Life Sciences Commons^™

Ecophysiological Implications Of Low Lignin In Eastern Leatherwood (Dirca Palustris L.), Anna Cole, Kayla Marie Rigdon, D. Gordon Brown, Katharine Lora Cary

Biology Faculty Publications

Dirca palustris L. (eastern leatherwood) is an understory shrub found throughout much of eastern North America. Dirca palustris wood has a low concentration of lignin, which is a molecule that grants structural rigidity to cell walls. The branches of D. palustris are thus remarkably flexible, but their low lignin content could cause greater vulnerability to water stress. We examined the conductivity, vessel anatomy, and field water potential of D. palustris and conducted ecological surveys. The data showed that D. palustris was not experiencing substantial drought-induced dysfunction in the field, even during an exceptionally hot and dry summer. Its water potentials …

Solanum Scalarium (Solanaceae), A Newly-Described Dioecious Bush Tomato From Judbarra/Gregory National Park, Northern Territory, Australia, Angela Mcdonnell, Tanisha Williams, Jonathan Hayes, Jason T. Cantley, Peter Jobson, Christine Martine

Biology Faculty Publications

A new species of functionally dioecious bush tomato of Solanum subgenus Leptostemonum is described. Solanum scalarium Martine & T.M.Williams, sp. nov., is a member of the taxonomically challenging “Kimberley dioecious clade” in Australia and differs from other species in the group in its spreading decumbent habit and conspicuously prickly male floral rachis. The species is so far known from one site in Judbarra/Gregory National Park in the Northern Territory. Ex situ crosses and confirmation of inaperturate pollen grains produced in morphologically cosexual flowers indicate that these flowers are functionally female and the species is functionally dioecious. The scientific name reflects …

Wildflower Of The Year—Cymes, Not Corymbs!, W. John Hayden

Biology Faculty Publications

I hit a snag while composing the text for this year’s wildflower of the year brochure on Wild Geranium, Geranium maculatum. The problem concerned the proper descriptive term for its inflorescence, i.e., the pattern in which its flowers are grouped. In more than one source, I read that, for the family Geraniaceae, inflorescences are cymes (Figures 1 and 2), but those same sources indicated that inflorescences of Geranium maculatum are corymbs (Figure 4). That conflict caused me to scratch my head because cymes and corymbs are fundamentally different kinds of inflorescences.

Difficult Creek, Difficult Management Choices, W. John Hayden

Biology Faculty Publications

Virginia is blessed with many botanical wonderlands; see Chapter 4 of the Flora of Virginia (Weakley et al. 2012) for thumbnail sketches describing 50 of these special places. One such treasure, Difficult Creek Natural Area Preserve, is home to a thriving population of the 2019 VNPS Wildflower of the year, Ceanothus americanus (New Jersey Tea). Paradoxically, however, our featured wildflower of last year is inextricably linked to a difficult conservation management decision.

Wild Geranium, Geranium Maculatum, 2020 Virginia Wildflower Of The Year, W. John Hayden

Biology Faculty Publications

Geranium maculatum was named by Linnaeus in his monumental Species Plantarum, published in1753. Geranium has long served as the type genus of Geraniaceae. The genus and family name are derived from the Greek word geranos, crane, in reference to the elongate fruiting styles common throughout the family. English common names like Cranesbill and Storksbill for relatives of Wild Geranium similarly refer to their elongate fruiting-stage styles. The species portion of the binomial, maculatum, means spotted, perhaps a reference to slight irregularities in petal pigmentation sometimes observed in this species.

Celebrating Nj Tea’S Unspecialized Pollination, W. John Hayden

Biology Faculty Publications

Specialized pollination systems are the source of some of the most compelling stories in natural history. There is something appealing to the human psyche about what seems to be a reciprocal agreement between a given plant and its dedicated pollinator: the plant attracts a pollinator and provides ample nectar and/or pollen as a reward for the pollinator’s service in moving pollen from anthers to stigmas while foraging for food. Of course, these organisms have neither signed agreements nor memos of understanding. Instead, it has merely proven to the benefit of the plant, over time, to form certain floral structures, and …

Nitrogen Fixation In Roots Of Ceanothus, W. John Hayden

Biology Faculty Publications

Roots are usually out of sight and, therefore, out of mind. But as any good gardener will tell you, it is of utmost importance to understand those unique plant organs, even if their essential functions occur hidden from cursory observation. The red roots of the 2019 VNPS Wildflower of the Year, Ceanothus americanus, are particularly important because they host symbiotic bacteria that perform the essential function of nitrogen fixation. These prominent, knobby, distinctively pigmented roots are also the inspiration for the common name Redroot, applied to many species in the genus.

