This week for Flora and Fauna Friday, we’re spying on the slightest of our shore nesting seabirds, the Least Tern (Sterna antillarum).
The Least Tern can be found in summer up and down most of the East coast of the United States, and year-round in the Caribbean. Here in South Carolina, they call the estuaries of our sea islands and the beachfront of our barrier islands their summer home. The Least Tern is our smallest species of Tern in the United States. They’re about the same size as a Purple martin, but with a much broader wingspan. Least Terns have long, pointed wings and a short “swallow-tail” trailing behind them. Their plumage is pale overall, white below, a cool silver-gray above, and with a dark leading edge to their wing tips. Whilst perched, Least Terns in breeding colors are readily recognized by not just their petite presence and pallid plumage but also a lemon-yellow bill, golden legs, and a full black cap with a distinct white triangle on their forehead. Their call is a squeaky, shrieky, raspy, resonant cry that trails down in volume as it progresses, and is similar but lighter and higher than other, larger Terns.
Least Terns here on Edisto subsist primarily on a diet of small fish. Like all our Terns, they hunt using plunge diving. They cruise up and down creeks and shallow flooded flats in a slow flight on deep, bobbing wing beats, scanning the water’s surface for schooling fish. Once a buffet bears itself beneath them, they lock on and drop down, plunging bill-first into the water to spear or snatch a meal, before their buoyant body buoys them back above.
Least Terns are a threatened species here in South Carolina and a species of significant conservation concern for SCDNR. In the Lowcountry, they principally nest on sand bars, beach dunes, and inlet sand banks right up against the ocean and they share this space with myriad other nesting shorebirds and seabirds each year. Least Terns are smaller than all other sea birds that nest here in the Lowcountry. Thus, they rely heavily on the more chaotic and dangerous beachfront nesting sites to raise their young, as they are easily pushed out by bigger birds from the other more favorable, safer sites on isolated, protected sand banks. Use of these extreme coastal nest sites not only places seabirds and their nests at heightened risk of harm from extreme weather and hurricanes, but also human induced pressures and disturbance. Erosion from coastal infrastructure shrinks banks, bars, and beach dunes to reduce the total area available as nesting habitat. Coastal development further eliminates potential nest sites by converting the landscape to an unusable state for wildlife, while also introducing invasive plants, feral animals, and general ecological imbalance that cause increased nest failure. Increased beach traffic, and especially unleashed dogs, disturb nesting birds in the dune systems, forcing them to waste energy when escaping to the air, preventing them from feeding their young, and exposing delicate eggs and fledgling birds to the broiling rays of a Lowcountry summer sun. Sea level rise compounds these threats further by shrinking the total area of beachfront and accelerating the shifting of these sandy lands. This cumulative stress on estuarine ecosystems is called ‘coastal squeeze’. Coastal squeeze is felt most sharply by intertidal and beach dependent species, and has rapidly become an existential threat to many species in recent decades.
Least Terns, thankfully, are one of the more resilient and adaptable beach nesting species when faced with such pressures. For example, they famously have begun nesting on flat, graveled rooftops Downtown and in other coastal cities. Nonetheless, the compounding impacts of coastal squeeze are taking their toll on Least Tern populations range wide. You can do your part to help protect Least Terns, and other seabird and shorebird nests, by staying off the beach dunes, keeping your dog on a leash whenever on the beach, and respecting SCDNR and other conservation signage you find that closes or restricts beach access for the wellbeing of some of our most imperiled and beloved Lowcountry birds.
This week for Flora and Fauna Friday we have the purple plumed imposter of the swamp, False Indigo-Bush (Amorpha fruticosa).
False Indigo-Bush is found across much of the South and Midwest, and is distributed throughout much of South Carolina. Here in the Lowcountry, it’s most often encountered in the floodplains and margins of freshwater rivers, particularly the fresh but tidal reaches of blackwater rivers, like the South Edisto. False Indigo-Bush is a member of the legumes and a mid-sized shrub, growing most often a bit over head high, and just as broad, on tangled twisting stems. It can spread through its roots to form small colonies, but around here is usually encountered as a singular clump or two. Its leaves are pinnately compound, with small ovular leaflets, and roughly hand length. It blooms here in April and May, peaking near the end of April. From the ends of its upper stems it bears half-foot long, dense, clustered spikes of flowers. Each flower is cylindrical in shape, with a single rolled royal-purple petal and a bouquet of golden-orange anthers bursting out from the center. It is a uniquely delightful color combination. Come summer into fall, the flowers of False Indigo-Bush mature into brown seedpods, each shaped like a tiny, warty butterbean and containing on average just one or two seeds. Birds and small animals feed on its scattered seeds. Its flowers provide nutritious pollen for bees, wasps, and other native pollinators. Some butterflies will even host their caterpillars on its leaves, such as the Silver-spotted Skipper.
