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- Raguso, Robert A., et al.
(author)
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Floral biology of North American Oenothera sect. Lavauxia (Onagraceae): Advertisements, rewards, and extreme variation in floral depth
- 2007
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In: Annals of the Missouri Botanical Garden. - 0026-6493. ; 94:1, s. 236-257
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Journal article (peer-reviewed)abstract
- We studied the floral biology of five North American members of Oenothera L. sect. Lavauxia (Spach) Endl. (Onagraceae L.) in field and common greenhouse settings. Oenothera sect. Lavauxia floral morphology ranges from small, cleistogamous flowers (O. flava subsp. flava (A. Nels.) Garrett in Garrett) to sonic of the longest-tubed flowers in North America (O. flava subsp. taraxacoides (Wooton & Standl.) W. L. Wagner). Our goal was to compare qualitative and quantitative aspects of floral advertisement and reward among taxa in section Lavauxia. All taxa are night-blooming and self-compatible, have yellow petals with ultraviolet reflectance, and produce floral scents dominated by nitrogenous compounds and monoterpenes. Methyl nicotinate is present in the fragrances of all taxa of section Lavauxia regardless of flower size or putative mating system. Because this floral volatile is largely absent from other Oenothera species, we hypothesize that it is a synapomorphy for section Lavauxia. The rare O. acutissima W. L. Wagner, which is endemic to the Uintah Mountains, is polymorphic for odors dominated by linalool- or ocimene-derived compounds). Field observations in its type locality in northeastern Utah, U.S.A., revealed frequent floral visitation by crepuscular hawkmoths during the first 1.5 hours after anthesis, a pattern common to O. flava subsp. taraxacoides and other large-flowered Oenothera throughout western North America. Quantitative aspects of floral advertisement (flower size, scent emission) and reward (nectar volume) are dramatically reduced in putatively autogamous taxa (O. flava subsp. flava, O. triloba Nutt.). whereas qualitative aspects (flower color, scent, and nectar chemistry) remain comparable. All taxa could be distinguished through ordination of characters related to flower size, herkogamy. and scent chemistry. Extreme nectar tube length variation across the range of O. flava renders this an excellent model system for measuring the costs and mechanisms of shifts between outcrossing and autogamy.
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| 2. |
- Daniel, Thomas F., et al.
(author)
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The "Tetramerium Lineage" (Acanthaceae : Acanthoideae : Justicieae) : Delimitation and intra-lineage relationships based on cp and nrITS sequence data
- 2008
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In: Systematic Botany. - 0363-6445 .- 1548-2324. ; 33:2, s. 416-436
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Journal article (peer-reviewed)abstract
- We used DNA sequence data from five genic regions (nrITS; chloroplast trnL-F, trnT-L, rps16, trnS-G) to study phylogenetic relationships of the Tetramerium lineage (Acanthaceae: Justicieae). From a sample of 70 species (representing 25 genera) previously affiliated with the Tetramerium lineage, 68 are included therein. Our analyses excluded Papuasian Calycacanthus and Neotropical Streblacanthus monospermus from the Tetramerium lineage; however, two species described in Justicia (J. gonzalezii and J. medranoi) and a Malagasy species of uncertain generic affinities are nested within the lineage. A monophyletic Tetramerium lineage consists of 23 currently recognized genera with at least 168 species, more than 70% of which occur in the New World. Old World Chlamydocardia and Clinacanthus are serially sister to all other members of the lineage. Other Old World taxa consist of: Ecbolium clade (all sampled species of Ecbolium plus Malagasy Populina richardii), Megalochlamys clade (Megalochlamys, Trichaulax and the unidentified Malagasy species), and two isolated taxa (Angkalanthus and Chorisochora). All analyses strongly support monophyly of the New World Tetramerium lineage. The basal clades of New World plants, all with nototribic flowers, are: 1) the taxonomically heterogeneous but palynologically consistent Mirandea clade, and 2) the Pachystachys clade + the South American Anisacanthus clade. The second is sister to all other NW plants, referred to here as the core Tetramerium lineage. We recognize five clades within the core Tetramerium lineage related as follows: (Henrya clade (Carlowrightia parviflora clade (North American Anisacanthus clade (core Carlowrightia clade + Tetramerium)))). Macromorphological synapomorphies are unknown for the Tetramerium lineage and for many of its constituent clades. However, we propose sternotribic flowers as synapomorphic for the core Tetramerium lineage, and flowers with the lower-central lobe of the corolla modified into a keel as a synapomorphy for a lineage consisting of Tetramerium and the core Carlowrightia clade. Palynological characters provide putative synapomorphies for some clades (e.g. Ecbolium clade, Mirandea clade) and autapomorphies for several species (e.g. Mexacanthus mcvaughii, Trichalux mwasumbii). An Old World origin is postulated for the Tetramerium lineage, and we posit a single dispersal event to America and subsequent extensive radiation there, especially in arid zones of Mexico and adjacent regions. Taxonomic implications of our results are extensive. Notably, many traditionally recognized genera (e.g. Anisacanthus, Carlowrightia, Mirandea) are not monophyletic and emphasis on floral form often has been phylogenetically misleading; for example, floral adaptations to pollination by hummingbirds have evolved at least eight times in the New World Tetramerium lineage.