Black Bugbane & The Blues: Interactions Between Our Wildflower Of The Year And The Insect World, W. John Hayden

Biology Faculty Publications

No, this article has nothing to do with American Roots music. Black Bugbane is one of several common names for the 2017 VNPS Wildflower of the Year, Actaea racemosa. And Blues refers to a subfamily of lycaenid butterflies, commonly referred to as Blues or Azures. The interactions between Black Bugbane, a.k.a., Black Cohosh, Appalachian Azure butterflies (Celastrina neglectamajor), and ants was recently summarized by VNPS charter member and past president Nicky Staunton (2015). In brief, Black Bugbane is the sole food source for caterpillars of Appalachian Azure butterflies, a situation that, superficially, might seem like any other caterpillar and host …

Sepals And Petals And Stamens—Oh, My! Or, A Brief Discourse On Putative Homologies Of Perianth Elements Of Common Black Cohosh, W. John Hayden

Biology Faculty Publications

I encountered some contradictory information while preparing to write the 2017 Wildflower of the Year brochure: some sources describe flowers of Actaea racemosa, Common Black Cohosh, as having petals, while others say petals are absent. How can that be? How could there be such uncertainty about this common plant, one known to science since before the time of Linnaeus? After a little research, I decided to describe Black Cohosh flowers as having a series of organs interpretable either as staminodes (nonfunctional stamens) or as petals located between its sepals and stamens (Figure 1). Frankly, I waffled on the petal issue, …

Actaea Racemosa: The Slender Wands Of Flowering Common Black Cohosh Beckon Us To Explore Woodlands, W. John Hayden

Biology Faculty Publications

Common Black Cohosh is a perennial rhizomatous forest herb. Its horizontal rhizomes bear numerous adventitious roots on the underside and aerial stems of annual duration on the upper side, along with knobby scars left from aerial stems of previous years. Leaves are alternate, twice or thrice compound in ternate or pinnate patterns, and large—up to 1 m long. Individual leaflet size and shape vary with position in the large compound leaves, with position of a leaf on the stem, and from population to population. Most often leaflets are coarsely serrate, lobed to deeply incised, with a truncate to cuneate base …

Endless Symbioses Most Intricate, W. John Hayden

Biology Faculty Publications

Orchids, such as our Wildflower of the Year for 2016, Downy Rattlesnake Plantain (Goodyera pubescens) (Fig. 1), exemplify the interconnectedness of life on Earth. As would be the case for many kinds of plants, pollination comes readily to mind as a prominent example of mutualistic symbiosis. Downy Rattlesnake Plantain is pollinated by bumblebees and other native bees. The bees gain nectar and the orchid gets an efficient means to move pollen from one flower to another; each organism gains benefit from the interaction, the very definition of mutualism. Pollination by bees is widespread among the orchids, but there …

Seed Dispersal: A Tale Of Two Species, W. John Hayden

Biology Faculty Publications

Orchids have minute, dustlike seeds. In this respect, Goodyera pubescens (Downy Rattlesnake Plantain), the 2016 VNPS Wildflower of the Year, is a typical orchid. Like all other orchids, Goodyera seeds contain little more than a few embryonic cells enclosed in a thin seed coat. There are two advantages to small seed size in orchids: minute seeds can be produced in prodigious quantities, and they can disperse over great distances by wind.

Jewels Of The Orchidaceae, W. John Hayden

Biology Faculty Publications

To temperate-zone plant enthusiasts, the orchid family seems more than a little strange. On the one hand, native orchids grow wild without assistance from people, they are rooted in the soil, and they survive freezing cold winter temperatures. On the other hand, the tropical orchids that we encounter are ornamental plants, pampered by their human caregivers, cultured indoors in pots filled with fir bark or other media designed to mimic the plants’ natural epiphytic habit, and, as a group, these ornamental tropical orchids have essentially zero tolerance to frost. Of course, their flowers, fruits, and seeds define them all as …

World Checklist Of Hornworts And Liverworts, Lars Söderström, Anders Hagborg, Matt Von Konrat, Sharon Bartholomew-Began, David Bell, Laura Briscoe, Elizabeth Brown, D. Christine Cargill, Denise P. Costa, Barbara J. Crandall-Stotler, Endymion D. Cooper, Gregorio Dauphin, John J. Engel, Kathrin Feldberg, David Glenny, S. Robbert Gradstein, Xiaolan He, Jochen Heinrichs, Jörn Hentschel, Anna Luiza Ilkiu-Borges, Tomoyuki Katagiri, Nadezhda A. Konstantinova, Juan Larraín, David G. Long, Martin Nebel, Tamás Pócs, Felisa Puche, Elena Reiner-Drehwald, Matt A.M. Renner, Andrea Sass-Gyarmati, Alfons Schäfer-Verwimp, José Gabriel Segarra Moragues, Raymond E. Stotler, Phiangphak Sukkharak, Barbara M. Thiers, Jaime Uribe, Jiří Váňa, Juan Carlos Villarreal, Martin Wigginton, Li Zhang, Rui-Liang Zhu