It’s been a hot minute since I’ve done one of these, but I reckon today is a good day to dust off and bust out the ‘name game’, as this plant is ripe for an etymological adventure. The common name “False Indigo-Bush” is pretty straightforward. This plant is a bush and it looks like Indigo (Indigofera spp.), except it’s not Indigo. The leaves of this plant are very similar in size and shape to cultivated Indigo species and the two genera looks especially similar when young or regenerating. The seedpods of False Indigo-Bush are also very similar to those of our native Carolina Indigo (Indigofera caroliniana), although the two inhabit very different habitats and have very different growth forms. More relevant, False Indigo-Bush does actually contain the precursors phytochemicals that can be processed into usable indigo dye. Yet, they are generally not in a high enough concentration within the plant tissue, nor is there often enough young plant tissue altogether, to be worth extracting and processing the dye at any meaningful scale. On an aside, a decent number of our native legumes contain the precursor compounds that can be processed to generate indigo dye. This collection of related phytochemicals have some insecticidal properties that help protect the plants producing them from insect munching.
The scientific name for this plant, “Amorpha fruticosa“, roughly translates as “Bush without Shape”. That’s a pretty apt name for this bush with a chaotic, disordered growth form in its branches. But many other bushes grow just the same way and this is oddly generic for a generic name. Therefore, we have to dig a bit deeper to reveal the whole truth hidden in its name. The genus name “Amorpha” really refers to this clade’s flowers. Botanists and taxonomists have long categorized clades of plants based on the shapes of their flowers. Flower shape is closely linked to reproductive success for plants. If they don’t reproduce, their lineage won’t survive through the ages. Meaning flower shape is often a ‘do or die’ trait, onto which natural selection then applies the adage of ‘if it ain’t broke, don’t fix it’. Mutations in flower shape are rarely inconsequential to the offspring of the individual expressing them and so they quickly get weeded out. Thus, flower characteristics are broadly well preserved through even 1,000s of generations and can be used to readily and reliably differentiate different lineages of plants into higher classifications, as the scientific community feels its way backwards through evolutionary history. But on the flipside, things like leaf shape, growth form, height, hairiness, and even flower color can mutate much more often and randomly with wanton abandon. These mutations can more easily persist for multiple generations, or even diverge a population into a unique form or subspecies if it confers a benefit in that space at that time. But I digress. What was I typing about? Oh yeah, “Amorpha” is really describing the shape of the flowers within this genus. They only have one, singular petal that rolls itself up like a burrito around its anthers and styles. This is an odd trait for the legumes (family Fabaceae) and that singular dimension of petal equated to a “shapeless-ness” for the botanists first describing its flowers, relative to other more “shapely” legumes.
This week for Flora and Fauna Friday, we’re tracing out the finely lined Eastern Ribbon Snake (Thamnophis sauritus).
The Eastern Ribbon Snake is found throughout South Carolina and much of the Eastern United States, excepting the Appalachian mountains. Ribbon Snakes grow up to two feet in length and have a very narrow, delicate body with a proportionately slightly oversized head and eyes. Their belly is a pale-yellow or ivory. Their back is a dark-walnut or chestnut-brown, sometimes with faint checkerboard pattering along their flanks, and has three obvious pale-yellow lines down their length, one in the center and one on each flank. Eastern Ribbon Snakes closely resemble their cousins, the Eastern Garter Snake (T. sirtalis sirtalis). However, the Garter Snake is heavier bodied, often greener in coloration, and has more pronounced checkering. A quick way to check between the two species is to look at the lower jaw. Garter Snakes generally have black lines between their labial scales while Ribbon Snakes have a solid white jaw.
