Bountiful Blue Wood Aster

Blue Wood or Heart-leaved Aster (Symphyotrichum cordifolium) began its seasonal bloom in late September, and amazingly, at the end of November it’s still possible to find some blossoms.

Blue Wood Aster (Symphyotrichum cordifolium) with Sweat Bee (Halictus species)

Blue Wood Aster (Symphyotrichum cordifolium) with Sweat Bee (Halictus species)

Like all Aster (Asteraceae) family members, each flower ‘head’ of Blue Wood Aster consists of many tiny flowers that bloom gradually over a period of several weeks, offering nectar and pollen to a variety of flower visitors.  Each Blue Wood Aster flower head has an outer ring of ice blue petal-like ray flowers designed to advertise this feast. Tiny tubular disk flowers form the center of the display; this is where Blue Wood Aster makes its bountiful food available in hope that while dining, visitors will pick up pollen and transfer it to another plant of the same species, enabling pollination to occur.

Blue Wood Aster’s disk flowers are pale yellow when they’re in bud and when they first open. They turn pink or magenta as they age, and when they have been successfully pollinated.  This color change is a signal to pollinators, directing them to the receptive yellow flowers which are not yet pollinated and that will reward them with nectar, and steering them away from blossoms that are already satisfactorily pollinated and will not produce a nectar reward.  This evolutionary adaptation makes the most efficient use of both the plant’s and the potential pollinator’s efforts.

To share in the bounty offered by Blue Wood Aster, I invite you to a virtual time-lapse visit to our garden in central New Jersey.  You can see the last Blue Wood Aster blossoms for this year, and a selection of the many of the visitors that this lovely plant hosted throughout the season. Notice that the potential pollinators are generally visiting the yellow disk flowers, those that are still open for business, not the pinkish flowers that have shut down their nectar production.

Bumble Bees are the most frequent visitors.

Bumble Bee (Bombus species) drinking nectar from Blue Wood Aster (Symphyotrichum cordifolium)

Bumble Bee (Bombus species) drinking nectar from Blue Wood Aster (Symphyotrichum cordifolium)

An athletic Bee drinking nectar from Blue Wood Aster (Symphyotrichum cordifolium). I'm not completely sure whether it's a Bumble Bee or an Eastern Carpenter Bee.

An athletic Bee drinking nectar from Blue Wood Aster (Symphyotrichum cordifolium). I’m not completely sure whether it’s a Bumble Bee or an Eastern Carpenter Bee.

But many species of Sweat Bees (Halictid bees), and even Honey Bees dine on Blue Wood Aster nectar and pollen.

Sweat Bee (Halictus species) with Blue Wood Aster (Symphyotrichum cordifolium)

Sweat Bee (Halictus species) with Blue Wood Aster (Symphyotrichum cordifolium)

Sweat Bee (Halictus species) drinking nectar from Blue Wood Aster (Symphyotrichum cordifolium)

Sweat Bee (Halictus species) drinking nectar from Blue Wood Aster (Symphyotrichum cordifolium)

A gang of Sweat Bees (Halictus species) drinking nectar from Blue Wood Aster (Symphyotrichum cordifolium)

A gang of Sweat Bees (Halictus species) drinking nectar from Blue Wood Aster (Symphyotrichum cordifolium)

Sweat Bees (Halictid bees) of two different species visiting Blue Wood Aster (Symphyotrichum cordifolium)

Sweat Bees (Halictid bees) of two different species visiting Blue Wood Aster (Symphyotrichum cordifolium)

A Sweat Bee (Halictid bee) drinking nectar from Blue Wood Aster (Symphyotrichum cordifolium)

A Sweat Bee (Halictid bee) drinking nectar from Blue Wood Aster (Symphyotrichum cordifolium)

A Sweat Bee (Augochlorella species) investigating Blue Wood Aster (Symphyotrichum cordifolium)

A Sweat Bee (Augochlorella species) investigating Blue Wood Aster (Symphyotrichum cordifolium)

A Sweat Bee (Augochlorella species) investigating Blue Wood Aster (Symphyotrichum cordifolium)

A Sweat Bee (Augochlorella species) investigating Blue Wood Aster (Symphyotrichum cordifolium)

A Honey Bee (Apis mellifera) nectaring from Blue Wood Aster (Symphyotrichum cordifolium)

A Honey Bee (Apis mellifera) nectaring from Blue Wood Aster (Symphyotrichum cordifolium)

A Mason Wasp stopped by for nourishment.

