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Fitzpatrick-cooper Julia - One of the best experts on this subject based on the ideXlab platform.

Hayden W. John - One of the best experts on this subject based on the ideXlab platform.

  • Upside-down Anthers of \u3ci\u3eClethra\u3c/i\u3e Stand Out
    UR Scholarship Repository, 2015
    Co-Authors: Hayden W. John
    Abstract:

    For the most part, the flowers of the 2015 VNPS Wildflower of the Year, Clethra alnifolia (Sweet Pepperbush), are unremarkable. Five separate sepals, 5 sepa rate petals, 10 stamens in 2 whorls, and a 3-carpellate superior ovary—an organization that can only be considered prosaic among the dicots. One floral feature, however, stands out: the anthers in the open flowers are upside-down! (See Figure 1A.) Further, these upside-down anthers open by pores (Figures 1B, 1C) rather than longitudinal slits, as in most flowering plants. These pores initially form on what would normally be the lowermost extremity of the anther, the inversion of which brings the pores to a forward position in the open flower. The significance of these acrobatic anthers—found not just in Sweet Pepperbush but through all 65 members of the genus Clethra—is twofold: anther inversion is essential to the plant’s pollen-presentation strategy, and the odd morphology taxonomically links Clethra with the large and diverse heath family (Ericaceae)

  • When It Comes to \u3ci\u3eClethra\u3c/i\u3e: Roots Matter
    UR Scholarship Repository, 2015
    Co-Authors: Hayden W. John
    Abstract:

    Roots, too often, are out of sight and out of mind, but they are critical for vigorous, healthy plant growth. All plant enthusiasts—including gardeners, farmers, foresters, and naturalists—should think about and appreciate roots if they wish to acquire a holistic understanding of plant biology. This article introduces readers to the mycorrhizal roots of the 2015 VNPS Wildflower of the Year, Clethra alnifolia (Sweet Pepperbush), and explores the diversity of mycorrhizae in a closely related family, Ericaceae

  • 2015 Virginia Wildflower of the Year: Sweet Pepperbush, \u3ci\u3eClethra alnifolia\u3c/i\u3e
    UR Scholarship Repository, 2015
    Co-Authors: Hayden W. John
    Abstract:

    Clethra alnifolia is a rhizomatous shrub with aerial stems from 1 to 3 m tall. Leaves are simple, alternate, and bear stellate hairs; petioles are short, 5–10 mm long; leaf blades are obovate to oblong, 5–10 cm long, with relatively blunt apices, cuneate (wedgelike) bases, and margins that are entire toward the base but finely serrate above the middle; venation is pinnate with secondary veins that extend to leaf margins. Stipules are lacking. Flowers are borne on erect terminal racemes that may be solitary or accompanied by additional racemes terminating few-leaved branches arising from upper nodes. Raceme axes and pedicels are minutely stellate-pubescent; individual flowers are subtended by deciduous bracts; these bracts are longer than the flower buds and therefore prominent before anthesis, but they are soon overtaken by the open flowers, and by full anthesis most bracts have been shed. Flowers are perfect (bisexual), radially symmetric, mostly 5-merous, and pungently sweet-fragrant, appearing from midsummer to late summer. Sepals are persistent, connate only at their base; petals are separate or slightly fused at their base, white or rarely pink, more or less oblong and slightly concave, especially toward their tips. There are 10 stamens present in two whorls; In the Wild Sweet Pepperbush inhabits acidic swamps and moist woods, where it may form extensive colonies that expand via rhizome growth. Ease of propagation and its rhizomatous habit make it a useful element in riparian restoration projects. Flowers are visited by a wide variety of bees and butterflies, the former presumably collecting both pollen and nectar, the latter, just nectar. In addition to cross-pollination by insect visitors, published observations indicate that the flowers are also capable of self-pollination. Where to See It Sweet Pepperbush is found in the coastal plain and outer piedmont of Virginia. As a species it ranges from Nova Scotia and Maine southward to Florida and eastern Texas; seldom found far inland, it is largely restricted to the coastal plain physiographic region of the southern states. Clethra alnifolia anthers invert as buds open and, thus, anther bases appear to be terminal in open flowers; anthers dehisce by pores, and pollen grains are shed singly (not as tetrads). Pistils are composed of three carpels; three stigmas join to form a common style above the three-lobed ovary. Fruits are three-valved capsules containing numerous small seeds

Braham Richard - One of the best experts on this subject based on the ideXlab platform.

