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Dorsey B.L.,University of Michigan | Haevermans T.,CNRS Systematics, Biodiversity and Evolution Institute | Aubriot X.,CNRS Systematics, Biodiversity and Evolution Institute | Morawetz J.J.,500 N College Avenue | And 3 more authors.
Taxon | Year: 2013

Euphorbia subg. Euphorbia is the largest and most diverse of four recently recognized subgenera within Euphorbia and is distributed across the tropics and subtropics. Relationships within this group have been difficult to discern due mainly to homoplasious morphological characters and inadequate taxon sampling in previous phylogenetic studies. Here we present a phylogenetic analysis of E. subg. Euphorbia, using one nuclear and two plastid regions, for the most complete sampling of molecular sequence data to date. We assign 661 species to the subgenus and show that it is comprised of four highly supported clades, including a single New World clade and multiple independent lineages on Madagascar. Using this phylogenetic frame-work we discuss patterns of homoplasy in morphological evolution and general patterns of biogeography. Finally, we present a new sectional classification of E. subg. Euphorbia comprising 21 sections, nine of them newly described here.

Tripp E.A.,University of Colorado at Boulder | McDade L.A.,500 N College Avenue
Systematic Biology | Year: 2014

More than a decade of phylogenetic research has yielded a well-sampled, strongly supported hypothesis of relationships within the large (>4000 species) plant family Acanthaceae. This hypothesis points to intriguing biogeographic patterns and asymmetries in sister clade diversity but, absent a time-calibrated estimate for this evolutionary history, these patterns have remained unexplored. Here, we reconstruct divergence times within Acanthaceae using fossils as calibration points and experimenting with both fossil selection and effects of invoking a maximum age prior related to the origin of Eudicots. Contrary to earlier reports of a paucity of fossils of Lamiales (an order of ~23,000 species that includesAcanthaceae) and to the expectation that a largely herbaceous to soft-wooded and tropical lineagewould have fewfossils,we recovered 51 reports of fossil Acanthaceae. Rigorous evaluation of these for accurate identification, quality of age assessment and utility in dating yielded eight fossils judged to merit inclusion in analyses.With nearly 10 kb of DNA sequence data, we used two sets of fossils as constraints to reconstruct divergence times.We demonstrate differences in age estimates depending on fossil selection and that enforcement of maximum age priors substantially alters estimated clade ages, especially in analyses that utilize a smaller rather than larger set of fossils. Our results suggest that long-distance dispersal events explain present-day distributions better than do Gondwanan or northern land bridge hypotheses. This biogeographical conclusion is for the most part robust to alternative calibration schemes. Our data support a minimum of 13 Old World (OW) to New World (NW) dispersal events but, intriguingly, only one in the reverse direction. Eleven of these 13 were among Acanthaceae s.s., which comprises >90% of species diversity in the family. Remarkably, if minimum age estimates approximate true history, these 11 events occurred within the last ~20 myr even though Acanthaceae s.s is over 3 times as old. A simulation study confirmed that these dispersal events were significantly skewed toward the present and not simply a chance occurrence. Finally, we review reports of fossils that have been assigned to Acanthaceae that are substantially older than the lower Cretaceous estimate for Angiosperms as a whole (i.e., the general consensus that has resulted from several recent dating and fossil-based studies in plants). This is the first study to reconstruct divergence times among clades of Acanthaceae and sets the stage for comparative evolutionary research in this and related families that have until now been thought to have extremely poor fossil resources. © The Author(s) 2014.

Morawetz J.J.,500 N College Avenue
Applications in Plant Sciences | Year: 2013

Premise of the study: Due to lack of success in clearing whole tissues using only classical clearing techniques (e.g., Heir's 4 12 solution, KOH, NaOH, lactic acid saturated with chloral hydrate), and because tissue degradation is often a result of harsh clearing agents (e.g., KOH, NaOH), a novel combined treatment was sought to improve the removal of obscuring tannins from intact haustoria. Methods and Results: Stockwell's bleach proved to be useful in removing tannins from haustoria, usually within 3 d (up to 10 d), rendering them opaque to (rarely) translucent. After bleaching, haustoria were successfully cleared in 1-3 d in a solution of lactic acid saturated with chloral hydrate at 42°C Conclusions: The two-step clearing protocol reported here will now facilitate structural studies on haustoria, such as those examining the presence and distribution of callose, and three-dimensional reconstmction using confocal microscopy. Tissues in this study did not suffer from the degradation in quality observed using harsher treatments. This protocol should be useful for other difficult-to-clear tissues that are unable to be cleared using classical protocols alone. © 2013 Botanical Society of America.

