Atlanta Nature Examiner Articles

Dragons, Damsels, and Robbers: Flights of Fancy at Newman Wetlands Center (Sunday at the Archives #26

Atlanta Nature Examiner Articles, Insects, Natural History No Responses »

Jun 292014

dfly This article and the photograph accompanying it are the fruits of a naturalist’s recent adventure at Melvin L. Newman Wetlands Center, administered by the Clayton County Water Authority and located just south of Jonesboro, Georgia. On a sunny afternoon stroll along the boardwalks, bridges, and gravel paths there, this author encountered dragons, damsels, and even a robber awaiting its next victim. And he returned from his journey with numerous photographs to share as evidence of his exploits, included as a slide show. Yes, it is true that they were all insects: dragonflies, damselflies, and robber flies. But they were particularly intriguing and colorful ones, nonetheless, and made fitting characters for a natural history flight of fancy in the midst of a Georgia summer.

The wetland edges were filled with dragonflies where the waters were still, and occasional damselflies near flowing sections. The insects were typically either flying about or perching on a cattail or other bit of tall vegetation. Dragonflies and damselflies are insects belonging to the order Odonata, also known as odonates. Odonates are characterized by having long, slender bodies with two sets of veined wings and large compound eyes.They also have life cycles with two parts. After hatching, odonate larvae live underwater in streams and ponds, preying on other insect larvae (including mosquitoes). During the larval stage, they tend to be dull in color, enabling them to blend into the rocks, mud, and underwater vegetation to avoid being eaten by a fish, turtle, frog, or bird. Then, after going through several molts enabling the larvae to grow, they climb up out of the water for a final molt, emerging as a winged adult. As adults, they are swift and fierce predators of other insects (including adult mosquitoes). Many are brightly colored, with brilliant shades of blue, green, and red, like flying jewels. (Indeed, one common damselfly in Piedmont Georgia, present at Newman Wetlands Center, is called the ebony jewelwing.)

While dragonflies and damselflies do not appear to have lived in Middle Earth (at least not as described by Tolkien in The Lord of the Rings), they were abundant way back in the Carboniferous Period, over 300 million years ago, long before there were mammals or even dinosaurs. Fossils reveal that the early dragonflies were enormous, with wingspans up to one meter. In that time before birds or even pterodactyls, they were the mighty predators of the air, patrolling the Carboniferous swamps where tree ferns and giant club mosses grew.

While odonates are much smaller nowadays, several Georgia dragonflies have bodies approaching 6 cm in length, with 10 cm wingspans. They are are at once fabulous and frustrating to photograph. Odonates are large and often dazzling in color, making them easy to spot. They frequently rest atop high vegetation, sometimes perching there to watch for prey, other times pointing the abdomens into the air in a behavior known as obelisking (a means of keeping cool by reducing exposure to the sun). Dragonflies, in this writer’s experience, tend to be more willing subjects for the photographer, frequently landing a few feet away along a boardwalk or on a nearby cattail stalk. If disturbed, they often take off, only to circle for a moment and then land again in nearly the same location as before. Damselflies, on the other hand, are exceedingly coy. They seem to sense when a photographer is getting ready to take a picture, dashing off to another branch a bit further way. Once the photographer has focused on the damselfly on its new perch, it abruptly takes off again.

Besides these behavioral distinctions (which may have had more to do with the particular odonate specimens that this author encountered on his walk) there are a couple of important anatomical differences between dragonflies and damselflies. Dragonflies belong to the sub-order Anisoptera, roughly meaning “unequal wings”, in reference to the fact that their two sets of wings are not the same size. They also tend to have larger. stockier bodies. At rest, they spread their wings out horizontally. Damselflies, on the other hand, belong to the sub-order Zygoptera, “equal wings”. Their sets of wings are the same size, and at rest, nearly all damselflies hold their wings vertically (though there is a group of damselflies called the spreadwings that doesn’t follow that pattern). In general, damselflies tend to be much smaller and daintier than dragonflies.

Dragonflies were especially abundant and diverse; this author photographed members of four different species and glimpsed a few others that got away without being captured by the lens. After a couple of attempts, he also photographed a lone species of damselfly. Fortunately, Giff Beaton recently published Dragonflies and Damselflies of Georgia and the Southeast. As a result of the superb photographs and species accounts in that guide, this author was able to identify each odonate to the species level with ease, and even determine whether the subjects were immature or adult and male or female.

There was a single robber fly sighting, too. It was resting on a wooden fence in the shade toward the end of this writer’s walk. Close up, it has a fairly ferocious appearance that fits its character well. A master predator, its victims commonly include bees and wasps, which it consumes by sucking the juices from their bodies. Members of the family Asilidae, robber flies are quite diverse in and of themselves, although decidedly less colorful and elegant than their odonate cousins. Not yet having merited a common field guide devoted to them, robber flies cannot be classified down to the species level using rudimentary guidebooks (such as the National Audobon Society’s otherwise excellent Field Guide to Insects & Spiders).

The result of the afternoon adventure is a collection of photographs, along with memories of “the ones that got away”. The reader might argue that this author’s exploits fall short of deserving a poetic cycle in the style of Homer, or even an ode, for that matter. But there is some satisfaction, this writer believes, in knowing that hunting for dragonflies and damselflies is actually becoming a popular pastime (if not yet on the scale of birding). Named after the odonates themselves, the hobby is known as oding.