The Eastern Ribbon Snake is found in wet habitats, most often along wetland margins, pond banks, pocosins, bottomlands, floodplains, and other areas where water intermingles with land. They are semi-aquatic, weaving through vegetation and swimming into shallow water in search of frogs, salamanders, fish, insects, invertebrates, and anything else succulent their svelte selves can siphon down. Eastern Ribbon Snakes are non-venomous and, due to their slimness, not constrictors either. They simply overpower and swallow their small, soft-bodied prey whole. If you happen to spot an Eastern Ribbon Snake sitting still, consider yourself lucky! They are quick little buggers and will often vanish like a flash into brush, vegetation, or murky water when walked up on.
This week for Flora and Fauna Friday, we have three ferns of a feather that fringe wetlands together, Virginia Chain Fern (Anchistea virginica), Netted Chain Fern (Lorinseria areolata), and Sensitive Fern (Onoclea sensibilis).
Here in South Carolina, we have two species of Chain Fern, Virginia Chain Fern and Netted Chain Fern. Both grow deciduous feathery fronds about a foot long, spread underground into small but sprawling colonies, and have a preference for isolated or ephemeral wetland systems in the understory and margin of a forest or woodland. Chain Ferns further get their common name from the net-like chains of circular veins that run down the midlines on the undersides of their fronds. (These two Chain Fern species used to share the genus Woodwardia, but were recently split into their own separate genera.) Sensitive Fern is unrelated to the Chain Ferns, but is similar enough in appearance and habits to warrant being part of the same conversation.
Virginia Chain Fern is restricted to the coastal plain of South Carolina, but nonetheless found throughout the Lowcountry. It is best adapted to locales with acidic soils, more direct sunlight, standing water, and increased disturbance from fire and other forces of nature. This makes it a common sight in Carolina Bays, Pocosins, ditches, and other isolated or ephemeral wetlands in pine dominated or poorly drained systems. However, it will also grow in much the same habitats as Netted Chain Fern when given the chance. Its fronds are a shiny emerald-green and feathery in appearance. Its central rachis, the stem of the frond, is smooth, wiry, and sometimes a dark-green or black. The pinnae have smooth margins and many small, stubby lobes that don’t fully divide to the midvein. Underneath, each of these lobes has a chain of circular veins down its center that radiate out many thin parallel veins towards the margin. Virginia Chain Fern produces fertile fronds that look the same as its sterile fronds but bear spores from granular sori arranged in parallel, angular lines from its chained midveins.
Netted Chain Fern can be encountered all across South Carolina, from the mountains to the sea. It is most commonly found in the understory of hardwood forests growing in wet depression or isolated wetlands, the margins of swamps and freshwater marshes, streambanks, and narrow floodplains outside of standing water. Its fronds are bright emerald-green with entire pinnae that merge together on the upper half of the frond, through a shared wing along the central rachis. Below, these fronds are covered in a net-like network of veins, with a central “chain” down the center of each pinnae. Netted Chain Fern produces spores on fertile fronds, which are similarly shaped to the normal sterile fronds but held upright and possessing a stringy, withered appearance. These fertile fronds bear elongated sori below that look like paired strands of sausage links.
Sensitive Fern is found statewide in similar habitats to Netted Chain Fern, and it shares a close physical resemblance. However, Sensitive Fern, in my experience, prefers to grow in the richer and wetter habitats within river floodplains, bottomlands, and their tributaries and is less abundant on the Sea Islands and along the coast. It can also have significantly larger fronds up to knee height that are more delicate in texture. Sensitive Fern gets it common name from the frost intolerance of its leaves, which wither and die at the first frost. By contrast, Chain Fern leaves are far hardier and leathery, and thus persist longer into winter. On Sensitive Fern, the fronds are often a pale bluish-green and the upper pinnae are solid blades that merge into a common wing along the rachis. The lower you go on the frond, the wavier the pinnae margins are, with the bottom two often prominently lobed. Underneath, it has a prominent, raised vein down the underside of each pinnae, rather than a chain of veins. The fertile fronds of Sensitive Fern are distinct and have upward pointing clusters of spherical sori, like strings of beads.
This week for Flora and Fauna Friday, it’s the façade of the forest’s eyes watching from the night, the Polyphemus Moth (Antheraea polyphemus).