A Mason Wasp (Ancistrocerus species) drinking nectar from Blue Wood Aster (Symphyotrichum cordifolium)

A Mason Wasp (Ancistrocerus species) drinking nectar from Blue Wood Aster (Symphyotrichum cordifolium)

Many fly species paused to drink, most disguised as bees or wasps in an attempt to appear threatening to potential predators.

A Syrphid or Flower fly drinking nectar from Blue Wood Aster (Symphyotrichum cordifolium)

A Syrphid or Flower fly drinking nectar from Blue Wood Aster (Symphyotrichum cordifolium)

A Syrphid or Flower Fly (Toxomerous geminatus) drinking nectar from Blue Wood Aster (Symphyotrichum cordifolium)

A Syrphid or Flower Fly (Toxomerous geminatus) drinking nectar from Blue Wood Aster (Symphyotrichum cordifolium)

A Syrphid or Flower Fly (Syrphus ribesii) drinking nectar from Blue Wood Aster (Symphyotrichum cordifolium)

A Syrphid or Flower Fly (Syrphus ribesii) drinking nectar from Blue Wood Aster (Symphyotrichum cordifolium)

A Syrphid or Flower Fly (Sericomyia chrysotoxoides) drinking nectar from Blue Wood Aster (Symphyotrichum cordifolium)

A Syrphid or Flower Fly (Sericomyia chrysotoxoides) drinking nectar from Blue Wood Aster (Symphyotrichum cordifolium)

A Syrphid or Flower Fly (Eristalis tenax) drinking nectar from Blue Wood Aster (Symphyotrichum cordifolium)

A Syrphid or Flower Fly (Eristalis tenax) drinking nectar from Blue Wood Aster (Symphyotrichum cordifolium)

Greenbottle Fly (Lucilia sericata) drinking nectar from Blue Wood Aster (Symphyotrichum cordifolium)

Greenbottle Fly (Lucilia sericata) drinking nectar from Blue Wood Aster (Symphyotrichum cordifolium)

Even late season butterflies and moths were able to refuel on Blue Wood Aster nectar.

A Clouded Sulphur butterfly drinking nectar from Blue Wood Aster (Symphyotrichum cordifolium). Notice the heart-shaped leaves that are characteristic of this species.

A Clouded Sulphur butterfly drinking nectar from Blue Wood Aster (Symphyotrichum cordifolium). Notice the heart-shaped leaves that are characteristic of this species.

A Pearl Crescent butterfly drinking nectar from Blue Wood Aster (Symphyotrichum cordifolium). Not only do these butterflies benefit from the nectar, but their caterpillars dine on the foliage of several aster species.

A Pearl Crescent butterfly drinking nectar from Blue Wood Aster (Symphyotrichum cordifolium). Not only do these butterflies benefit from the nectar, but their caterpillars dine on the foliage of several aster species.

A Corn Earworm Moth drinking nectar from Blue Wood Aster (Symphyotrichum cordifolium).

A Corn Earworm Moth drinking nectar from Blue Wood Aster (Symphyotrichum cordifolium).

A Yellow-collared Scape Moth (Cisseps fulvicollis) and Bumble Bee on Blue Wood Aster (Symphyotrichum cordifolium).

A Yellow-collared Scape Moth (Cisseps fulvicollis) and Bumble Bee on Blue Wood Aster (Symphyotrichum cordifolium).

Meanwhile, a Brown-hooded Owlet Moth caterpillar dined on the leaves and spent flowers of Blue Wood Aster.

