy and phylogeny of Sarcocapnos DC. (Fumariaceae)

 To solve problems concerning the status of the taxa described in the genus Sarcocapnos, we have conducted a study using morphological, pollen morphology (light microscopy), cytogenetic and molecular techniques. Focusing on the last technique, we have sequenced ITS-1 and ITS-2 of nuclear rDNA. The species differ basically according to 5 morphological traits (leaf shape, flower spur, corolla colour, corolla size, and crest of the stigmatic surface). The cytogenetic analyses indicated n=16 to be the standard chromosome number. The ITS analyses showed that the genus is monophyletic, defining two main well-supported clades, one containing S. saetabensis and S. enneaphylla, and one containing the rest of the species. In this second clade, S. speciosa, S. pulcherrima, and S. baetica subsp. ardalii are related, as are S. integrifolia, S. crassifolia subsp. crassifolia, and S. crassifolia subsp. atlantis; S. baetica subsp. baetica forms a trichotomy with the foregoing groups. S. speciosa is shown to be a species separate from S. crassifolia subsp. crassifolia, as in the case of S. baetica with respect to S. integrifolia. Palynologically, the parameters used enabled us to establish clear differences between the taxa, often corroborating the macromorphological and genetic data. The flower spur has been reduced several times in different groups of the genus, for which the classifications established on the basis of this trait are paraphyletic. Received July 16, 2002; accepted December 11, 2002 Published online: March 31, 2003     

Molecular phylogeny supports the morphologically based taxonomic transfer of the “medicagoid”Trigonella species to the genus Medicago L.

 The taxonomic transfer of the 23 Trigonella species previously known as medicagoids to the genus Medicago L. is reanalyzed on the basis of a molecular phylogenetic approach. The internal and external transcribed spacers of 53 Medicago species s. str. and 10 of the 23 medicagoid species were sequenced. Both maximum parsimony or maximum likelihood criteria joined medicagoid species more confidently with Medicago rather than with Trigonella. The basal position of the medicagoid species within the genus Medicago, together with morphologically atypical Medicago species (such as M. radiata and M. platycarpa), raised the question of the expediency to define a new genus and is discussed, relatively to the support of each clade. Using criteria of monophyly and support, it was concluded that the medicagoids are better joined in Medicago rather than placed in a new genus. Received February 6, 2001 Accepted July 17, 2001     

Tests of the accuracy of cladograms in Gilia (Polemoniaceae) and some other angiosperm genera

 This paper deals with the use of cladistic methods and cladograms in phylogeny reconstruction in plant groups containing numerous taxa. How accurate are the cladograms as to details? Accuracy tests at the level of details require an independently known phylogeny, which excludes most plant groups, but such tests can be carried out in domesticated and experimental plant groups which have documented pedigrees. Four such tests are known and are presented here: a new case in Gilia and three previously published cases in Avena, Hordeum, and Helianthus. The four cases include domesticated and experimental plants, use of morphological and molecular evidence, and presence of dichotomous as well as reticulate phylogenies. The cladograms of the four plant groups all differ in significant details from the known pedigrees. These results are discussed in relation to problems of interpretation of cladograms. Received March 21, 2000 Accepted August 16, 2001     

Phylogenetic position of the Sphaeropleaceae (Chlorophyta)

 The complete 18S rRNA gene sequences of four Sphaeroplea C.A. Agardh strains (Sphaeropleales, Sphaeropleaceae), two Atractomorpha Hoffman strains (Sphaeropleales, Sphaeropleaceae) and two Ankyra Fott strains (Chlorococcales, Characiaceae) were determined and subjected to phylogenetic analyses. The analyses indicated that all these taxa belong to a monophyletic lineage (Sphaeropleaceae) and are related to a group of chlorophycean algae comprising autosporic taxa and taxa that reproduce by zoospores which are characterized by directly opposed basal bodies. The taxonomic assignment of the Sphaeropleaceae as a family within the Sphaeropleales (Chlorophyta, Chlorophyceae) is discussed. Received December 22, 2000 Accepted September 25, 2001     

Inflorescence development of Whytockia (Epithemateae, Gesneriaceae) and phylogenetic implications within Gesneriaceae

 The inflorescence development in Whytockia has been studied in order to explore the developmental basis for inflorescence architecture. The developmental pattern of the pair-flowered cyme in Whytockia basically conforms to that of most members in Gesneriaceae. However, the additional flower beside the terminal one in Whytockia is not equivalent to the frontal flower as in other Gesneriaceae because the former is located in the front-lateral position while the latter is in the front-median position. Also, the zigzag monochasial branching system in Whytockia represents the consecutive front-lateral branches rather than the lateral branches as in other Gesneriaceae. The inflorescence in Whytockia is flowering in a basipetal sequence, and its seemingly acropetal flowering sequence is due to the vigorous development of the consecutive front-lateral branches. In addition, the inflorescence of Whytockia does not represent the basic unit of the inflorescence in Epithemateae, and it is derived as compared to that of Rhynchoglossum. The development relationships of the inflorescence between Whytockia and its allies in Epithemateae are discussed on the basis of developmental and comparative evidence. Received February 15, 2002; accepted September 17, 2002 Published online: December 11, 2002     

A phylogenetic analysis of Primulaceae s.l. based on internal transcribed spacer (ITS) DNA sequence data