Warm spring day. Cool spring night. Saturated air. Land slicked with dew. Wrapped in the cloak of dark. Tucked beneath the canopy. The forest yet stirs restlessly. The excitement of spring. Crickets chirp, toads shuffle, raccoons squabble while rodents skitter to and fro. Through that thick air frolics forward a specter. Like a leaf loosed from the lead of the wind and the fetters of gravity, it floats any direction it may please. It settles and re-adheres itself to the surety of a tree. Two ochre eyes gaze back outward as a Polyphemus Moth greats the night, its world, wide-eyed.
The Polyphemus Moth can be found in hardwood forests throughout the Eastern United States and much of the west. It’s a large moth, growing to about six inches in wingspan. From below its wings are a ruddy-brown with a wash of silvery variegation for camouflage. From above, it’s a warm brown across most of its wings but bearing a thick outward fringe of orange-brown with an inward border of black and white. Peering out from the middle of all four wings is a single eyespot. The forewing eyespot is a single translucent circle ringed with gold. The hindwing eyespot is the same design but larger and with silvery frosting gradating out from above into the large black oval it is set within. They are a hard moth to mistake in the Lowcountry. Their name “Polyphemus” is Greek and comes from Homer’s Odyssey, it’s the name of the demigod cyclops that was blinded by Odysseus.
Polyphemus Moth caterpillars are large, heavy-bodied, and bright-green with a brown face and fine vertical slashes down their side with narrow red spots amidst them. Their caterpillars feed on the leaves of many genera of hardwood trees, including birches, maples, willows, hickories, and oaks. The Polyphemus Moth is a member of the family Saturniidae, the Silk Moths. This family contains our largest moth species here in the Southeast, but actually doesn’t include the domestic Silk Moth (Bombyx mori). Although all moth and butterfly caterpillars can spin silk, many Saturniids use a gracious plenty of it when they construct the cocoons that protect them as a pupa. The Polyphemus Moth is a particularly noteworthy silk spinner. They spin a thick walled, pale-brown silk cocoon that’s about two inches long and just under an inch wide. They secure this cocoon with a broad tether to the limb of their host tree. Adult Polyphemus Moths are most abundant in April, May, and July. But their silk cocoons can often be spotted high above in winter, or empty and strewn about the forest floor throughout the year.
This week for Flora and Fauna Friday we have a miniature mallow, Carolina Bristle Mallow (Modiola caroliniana).
Carolina Bristle Mallow is a perennial wildflower that flattens itself across the ground with a prostrate growth form. As the common name implies, it is indeed a Mallow and it has many of the typical characters one expects from that lineage. It has emerald-green, inch-wide leaves with coarsely serrate margins and usually three to five lobes in an overall palmate-shape that is quintessential to Mallows. Its stems and leaves are covered in hairs. Its foliage can serve as the host plant for a handful of native butterflies, chiefly the 3 species of Checkered-Skipper (Burnsius spp.) found in the Carolinas. Carolina Bristle Mallow blooms throughout April with a small, 5-petalled, bowl-shaped flower coral-pink in color with a yellow center ringed in crimson. Its flowers mature into a flattened fruit of a dry capsule containing about 1-2 dozen seeds.
Carolina Bristle Mallow is most often found interspersed in lawns, along roadsides and trails, on parking lot margins, in agricultural fields, and about other disturbed areas dominated by sparse, low growing vegetation. It can be encountered throughout the southern US but is rather sporadically scattered around the landscape. Despite the “Carolina” in its common name, Carolina Bristle Mallow is more than likely an adventive species from South America that hitched a ride across the hemisphere on the coattails of humans. Carolina Bristle Mallow is a fairly innocuous herb here today in the Lowcountry that rarely, if ever, causes an issue in our natural landscapes. Thus it falls squarely into the “naturalized” bucket and doesn’t achieve that infamous entitlement of “invasive” species. Most often, it’s found making bedfellows with the other non-native herbs and grasses that have come to dominate the botanical witch’s-brews of suburban and urban landscapes, where the harm is already done and only the plants most tolerant of the mower deck can persist.
This week for Flora and Fauna Friday we’re getting acquainted with the dark sheep of the frogs, the Eastern Narrow-mouthed Toad (Gastrophryne carolinensis).
The Eastern Narrow-Mouthed Toad is found throughout South Carolina and in all but the highest elevations of the Southeast. It’s a resident of woodlands and savannas, where below abundant humidity and ample water make for a cozy home for this amphibian. Narrow-mouthed Toads are fossorial, living in the soil underneath fallen logs and leaf litter for most of their lives. Their pointed head and flattened bodies lets them push through soil and wedge beneath rocks and logs. This subterranean environment is far more stable than the surface world and allows them to better conserve water. Their namesake ‘narrow mouth’ defines their diet. They specialize in eating some of the tiniest, yet most abundant, of our insects, the ants and termites that are prolific in leaf litter and the soil.