Xiao-ping Zhang - One of the best experts on this subject based on the ideXlab platform.

  • Phylogenetic relationships of Cyrillaceae and Clethraceae (Ericales) with special emphasis on the genus Purdiaea Planch
    Organisms Diversity & Evolution, 2002
    Co-Authors: Arne A. Anderberg, Xiao-ping Zhang
    Abstract:

    Abstract The phylogenetic relationships and systematic position of the three genera of Cyrillaceae (Ericales), Cyrilla , Cliftonia , and Purdiaea , were investigated by jackknife analysis of a combination of DNA sequences from the plastid genes atp B, ndh F, and rbc L. The results show that Cyrilla and Cliftonia together are the sister group of Ericaceae, whereas Purdiaea groups with Clethra of Clethraceae. Together, Clethra and Purdiaea form the sister group of ( Cyrilla + Cliftonia )+Ericaceae. It is concluded that Purdiaea should be moved to Clethraceae. A cladistic analysis based on morphological data was performed to investigate relationships among the species of Purdiaea . The results indicate that Purdiaea belizensis from Central America is sister to all other species of the genus, and that Purdiaea nutans from northern South America is sister to the remaining group of species which are all Cuban endemics, among which P. cubensis from Pinar del Rio in western Cuba is sister to the eight species occurring in the Oriente province in eastern Cuba.

  • Pollen morphology in the ericoid clade of the order Ericales, with special emphasis on Cyrillaceae
    Grana, 2002
    Co-Authors: Xiao-ping Zhang, Arne A. Anderberg
    Abstract:

    Pollen morphology and pollen wall structure in 23 species representing all families of the ericoid clade of order Ericales, i.e. Actinidiaceae, Sarraceniaceae, Roridulaceae, Clethraceae, Cyrillaceae, and Ericaceae, was investigated by means of light microscopy and SEM. The pollen wall of all taxa was found to consist of two solid strata, a tectum and foot layer, separated by a more or less narrow infratectum with granular elements. The three genera of Cyrillaceae were found to differ from each other. In Cyrilla and Cliftonia the pollen is psilate, often more than 20 mum in diameter, spheroidal with an indistinct colpus rim; in contrast, pollen of Purdiaea are rugulate and slightly different between species, smaller and often less than 20 mum in diameter, oblate with a projecting rim reaching over the colpus. In several characteristic features, pollen of Purdiaea is more similar to pollen of Clethra (Clethraceae), than to pollen of Cyrilla and Cliftonia .

Arne A. Anderberg - One of the best experts on this subject based on the ideXlab platform.

  • Phylogeny, Taxonomy, and Systematic Position of Clethra (Clethraceae, Ericales) with Notes on Biogeography: Evidence from Plastid and Nuclear DNA Sequences
    International Journal of Plant Sciences, 2003
    Co-Authors: Simone Fior, Per Ola Karis, Arne A. Anderberg
    Abstract:

    The phylogenetic relationships of Clethra were investigated by cladistic analyses of DNA sequences from the plastid region trnL‐F and the nuclear region ITS. In accordance with the current taxonomy of the genus, section Clethra and section Cuellaria constitute two separate monophyletic groups, but the species Clethra arborea is to be moved to section Clethra from its former position in the monotypic subsection Pseudocuellaria of section Cuellaria. No support for any of the four series within subsection Cuellaria (section Cuellaria) was obtained. Most of the few morphological characters used as a basis for the current classification are homoplasious when optimized on the molecular phylogeny. An extended data set including various representatives of the ericoid clade was analyzed in order to test whether the choice of outgroup would influence the results, but no variation in the general topology of the tree was observed. The same analysis was used to explore the basal branching of the ericoid clade obtained...