Brown-hooded Owlet caterpillar eating Blue Wood Aster (Symphyotrichum cordifolium) leaves and flowers.

Brown-hooded Owlet caterpillar eating Blue Wood Aster (Symphyotrichum cordifolium) leaves and flowers.

Blue Wood Aster is native in much of the eastern half of the United States, and in British Columbia, Manitoba, Ontario, Quebec, Prince Edward Island and Nova Scotia in Canada. It can be found in a variety of habitats, including woodlands, meadows and roadsides.  There may still be some blooming near you!

 

Related Posts

Asters Yield a Treasure Trove!

New England Asters – A Hotbed of Activity!

Mysterious Bumble Bee Behavior

Resources

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

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

Mader, Eric; Shepherd, Matthew; Vaughan, Mace; Black, Scott Hoffman; LeBuhn, Gretchen. Attracting Native Pollinators: Protecting North America’s Bees and Butterflies. 2011.

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

Wagner, David L.; Caterpillars of Eastern North America, 2005.

Wilson, Joseph S.; Carril, Olivia Messinger. The Bees in Your Backyard. 2016.

USDA NRCS Plant Database

 

Sneezeweed

Sneezeweed (Helenium autumnale) blooms for many weeks, starting in late summer and continuing through mid-fall, offering nectar and pollen for hungry insect foragers late in the growing season.

Sachem on Sneezeweed (Helenium autumnale)

Sachem on Sneezeweed (Helenium autumnale)

It is a member of the Aster family, a vast group second only to the Orchid family in the number of species it includes. There are Aster family members blooming in early spring, but mid-summer through the end of fall is the time that ‘asters’ really dominate the landscape.  Coneflowers, goldenrods, asters, bonesets, tickseeds, beggar-ticks, dandelions and more all belong to this huge plant family.

Goldenrods and New England Asters (Symphyotrichum novae-angliae) are Aster (Asteraceae) family members

Goldenrods and New England Asters (Symphyotrichum novae-angliae) are Aster (Asteraceae) family members

The Aster family is also sometimes called the Composite family, because their many tiny flowers grow in clusters, called heads, that look to us like a single flower. There are two types of flowers possible in an ‘aster’ flower head, ray flowers and disk flowers.  Sneezeweed has both.  Ray flowers look like petals, and disk flowers are tiny tubular flowers clustered in the center of the flower head.  When both ray and disk flowers are present in a flower head, the ray flowers may not produce any nectar or have any reproductive parts.  In this case, the function of the petal-like ray flowers is primarily to add to the floral display and landing platform that will entice pollinators to come to visit.  The disk flowers are where all the action takes place, offering nectar and pollen to potential pollinators.  The photo below shows a butterfly foraging on the disk flowers of a Sneezeweed flower head.

Pearl Crescent drinking nectar from the disk flowers of a Sneezeweed (Helenium autumnale) flower head (inflorescence). The petal-like floral structures are ray flowers.

Pearl Crescent drinking nectar from the disk flowers of a Sneezeweed (Helenium autumnale) flower head (inflorescence). The petal-like floral structures are ray flowers.

Which brings us to the name, Sneezeweed. Is this the plant that has been causing you to sneeze, making your eyes itchy and watery, and your nose runny?  No!  Well, maybe it’s goldenrod?  No again!  We can tell just by looking at these plants that they are unlikely to cause allergies.  How?  Because they have bright, attractive flowers.  Plants that have showy flowers have evolved to use their floral display and food rewards to entice animals to visit.  The animals, usually insects, become unwitting partners with the plants, helping them to achieve their pollination goals.  The flowers’ pollen is heavy and waxy, designed to adhere to a pollinator’s body and highly unlikely to float in the wind.  Plants that are wind pollinated, like Ragweed, have light, fluffy pollen that may find its way up your nose or in your eyes.

The flowers are visited by bees, butterflies, moths and beetles.