Because Eastern Narrow-Mouthed Toads are subterranean, they are rarely seen. But that doesn’t mean they’re rare or hard to observe, quite the opposite. They’re a very common species and, during wet nights in spring and fall, they can be heard wailing along freshwater wetlands and down roadside ditches all across the Lowcountry. The male’s courtship croak is the unmistakable bleat of a lamb, albeit a bit more monotone, which lasts for two to four seconds. But good luck trying to spot one calling!
Eastern Narrow-mouthed Toads are just as secretive on the water as they are on land. But when you do chance upon one, most often when flipping rocks or rolling logs, they are an obvious sight. A plump little body just over an inch long on short legs and covered in subtle warts over moist skin, a tiny head with a pointed nose, and a brown-gray triangle on the back flanked by wide ruddy-tan stripes are features that give this toad a unique shape among all our other local frogs and toads. Speaking of frogs and toads, the Eastern Narrow-Mouthed Toad is really a frog, not a toad. Well, all toads are frogs, but not all frogs are toads. (Same situation as Turtles and Tortoises, rectangles and squares.) True Toads belong to the family Bufonidae, they have dry skin, obvious warts, poisonous parotoid glands behind their head, short legs for walking, and mainly live on land. However certain frogs, like the Eastern Narrow-Mouthed Toad, can check most of those boxes and so are commonly called toads. This similarity is a product of convergence, multiple lineages of life finding the same answers to the same problems.
This week for Flora and Fauna Friday we have the saline, sea breeze swaying Saltmarsh Bulrush (Bolboschoenus robustus).
Saltmarsh Bulrush, also called Seacoast Clubrush, is a species of sedge found up and down the Eastern Seaboard of the United States. It used to belong to the genus Schoenoplectus but was recently split off into Bolboschoenus and, between these two genera, there are about seven species of Bulrush found in South Carolina, three of those being fairly rare in our State and then two of those rare species being mainly inland and submergent in growth form. But here on the coast, Saltmarsh Bulrush is the most common species you’ll encounter in our salt suffused marshes around the Sea Islands. Saltmarsh Bulrush has more salt tolerance than other Bulrushes and grows abundantly in the brackish marshes of tidal rivers, especially in old tidal rice impoundments where it can be the dominant vegetation. It also occurs on brackish pond banks and on the upland borders of salt marshes, in the uncommon spots where there is consistent confluence of upland groundwater running out to sea and intermingling with tidewater to create micro-habitats of brackish marsh.
Saltmarsh Bulrush is a perennial aquatic sedge that spreads clonally through underground rhizomes. It has a grassy appearance and emerald-green leaves and stems reaching up to waist-high. As a sedge, not a grass, it has stems that are triangular in cross-section and leaves with a strong crease down the center. In ideal conditions, it grows vigorously and can form a monoculture in shallow brackish waters. Saltmarsh Bulrush flowers appear at the top of the stem from brown, hairy, teardrop-shaped structures in clusters of a dozen or two. It begins to bloom in early spring and can continue blooming throughout summer. Its seeds mature within these same structures before being shed into the water below, where they drift to shore or settle below into the sediment. These seeds provide food for waterfowl, rails, and rodents and the Bulrushes themselves provide cover and protection for these same critters, and many more.
This week for Flora and Fauna Friday we have a pair of feminine flutterbys that share their face but live worlds apart, the Lady Butterflies (Vanessa spp.).
Here in the Southeast we have three species of butterfly in the genus Vanessa: the American Lady (Vanessa virginiensis), the Painted Lady (Vanessa cardui), and the Red Admiral (Vanessa atalanta). Today we’ll be giving the local Ladies their due attention, and we’ll host the Admiral for conversation at a later date.