This article was originally published on 5 July 2010.

A Sense of Purples (Sunday at the Archives #26)

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Jun 222014

Purples One Purple is a color that usually evokes late summer: the deep, dark purple of pokeweed berries (just now coming into bloom here in Georgia) and the succulent reddish-purple of the muscadines. But even now, on the cusp of the summer solstice, the observant naturalist can discover abundant shades of purple, from pinkish tones to violet ones, on a roadside walk. A brief stroll along the road edges here in Chattahoochee Hills, Georgia, revealed enough purple tones to write about: three flowers and two early fruits. The first flash of purple was toward the pinkish-blue shade, catching the eye amongst the various greens of roadside grasses and weeds. This five-petaled beauty (shown on the left) is a hairy ruellia (Ruellia caroliniensis), also known as Carolina wild petunia. A trumpet-shaped flower about one inch across, it looks like the kind of flower that would be found on a Hawaiian lei. Indeed, the genus Ruellia is largely a tropical one. Common throughout the eastern and central U.S., this perennial wildflower bears blooms that last for only one day.

Purples Two The gravel road passes through a wooded area with a canopy of loblolly pine and sweetgum, and an understory of oaks, black cherries, and persimmons. On a steep bank beside the road, in the shade, a stunning pinkish lavender flower is in bloom. Its irregular shape indicates that it is a member of the pea family (Fabaceae). Called butterfly pea (Clitoria mariana), it is a native perennial common to open areas throughout the eastern U.S. Another primarily tropical genus, Clitoria is abundant in Southeast Asia, where flowers are used for dyes and are also batter-dipped and deep-fried. Only two members of Clitoria are found in the U.S.; the second one (Clitoria fragrans) is restricted to sandlands in Florida. For those wondering, the rather racy genus name comes from the shape of the flower.

Purples Three Back out into the sunlight of a steamy late June morning, and along a grassy verge, a number of tiny violet and white flowers are in bloom in a short, cylindrical spike atop a stalk about one and a half feet tall. A Eurasian roadside wildflower, heal-all (Prunella vulgaris) is a member of the mint family (Lamiaceae). As its name suggests, heal-all has been used as a traditional folk remedy for many complains. The leaf tea, for instance, was used to treat mouth sores, sore throats, fevers, and diarrhea, while a poultice from this plant has been used for treating wounds, Chemcial analysis of this plant has revealed that it contains compounds with antibiotic, anti-tumor, and hypertensive properties. It contains large quantities of a powerful antioxidant called rosmarinic acid (named for rosemary, which also contains the compound).

Purples Four On the way home along the edge of a loblolly pine woods, a small dark purple fruit less than half an inch in diameter can be seen among the eliptical leaves of an understory tree. The fruit belongs to the black cherry (Prunus serotina), a much-prized deciduous tree common to the eastern and central U.S. Although the fruit is somewhat bitter, it is edible, and is often used for making wine and preserves. Birds feast on the fruits, while deer and other animals eat the leaves. Extracts of the inner bark are also used to make cough syrup. The wood of mature trees has a fine grain and rich orange-rose color, and is much valued by furniture-makers.

Purples Five Not far from the black cherry tree is a dense thicket of shrubs and vines edging a roadside stream. Amongst the tangle of grape vines and elderberry bushes grow a number of black raspberries (Rubus occidentalis) just coming into fruit. The deep purple to black orbs look inviting, but first must be inspected carefully for ants that are also dining on them. This thorny cane, common in disturbed areas in the Eastern U.S., appears quite similar to the southern blackberry (Rubus argutus). However, while the black raspberry fruits separate easily from their receptacles (as evident in the photograph above), blackberry fruits do not. After several minutes of carefully investigating this year’s black raspberry harvest, this author returned home, purple-fingered and purple-tongued.

This article was originally published on June 18, 2010.

Ladies’ Tresses in the Lawn (Sunday at the Archives #25)

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Jun 152014

OLYMPUS DIGITAL CAMERA There is much to be said for leaving a lawn untouched. First there is the matter of money and labor associated with applying various fertilizers and weed-killers. Then there is the blatant fact that a well-tended lawn is boring. It is analogous to an outdoor carpet: single tone of color, a few species of grasses (perhaps only one), few insects (and therefore few insect predators as well). But if one leaves a lawn alone, wonderful things can begin to happen.

Yes, there is the inevitable crabgrass and Bermuda grass, seedlings of sweet gum and loblolly pine, and pokeweed resolutely striving to gain a foothold. Then there are the invasive plants — most noticeably in this Chattahoochee Hills yard, honeysuckle and privet. But there are also annual and perennial wildflowers of meadow and roadside that begin to make an appearance. Given time, dry ground, and plenty of sunlight, an orchid might even grow in the yard.

And that is how, after several years of a lawn-care regimen consisting of mowing perhaps four times every summer but otherwise leaving the grass alone, several ladies’ tresses appeared in this writer’s lawn. More specifically, they were little ladies’ tresses, also known as little pearl-twist (Spiranthes tuberosa). Found from Texas to Massachusetts and Kansas to Florida, little ladies’ tresses is one of 17 species of ladies’ tresses present in the Southeast. Even trained botanists sometimes have great difficulty telling the different species (not to mention their hybrids) apart; fortunately, the little ladies’ tresses is the only member of the genus that blooms at midsummer here in Georgia, and is also unique for not having its basal leaves present during flowering. Most other members of Spiranthes (even the misnamed spring ladies’ tresses, Spiranthes vernalis) bloom in late summer or early autumn, and retain their leaves all summer long.

