A cladistic analysis ofAnisopappus (Asteraceae: Inuleae)

A cladistic analysis of the genusAnisopappus (Asteraceae: Inuleae) has been undertaken. A hypothesis of species interrelationships in the genus is presented for the first time. The analysis also includedArctotis (Arctoteae), used as outgroup, and five additional genera from theInuleae: Geigeria, Calostephane, Asteriscus, Buphthalmum, Pulicaria, andInula. It is concluded thatAnisopappus is a monophyletic group situated at the base of the tribe, diagnosed by, e.g., their obtuse stylar sweeping-hairs. The species with acute sweeping-hairs were found to be derived within the genus. Problems concerning species delimitation, biogeography and character evolution in the genus are briefly discussed.     

A cladistic analysis of the genus Lopezia (Onagraceae)

Lopezia, a genus of 22 species largely restricted to Mexico, forms a monophyletic group defined by the possession of two stamens in tetramerous flowerS. A cladistic analysis of the genus was performed using 16 characters from morphology, anatomy and embryology. Twenty of the 22 species were considered the terminal taxa. Polarity of the characters was based on the outgroup comparison method, using three alternative outgroups: the genus Fuchsia, Onagraceae excluding Ludwigia, and Epilobieae-Onagreae. Using Fuchsia as outgroup, 29 equally parsimonious cladograms were produced, each with 24 steps and a consistency index of 0.75. A successive weighting procedure was applied, resulting in 15 cladograms with consistency index of 0.85. The strict consensus cladogram defines eight monophyletic groups and supports most of the current sectional classification of Lopezia, with the exception that no synapomorphy defines section Jehlia. The larger sections Lopezia and Pelozia, although well-defined as clades, are not fully resolved internally. All cladograms support section Riesenbachia as monophyletic. The two alternative hypotheses for outgroups produced similar results: 61 most parsimonious trees, reduced after the successive weighting procedure to 15, which are identical to those produced with Fuchsia as outgroup. These results are discussed in the context of data on cytology and pollination biology.     

Patterns of genetic diversity in colonizing plant species: Nassauvia lagascae var. lanata (Asteraceae: Mutisieae) on Volcan Lonquimay, Chile

The effect of colonization on the distribution of genetic diversity within and among populations in relation to species characteristics remains an open empirical question. The objective of this study was to contrast genetic diversity within and among established and colonizing populations of Nassauvia lagascae var. lanata on Volcán Lonquimay (Araucanía Region, Chile), which erupted on 25 December 1988, and relate genetic diversity to biological characteristics of the populations. We analyzed a total of 240 individuals from 15 populations distributed along the Andes Cordillera using AFLP and obtained a total of 307 AFLP bands, of which 97.7% are polymorphic. Values of population differentiation (F(ST)) did not differ significantly among established and colonizing populations, but colonizing populations did have reduced levels of genetic divergence (as indicated by private and rare bands) and genetic variation (e.g., Shannon index). We conclude that a founder effect through limited numbers of founding propagules derived from nearby source populations has not yet been compensated for by subsequent population growth and migration. Low rates of secondary dispersal via running water, kin-structure within populations, and slow population growth seem to contribute to the slow recovery of genetic diversity.     

Molecular cytogenetics of Xeranthemum L. and related genera (Asteraceae, Cardueae)

Abstract: Seven representatives of the genera Amphoricarpus, Chardinia, Siebera, and Xeranthemum, all of them closely related as demonstraded by molecular phylogeny, have been studied from a cytogenetic perspective. Morphometrical karyotype parameters were calculated and idiograms obtained. Fluorochrome banding was performed with chromomycin A₃ to identify GC-rich regions in the chromosomes. Fluorescence in situ hybridization allowed us to locate the sites of 18S-5.8S-26S and 5S rDNA. Silver nitrate staining was used to count the number of nucleoli and to detect the active nucleolar organizing regions. Systematic and evolutionary issues are addressed in the light of these data.     