Both the American Lady and Painted Lady are well traveled throughout the Southeast and can be encountered most anywhere in either of the Carolinas. They are often found in open, sunny areas such as field margins, forest edges, brushy lawns, roadsides, meadows, and prairies. Ladies are members of the diverse Brushfoot family, Nymphalidae, and share many of its familial traits, like standing on only four feet, having elongated forewings, and being equally likely to perch with wings either outstretched or tucked upward. Both butterflies have a wingspan of two to two-and-a-half inches and share the same wardrobe. With wings folded, they are predominantly a cryptic pattern brown and white with black accents, but with a hidden wash of salmon-pink on the forewing. With wings unfurled, they are mainly a warm-orange around the body but with black forewing tips peppered with white spots and four small dark spots at the edge of the hindwing.
To be more specific, the American Lady is the more widespread and abundant of the two here in the Lowcountry. They begin to fly at the doorstep of spring and can be encountered all the way into December. Their caterpillars host on a handful of low-growing annual wildflowers, most often Rabbit Tobacco (Pseudognaphalium obtusifolium) but also Cudweeds (Gamochaeta spp.) and Annual Trampweed (Facelis retusa). Their caterpillars are strikingly colored with alternating bands of bone-white pinstripes or a calico of black, white, and cinnabar-red and with each of those red blotches bearing a black jagged thorny spine. Their caterpillars have a unique way of feeding too. They’ll bend the tip of a flower stalk or twig from their host plant over and tie it back onto itself before encapsulating the arch in silk, to form an upside-down sleeping bag for themselves. The caterpillar will hide inside for protection and emerges only to feed on foliage and flower buds, often in the morning. Adult butterflies of both species look very similar but can be told apart with either wings closed or spread. With wings open the differences are subtle. On the American Lady, look for a small white dot in the center of the top orange cell on the edge of the forewing. With wings open, that same spot may also be visible but look instead to the hindwing where you’ll find two large eyespots and an obvious jagged white band across the whole hindwing.
The Painted Lady is a cosmopolitan species, being found across Europe, Asia, Africa, and North America. They are not frost hardy. So their core populations are found only in the tropics. To compensate for this limitation, they are a tropical migrant. Tropical migrants are butterfly species that overwinter in the tropics but migrate north into temperate regions in the spring and summer to take advantage of a much larger territory, before retreating towards the equator in fall. This is an arduous but not uncommon strategy employed by many of our “local” butterflies and takes multiple generations to complete the circuit in a year. As a tropical migrant with a regional core population in Mexico and the Caribbean, the Painted Lady is more sporadic in its abundance. It is most often encountered in South Carolina from August through October, as its abundance swells across the United States in summer and northeastern butterflies fly south to escape the winter. This species has a propensity for getting a wild hair of wanderlust too. Painted Ladies will be swept up in the trade winds of the Atlantic and have been flung to nearly every remote island in the Atlantic Ocean at some point, and some with great regularity. This is almost assuredly how their North American population was established. The Painted Lady’s caterpillar hosts on Thistles (Cirsium spp.) most often and they also form a silken sleeping tent from their host’s foliage up above the ground. Their caterpillar is just a spiny as their American sister but is more variable in their coloration. Sometimes they’re mainly black with yellow and orange accents, sometimes they’re a frosty-gray with orange bands, and other times they’re a custom palette somewhere in between. The adult Painted Lady butterfly lacks the white spot on the outer center of the forewing, which is seen in the American Lady. On the underside of the hindwing they have four eyespots on the outer edge, with the inner two being about half the size of the outer two, and their overall wing pattern is a uniform cobweb of white on brown with no obvious bands. Further, their overall coloration below tends to be a warmer brown and the color showing on their forewing tends to be closer to orange than pink.
This week for Flora and Fauna Friday it’s a three-leaved weed of spring, Wood-Sorrel (Oxalis spp.).
Here in the Lowcountry we can expect to find six species of Wood-Sorrel. Three of those are native species: Slender Yellow Wood-Sorrel (Oxalis dillenii), Common Yellow Wood-Sorrel (Oxalis stricta), and Violet Wood-Sorrel (Oxalis violacea). The other three are exotic species: Creeping Wood-Sorrel (Oxalis corniculata), Large-flowered Pink Wood-Sorrel (Oxalis debilis), and Pink Wood-Sorrel (Oxalis articulata). All six of these Wood-Sorrel species share a few common features, making this genus easy spot out in the wild. Our Wood-Sorrels are low growing forbs, often not getting more than three to six inches tall. They have five-petalled, funnel shaped flowers and they bloom mainly in early spring. Most notably, Wood-Sorrels have symmetrical compound trifoliate leaves. Each of its three leaflets are heart-shaped with a seam down its middle. In response to light or heat stress, their leaves can both fold upward and lower downward into a unique shape, kind of like a paper fortuneteller. Their overall three-way leaf shape resembles that of Clover (Trifolium spp.), which is another common group of, low-growing, spring wildflowers. However, Clover leaflets usually aren’t heart-shaped and are rarely ever all symmetrical in size and shape.