Ladies’ tresses are lovely not so much for their flowers as for the elegant form of their presentation on the stalk. The individual flowers are pure white, very small (about 4 mm long) and otherwise unspectacular; however, they are arranged in a lovely spiral pattern. That is the origin of the genus name Spiranthes, which means “coil flower”. There is much variability from one plant to the next. Some have their blooms arrayed in multiple tight spirals, twisted to the point that they seem to be in three or four columns. Others have no spiral at all, forming a single column on one side of the stalk. The most striking, to this writer’s eye, are the ones that have two or three gentle spirals of flowers running up the stalk in waves.

Spiranthes One particular little ladies’ tresses was being visited by a small beetle when the author photographed it on a morning in mid-June (see photograph on the right). The beetle was metallic black in color, and less about half a centimeter long, and perched on one of the flower blossoms. According to An Atlas of Orchid Pollination by Nelis Cingel, orchids in the genus Spiranthes are all pollinated by long-tongued bees, including some halictid bees (also called “sweat bees”) and bumblebees. What, then, was the beetle doing there? Beetles are exceedingly diverse and usually quite difficult to identify down to the species or even genus level. With that caveat, it was probably a ground beetle in the genus Cymindis. Unique among the ground beetles, species of Cymindis tend to be active during the daytime, and visible on flowers and foliage. They do not drink nectar, but instead feed on insects such as plant lice. It is possible that this particular beetle was hunting for a meal, or perhaps just resting at a particularly beautiful spot.

This article was originally published on June 29, 2010.

Southern Magnolia: From “Unimaginable Antiquity” to the Antebellum South (Sunday at the Archives #24)

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Jun 082014

magnolia photo The southern magnolia (Magnolia grandiflora) is of an ancient lineage. Emblem of the old South, its roots reach back much further into the evolutionary past. In his marvelous book, A Natural History of Trees of Eastern and Central North America, Donald Culross Peattie wrote of how magnolias “have come down to us, by the winding ways of evolution, from an unimaginable antiquity.” Paleontologists have found fossils of past species of Magnoliaceae, the family of plants to which magnolias belong, stretching back 95 million years. Those earliest ancestors of the magnolias of today flourished during the mid-Cretaceous Era in the days of the dinosaurs, before Tyrannosaurus rex even appeared on the scene. A species of magnolia tree similar to magnolias of today has been identified from fossils dating back to twenty million years ago. Once spanning the globe, Ice Age glaciation extirpated magnolias from many places, leaving behind a disjunct distribution of species. Of the 245 species of trees and shrubs in Magnoliaceae, two-thirds are found in Asia, and forty percent of these are in southern China alone. The other third is found in eastern North America, the West Indies, Central America, and South America. Over half of these 245 species are now approaching extinction in the wild, due to rapid destruction of their forest habitat.

Denizen of the southern Coastal Plain and established guest across much of the southern Piedmont, the southern magnolia fortunately has a fairly secure future. It has become emblematic of the old South, and is commonly seen growing on the properties of antebellum plantation homes, as well as many a suburban front yard. This author visited an antebellum mansion, now a bed and breakfast, in eastern Georgia a few years ago. In the front yard were a pair of mighty magnolias with immense trunks. The same trees could be seen as slender saplings in a photograph of the house taken just prior to the Civil War.

To view a blossoming magnolia and breathe in its strong lemony fragrance is at once to connect with both the heritage of the South and another heritage that reaches back to the very evolutionary origins of the angiosperms, or flowering plants. While not the most primitive of flowers (botanists grant that status to water lilies), magnolias are not far behind. They evolved before bees did, so they rely instead upon beetles for pollination. This may seem unusual, but in fact, beetles actually pollinate an amazing eighty-eight percent of all the flowering plants around the world. As pollinators, beetles lack the delicate elegance of a hummingbird or butterfly. They tend to be quite messy, bumbling about and damaging flowers in the process, and sometimes defecating and leaving waste behind. For this reason, magnolias have very hardy flowers, with thick sepals and petals and tough carpels. They do not secrete nectar. Instead, they produce protein-rich pollen upon which the beetles feed.

A number of other features of the magnolia blossom indicate its ancient lineage. As Peatiie wrote of its close relative the mountain magnolia (Magnolia fraseri), “Its antiquity is visible in its flower structure, which is primitive, and so is that of the fruit and of the wood.” Although most flowering plants have blooms in which the petals and sepals (modified leaves that protect the flower bud) look quite different (often the sepals are green and the petals brightly colored), the petals and sepals of magnolia flowers are virtually identical. The are arranged in a simple whirl pattern. The flower also produces no complex structures for limiting flower access to certain species of pollinators or for controlling pollinator behavior. Magnolia flowers are also unusual for having many stamens (male flower parts) and pistils (female flower parts). The receptacle to which both are attached bears the stamens at its base and the pistils at the top.