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| 3. |
- McDade, Lucinda A., et al.
(author)
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Phylogenetic placement, delimitation, and relationships among genera of the enigmatic Nelsonioideae (Lamiales: Acanthaceae)
- 2012
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In: Taxon. - : Wiley. - 0040-0262 .- 1996-8175. ; 61:3, s. 637-651
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Journal article (peer-reviewed)abstract
- We took a two-tiered approach to test monophyly of Nelsonioideae and place the group within Lamiales, and to determine relationships among taxa within the group. Phylogenetic analysis of a molecular dataset (ndhF+trnL-F) for a broad sample of Lamiales supports monophyly of Nelsonioideae and places the clade with strong support as sister to a lineage composed of all other plants treated as Acanthaceae (Avicennia, Thunbergioideae, Acanthoideae). We propose to treat this entire group as Acanthaceae s.l. and hypothesize that indurate, explosively dehiscent capsules are a synapomorphy for the family, albeit with autapomorphic fruit types in Avicennia and Mendoncia. These results further support monophyly of family-level groups that have emerged from recent studies of Lamiales but are largely unsuccessful in resolving relationships among these groups, as also encountered by other workers. Our results contradict some aspects of relationships that have seemed resolved by earlier studies, notably among Byblidaceae, Scrophulariaceae, Thomandersia, and other Lamiales. Among Nelsonioideae, analysis of sequence data from rapidly evolving genic regions (trnS-G, ndhF-rpl32+rpl32-trnL((UAG)), nrITS) and a larger sample of nelsonioids (i.e., all genera and multiple taxa to represent the diversity of species-rich genera) indicates that Nelsonia and Elytraria are monophyletic with strong support, but with only moderate support for Nelsonia as the first branching clade and Elytraria sister to the remaining nelsonioids. An African clade comprising monospecific Saintpauliopsis sister to Anisosepalum (two of three species sampled) is sister to a clade that includes all sampled members of pantropical Staurogyne plus New World Gynocraterium and Asian Ophiorrhiziphyllon. Gynocraterium is sister to all sampled members of New World Staurogyne; this last clade is sister to a clade comprising the other sampled Staurogyne plus Ophiorrhiziphyllon, which is nested among Asian Staurogyne. The taxonomic implications of these patterns of relationship are discussed. Our results suggest that Nelsonioideae have a complex history of inter-continental dispersals compared to other lineages of Acanthaceae of similar to much larger size in terms of number of species, making it an interesting group for biogeographic study.
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| 4. |
- McDade, Lucinda A, et al.
(author)
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Phylogenetic placement, delineation, and relationships among genera of the enigmatic Nelsonioideae (Lamiales: Acanthaceae)
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Other publication (other academic/artistic)abstract
- We took a two-tiered approach to test monophyly of Nelsonioideae and place the group within Lamiales, and to determine relationships among taxa within the group. Phylogenetic analysis of a molecular data set (ndhF + trnLF) for a broad sample of Lamiales supports monophyly of Nelsonioideae and places the clade with strong support as sister to a lineage composed of all other plants treated as Acanthaceae (i.e., Avicennia, Thunbergioideae, Acanthoideae). We propose to treat this entire group as Acanthaceae s.l. and advance indurate, explosively dehiscent capsules as a synapomorphy for the family, albeit with autapomorphic fruit types in Avicennia and Mendoncia. These results further support monophyly of family level groups that have emerged from recent studies of Lamiales but are largely not successful in resolving relationships among these groups, as also encountered by other workers. In fact, our results contradict some aspects of relationships that have seemed resolved by earlier studies, notably among Byblidaceae, Scrophulariaceae, Thomandersia, and other Lamiales. Among Nelsonioideae, analysis of sequence data from more rapidly evolving genic regions (i.e., trnS-G, ndhF-rpl32 + rpl32-trnL(UAG), nrITS) and a larger sample of nelsonioids (i.e., all genera and multiple taxa to represent the diversity of species-rich genera) indicates that Nelsonia and Elytraria are monophyletic with strong support but with only moderate support for Nelsonia as the first branching clade and Elytraria sister to the remaining nelsonioids. An African clade comprising monospecific Saintpauliopsis sister to Anisosepalum (2 of 3 species sampled) is sister to a clade that includes all sampled members of pantropical Staurogyne plus New World Gynocraterium and Asian Ophiorrhiziphyllon. Gynocraterium is sister to all sampled members of New World Staurogyne; this last clade is sister to a clade comprising the other sampled Staurogyne plus Ophiorrhiziphyllon which is nested among Asian Staurogyne. The taxonomic implications of these patterns of relationship are discussed. Our results suggest that Nelsonioideae have a complex history of inter-continental dispersals compared to other acanth lineages of similar to much larger size in terms of number of species, making it an interesting group for biogeographic study.
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