Karyological evolution in Rhaponticum Vaill. (Asteraceae, Cardueae) and related genera

Chromosome counts are reported in 29 populations representing 20 species and one subspecies of the genera Callicephalus (one sp.), Klasea (seven spp.), Myopordon (two spp.), Oligochaeta (one sp.), and Rhaponticum (nine spp., one ssp.). Eleven reports are new, the others supplement limited previous data. New and published cytological data are summarized and evaluated critically in light of current taxonomic treatments and evolutionary hypotheses. Basic chromosome numbers are a valuable source of taxonomic information and relate well to the phylogeny. They are quite conserved in Klasea (only x  = 15), the sister group of the remaining genera, and in the early branching genera of the Rhaponticum group ( x  = 14 for Centaurothamnus and Callicephalus ). However, a more complex pattern of genome evolution is present among the more derived clades, Oligochaeta plus Myopordon ( x  = 12, 14) and the genus Rhaponticum ( x  = 12, 13). The occurrence of x  = 12 in Oligochaeta divaricata and Rhaponticum carthamoides seems to be the result of a recent event of chromosome fusion, as suggested by the fragility of particularly long pairs of chromosomes. The use of chromomycin staining, including an enzymatic digestion step that facilitates spreading and permits a reduction of potential fragmentation, only partially resolves this problem.  © 2007 The Linnean Society of London, Botanical Journal of the Linnean Society , 2007, 153 , 193–201.     

A cladistic analysis of the tribeAstereae (Asteraceae) with notes on their evolution and subtribal classification

TheAstereae were surveyed and the genera arranged in 23 informal groups. The generic groups were used to sample representative genera for a cladistic analysis based on morphological characters. The resulting cladogram was used for discussion of evolution and subtribal classification within the tribe. The lower basic chromosome numbers x = 4, 5, 6, and 8 are interpreted as reductions from a primitive x = 9. The subtribeGrangeinae occupies a phylogenetically basal position as sister group to the rest of the tribe. This may be divided into two large groups, largely corresponding to the homochromousSolidagininae and to the heterochromousAsterinae sensu lato, i.e. including theBellidinae, Hinterhuberinae, Conyzinae, andBaccharidinae. The latter four subtribes are derived within theAsterinae, and hence reduced to synonymy. Several intercontinental relationships indicate that a geographical subdivision of the tribe should be avoided, although in our analysis most of the groups proved to be restricted to one of five major regions.     

The infraspecific taxa of Pleiotaxis huillensis (Mutisieae, Asteraceae)

The species from Angola Pleiotaxis huillensis (Mutisieae, Asteraceae) is subdivided into three subspecies and one variety. Specifically, P. huillensis subsp axillaris and P. huillensis subsp. huillensis var. macrocephala are described as new taxa, and a new nomenclatural combination is proposed ( P. huillensis subsp. argentea ).     

A new species of the South American genus Nassauvia (Compositae: Mutisieae) from Chilean Patagonia

Nassauvia coronipappa Arroyo & Marticorena, from Cerro Donoso in eastern Chilean Patagonia, is described and illustrated. It is distinguished by trifid inner involucral bracts and persistent, brief, laciniate-dentate, crown-like pappus incompletely surrounding summit of the achene. The distinctive pappus may be related to selection, in harsh alpine habitats, against dispersal away from nurse sites.Nassauvia coronipappa belongs to subgenusNassauvia. It is seen as a relict member of an independent line of evolution, whose closest affinities are with sectionNassauvia of that subgenus.     

Evolution of secondary heads in Nassauviinae (Asteraceae, Mutisieae)

The evolution of the inflorescence head in Asteraceae is important in the diversification of this largest angiosperm family. The aggregation of heads into higher-order capitulescences (secondary heads or syncephalia) is considered evolutionarily advanced. The genera Moscharia, Nassauvia, Polyachyrus, and Triptilion of the subtribe Nassauviinae (Mutisieae) have syncephalia with differing degrees of capitula condensation. ITS and plastid trnL-trnF regions were analyzed separately and together using maximum parsimony and maximum likelihood to examine the evolution of syncephalia in the Nassauviinae. The four genera displaying syncephalia do not form a clade minus taxa without syncephalia, indicating that secondary heads in Nassauviinae have either convergently evolved twice in the subtribe (or, very unlikely) once with multiple reversions. Strong support was obtained for a sister relationship between Leucheria (without syncephalium) and Polyachyrus, and both sister to Moscharia. Nassauvia and Triptilion form a distinct clade but are sister to other genera, Perezia and Panphalea, without syncephalium. Previous hypotheses postulated the evolution from simple to more complex secondary heads. We show that the ancestor of Moscharia, Polyachyrus, and Leucheria, in a more arid habitat, had a complex type of secondary head, and loss of complexity occurred in response to a shift from arid to mesic conditions.     