Tripp E.A.,500 N College Avenue | Tripp E.A.,University of Colorado at Boulder | Daniel T.F.,California Academy of Sciences | Fatimah S.,500 N College Avenue | Mcdade L.A.,500 N College Avenue
International Journal of Plant Sciences | Year: 2013

Phylogenetic knowledge of the large plant family Acanthaceae has been greatly advanced over the last 2 decades. Studies have demonstrated the existence of several major lineages, most of which have been the focus of subsequent investigation. Missing among these is comprehensive study of the 48 genera currently classified in tribe Ruellieae, a pantropical lineage that includes several species-rich genera. We compared the number of validly published names to current estimates of species richness per genus in Ruellieae and found more than 2600 names available for ~1200 species. Using molecular data from two nuclear (ITS+5.8S, Eif3E) and three chloroplast (trnG-trnR, trnG-trnS, psbA-trnH) markers, we test the placement of these 48 genera in Ruellieae, explore the monophyly of currently recognized taxa, and propose morphological features to diagnose major clades within the tribe.We were able to sample all but four of 48 genera, and all were resolved in Ruellieae except Zygoruellia. Many monospecific or oligospecific genera are nested within clades of more species-rich genera. We propose several new generic synonymies to reflect these results and insights from morphology. Finally, we present a revised classification of Ruellieae that contains seven subtribes. A solid phylogenetic hypothesis of relationships within Ruellieae contributes to progress in biology in three important ways: (1) it enables better assessment of trait homologies and thus characters upon which genera are delimited, (2) it contributes to the Global Strategy for Plant Conservation's initiative to document plant biodiversity, and (3) it facilitates cross-family comparative evolutionary analyses, including large-scale hypothesis testing of biogeographic patterns, clade size asymmetries, and differential diversification within Acanthaceae. © 2012 by The University of Chicago.

Baldwin B.G.,University of California at Berkeley | Friar E.A.,500 N College Avenue
Novon | Year: 2010

Dubautia carrii B. G. Baldwin & Friar and D. hanaulaensis B. G. Baldwin are new species in Dubautia Gaudich. sect. Railliardia (Gaudich.) G. D. Carr (Compositae, Madiinae) of the Hawaiian silversword alliance that were previously treated within the circumscription of D. linearis (Gaudich.) D. D. Keck subsp. opposita (Sherff) G. D. Carr. The two species are allopatric, with D. carrii in mesic to wet shrubland and forest on eastern Moloka'i and D. hanaulaensis in mesic shrubland and forest on southern West Maui. Although closely resembling D. linearis subsp. linearis and D. linearis subsp. hillebrandii (H. Mann) G. D. Carr in habit and capitulescence characteristics, D. carrii and D. hanaulaensis differ from both subspecies of D. linearis in the sense adopted here by having consistently opposite (rather than variable) phyllotaxy and toothed (rather than entire) leaf apices, and by occurring in mesic or wet (rather than mostly dry) habitats. Dubautia carrii and D. hanaulaensis are highly similar morphologically; they commonly differ from one another in stature, stem vestiture, leaf shape, capitulescence size, and receptacular-bract glandulosity. Molecular phylogenetic data indicate that D. carrii is most closely related to the East Maui endemic species of Dubautia sect. Railliardia (i.e., D. menziesii (A. Gray) D. D. Keck, D. platyphylla (A. Gray) D. D. Keck, D. reticulata (Sherff) D. D. Keck, and D. waianapanapaensis G. D. Carr), and D. hanaulaensis represents an early-diverging lineage within the Maui NuiHawai'i (Big Island) clade of Dubautia sect. Railliardia. High similarity of D. carrii and D. hanaulaensis in morphology and ecology may reflect retained ancestral or plesiomorphic states shared with the common ancestor of the Maui NuiHawai'i clade of Dubautia sect. Railliardia, a lineage otherwise known for exceptional adaptive radiation. © Missouri Botanical Garden 2010.

Hird A.,500 N College Avenue | Kramer A.T.,Botanic Gardens Conservation International U.S.
Annals of the Missouri Botanical Garden | Year: 2013

How much progress has North America made toward the Global Strategy for Plant Conservation (GSPC) Target 8 of at least 75% of threatened plant species in accessible ex situ collections by 2020 To answer this, the North American Collections Assessment was carried out in 2010. More than 200 botanical and conservation institutions in the United States, Canada, and Mexico contributed taxa lists to the Botanic Gardens Conservation International's (BGCI) online PlantSearch database for this assessment. By cross-referencing collection information with globally threatened species lists from the International Union for Conservation of Nature and Natural Resources (IUCN), NatureServe, and Mexico's Red List, we found that approximately 35% of North America's nearly 5000 most threatened taxa are currently in ex situ collections. This marks considerable progress toward the GSPC Target 8, but there is clearly much more to do. Future priorities include collaboratively and strategically increasing threatened species representation in collections and assessing genetic diversity among collections by comparing accession-level data.

