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Redbud Seedpods Hold Surprises, W. John Hayden
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, …
Redbuds Similar Around The World, W. John Hayden
Redbuds Similar Around The World, W. John Hayden
Biology Faculty Publications
Like music, one of the hallmarks of biodiversity is theme and variation. Redbuds—species of the genus Cercis— from around the world illustrate this analogy well. Because all redbud species conform to a certain morphological theme, anyone familiar with one particular species of redbud should be able to recognize without hesitation any other redbud species as a member of the genus Cercis. In brief, the redbud theme consists of broad, basally-lobed, leaves with pulvinar petiole thickenings, and pea-like red-purple (rarely white) flowers that may arise on small twigs or main trunks. In fact, these plants are so distinctive, it would …
Redbuds And Legumes Subfamilies, W. John Hayden
Redbuds And Legumes Subfamilies, W. John Hayden
Biology Faculty Publications
Although legumes constitute one of the largest families of flowering plants in the world, and despite 25 years of celebrating Virginia’s wildflowers, redbud (Cercis canadensis) is the first legume to be recognized as a VNPS Wildflower of the Year. This article addresses the relationships of Cercis with the rest of the legumes (family Fabaceae, or Leguminosae in older literature).
Closely Paired Flowers Produce Single Fruit, W. John Hayden
Closely Paired Flowers Produce Single Fruit, W. John Hayden
Biology Faculty Publications
Perhaps one of the most striking features of partridge berry (Mitchella repens), the 2012 VNPS Wildflower of the Year, is its closely paired flowers that yield a single berry fruit (figure 1). That these fruits are double structures, formed by pairs of flowers, is revealed in the presence of two discrete rings of five sepals each on the fruit apex, or in some cases, by a single ring of 10 sepals. Viewed in isolation, without context, the nature of these double fruits may seem perplexing, but as in so many things, a comparative perspective helps to make sense …
White Oak Part Of Global Oak Presence, W. John Hayden
White Oak Part Of Global Oak Presence, W. John Hayden
Biology Faculty Publications
As we act locally celebrating white oak, Quercus alba, as the 2011 VNPS Wildflower of the Year, it is perhaps appropriate to think globally for a few moments and consider the breadth of diversity encompassed by the oaks. Quercus is a big genus, easily the largest in its family, the Fagaceae. Approximately 400 species of oak are known, and they are widely distributed in the northern hemisphere. We tend to think of oaks as temperate zone trees, but in the New World, their range extends south through the mountains of Central America to Colombia and in the Old World, …
One Lump Or Two: How Many Wild Gingers Inhabit North America?, W. John Hayden
One Lump Or Two: How Many Wild Gingers Inhabit North America?, W. John Hayden
Biology Faculty Publications
Depending on which source one consults, the answer is either one (Asarum), or two (Asarum + Hexastylis). It is a classic lump-or-split situation. To mention just a few sources, Fernald (1950) and Gleason & Cronquist (1991) lump all the wild gingers into a single genus, whereas Radford et al. (1968), the Digital Atlas of the Virginia Flora (Virginia Botanical Associates 2010), and the Flora of North America (Whitmore & Gaddy 1997; Whitmore et al. 1997) split Asarum and Hexastylis apart. Deference to authority is a poor way to assess any scientific question, and for these wild …
Vascular Flora Of Powhatan County, Virginia, Michael Austin Terry, W. John Hayden
Vascular Flora Of Powhatan County, Virginia, Michael Austin Terry, W. John Hayden
Biology Faculty Publications
Powhatan County is a largely rural county of the Virginia piedmont currently experiencing exurban development pressure. Commercial pine forests occupy much of the land area; most natural vegetation occurs in various hardwood forests. Plant life is supported largely by soils derived from Proterozoic to Paleozoic metamorphic and igneous rocks, soils developed over Triassic basins, and riparian soils associated with the James and Appomattox Rivers. The annotated checklist is based on new collections gathered between September 2003 and August 2005, supplemented with records from regional herbaria and the Atlas of the Virginia Flora. Field work sampled at least 12 distinct community …
The Vascular Flora Of The Potomac River Watershed Of King George County, Virginia, Mark P. Simmons, Donna M.E. Ware, W. John Hayden
The Vascular Flora Of The Potomac River Watershed Of King George County, Virginia, Mark P. Simmons, Donna M.E. Ware, W. John Hayden
Biology Faculty Publications
The results of two floristic studies of King George County, Virginia, are combined into an annotated checklist. Field work was initiated in 1983-84 with a study of Caledon Natural Area, a 2,500-acre tract with 3.5 miles of frontage on the Potomac River. Collecting resumed in 1991 and 1992 to include other portions of the county drained by the Potomac River. The study area contains a wide variety of habitats including dry upland woods, mesic ravines, low elevation river flats, beaches, swamps, marshes, and creeks; creeks and marshes include both brackish and freshwater environments. The Potomac River watershed of King George …