Water-use efficiency and nitrogen-use efficiency of C(3) -C(4) intermediate species of Flaveria Juss. (Asteraceae)

Plants using the C(4) pathway of carbon metabolism are marked by greater photosynthetic water and nitrogen-use efficiencies (PWUE and PNUE, respectively) than C(3) species, but it is unclear to what extent this is the case in C(3) -C(4) intermediate species. In this study, we examined the PWUE and PNUE of 14 species of Flaveria Juss. (Asteraceae), including two C(3) , three C(4) and nine C(3) -C(4) species, the latter containing a gradient of C(4) -cycle activities (as determined by initial fixation of (14) C into C-4 acids). We found that PWUE, PNUE, leaf ribulose 1·5-bisphosphate carboxylase/oxygenase (Rubisco) content and intercellular CO(2) concentration in air (C(i) ) do not change gradually with C(4) -cycle activity. These traits were not significantly different between C(3) species and C(3) -C(4) species with less than 50% C(4) -cycle activity. C(4) -like intermediates with greater than 65% C(4) -cycle activity were not significantly different from plants with fully expressed C(4) photosynthesis. These results indicate that a gradual increase in C(4) -cycle activity has not resulted in a gradual change in PWUE, PNUE, intercellular CO(2) concentration and leaf Rubisco content towards C(4) levels in the intermediate species. Rather, these traits arose in a stepwise manner during the evolutionary transition to the C(4) -like intermediates, which are contained in two different clades within Flaveria.     

A new taxonomic interpretation of the Dicoma anomala complex (Mutisieae, Asteraceae)

The polymorphic African species D. anomala is subdivided in three subspecies and two new nomenclatural combinations in the genus Dicoma (Mutisieae, Asteraceae) are proposed: Dicoma anomala subsp. attenttata and D. anomala subsp. gerrardii .     

Contribution to the karyological knowledge of Echinops (Asteraceae, Cardueae) and related genera

Twenty-six chromosome counts were made of several genera of the tribe Cardueae from various European and Asian provenances: Acantholepis (one species studied), Amphoricarpus (1), Chardinia (1), Echinops (14 species, 15 populations), Siebera (1), Staehelina (3) and Xeranthemum (4). Eleven of the reports are made for the first time, ten confirm previous counts, while the remainder report disparities with earlier records. The existence of different basic chromosome numbers and ploidy levels suggests dysploidy and polyploidy as the main mechanisms of chromosomal evolution in the taxa considered.  © 2004 The Linnean Society of London, Botanical Journal of the Linnean Society , 2004, 145 , 337−344.     

A cladistic study of North AmericanCoreopsis (Asteraceae: Heliantheae)

A cladistic study of all 44 species of North AmericanCoreopsis was performed using 35 characters. The resulting cladogram indicated that all 11 sections are monophyletic. At the intersectional level, two lineages were revealed, one consisting of six sections occurring almost exclusively in Mexico and California, and another comprising five sections restricted largely to the eastern and southeastern United States. The cladogram is similar to phylogenies produced by less explicit methods but it differs in two major respects: the monotypic sect.Silphidium is placed with other sections from the southeastern United States rather than with Mexican sections, and sect.Anathysana from Mexico is more closely allied with the three California sections than with sect.Electra from Mexico.     

Taxonomy and distribution of Chaptalia dentata and C. Albicans (Asteraceae: Mutisieae)

Chaptalia dentata (L.) Cass. andC. albicans (Sw.) Vent. ex Steudel incorrectly have been recognized as conspecific in recent treatments. Although they are vegetatively similar, they differ in features of the flowers and fruits—especially the mature achenes. Both species occur in the Bahamas and the Greater Antilles of the West Indies:Chaptalia dentata is endemic to that area, absent only from Jamaica;C. albicans is more widespread, as it occurs in Jamaica as well as in scattered localities on the American mainland—southern Florida, various localities in Belize, Honduras, and Guatemala, and the Mexican states of Veracruz, San Luis Potosí, Chiapas, and Yucatán.     

Phylogeny and evolution of Perezia （Asteraceae： Mutisieae： Nassauviinae）

A molecular phylogenetic analysis of most of the species of Perezia reveals that, as traditionally defined, the genus is not monophyletic with two species more closely related to Nassauvia than to Perezia. In addition, our results show that Burkartia （Perezia） lanigera is related to Acourtia and is the only member of that clade in South America. The remaining species are monophyletic and show a pattern of an early split between a western temperate and an eastern subtropical clade of species. Within the western clade, the phylogeny indicates a pattern of diversification that proceeded from southern, comparatively low-elevation habitats to southern high-elevation habitats, and ultimately into more northern high-elevation habitats. The most derived clades are found in the high central Andes, where significant radiation has occurred.     

蓝花野茼蒿，中国菊科一新记录归化种

蓝花野茼蒿Crassocephdum rubens(Juss.ex Jacq.)S.Moore是一种原产非洲的常见菊科杂草,近年在我国云南发现有逸生,为我国新记录的归化种.