 Phylogenetic relationships in Primulaceae were investigated by analysis of nuclear rDNA ITS sequences. Thirty-four species of Primulaceae, two of Myrsinaceae and four outgroup taxa were analyzed. In accordance to the results of recently published papers on the phylogeny of Primulaceae we found the family to be paraphyletic and resolved the positions of some genera. Our results show (a) the rather basal position of Centunculus within Lysimachieae, the genus thus being rather distantly related to Anagallis, (b) the close relationship between Lysimachia sect. Lerouxia, Anagallis, Asterolinon, and Pelletiera, (c) the well-supported monophyly of a group consisting of the four genera Hottonia, Omphalogramma, Bryocarpum, and Soldanella, and (d) the affinity of Stimpsonia to the Myrsinaceae-Lysimachieae-Ardisiandra clade. The ITS sequence data do not provide sufficient information to resolve basal relationships within the Primulaceae s.l. There is evidence against the monophyly of the large genera Primula, Androsace, and Lysimachia. In contrast to the phylogenetic reconstructions based on plastid gene sequences, Cyclamen does not appear as a member of the Myrsinaceae-Lysimachieae clade, but its position remains unclear. Revised July 10, 2002; accepted November 21, 2002 Published online: March 20, 2003     

Ontogeny of pistillate flowers and inflorescences in Nothofagus subgenus Lophozonia (Nothofagaceae)

  Cupule and pistillate inflorescence morphology is described in detail for the first time for a number of species in Nothofagus subgenus Lophozonia. The architecture and temporal appearance of prophylls, flowers, and cupule valves is dichasial; the cupule valves are third and higher order shoot systems. Comparative studies demonstrate that the dorsal rows of appendages on the cupule valves have a similar arrangement, and each row exhibits the same temporal pattern of development. This suggests that the cupule valves in all species have a modular construction and consist of rows of homologous appendages. This study clearly demonstrates the uniform groundplan of the pistillate inflorescence in this subgenus. Received March 14, 2002; accepted May 8, 2002 Published online: September 13, 2002     

Ontogeny and evolution of the flowers of South African Restionaceae with special emphasis on the gynoecium

 The South African Restionaceae make up a highly diverse group of genera displaying several reductive trends in the configuration of the flower, especially in the gynoecium. In this paper the floral ontogeny of fourteen species representing nine of the 11 genera of the Restio clade is studied with the SEM. Although flowers are basically simple, the variability in both mature and developmental stages is striking. Differences between species are the result of changes in growth rate, coupled with differential pressures of organs. Trends in the elaboration of bracts, perianth, androecium and gynoecium are compared. Together with data that have been presented elsewhere about the other clade of African Restionaceae, viz. the Willdenowia-clade, a scheme with potential developmental pathways is proposed and the most evident routes are selected based on ontogenetic evidence. Nine possible reductions are presented arising through three main routes. Received August 27, 2001 Accepted October 26, 2001     

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.     

Infraspecific genetic variation in Biscutella laevigata (Brassicaceae): new focus on Irene Manton's hypothesis

 Genetic variation in 42 populations throughout the range of Biscutella laevigata L. (Brassicaceae), a morphologically variable central European species, has been investigated by enzyme electrophoresis with three loci (Amy1, Amy2, and Gpi2). Genetic identities and the Fitch-Margoliash tree suggest differentiation into four regional groups: 1) a northwestern diploid group (northern France and northern Germany), 2) a northeastern diploid group (southern Germany, Upper Austria, northern Lower Austria, Poland, and Romania), 3) a central diploid group in southern Lower Austria corresponding to subspecies austriaca, and 4) a southern tetraploid group in Alpine areas of France, Germany, Switzerland, Austria, Italy, and Slovenia corresponding to subspecies laevigata. Geographically isolated diploid relic populations that are genetically depauperate are found in the NW and NE diploid groups. On the other hand, the diploid relic subspecies austriaca from the NE Prealps and Alps is highly variable. Subspecies laevigata appears to be a genetical autotetraploid with multiple origins involving several diploid progenitors (the NW diploids, subspecies austriaca and B. prealpina). Received April 6, 2001; accepted March 6, 2002 Published online: October 14, 2002 Addresses of the authors: Karin Tremetsberger (e-mail: k.tremetsberger@gmx.net), Christiane K?nig, Rosabelle Samuel, Tod F. Stuessy, Department of Higher Plant Systematics and Evolution, Institute of Botany, University of Vienna, Rennweg 14, A-1030 Vienna, Austria. Wilhelm Pinsker, Institute of Medical Biology, University of Vienna, Waehringerstra?e 10, A-1090 Vienna, Austria.     

Molecular relationships in Genista L. Sect. Spartocarpus Spach (Fabaceae)

 A molecular investigation on the species of Genista belonging to sect. Spartocarpus was undertaken with the aim of inferring phylogenetic relationships within the section. The combined cladistic analysis of ITS 1 and 2 and of the chloroplast DNA trnL^(UAA) intron yielded a single most parsimonious cladogram with G. aetnensis as sister group to the rest of the section, which is in turn divided into two major clades, one of which includes G. nissana, G. aucheri, G. sessilifolia, G. spartioides and G. haenseleri, and the other the remaining species of the section. This latter group has G. holopetala and G. radiata forming a clade, which is a sister group to a not entirely resolved monophylum including the G. ephedroides species complex. The latter shows a basal collapse of G. cilentina, G. dorycnifolia and G. numidica, and then a clade including G. ephedroides and G. valsecchiae, as well as a collapsed monophylum with G. demarcoi, G. gasparrini and G. thyrrena. The clade including the G. ephedroides species group has the lowest within-group molecular variation and appears to be recent in origin, as compared to the rest of the section. The pattern of cladogeny in the section seems to be related to geographical isolation, and is broadly congruent with palynological and biogeographical evidence. Received March 3, 2001 Accepted October 8, 2001