Biology Faculty Publications

A working checklist of accepted taxa worldwide is vital in achieving the goal of developing an online flora of all known plants by 2020 as part of the Global Strategy for Plant Conservation. We here present the first-ever worldwide checklist for liverworts (Marchantiophyta) and hornworts (Anthocerotophyta) that includes 7486 species in 398 genera representing 92 families from the two phyla. Th e checklist has far reaching implications and applications, including providing a valuable tool for taxonomists and systematists, analyzing phytogeographic and diversity patterns, aiding in the assessment of floristic and taxonomic knowledge, and identifying geographical gaps in our understanding of …

2016 Virginia Wildflower Of The Year: Downy Rattlesnake Plantain, Goodyera Pubescens, W. John Hayden

Biology Faculty Publications

Regardless of season, Downy Rattlesnake Plantain is a delight to encounter in the woods of Virginia. This evergreen orchid is a perennial rhizomatous herb of the forest floor. The horizontal rhizomes, usually covered lightly by leaf litter, bear roots at intervals and terminate in a rosette of leaves. Leaves are alternate, somewhat crowded together, and only slightly elevated above ground level. Leaf blades are ovate, 3–8 cm long, and 1.5–3 cm wide, often of varying size within a rosette. Leaves are present year-round, bluish-green, with prominent white veins; on each leaf, a broad midvein is flanked by two smaller veins …

There's Much Left To Learn: Clethra's Chromosomes, W. John Hayden

Biology Faculty Publications

Many would argue that chromosomes, genes, and DNA form the ineluctable essence of modern biology. Not only do these fundamental components of living cells provide moment-to-moment instructions by which cells carry out basic life processes, they also control inheritance of characteristics from one generation to the next. These essential functions of DNA stem from its repetitive structure. Hugely long DNA molecules are built from just four components, referenced by their singleletter abbreviations, A, C, G, and T. It is the specific sequence of these As, Cs, Gs, and Ts that constitutes the coded information of DNA. Moreover, molecular biologists have …

When It Comes To Clethra: Roots Matter, W. John Hayden

Biology Faculty Publications

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.

E151 (Sym15), A Pleiotropic Mutant Of Pea (Pisum Sativum L.), Displays Low Nodule Number, Enhanced Mycorrhizae, Delayed Lateral Root Emergence, And High Root Cytokinin Levels, James M.C. Jones, Lindsey Clairmont, Emily S. Macdonald, Catherine A. Weiner, R.J. Neil Emery, Frédérique C. Guinel

Biology Faculty Publications

In legumes, the formation of rhizobial and mycorrhizal root symbioses is a highly regulated process which requires close communication between plant and microorganism. Plant mutants that have difficulties establishing symbioses are valuable tools for unravelling the mechanisms by which these symbioses are formed and regulated. Here E151, a mutant of Pisum sativum cv. Sparkle, was examined to characterize its root growth and symbiotic defects. The symbioses in terms of colonization intensity, functionality of micro-symbionts, and organ dominance were compared between the mutant and wild type. The endogenous cytokinin (CK) and abscisic acid (ABA) levels and the effect of the exogenous …

Maria Sibylla Merian (1647-1717): Pioneering Naturalist, Artist, And Inspiration For Catesby, Kay Etheridge, Florence F.J.M. Pieters

Biology Faculty Publications

Book Summary: While accessible to the interested general reader, it is a technical standard that is usable academically. Containing significant new information, this work is the most comprehensive and accurate book written about Catesby and is the legacy of the Catesby Commemorative Trust’s Mark Catesby Tercentennial symposium held in 2012.

Chapter Summary: Merian's books on European and Surinamese insects and plants provided new models for representing nature that were echoed in the work of artists and naturalists working in the eighteenth century and beyond. This chapter discusses how Mark Catesby, the subject of the book, was particularly influenced by Merian.

Upside-Down Anthers Of Clethra Stand Out, W. John Hayden

Biology Faculty Publications

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 …

Little Things Reveal The Big Picture, W. John Hayden

Biology Faculty Publications

As enthusiasts who enjoy native plants in natural habitats, we tend to focus on gross morphology— aspects of plant form that can be readily observed with the naked eye or with a hand lens. And there is plenty to see at the gross level. The Flora of Virginia contains 1,269 pages of keys and descriptions devoted to gross morphology of the commonwealth’s botanical treasures. Morphological diversity, however, does not stop at the magnifi cation limit of a hand lens. Light and electron microscopes open up whole new worlds of intricate structure for appreciation and study. And tiny structural details can …

