Cut-leaved Toothwort

Posted on April 26, 2015 by Mary Anne Borge

Last week’s star players in the world of woodland understory plants in the eastern deciduous forest in my neighborhood were Bloodroot (Sanguinaria canadensis)

Bloodroot (Sanguinaria canadensis)

and Trout Lily (Erythronium americanum).

Trout Lily (Erythronium americanum)

This week Bloodroot is already developing fruit capsules. Trout Lily is still blooming on warm days, but will finish soon. New stars have emerged from the obscurity of their winter blanket of fallen leaves to take center stage. Rue Anemone (Thalictrum thalictroides), completely invisible a week ago, is now in full bloom.

Rue Anemone (Thalictrum thalictroides)

Spicebush (Lindera benzoin) is blooming, too, and the Spring Azure in the photo below is taking advantage of the nectar offered by the starburst yellow flowers. At first I couldn’t understand why she was practically laying on her side while she sipped. It seemed like an unusual posture for a nectaring butterfly, until I finally realized that she was positioning herself to catch the sun’s rays on a slightly cool and breezy spring day. Very efficient!

Spicebush (Lindera benzoin) with nectaring Spring Azure

Cut-leaved Toothwort (Cardamine concatenata) blossoms are lighting up the forest floor. It gets its name from its deeply lobed leaves, and the tooth-shaped projections on its rhizomes. Typical of a member of the mustard family, Cut-leaved Toothwort’s flowers have four petals arranged in a cross shape, for this species forming a tube at their base. The buds have a hint of pink or violet, and while the flowers may retain a blush when open, they are most often white.

Cut-leaved Toothwort (Cardamine concatenata)

Look closely at a Cut-leaved Toothwort flower, and see if you can see that it has six stamens (the male reproductive flower parts). In Cut-leaved Toothwort, the stamens are of two different heights; four stamens are long, and surround the pistil (the female flower part), while the other two are shorter and slightly apart from the others. The stamens are tipped with anthers that open to release the pollen. The pistil is a bit longer than the stamens, offering at its tip the stigma, its receptive part, for incoming pollen deposits.

Cut-leaved Toothwort (Cardamine concatenata)

Plants evolve to be as efficient as possible in attracting pollinators, and in manipulating them to pick up and deposit pollen. So why would Cut-leaved Toothwort have evolved to have anthers of two different heights? If we look at some flower visitors at work we might find some clues.

Cut-leaved Toothwort (Cardamine concatenata) with visitors

The bee-fly (Bombylius major) below is interested in nectar, which in Cut-leaved Toothwort can be found in nectaries well inside the flower. The bee-fly’s long tongue and legs enable it to eat without its body going very deep into the flower, but it may brush against at least the anthers on the taller stamens. The bee-fly’s hairy head and body are effective in picking up and transporting pollen, so it is a potential pollinator. But based on its position when visiting the flower for nectar, it may be somewhat random as to whether the bee-fly brushes the stigma to deposit the collected pollen on the next flower it visits.

Cut-leaved Toothwort (Cardamine concatenata) with bee-fly (Bombylius major)

Bees drink nectar, and they may also eat pollen. Female bees collect both pollen and nectar to bring back to their nests as food for their larvae. The bee in the photo below appears to be harvesting pollen from the anther of one of the shorter stamens, while at the same time its lower abdomen is brushing against the stigma, depositing any pollen it might have brought in from another Cut-leaved Toothwort flower. It will likely also pick up pollen from the taller stamens to take to the next flower it visits. So for this bee, the pollen on the short stamens offer an enticement and reward for visiting, while it is unknowingly partnering with the plant to assist in pollination when it brushes against the stigma and the pollen on the taller stamens. This could be the explanation for the two tiers of stamens. It would also seem to indicate that not all flower visitors are equally effective pollinators.

Cut-leaved Toothwort (Cardamine concatenata) with bee

Cut-leaved Toothwort is native in deciduous woodlands in much of the eastern two thirds of North America, from North Dakota, Ontario and Quebec in the north to Texas and Florida in the south. It’s a food plant for the caterpillars of the West Virginia White and Mustard White butterflies. Populations of both of these butterfly species have declined in recent years as a result at least in part of both habitat loss and the influx of Garlic Mustard (Allaria petiolata), a species native to Europe that is invasive in North America because it lacks predators here. The caterpillars of the West Virginia White butterflies in particular are able to digest only a few species of the mustard family, those with which the butterflies evolved. Garlic Mustard’s chemical composition is similar enough to Cut-leaved Toothwort’s to lure female butterflies to lay their eggs on it, but the resulting caterpillars can’t survive on a diet of Garlic Mustard. They need Cut-leaved Toothwort.