After pollination, the flower loses its petals and sepals, and the aggregate fruit begins to develop. The follicles (former pistils) form a cone-like structure. In time, these follicles split, releasing dry, seeds with bright red fleshy coverings called arils. High in fat, these seeds provide excellent forage for many species of small mammals and birds in the autumn. The birds are particularly familiar visitors, since they are themselves the descendants of dinosaurs. Their own ancestors may well have walked among (or trampled down, or eaten) some of the earliest members of the magnolia family, tens of millions of years ago.

This article was originally published on June1, 2010.

Living Monuments for Memorial Day (Sunday at the Archives #22)

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May 252014

As Memorial Day approaches yet again, the naturalist’s thought turns to how we memorialize those our nation has lost in wars. We construct monuments of granite and marble, polished stone faces with lettering that has come to signify, in our culture, the tragic reality of death, of loss. Perhaps on Memorial Day we might visit a memorial, brush our fingertips against the cold stone letters, and touch, for a moment, our own inevitable mortality. Perhaps even while standing beneath an appropriately leaden sky, we weep for the enormity of our losses along the path to maintain the freedom we first fought for over two hundred years ago. And while we weep, the chainsaws growl, and another tree falls in a stand of forest that stood untouched for the past fifty years or more. Bulldozers scrape their way across the land, and the forest is forgotten.

There is another way.

There is a way to honor our fallen and also to protect and cherish the living forests all around us. It is a model whose roots go back at least to ancient Greece, and probably further. The Greeks (and many other civilizations) maintained sacred groves, patches of forest where they could approach the great Mystery through ritual. The forest was a place for spiritual connection — an awareness not lost on Joseph Smith, founder of the Mormon religion, who had a vision of God and Jesus while praying in a ten-acre beech grove on his family farm in 1820. As a result of this vision, that patch of forest is now cared for and protected. As Donald Enders writes in an article at www.LDS.org, “The Sacred Grove is one of the last surviving tracts of primeval forest in western New York state….. The Church has for some years been directing a program to safeguard and extend the life of this beautiful woodland that is sacred to Latter-day Saints.” Along the streets of Rehoboth Beach, Delaware, and many other towns and cities across the United States, trees have been planted to honor the deceased. Beside the trees, small stone plaques bear a name, a few words of remembrance, and birth and death dates. Within this tradition, the idea of honoring the dead through caring for the living still remains. The next step back to the grove would be to recognize healthy, mature forests as being fitting sacred sites.
Through dedication ceremonies and markers in the forest, they can become places to acknowledge our losses while celebrating life’s continuance, in leaves of an oak and flowers of a tulip poplar. It is this very idea that Joan Maloof proposes in Teaching the Trees: Lessons from the Forest.

On the Eastern Shore of Maryland where she lives, a tract of mature forest was obtained by her county for conversion into a public park. For many residents and county officials, such a park meant ball fields, parking areas, and open spaces — not necessarily a forest. And then September 11th happened. In her grief, inspired by a talk on Buddhist approaches to nature, she decided to turn the forest grove into a memorial for the victims. With red yarn, she hung name tags of the fallen on trees, creating the September 11 Memorial Forest. The act at once established a sacred space for grieving, and protected the trees from being cut. Imagine another Memorial Day in Georgia, years from now. Families gather together, fill their picnic baskets, and wander off into the forest. They come at last to a sturdy beech, or sweet gum,
or sycamore, growing along the banks of a stream. At its base, a small stone bears the name of a brother, a husband, a son. Against a backdrop of birdsong and flowing water, they share memories of the love he had given, and tears, too, for the loss they have endured without him. All
around, they are consoled by the living presence of nature, in a forest forever protected as a memorial grove.

May 27, 2010

And while we weep, the chainsaws growl, and another tree falls in a stand of forest that stood untouched for the past fifty years or more. Bulldozers scrape their way across the land, and the forest is forgotten.

There is another way.

Along the streets of Rehoboth Beach, Delaware, and many other towns and cities across the United States, trees have been planted to honor the deceased. Beside the trees, small stone plaques bear a name, a few words of remembrance, and birth and death dates. Within this tradition, the idea of honoring the dead through caring for the living still remains. The next step back to the grove would be to recognize healthy, mature forests as being fitting sacred sites. Through dedication ceremonies and markers in the forest, they can become places to acknowledge our losses while celebrating life’s continuance, in leaves of an oak and flowers of a tulip poplar.

It is this very idea that Joan Maloof proposes in Teaching the Trees: Lessons from the Forest. On the Eastern Shore of Maryland where she lives, a tract of mature forest was obtained by her county for conversion into a public park. For many residents and county officials, such a park meant ball fields, parking areas, and open spaces — not necessarily a forest. And then September 11th happened. In her grief, inspired by a talk on Buddhist approaches to nature, she decided to turn the forest grove into a memorial for the victims. With red yarn, she hung name tags of the fallen on trees, creating the September 11 Memorial Forest. The act at once established a sacred space for grieving, and protected the trees from being cut.

Imagine another Memorial Day in Georgia, years from now. Families gather together, fill their picnic baskets, and wander off into the forest. They come at last to a sturdy beech, or sweet gum, or sycamore, growing along the banks of a stream. At its base, a small stone bears the name of a brother, a husband, a son. Against a backdrop of birdsong and flowing water, they share memories of the love he had given, and tears, too, for the loss they have endured without him. All around, they are consoled by the living presence of nature, in a forest forever protected as a memorial grove.

