Recent molecular phylogenies of the grasses (Poaceae) have revealed unexpected relationships among species with disparate inflorescence morphologies. ''Panicum'' bulbosum (Panicum sect. Bulbosa) was recently placed in the ''bristle clade,'' a monophyletic clade in the Paniceae whose members have inflorescences containing both bristles and spikelets, even though ''P.'' bulbosum appears to lack bristles. This placement of ''P.'' bulbosum also indicates that it is not related to true Panicum (Panicum sect. Panicum). Here, the placement of ''P.'' bulbosum is confirmed using chloroplast markers ndhF and trnL. The closest relatives of the species are thus morphologically quite different from ''P.'' bulbosum, and conversely the morphologically similar species of true Panicum are unrelated. To investigate the morphological differences more carefully, we used scanning electron microscopy to detail the development of inflorescence structures of ''P.'' bulbosum and to compare it with bristle-bearing grasses and true Panicum. We find that inflorescence development of ''P.'' bulbosum closely resembles that of the type species of true Panicum, Panicum miliaceum. Thus ''P.'' bulbosum is a morphological anomaly, having lost the synapomorphy of its clade and sharing many characters with more distant relatives.

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Aim The use of intuitive or explicit biogeographical reconstruction techniques to estimate the timing of species radiations on the Hawaiian Islands, while often incorporating evidence on the timing of island formation, may be misleading if the effects of extinction are overlooked. Using phylogenies of the bark louse genus Ptycta (Psocidae), we compared results from biogeographical character mapping with those from molecular dating analyses. These results were used to evaluate the 'progression model', which predicts an oldest-toyoungest pattern of island colonization.Location The main Hawaiian Islands (Kauai, Oahu, Maui, Lanai, Molokai and Hawaii).Methods With a data set including 101 Hawaiian Ptycta specimens and 18 outgroup species, we constructed molecular phylogenies based on sequences of the nuclear gene wingless and mitochondrial genes 12S, 16S and cytochrome c oxidase subunit I (COI). Maximum-likelihood, maximum-parsimony and Bayesian phylogenetic analyses were used. We used beast to estimate a timecalibrated tree under a relaxed clock model. ResultsOur analyses suggested a single colonization event, followed by extensive movement of Ptycta among islands and species radiations within and between islands. This monophyletic radiation is composed of two wellsupported clades that are also supported by two synapomorphic characters of the male genitalia.Main conclusions Very different biogeographical patterns are inferred by molecular dating versus approaches based on character mapping. Simple biogeographical reconstruction over the molecular phylogeny supports a pattern of youngest-to-oldest island colonization, the reverse of that predicted by the 'progression model', and implies that this radiation could be as young as the most recent islands of Maui (1.4 Ma) or Hawaii (0.5 Ma). Molecular dating, however, infers a pattern consistent with oldest-to-youngest island colonization, and suggests a lineage age of 7.1 Ma. Extinction on the oldest island of Kauai may account for the differences in results between the two analyses.

This article documents the addition of 205 microsatellite marker loci to the Molecular Ecology Resources Database. Loci were developed for the following species: Bagassa guianensis, Bulweria bulwerii, Camelus bactrianus, Chaenogobius annularis, Creontiades dilutus, Diachasmimorpha tryoni, Dioscorea alata, Euhrychiopsis lecontei, Gmelina arborea, Haliotis discus hannai, Hirtella physophora, Melanaphis sacchari, Munida isos, Thaumastocoris peregrinus and Tuberolachnus salignus. These loci were cross-tested on the following species: Halobaena caerulea, Procellaria aequinoctialis, Oceanodroma monteiroi, Camelus ferus, Creontiades pacificus, Dioscorea rotundata, Dioscorea praehensilis, Dioscorea abyssinica, Dioscorea nummularia, Dioscorea transversa, Dioscorea esculenta, Dioscorea pentaphylla, Dioscorea trifida, Hirtella bicornis, Hirtella glandulosa, Licania alba, Licania canescens, Licania membranaceae, Couepia guianensis and 7 undescribed Thaumastocoris species.