Tripp E.A.,500 N College Avenue | Dexter K.G.,Royal Botanic Garden Edinburgh
Systematic Botany | Year: 2012

Recent fieldwork in Namibia has led to the discovery of two undescribed species of Ruellia, Ruellia acetabula and Ruellia kaokoana . These taxa are described and illustrated. Additionally, new lectotypifications are proposed for Ruellia marlothii and Ruellia diversifolia. Some specimens previously identified as Ruellia diversifolia are ascribed to the two new species. A revised checklist and a key to distinguish the nine species of Ruellia native to Namibia plus the Angolan R. diversifolia are provided. © Copyright 2012 by the American Society of Plant Taxonomists.

Daly D.C.,New York Botanical Garden | Neill D.,Missouri Botanical Garden | Martinez-Habibe M.C.,500 N College Avenue
Brittonia | Year: 2012

Dacryodes uruts-kunchae is described, illustrated, and contrasted with D. steyermarkii. It is from white-sand plateaus and slopes of the sub-Andean cordilleras east of the Eastern Cordillera of the Andes in Ecuador, and from eastern foothills of the Andes in Peru. The new species is unusual for a number of reasons: (1) relatively few Burseraceae are found in tropical pre-montane and montane habitats; (2) it is dominant where it occurs, a rare phenomenon for Neotropical Dacryodes; (3) its staminate flowers show three stages in the transition from disk+pistillode to "ovariodisk"; and (4) it has relatively small, densely glandular-punctate, sclerophyllous leaflets. © 2011 The New York Botanical Garden.

Ripma L.A.,San Diego State University | Simpson M.G.,San Diego State University | Hasenstab-Lehman K.,500 N College Avenue
Applications in Plant Sciences | Year: 2014

Premise of the study: As systematists grapple with how to best harness the power of next-generation sequencing (NGS), a deluge of review papers, methods, and analytical tools make choosing the right method difficult. Oreocarya (Boraginaceae), a genus of 63 species, is a good example of a group lacking both species-level resolution and genomic resources. The use of Geneious removes bioinformatic barriers and makes NGS genome skimming accessible to even the least tech-savvy systematists. Methods: A combination of de novo and reference-guided assemblies was used to process 100-bp single-end Illumina HiSeq 2000 reads. A subset of 25 taxa was used to test the suitability of genome skimming for future systematic studies in recalcitrant lineages like Oreocarya . Results: The nuclear ribosomal cistron, the plastome, and 12 mitochondrial genes were recovered from all 25 taxa. All data processing and phylogenomic analyses were performed in Geneious. We report possible future multiplexing levels and published low-copy nuclear genes represented within de novo contigs. Discussion: Genome skimming represents a much-improved primary data collection over PCR +Sanger sequencing when chloroplast DNA (cpDNA), nuclear ribosomal DNA (nrDNA), and mitochondrial DNA (mtDNA) are the target sequences. This study details methods that plant systematists can employ to study their own taxa of interest. © 2014 Ripma et al. Published by the Botanical Society of America.

Tripp E.A.,500 N College Avenue | McDade L.A.,500 N College Avenue
Brittonia | Year: 2012

As part of our study of the Acanthaceae of Costa Rica and from a phylogenetic study of Ruellia as a whole, we place R. barbillana and R. metallica in synonymy with R. terminalis. We discuss species limits of R. terminalis and provide a key that distinguishes it from close relatives including R. grantii, R. oaxacana, and R. phyllocalyx. Ruellia puri is put into synonymy with R. jussieuoides, and R. standleyi is synonymized with R. ochroleuca. Disjunct distributions characterize R. terminalis, R. jussieuoides, and R. ochroleuca, although this pattern is most extreme in R. ochroleuca. Phylogenetic analysis of DNA sequence data lends support to our synonymy decisions. New lectotypifications are provided for Arrhostoxylum achimeniflorum, Dipteracanthus puri, Dipteracanthus puri β angustifolius, Dipteracanthus puri γ gymnocladus, Lychniothyrsus ochroleucus, and Otacanthus pearcei. © 2012 The New York Botanical Garden.

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