Beauty of the Beasts: Appreciating the Beauty of Backyard Bugs and Spiders (Sunday at the Archives #21)

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May 182014

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Last month, before the current vicious hot spell and drought seized hold of Georgia, this writer spent many hours at work in the gardens around his home. “Garden” is not really the appropriate term; “weed haven” is far closer to the truth, or possibly “sweet gum seedling nursery, blackberry cane patch, and dog fennel maintenance area”. There is an ongoing battle, never to be won, between the commonplace and often invasive plants with little ecological value and the plants this author prefers to find growing nearby: native plants that are attractive to pollinators such as butterflies and hummingbirds, yet unpalatable to the deer. It was in the midst of such a skirmish that the author encountered the two small creatures that are the theme of this article: one a bug, the other a spider. Despite the many small invertebrates this writer has found (and in many cases written about) here in Georgia (and often in and around his property), both of these were first encounters for him. And both of them were, in this writer’s opinion, beautiful.

The bug was crawling slowly about on a stalk of blackberry cane. What was striking about it was the patterning on its back, which was somewhat evocative of Zuni art of the Southwest. For example, compare the photograph of the insect that accompanies this article with this piece of jewelry. Although smaller than my thumbnail, its intricate, colorful pattern was quite evident, even to the naked eye. But what was it?

Alas, it turned out to be a much-maligned insect, one responsible for extensive crop damage in the Southeast. The insect lays its barrel-shaped egg cases on the surfaces of leaves. The eggs hatch, and for the next several weeks, the insect is in its nymph form — small, colorful, and unable to fly. After molting five times, it takes on more frequently photographed adult form by which it is known: the Southern green stink bug, Nezara viridula. In Garden Insects of North America, the author, Whitney Cranshaw, offers no kind words about this aggressive herbivore. He writes that “it is considered an important pest of vegetables and field and orchard crops. Legumes and crucifers are particularly favored…. Feeding on buds and blossoms causes them to wither and die. Feeding punctures of fruit cause deformed growth, and seeds may be shriveled.” What of the insect’s appearance? Cranshaw observes simply that the adults are “dull green” while the nymphs are “pinkish but turn increasingly green with age.” After searching several websites and three different insect field guides, “pinkish [turning] green” was the closest to a description of the insect’s patterning that this author could find.

This is not to say that farmers ought to welcome Southern green stink bugs with open arms. The insects feed widely on agricultural crops, from peach and citrus trees to tomatoes, potatoes, cotton, and soybeans. But while field guides celebrate the ornate and colorful patterns on the wings of dragonflies and butterflies, they ignore Nezara viridula. Sure, it is an insect pest, and yes, it is a stink bug at that (insects known for “the copious amounts of foul-smelling liquid they discharge when disturbed,” as explained in the National Audubon Society Field Guide to Insects and Spiders). But all of that ought not to detract from its lovely patterning in the nymph form, a design which one might even refer to as living jewelry.

The spider was nearby, on a simple dark-green leaf edged in orange-red. (The plant in question has appeared in several places around the author’s backyard, but so far, its identity is a botanical mystery.) The spider was a quarter inch in size, with a translucent green body, long legs, black spots on the abdomen, and vertical chelicerae (hollow mouth parts for grasping food and injecting venom) – all characteristics indicating that it was a female magnolia green jumper (Lyssomanes viridis). The genus Lyssomanes is a tropical one, with eighty species that range from the Southern United States down through Central and South America. Motionless when I encountered her, she was waiting patiently for prey to pass by – midges, aphids, small wasps and flies, and perhaps even a green stink bug nymph. Like other jumping spiders, the magnolia green jumper does not build a web. Instead, it chases and pounces on its prey, bounding from leaf to leaf, leaving a slender silken line to mark its passage. As the name suggests, the magnolia green jumper frequents magnolia leaves, along with the leaves oaks and evergreen trees and shrubs in Southeast woodland, particularly in wetlands and on coastal barrier islands.

A particularly striking feature of the magnolia green jumper is its eyes, situated on an “eye mound” ringed with brownish-orange. Four of the eyes, along the sides of the mound, are simply large black dots. The other two are larger and much more prominent. They have dark half-moon-shaped retinas that swivel independently, a bit like they eyes of a chameleon. Like all jumping spiders, the magnolia green jumper has superb vision, which is necessary for an active daytime hunter. (Web-weaving spiders, by comparison, simply lie in wait for their prey and tend to have much poorer eyesight.)

While the magnolia jumping spider lacks the vivid color patterning of a butterfly, it has beauty of its own. It is a beauty of form: lithe, nimble, quick-moving, almost graceful. (For instance, in this video, watch as two magnolia green jumpers, meet, court and mate.) And there is something about the eyes, too. Look closely, and you can almost see the spider looking back at you. At such a moment, you may even be tempted to wonder: what does she think of us?

This article was originally published on June 10, 2011.

A Woodland Bouquet for Mother’s Day (Sunday at the Archives #20b)

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May 112014

A wild azalea blooms along Bear Creek, Cochran Mill Park, South Fulton County, Georgia.

Wild azalea along Bear Creek, Chattahoochee Hills. Author.