Cut-leaved Toothwort (Cardamine concatenata) with possible nectar thief

Everything changes so rapidly in spring. Don’t miss a single scene of the show!

Related Posts

Spicebush or Forsythia?

Spring Comes to the Sourlands

Signs of Spring – Mining Bees

Resources

Cech, Rick; Tudor, Guy. Butterflies of the East Coast. 2005.

Eastman, John. The Book of Forest and Thicket. 1992.

Eaton, Eric R.; Kauffman, Ken. Kaufman Field Guide to Insects of North America. 2007.

Glassberg, Jeffrey. A Swift Guide to Butterflies of North America. 2012.

Rhoads, Ann Fowler; Block, Timothy A. The Plants of Pennsylvania. 2007

Late Winter Bird Food

Posted on March 1, 2015 by Mary Anne Borge

A Downy Woodpecker and Goldfinches sharing a meal

The ground has been solidly snow covered for weeks. As a result, traffic at bird feeders is heavy, with birds often emptying our feeder in less than a day. It’s especially tough on birds that feed on the ground, like Cardinals,

Female Northern Cardinal

Male Northern Cardinal with American Goldfinches and Song Sparrow

White-throated Sparrows

White-throated Sparrow

and Dark-eyed Juncos.

Dark-eyed Junco with American Goldfinch

In our yard, a flock of Goldfinches moved back and forth from the feeder to the ground below,

American Goldfinches with Dark-eyed Junco

joined by a trio of Pine Siskins, visiting us for the past few weeks.

Pine Siskins and American Goldfinches

Pine Siskins

Birds take advantage of the food we provide, but what else do they eat in winter?

White-throated Sparrow

Just as in the warm months, insects are still an important part of their diet. As soon as there is open ground, birds begin tossing and probing leaves, looking for overwintering insects to eat.

Tufted Titmouse

Tufted Titmouse searching for food

Watch for Chickadees and Titmice searching branches of trees and shrubs for eggs, chrysalises, caterpillars and other insects sheltering there.

Carolina Chickadee

Chickadees investigate curled leaves clinging to branches, knowing that a leaf might be a winter insect shelter.

Carolina Chickadee searching for an insect in a leaf

Nuthatches travel down tree trunks probing bark crevices, looking for a winter insect snack. Brown Creepers cover the same territory in the opposite direction, eating what the Nuthatches miss.

White-breasted Nuthatch

Downy Woodpeckers explore both branches and tree trunks looking for food.

Downy Woodpecker

This Pileated Woodpecker

Pileated Woodpecker

found a branch that promised her an insect reward, probably Carpenter Ants.

Pileated Woodpecker, excavating a branch for ants

Signs of spring are beginning to show. Look closely at the plumage of male Goldfinches and you’ll see some splotches of bright yellow, the beginning of their molt to summer garb. This White-throated Sparrow is already sporting its summer suit, in spite of the snow!

White-throated Sparrow

Reasons to Love Winter

Posted on January 31, 2015 by Mary Anne Borge

Stowe, Vermont

Have you been ready for spring since about January 2? Wondering how you’ll ever get through the remaining weeks of winter? The best way I know is to get outside and enjoy what nature has to offer. When there’s enough snow, cross country skiing or snowshoeing are both good ways to keep warm enough to enjoy exploring the beauty of your surroundings. Or go for a walk in a nearby park, natural area, or your own garden.

Thirteenth Lake, Garnet Hill Lodge, North Creek, New York

View from a ski trail: Haul Road, Trapp Family Lodge, Stowe, Vermont

Cross Country skier in the woods, Trapp Family Lodge, Stowe, Vermont

While you’re out you’ll almost certainly spot animal tracks.

Raccoon tracks, Bowman’s Hill Wildflower Preserve, New Hope, Pennsylvania

Fox tracks

Grouse tracks, Trapp Family Lodge, Stowe, Vermont

If you’re really lucky, you’ll spot the critter that made the tracks.