2015 Virginia Wildflower Of The Year: Sweet Pepperbush, Clethra Alnifolia, W. John Hayden

Biology Faculty Publications

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 …

Native Orchids In Winter?, W. John Hayden

Biology Faculty Publications

A very special place in Southwest Virginia will soon expand its borders, thanks in part to the annual fundraising appeal by the Virginia Native Plant Society. The Cedars Natural Area Preserve supports ex ceptional natural communities including rocky, dry limestone glades and woodlands located across nearly 20 square miles in Lee County near the Powell River. The karst landscape, where thin soils develop over easily dissolved limestone bedrock, creates terrain that tends to be rolling, rocky, rugged, and full of sinkholes, caves, and sinking streams. The preserve is a haven for rare plants that have adapted to the mostly thin, …

Oh No! Something Is Eating My Coral Honeysuckle!, W. John Hayden

Biology Faculty Publications

Let’s imagine a situation that could happen in your own backyard. Suppose you have a healthy specimen of 2014’s Virginia Native Plant Society Wildflower of the Year, coral honeysuckle (Lonicera sempervirens). Suppose further that this plant rewards you every spring with a flush of flashy red flowers that you treasure all the more because they consistently bring hummingbirds to your yard. Now imagine that one fine morning you notice some little green caterpillars voraciously eating the leaves of your beloved coral honeysuckle. What do you do?

Coral Honeysuckle Easy To Propagate With Cuttings, W. John Hayden

Biology Faculty Publications

One of my earliest botanical/horticultural memories involves time spent with my dad taking cuttings of ornamental plants. Every spring, he would start several dozen new chrysanthemums from carefully overwintered stock plants. He was also fond of long yew hedges that he developed by taking numerous cuttings from just a few original shrubs in our yard. And, from time to time, both my grandmothers would propagate, via cuttings, house plants like geraniums, African violets, and Christmas cacti. But I think it was my dad’s comparatively larger scale operation that fascinated me; with just a little effort, a single shrub could yield …

Humming Birds: Pollination Facts And Fancy, W. John Hayden

Biology Faculty Publications

Coral honeysuckle (Lonicera sempervirens), the 2014 VNPS Wildflower of the Year, is a classic example of a hummingbird-pollinated flower: bright red petals, often with contrasting yellow tones in the corolla throat, provide visual attraction, drawing hummingbirds to the flowers, where they are rewarded with a rich supply of nectar. Whereas hummingbirds have good color vision, they have a poor sense of smell. So it is not surprising that coral honeysuckle flowers are nearly scentless, at least to the human nose; even modern analytical instruments detect only traces of volatile molecules emanating from them. And open coral honeysuckle flowers, …

Two Honeysuckles: A Tale Of Dr. Jekyll And Mr. Hyde, W. John Hayden

Biology Faculty Publications

There are about 180 species of Lonicera (honeysuckles) widely distributed in the north temperate zone. These are mostly shrubby plants, but in Virginia, we have two species that are woody vines (lianas). These two lianous honeysuckles should be familiar to all Virginia Native Plant Society members. One is this year’s VNPS Wildflower of the Year, Lonicera sempervirens (coral honeysuckle), and the other is Lonicera japonica (Japanese honeysuckle), widely and deservedly reviled as one of our most aggressive invasive exotic species. Together, these two plants make an odd pair, a sort of botanical Dr. Jekyll and Mr. Hyde. What is it, …

2014 Virginia Wildflower Of The Year: Coral Honeysuckle, Lonicera Sempervirens, W. John Hayden

Biology Faculty Publications

The flashy red flowers of coral honeysuckle beckon hummingbirds to their sweet nectar. Coral honeysuckle is a twining woody vine, usually climbing on other vegetation but sometimes trailing along the ground; older stems have papery-brown exfoliating bark.

Commelina Benghalensis New To Virginia, W. John Hayden

Biology Faculty Publications

This is the first report of Commelina benghalensis (Benghal dayflower, tropical spiderwort) in Virginia. Three mature plants with intertwined stems bearing numerous chasmogamous and cleistogamous flowers were discovered as weeds in a landscape planting of hybrid Hemerocallis, hybrid Iris, and a dwarf cultivar of Nandina domestica; nine nonreproductive seedlings were found about one meter distant in the same flower bed.

Redbud Seedpods Hold Surprises, W. John Hayden

Biology Faculty Publications

As fall advances across the Old Dominion, canopies of redbud, the 2013 VNPS Wildflower of the Year, transform themselves from green to gold, revealing seed pods also changing color from pale green to dark chocolaty brown. These seedpods, which may be retained on the tree into winter, are typical legume fruits, the product of the flower’s simple pistil, each containing several seeds. Unlike most legumes, however, redbud seed pods seem disinclined to open and release individual seeds for dispersal. Redbud fruits tend to disperse intact. Once on the ground, the inevitable action of weather and microbes gradually degrades the pod, …