Come along with me on a woodland wildflower walk in celebration of Mother’s Day. We will leave the sun and dust of the roadway behind, retreating to the cool shade of the Georgia forest, in Cochran Mill Park, Chattahoochee Hills. We will also leave behind a number of Eurasian roadside “weeds” in favor of our native wildflowers. Weeds flourish in the ruderal, or disturbed, zone at the road’s edge, while the forest floor is a haven for many colorful and delicate native plants. One of them that greets us on this mid-Spring day is a wild azalea (Rhododendron canescens), blooming along the edge of Bear Creek. Like many of the wildflowers we will encounter on our journey, this one does not keep well if cut and taken home, so instead we will gather a photographic bouquet to honor the mothers in our lives.

Yellow star grass blooms at Cochran Mill Park, Georgia.

Yellow stargrass; photo by author.

Nearby, in dappled sunlight near the stream’s edge, we find yellow stargrass, also called yellow goldstar (Hypoxis hirsuta). When not in bloom, this inconspicuous plant (rarely exceeding six inches in height) appears to be a kind of grass, but it catches the eye once the star-shaped, six-petaled bright yellow flowers burst open. The flowers are pollinated by a variety of small bees.

Wild comfrey blooms at Cochran Mill Park, Georgia.

Wild comfrey; photo by author.

Our trail wends its way uphill, deeper into the forest. In the relative absence of loblolly pines (commonly a dominant tree in the most recently-farmed parts of the Georgia piedmont, accompanied by sweet gum), there is a rich, deep layer of leaf litter beneath our feet. Thriving among the leaves is a plant with large (four- to eight-inch-long) oval to elliptical leaves. Above the leaves rises a single, forking flowerhead bearing small pale blue flowers that seem out of scale for the large size of the leaves. Known as wild comfrey (Cynoglossum virginianum), it has many traditional uses as a medicinal herb, including as a skin salve for wounds and as a tonic for digestive and respiratory ailments.

Pale blue-eyed grass; photo by author.

We pause along the path to observe, emerging from last year’s fallen leaves, the slender blades of pale blue-eyed grass (Sisyrinchium albidum). The linear leaf blades look like those of an iris, reaching perhaps a foot in height. The pale blue flower has six petals and a yellow center. Although its common name identifies it as a grass, it is actually a member of the Iris Family.

Common yellow wood sorrel, Cochran Mill Park, Georgia.

Common yellow wood sorrel; author.

Another small five-petalled yellow flower blooms among the leaf litter. Its shamrock-shaped leaves tinged with red-brown identify it as a wood sorrel, and more specifically, the common yellow wood sorrel, or sourgrass (Oxalis stricta). As the genus name hints, the leaves of wood sorrels contain oxalic acid, which imparts a lemony flavor to them. A small handful of wood sorrel leaves can make a tangy addition to salads; however, they can be poisonous if eaten in large doses.

False rue anemone blooms at Cochran Mill Park.

False rue anemone; photo by author.

Wandering off the trail near a rocky ledge above a stream, we find white blooms of both the rue anemone (Thalictrum thalictroides) and its showier cousin, the false rue anemone (Enemion biternatum). Both belong to the buttercup family, and both do not actually have flower petals; instead, the sepals serve that role. The false rue anemone has robust flowers with only five parts, and deeply-lobed leaves, while the rue anemone has more delicate, slender-sepaled flowers with five to ten parts, and leaves with rounded teeth.

Violet wood sorrel blooms at Cochran Mill Park, Georgia.

Violet wood sorrel; photo by author.

Nearby is yet another wood sorrel, this time with five white petals tinged with pinkish-purple. Known as the violet wood sorrel (Oxalis violacea), it was first described by the father of botanical taxonomy, Carl Linnaeus, in 1753. Like all wood sorrels, it has leaves that are shaped like shamrocks, giving sorrels the collective common name of “wild shamrocks”. The word “sorrel” is German for “sour”, referring to the sour, lemony flavor of the leaves.

Jack-in-the-pulpit blooms at Cochran Mill Park, Georgia.

Jack-in-the-Pulpit; author.

Our path winds along a stream and into an adjacent wooded wetland. There, growing in the dappled sunlight in the mucky soil, is a Jack-in-the-pulpit or Indian turnip (Arisaema triphyllum). The flower consists of a central club-shaped spadix (“Jack”) surrounded by a leaf-like bract called a spathe (“the pulpit”). While the spathe’s exterior is a subdued greenish white, the interior is decorated with a dramatic reddish-purplish-black that is solid above and striped with white below. With its three enormous leaflets and highly distinctive flower shape, it is one of the easier woodland wildflowers to identify. As such, it has also been given dozens of fascinating names, including pepper turnip, bog onion, brown dragon, Indian cherries, Indian cradle, marsh turnip, and Plant-of-Peace. It’s fascinating organic form rounds out our woodland bouquet beautifully.

For more information about Georgia’s wildflowers. this author recommends that you obtain a copy of a good wildflower guide, ideally Wildflowers of Tennessee, the Ohio Valley, and the Southern Appalachians, listed here.

This article was originally published on May 8, 2010.

A Bouquet of Roadside Flowers for Mother’s Day (Sunday at the Archives #20a)

Atlanta Nature Examiner Articles, Backyard Nature, Natural History No Responses »

May 112014

Southern ragort blooms along a rural roadside in Chattahoochee Hills, Georgia.