The Irish term “Shamrock” generically refers to Clovers, but it also was historically applied to Wood-Sorrels on occasion. I won’t here attempt to decant a multi-century Irish history lesson down into two sentences, but just know Shamrock is an old term that symbolized Clovers and came to represent St. Patrick, and eventually Ireland at large. However, here in America, we have collectively decided to represent the term with an imaginary plant that is a curious amalgamation of both Wood-Sorrel and Clover. Our modern Shamrock has the leaf arrangement of a Clover but the leaflet shape of a Wood-Sorrel. It’s a strange fake plant which we plaster all about the place every St. Patrick’s Day and is a curiosity most people don’t recognize, nor care about after their seventh Guinness of the morning. Yet it drives pedantic botanists (like me) mad every March.
Slender Yellow Wood-Sorrel is by far our most common Wood-Sorrel in South Carolina and also a native species. It grows as an annual most often, but can survive as a perennial with some irregularity. It has a single stem and a bushy, upright growth form. Its leaves are small and emerald-green and its flowers a pure lemon-yellow. Its stems, upon close examination, have sparse, fine hairs that lay flat upward against the stem, an important feature to note. It is found commonly in lawns, garden beds, forest clearings, roadsides, and other disturbed areas.
Common Yellow Wood-Sorrel is native and, ironically, not all that common in the Lowcountry, instead being more abundant in the Northeast and Midwest. It looks nearly identical to Slender Yellow Wood-Sorrell: a single stem taking on a bushy, upright growth form, small emerald-green leaves, and small lemon-yellow flowers. However, its stems have a profusion of fine hairs that extend perpendicular from its stems. Its flower clusters also tend to have double the number of flowers and fruits. It’s also a weak perennial and found in disturbed, sunny areas as well as forest clearings.
Violet Wood-Sorrel is a native species and a perennial. It grows a small bulb underground and spreads through roots to form small colonies. Its leaves hug the ground, forming a carpet of foliage. The leaves of Violet Wood-Sorrel are often a jade-green but can flush from the center of each leaflet with a rich, dark-purple that either appears as a horizontal slash, a central splotch, or suffuses the entire leaf. The underside of its leaves are the same purple color. Its flowers are borne singly and are hot-pink with a yellow-green center. Its flowers are about the same size as its leaves. Violet Wood-Sorrel is most often found in rich, moist hardwood forests with some amount of slope. This makes it a very rare sight on the Sea Islands but relatively abundant towards the mountains of South Carolina.
Creeping Wood-Sorrel is an exotic species believed to originate from Southeast Asia. It has an appearance much like Common Yellow Wood-Sorrel, including its hairy stems. However, Creeping Wood-Sorrel creeps laterally along and under the ground rather than growing upright. Its yellow flowers sometimes show orange-red near the center and are very small relative to its leaf size. Its leaves can turn a reddish-purple when exposed to excessive sun and stress. This species is most often encountered in heavily disturbed areas and is particularly fond of growing in sidewalk cracks. It is a weak perennial that may or may not overwinter.
Large-flowered Pink Wood-Sorrel is an exotic species native to South America that has since spread across the globe. It is easily recognized by its large, inch-and-a-half or wider, smooth but slightly wrinkled leaves and large hot-pink flower with fine magenta stripes and a green-yellow center. It is a perennial with a sizable underground bulb. Large-flowered Pink Wood-Sorrel is sometimes sold as an ornamental and can be found commonly around house and in garden beds, as well as roadsides in the Lowcountry.
Pink Wood-Sorrel is an exotic species native to the subtropics of South America. It is a strong perennial with a woody, taproot-like rhizome that extends down several inches into the soil. Its leaves have fine hairs across their surface and these leaves can range widely in size from and an inch to two inches across. Its flowers are large and hot-pink with fine magenta lines and most often a burgundy center. Pink Wood-Sorrel is commonly sold as an ornamental and can sometimes be found around homes, gardens, and roadsides in the Lowcountry.