Ruffed Grouse

White-tailed Deer

You may see evidence of insects or spiders attempting to survive the winter in one form or another.

Braconid wasp cocoon bundle

Well-camoflaged spider on Culver’s Root (Veronicastrum virginicum), facing south to catch the sun’s warmth

Mystery cocoon made from a leaf and silk. Could it be a moth? A spider?

Or you may find evidence that some insects have instead become food for birds. In the photo below, the holes in the tree were made by a Pileated Woodpecker, the result of excavating for a meal of carpenter ants or other insects.

Holes excavated by Pileated Woodpecker

With the leaves mostly off the trees, the spotlight is on the beauty of bark

Pealing birch bark

and the mosses,

Moss on tree bark

lichens,

Lichens

and mushrooms that decorate tree trunks and branches.

Common Split Gill mushrooms, commonly found on dead branches, help decompose the wood

Winter buds are a promise of spring to come, showing subtle color and offering a way to identify trees in winter.

Bitternut Hickory (Carya cordiformis) buds and leaf scar

Basswood (Tilia americana) bud

Umbrella Magnolia (Magnolia tripetala) bud and leaf scar

Winter fruits can be as beautiful as the flowers that produced them.

Wild Hydrangea (Hydrangea arborescens)

New York Ironweed (Vernonia noveboracensis)

Elephant’s foot (Elephantopus carolinianus)

Birds, including some that you may only see in winter, eat some of the fruits.

Dark-eyed Junco

The low angle of winter light flatters the landscape.

View from Trapp Family Lodge, Stowe, Vermont

Stowe, Vermont

These are just a few of the reasons to love winter as much as the other seasons. Go out and explore while you can!

Wonders of a Winter Walk – The Marsh

The Mist, the Meadow, and a Mystery

Backyard Birds, Snowstorm Number ??

American Beech

Posted on January 9, 2015 by Mary Anne Borge

American Beech (Fagus grandifolia)

It can be surprising to see leaves clinging to deciduous trees in mid-winter. In eastern North America, some oak species and American Hophornbeam (Ostrya virginiana) may retain their leaves but American Beech (Fagus grandifolia) trees are among the most conspicuous to do so. By January its leaves are bleached to a papery pale tan, catching the bright winter light while fluttering in the winter wind. The leaves look delicate, but give one a tug and you’ll see how tenaciously they adhere to their branches. American Beech leaves typically stay on the trees until early spring, withstanding the effects of even ice and snow.

American Beech (Fagus grandifolia), in March

Why do American Beech and other trees keep some of their leaves in winter? There are many theories: the dry leaves may be a deterrent to winter browsing by deer, moose and other mammals; holding some of the leaves until spring may be the trees’ way of time-releasing some nutrients for recycling into the soil; the leaves may funnel more snow melt to the tree’s root system. But no one knows for certain what caused this trait.

The smooth, pale gray bark is an unmistakable characteristic of American Beech, often tempting passers-by to carve their initials. A more interesting possibility is a sighting of animal ‘tracks’ – claw marks from animals that may have climbed the tree at some point.

Animal ‘tracks’ on American Beech (Fagus grandifolia)

Trees are susceptible to frost cracks in winter, caused by warming from the low-angled rays of the winter sun, followed by rapid cooling when the sun sets or disappears behind a cloud. Both the bark and the wood it encompasses expand in the warm sun, but the bark may cool more quickly than the wood when the sun disappears, causing lengthwise cracks to occur in the bark. If temperatures are warm enough, portions of the inner bark may become active, only to be killed if a rapid refreeze occurs. American Beech evolved to minimize the harsh effects of the sun by having light-colored bark that reflects the sun’s rays. The winter leaves may provide an additional layer of protection from the warm sunlight.

American Beech’s long, sharply pointed copper-colored buds are another distinctive winter identification feature.

American Beech (Fagus grandifolia) buds

As spring approaches, American Beech buds grow longer and plump, eventually opening to reveal newly unfurling leaves, accordion pleated and hairy as they first emerge. The long silky hairs are an adaptation to make the new leaves less appealing to the many species of hungry caterpillars and other insects that may eat the leaves later as the hairiness dissipates.