Southern ragwort in bloom; photograph by author.

Join me on a Georgia roadside walk in mid-spring, and let us see what flowers we might gather in honor of Mother’s Day. Most wildflowers of the rural road edges do not hold up well cut and placed into a vase; they thrive better where they grow, in ditches or along embankments. For this reason, we will seek instead a photographic bouquet, which lasts far longer and (in the case of our thistle species, at least) is far less prickly. One of our first discoveries, perhaps because it is so abundant, is a plant with stalked clusters of yellow flowers, vaguely reminiscent of a brown-eyed Susan without the brown eye and with fewer petals. The basal leaves of the plant are somewhat elliptical in outline and highly serrated. The plant is Southern ragwort, also called Small’s ragwort (Senecio anonymus), a member of the Aster or Sunflower Family. Although used medicinally by Native Americans, this native plant has been found to contain toxins that can cause a number of ill effects, and should best be appreciated for its visual qualities only.

Rough cat’s ear; photograph by author.

Continuing down the dusty gravel road, we pass an extensive grassy area filled with flowers that look like over-sized dandelions. They rise above the ground up to two feet on their slender stalks. Their leaves are all in a rosette at the base, and look nearly identical to those of the dandelion, only a bit larger. The plant in question is the rough cat’s ear (Hypochaeris radicata), a Eurasian plant that is now widespread across the United States. Unlike the ragwort, this plant is a worthy salad additive; both the young leaves and the flower heads can be eaten raw.

Hop clover in bloom along a rural roadside in Chattahoochee Hills, Georgia.

Low hop clover; photograph by author.

Next we encounter a clump of low, clover-leaved plants, each having bright yellow heads that with forty minute florets each. Called low hop clover (Trifolium campestre), the plant is a Eurasian native that has become established throughout the United States. Because it is a legume (a member of the Bean or Pea Family), it helps to add nitrogen to the soil. (Nitrogen is a nutrient necessary for plant growth.) As the flower head dies, the florets all droop downward, making the head appear like dried hops. While blooming, the flowers are frequented by honeybees.

Beaked corn salad in bloom along a rural roadside in Chattahoochee Hills, Georgia.

Beaked corn salad; photo by author.

Our next discovery is an inconspicuous plant with minute, five-lobed white flowers, having a most distinctive name. Called beaked corn salad (Valerianella radiata), it can be identified by its forked stem with sessile stem leaves (meaning that they are attached directly to the stem, without a petiole). Its name originates from its habit of growing wild in corn fields. The leaves make an excellent salad ingredient, with a delicious nutty flavor. The European corn salad (Valerianella locusta) is nearly identical but has pale blue flowers. A popular green, it is also called lamb’s lettuce.

Bull thistle blooms along a rural roadside in Chattahoochee Hills, Georgia.

Bull thistle; photograph by author.

Our Georgia roadside walk would not be complete this time of year without spotting one thistle blooming in a pasture or roadside ditch (or, as cattle farmers who consider it a noxious weed would prefer to call it, a “blooming thistle”.) Closely related to artichokes, thistles are almost entirely edible, from their roots and leaf ribs to their flower stalks and flower heads (equivalent to the artichoke heart). They are edible, that is, if one has a lot of patience, a lot of time, and a lot of thistles. For our purpose, this purple bull thistle from Eurasia (Circium vulgare) will add a splash of vibrant color to the whites and yellows of our bouquet.

This article was originally published on May 8, 2010.

Why Do Leaves Have So Many Shapes? (Sunday at the Archives #19)

Atlanta Nature Examiner Articles, Geometry and Nature, Natural History No Responses »

May 042014

1-DSC09743 Now that all of our deciduous trees are in leaf, and roadside ditches and forest floors in the Georgia Piedmont are green with life, it is a marvelous time to take a walk and see how many different leaf shapes you can find. Many shapes are particular to a certain kind of tree, shrub, or vine; some, like that of the maple, have even been celebrated on a country’s flag. There are the three jagged leaflets of poison ivy, and five of Virginia creeper; the many lobes (rounded or jagged) of the oaks; the tulip-shaped leaves of the tulip tree tree; the five-pointed star of the sweet gum; and the heart-shaped leaves of the wild yam. Some plants cannot settle upon one leaf shape, but instead have several. Leaves of the sassafras tree can be simple ovals, shaped like mittens, or have three broad, blunt lobes.

It is one of those wonders of the natural world that there is such diversity in the shapes of leaves. As one website on leaf shapes remarks, “Plants have leaves in many different shapes – the thicker the book you refer to, the more leaf shapes they seem to find.” The various classifications and permutations of shape form an arcane language, limited to a handful of botanists and elementary Montessori school students: terms such as runcinate, trifoliate, cordate, digitate, and deltoid. Although the words may be unfamilar, they describe the shapes of leaves encountered all around us: dandelion, clover, morning glory, maple, cottonwood. Beyond terms for general shape are further classifications for leaf form: toothed or untoothed, simple or compound, entire or lobed. Finally, even though one set of terms might be used to classify a leaf from a particular species of plant, some plants, particularly oaks, have leaves that vary considerably while keeping to generally the same overall shape.