  • Phylogenetic relationships of Cyrillaceae and Clethraceae (Ericales) with special emphasis on the genus Purdiaea Planch
    Organisms Diversity & Evolution, 2002
    Co-Authors: Arne A. Anderberg, Xiao-ping Zhang
    Abstract:

    Abstract The phylogenetic relationships and systematic position of the three genera of Cyrillaceae (Ericales), Cyrilla , Cliftonia , and Purdiaea , were investigated by jackknife analysis of a combination of DNA sequences from the plastid genes atp B, ndh F, and rbc L. The results show that Cyrilla and Cliftonia together are the sister group of Ericaceae, whereas Purdiaea groups with Clethra of Clethraceae. Together, Clethra and Purdiaea form the sister group of ( Cyrilla + Cliftonia )+Ericaceae. It is concluded that Purdiaea should be moved to Clethraceae. A cladistic analysis based on morphological data was performed to investigate relationships among the species of Purdiaea . The results indicate that Purdiaea belizensis from Central America is sister to all other species of the genus, and that Purdiaea nutans from northern South America is sister to the remaining group of species which are all Cuban endemics, among which P. cubensis from Pinar del Rio in western Cuba is sister to the eight species occurring in the Oriente province in eastern Cuba.

  • Pollen morphology in the ericoid clade of the order Ericales, with special emphasis on Cyrillaceae
    Grana, 2002
    Co-Authors: Xiao-ping Zhang, Arne A. Anderberg
    Abstract:

    Pollen morphology and pollen wall structure in 23 species representing all families of the ericoid clade of order Ericales, i.e. Actinidiaceae, Sarraceniaceae, Roridulaceae, Clethraceae, Cyrillaceae, and Ericaceae, was investigated by means of light microscopy and SEM. The pollen wall of all taxa was found to consist of two solid strata, a tectum and foot layer, separated by a more or less narrow infratectum with granular elements. The three genera of Cyrillaceae were found to differ from each other. In Cyrilla and Cliftonia the pollen is psilate, often more than 20 mum in diameter, spheroidal with an indistinct colpus rim; in contrast, pollen of Purdiaea are rugulate and slightly different between species, smaller and often less than 20 mum in diameter, oblate with a projecting rim reaching over the colpus. In several characteristic features, pollen of Purdiaea is more similar to pollen of Clethra (Clethraceae), than to pollen of Cyrilla and Cliftonia .

  • Cladistic analysis of Enkianthus with notes on the early diversification of the Ericaceae
    Nordic Journal of Botany, 1994
    Co-Authors: Arne A. Anderberg
    Abstract:

    The genus Enkianthus (Ericaceae) has been subject to a cladistic analysis of morphological, anatomical, embryological, and cytological data, using two species of Clethra as outgroup. In order to evaluate the monophyly of Enkianthus, the genera Epigaea and Phyllodoce from the subfamily Rhododendroideae, and the genus Andromeda from the subfamily Vaccinioideae were also included in an initial analysis which yielded 20 equally parsimonious cladograms. The results indicated that Enkianthus is monophyletic, and a subsequent analysis with only the outgroup taxa and 14 species of Enkianthus yielded two equally parsimonious cladograms with a more resolved topology. In order to obtain strictly monophyletic taxa, the current subgeneric classification of Enkianthus is revised, recognizing four sections: Enkianthus (9 spp.), Andromedina (2 spp.), Meisteria (2 spp.), and Enkiantella (4 spp.). The paper provides a key, illustrations of representative taxa, a cladogram, and strict consensus trees.