Newly unfurled leaves of American Beech (Fagus grandifolia)

According to Bringing Nature Home by Douglas Tallamy, American Beech provides food for the caterpillars of over 100 species of butterflies and moths. Among them is the Early Hairstreak butterfly, a rare species found in deciduous or mixed woodlands from the maritime provinces of Canada to northern Michigan and Wisconsin through the Appalachians to Tennessee and North Carolina. Early Hairstreak caterpillars can only eat the leaves of American Beech and Beaked Hazelnut (Corylus cornuta). The presence of caterpillars attracts predatory insects and arachnids to feed on them, including many species of spiders, wasps, ants and flies. These insects are beneficial to the trees, because they help keep the caterpillar population in check.

In addition to butterfly and moth caterpillars, a few of the insects that use American Beech include Leaf-footed Bugs,

Leaf-footed Bug (Acanthocephala species) on American Beech (Fagus grandifolia)

leaf-rollers,

Insect shelter, likely leaf-rolling weevil nest

and Woolly Beech Aphids.

Woolly Beech Aphids (Phyllaphis fagi)

The Woolly Beech Aphids’ honeydew in turn attracts other insects who eat it, including wasps and ants.

Ants harvesting Woolly Beech Aphid Honeydew

Ants help protect the tree from the insects that feed on its leaves, by aggressively attacking them.

The Harvester butterfly also feeds on the Woolly Beech Aphid’s honeydew, although its first choice is Wooly Alder aphids. The Harvester’s caterpillars eat the aphids themselves.

Harvester Butterfly

A non-native scale insect (cryptococcus fagisuga) introduced through the nursery trade on European Beech threatens the health of American Beech by providing an opening in the bark that together with a fungus enables beech bark disease. This is a good example of the importance of using native plants in your own garden, and the danger of using introduced exotic plants.

There is a fungus species that grows exclusively on the Woolly Beech Aphid’s honeydew, a sooty mold descriptively named Beech Aphid Poop-eater (Scorias spongiosa). Some studies have shown that leaves covered in sooty molds are more effective at removing pollution from the air than other leaves are.

Beech Aphid Poop-eater (Scorias spongiosa)

Oyster (Pleurotus ostreatus) and Burnt-Orange Bolete (Tylopilus ballouii) mushrooms, both edible, are among the other fungi that may be found on or near American Beech.

American Beech develops natural cavities that provide nesting sites for cavity nesting birds like Titmice, Chickadees, Woodpeckers and Nuthatches, all of whom rely on insects for a large part of their diet, and will help protect the tree from insect leaf-eaters. Chipmunks, squirrels, porcupines and other mammals also take advantage of the natural shelter American Beech offers.

Gray Squirrel in cavity of American Beech

Other birds, like the Wood Thrush below, may nest on the limbs of American Beech, using some of the previous year’s fallen leaves as nesting material.

Wood Thrush on her nest in an American Beech. Some old Beech leaves have been used as nest material.

American Beech’s fallen leaves may offer insect protein for ground-feeders like the Ovenbird.

Insect nest on fallen American Beech leaf

Ovenbird in American Beech

Beechdrops (Epifagus virginiana) depends on American Beech for its survival, since it gets its food from the tree’s roots. Look for the flowers in late summer or early fall, and the brown seed capsules throughout the winter.

Beechdrops (Epifagus virginiana) flowers

Beechdrops (Epifagus virginiana) in winter

American Beech flowers are wind pollinated, with separate male and female flowers both on the same plant. They bloom as the leaves are opening.

Male flowers of American Beech (Fagus grandifolia)

Nuts are produced if the flowers are successfully pollinated, usually 2 or 3 three-sided nuts per husk.

American Beech (Fagus grandifolia) nuts

The nuts are a source of high protein and fat for mammals and birds, including red, gray and flying squirrels, chipmunks, bears, Blue Jays, Tufted Titmice, Wild Turkey, and Ruffed and Spruce Grouse.

Tufted Titmouse eating American Beech nut

Nothing goes to waste in nature, so an empty beechnut husk may be reused as a shelter by an insect.

Insect nest in husk of American Beech

As the nights get longer and the temperatures drop in the fall, the American Beech begins to prepare for winter. The leaves gradually stop producing chlorophyll, which reduces the green color visible in the leaves, revealing the yellows and oranges of carotenes, and the brown tannins, .

American Beech (Fagus grandifolia) leaf in fall

American Beech is native in moist woodlands in the eastern United States and Canada. The bounty of insects supported along with its nutritious nuts makes it one of our most valuable tree species for wildlife.