Why? Why is there such diversity in leaves? What makes one leaf angular and another rounded, one leaf wide and another narrow? These are the kinds of questions wondering children might ask, after being satisfied with a general explanation for the color of the sky and the forces causing the wind to blow. And, like most questions children generate, the answer is not an easy one. Indeed, there is no one clear explanation out there. Only a few days ago, a physics blog reported a new theoretical model that purports to explain all leaf shape variation as an incidental effect of the different patterns of veins in the leaf.

Some aspects of leaf shape have been explained based upon comparing tropical forest plants with temperate forest ones, such as those here in Georgia. A visit to a tropical rainforest, or a greenhouse full of tropical plants, will reveal that most tropical leaves are thicker than temperate ones, as well as more rounded and smooth-edged (untoothed). Tropical plants retain their leaves for years, while deciduous plants in Georgia forests all keep their leaves only for one season. As a result, tropical leaves are sturdier than temperate forest ones, and therefore thicker. Thinner leaves require less energy to produce, and are more effective at gas exchange needed for photosynthesis. However, there is a cost of having thinner leaves: they are not as sturdy, particularly in areas distant from the major leaf veins (which provide structural support for the leaf). So those distant areas are simply done away with, resulting in lobed leaves like those of the white oak. The lobes (or teeth) of many leaves of Georgia plants also help to reduce wind resistance (and the damage that could result from it). Also, botanists have noticed that lobed or toothed leaves can permit sunlight to reach leaves beneath them, so perhaps the indentations help the plants filter sunlight down to leaves on their lower branches or stems.

Ultimately, we simply do not know why there are so many leaf shapes are out there, and how (if at all) a star-shaped leaf might better serve a sweet gum tree’s needs than the compound structure of ovate leaflets of a hickory. It is humbling and perhaps even a bit comforting, though, that something so commonplace as the forms that leaves take has managed to remain so mysterious for so long a time.

This article was originally published on May 8, 2010. The original photo has been replaced with a recent one I took, of a sassafras leaf.

Learning to Live with Poison Ivy (Sunday at the Archives #18)

Atlanta Nature Examiner Articles, Backyard Nature, Native Plants, Uncategorized 2 Responses »

Apr 272014

A poison ivy vine blooms in the May Day sunshine in Chattahoochee Hills, Georgia. As spring advances, the observant naturalist notices an array of flowers coming into bloom along roadsides and forest paths. One flower blooming now that is easily missed belongs to a leafy vine that should not be overlooked: poison ivy (Toxicodendron radicans). Few of our native plants have as black a reputation as this member of the cashew family, frequently encountered along forest edges, roadsides, and in other disturbed areas. After all, how many other native plants are the subject of rhymes about their dangers? “Leaflets three / let them be.”

Certainly poison ivy’s reputation is, to some extent, richly deserved. Unless you happen to belong to the twenty percent or so of the population that can handle poison ivy plants with impunity, contact with them can have memorable but unpleasant consequences. Poison ivy’s shiny leaves and hairy vines both contain an oily sap, urushiol, which can penetrate the skin and provoke an allergic reaction that produces a rash, blisters, intense itchiness, and general misery. Some people are so sensitive to this allergen that merely coming into close proximity with poison ivy may be enough to have an effect.

But with respect for those so severely afflicted, poison ivy is actually a highly beneficial plant for our native wildlife. Strangely enough, humans appear to be almost its only animal victims. White-tailed deer actually forage preferentially on poison ivy leaves. But birds are the main beneficiaries. Woodpeckers, flickers, grouse, pheasants, bobwhites, and warblers are all drawn to poison ivy’s small, spherical, tan fruits in the fall and winter. The seeds pass through these birds’ digestive tracts, helping to spread poison ivy far and wide. To aid in its own dispersal, poison ivy practices foliar fruit flagging, a technique also used by flowering dogwood. In the autumn, poison ivy leaves turn to blazing shades of red and gold. This bright coloration signals to the birds that food is available.

This early in the year, though, poison ivy sports bright-green, shiny leaves. Beneath the leaves hang panicles (dense, branching clusters) of minute, greenish-white flowers. In close-up photographs (such as the one available about halfway down on the left on this page), the minute flowers with their five petals forming a star and their white and yellow pistils and stamens look almost elegant. But to appreciate them under a hand lens requires putting the hands, arms, and face at too great a risk to be worthwhile, in this writer’s opinion.

A hardy survivor, poison ivy spreads not only by seeds, but vegetatively as well. The vines that appear to be hairy are, in fact, covered with rootlets, ready to take hold of a tree trunk or burrow into the soil. Considering its predilection for covering extensive ground, this writer confesses to eying the plant with suspicion when encountering it in the yard, despite its benefits to deer and songbirds. But inevitably, it is easiest to let a few vines be, provided they not overstep their bounds. After all, poison ivy is here to stay.

In fact, recent studies of forest plant response to increasing atmospheric carbon dioxide levels indicate that it leads to a significant increase in poison ivy growth — on the order of 150 percent. This result is known as the “carbon dioxide fertilization effect.” Accompanying that surge, it appears that the increased carbon dioxide also enables the poison ivy to produce a more virulent strain of urushiol, leading to worse allergic reactions than are presently experienced. At least we can look forward to the day when the poison ivy begins to choke out our invasive plant species — kudzu, privet, honeysuckle, wisteria, and others. That is some small consolation, perhaps, at least for the die-hard naturalists out there.

This article was originally published on May 2, 2010.

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