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Vereecken N.J.,Free University of Brussels | Wilson C.A.,500 North College Avenue | Hotling S.,TU Braunschweig | Schulz S.,TU Braunschweig | And 2 more authors.
Proceedings of the Royal Society B: Biological Sciences

Pollination by sexual deception is arguably one of the most unusual liaisons linking plants and insects, and perhaps the most illustrative example of extreme floral specialization in angiosperms. While considerable progress has been made in understanding the floral traits involved in sexual deception, less is known about how this remarkable mimicry system might have arisen, the role of pre-adaptations in promoting its evolution and its extent as a pollination mechanism outside the few groups of plants (primarily orchids) where it has been described to date. In the Euro-Mediterranean region, pollination by sexual deception is traditionally considered to be the hallmark of the orchid genus Ophrys. Here, we introduce two new cases outside of Ophrys, in plant groups dominated by generalized, shelter-mimicking species. On the basis of phylogenetic reconstructions of ancestral pollination strategies, we provide evidence for independent and bidirectional evolutionary transitions between generalized (shelter mimicry) and specialized (sexual deception) pollination strategies in three groups of flowering plants, and suggest that pseudocopulation has evolved from pre-adaptations (floral colours, shapes and odour bouquets) that selectively attract male pollinators through shelter mimicry. These findings, along with comparative analyses of floral traits (colours and scents), shed light on particular phenotypic changes that might have fuelled the parallel evolution of these extraordinary pollination strategies. Collectively, our results provide the first substantive insights into how pollination sexual deception might have evolved in the Euro-Mediterranean region, and demonstrate that even the most extreme cases of pollinator specialization can reverse to more generalized interactions, breaking 'Cope's rule of specialization'. © The Royal Society 2012. Source

Morawetz J.J.,Ohio State University | Morawetz J.J.,500 North College Avenue | Randle C.P.,Sam Houston State University | Wolfe A.D.,Ohio State University

The tropical clade of Orobanchaceae contains approximately forty genera, typically with fewer than ten species each, and contributes significantly to the variation in floral morphology found within the family. Despite the economic importance of this clade, which contains three of four most important genera of crop parasites within the family, it has been under-sampled in previous phylogenies. We tested the monophyly of the tropical clade and its major genera using DNA sequences from the nuclear (internal transcribed spacer) and plastid (rpl16, trnT-L) genomes. The tropical clade was strongly supported as mono-phyletic in all analyses, and four main clades were recovered. The earliest diverging lineage from the remainder of the tropical clade is comprised of the shrubby genera Asepalum and Cyclocheilon, previously placed within Cyclocheilaceae. The atypical holoparasitic Alectra alba was shown to belong within the primarily holoparasitic Harveya, and the hemiparasitic Harveya obtusifolia was shown to belong to an otherwise holoparasitic lineage within Harveya. Both New World Melasma species were included here for the first time, and these were shown to be more closely related to the Neotropical hemiparasitic Escobedia than the African Melasma lineage. These results support a previous study recognizing Nesogenes within the tropical clade of Orobanchaceae rather than the separate family Nesogenaceae. Source

Porter J.M.,500 North College Avenue | Johnson L.A.,Brigham Young University | Wilken D.,Santa Barbara Botanic Garden
Systematic Botany

The genus Ipomopsis (Polemoniaceae) encompasses about 29 species and 24 subspecies generally divided into three sections: sect. Ipomopsis, sect. Microgilia, and sect. Phloganthea. We employed maximum likelihood and Bayesian inference of DNA sequences from the nuclear ribosomal ITS region (ITS1, 5.8S ribosomal subunit, ITS2) and the chloroplast trnLF region (trnL intron + trnLtrnF intergenic spacer) to estimate phylogenetic relationships within this genus and its placement among other genera of Polemoniaceae. The chloroplast and combined sequences provide support for the monophyly of Ipomopsis, but only if four species previously included in the genus are removed: Ipomopsis havardii, I. sonorae, Microgilia minutiflora (= I. minutiflora), and Loeseliastrum depressum (= I. depressa). Of the three sections, two are conditionally supported as being monophyletic. Section Microgilia (with 11 species and 11 infra-specific taxa) is supported as monophyletic if I. polycladon, I. sonorae, I. depressa, and I. minutiflora (the type of the section) are removed. This clade is treated here as section Elaphocera. Section Ipomopsis is inferred to be monophyletic with the inclusion of several members of sect. Phloganthea (I. multiflora, I. pinnata, and I. polyantha). There is no support for monophyly or paraphyly of sect. Phloganthea. The Giliopsis group (I. effusa, I. guttata, and I. tenuifolia) is supported as monophyletic by both data sets, and the cpDNA sequences place it as sister to the remainder of Ipomopsis. This clade is treated as a new section, Giliopsis. Nuclear data place Giliopsis in a clade with Ipomopsis havardii, I. sonorae, Microgilia minutiflora, Loeseliastrum depressum, Eriastrum spp., Langloisia, and Dayia grantii. Using the Eocene fossil Gilisenium hueberii to calibrate the most recent common ancestor of tribe Gilieae, we estimate that Ipomopsis has its origin 28.2 ± 0.40-39.0 ± 1.14 MYA (trnL-F and ITS, respectively). Using this same relaxed clock, the node (or coalescent event) that defines the I. aggregata complex is dated at 16.2 ± 0.38 and 27.1 ± 0.83 MYA (trnL-F and ITS, respectively). The deep divergence of the I. aggregata complex suggests that reticulation, rather than lineage sorting, is the source of conflict among phylogenetic markers used to infer the placement of I. macrosiphon. © Copyright 2010 by the American Society of Plant Taxonomists. Source

Poinar Jr. G.,Oregon State University | Columbus J.T.,500 North College Avenue
Historical Biology

Alarista succina gen. et sp. nov. (Poaceae) is described from a single floret preserved in amber of Tertiary age originating from the Dominican Republic. The new genus is characterised by (1) a narrow-winged lemma awn, (2) numerous (as many as 17) lemma nerves, (3) a lengthy rachilla internode (implying a lax spikelet), (4) sinuous-margined long cells, (5) silica cells arranged transversely, (6) stomatal subsidiaries low domed and (7) papillae. The epidermal features are characteristic of the abaxial leaf blade surface of members of the Bambusoideae and the fossil is placed in this group. htp://zoobank.org/033FCBF4-CD61-4C85-97E4-8418C9ABA5E6. © 2013 Copyright Taylor and Francis Group, LLC. Source

Phylogenetic relationships among the six Iris subgenera were reconstructed based on chloroplast sequence data using maximum likelihood and Bayesian inference methods. Previous studies indicated that the current subgeneric classification based on an intuitive interpretation of morphology was not concordant with evolution in Iris. This study more than doubled the number of taxa sampled and increased the number of molecular markers providing a more robust assessment of phylogeny. Iris subg. Nepalensis and subg. Xiphium were resolved as monophyletic, while subg. Hermodactyloides, subg. Limniris, subg. Iris and subg. Scorpiris were not. The three monotypic genera, Belamcanda, Pardanthopsis and Hermodactylus, recognized by some workers were resolved within Iris with strong support. The three bulbous subgenera, sometimes recognized as distinct genera, were resolved within Iris. A preliminary subgeneric classification is presented. Source

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