Sweat Bee on Sneezeweed (Helenium autumnale)

Sweat Bee on Sneezeweed (Helenium autumnale)

Pearl Crescent on Sneezeweed (Helenium autumnale)

Pearl Crescent on Sneezeweed (Helenium autumnale)

Ailanthus Webworm Moth on Sneezeweed (Helenium autumnale)

Ailanthus Webworm Moth on Sneezeweed (Helenium autumnale)

A soldier beetle, Pennsylvania Leatherwing (Chauliognathus pensylvanicus) on Sneezeweed (Helenium autumnale)

A soldier beetle, Pennsylvania Leatherwing (Chauliognathus pensylvanicus) on Sneezeweed (Helenium autumnale)

Sneezeweed flowers seem to be a popular location for meeting members of the opposite sex, at least if you are an insect.

Pearl Crescents on Sneezeweed (Helenium autumnale)

Pearl Crescents on Sneezeweed (Helenium autumnale)

Two pairs of beetles on Sneezeweed (Helenium autumnale). The dark pair in the upper right of the flower head are a lady beetle species, Microwesia misella.

Two pairs of beetles on Sneezeweed (Helenium autumnale). The dark pair in the upper right of the flower head are a lady beetle species, Microwesia misella.

Then why is this plant called Sneezeweed? Because many Native American tribes used dried flowers or leaves of this plant as snuff to induce sneezing, especially as a treatment for colds.  Gardeners considering using this plant may find its alternative common name, Helen’s Flower, more appealing.  This name is a reflection of Sneezeweed’s genus, Helenium, and a reference to Helen of Troy.

Sneezeweed has chemicals that are toxic to mammals, so it is highly deer resistant. It is native in 47 of the 48 the contiguous United States (New Hampshire is the exception), and much of Canada.  Sneezeweed can be found in sunny locations with moist or wet soil, in marshes, along river or stream banks and in wet meadows.

Sneezeweed – Not the most enticing name for such a beautiful flower!

Sachem on Sneezeweed (Helenium autumnale)

Sachem on Sneezeweed (Helenium autumnale)

Related Posts

Asters Yield a Treasure Trove

New England Asters – A Hotbed of Activity!

Fall Allergies? Don’t Blame Goldenrod!

Feasting on Green-headed Coneflower

Resources

Evans, Arthur V. Beetles of Eastern North America.  2014.

Native American Ethnobotany Database

USDA Forest Service Plant of the Week

USDA NRCS Plant Database

 

 

 

 

 

Who Uses Black Cohosh?

Black Cohosh (Actaea racemosa, synonym Cimicifuga racemosa) blooms in mid-summer, lighting up the forest understory.

Black Cohosh (Actaea racemosa, syn. Cimicifuga racemosa)

Black Cohosh (Actaea racemosa, syn. Cimicifuga racemosa)

The spikes of white flowers seem to glow even in the dark, begging to be called Fairy Candles, one of the other common names by which Black Cohosh is known.

Black Cohosh (Actaea racemosa, syn. Cimicifuga racemosa)

Black Cohosh (Actaea racemosa, syn. Cimicifuga racemosa)

Black Cohosh flowers are arranged in long narrow clusters called racemes, blooming from the bottom of the flower stalk to the top. Each individual flower looks like a pom-pom, formed by an aggregation of many stamens (the male reproductive parts) surrounding a single pistil (the female reproductive part).

Black Cohosh (Actaea racemosa, syn. Cimicifuga racemosa) flowers

Black Cohosh (Actaea racemosa, syn. Cimicifuga racemosa) flowers

Black Cohosh depends on the assistance of animals to achieve pollination. The flowers are visited by many species of insects whose bodies may come in contact with pollen dispensed from anthers at the tips of the stamens.  Some of that pollen may adhere to the insect’s body.  When the insect moves to a flower of another Black Cohosh plant and brushes against the flower’s stigma (the receptive part of the pistil), then Black Cohosh’s pollination goal is achieved.

It’s not an accident that insects visit the flowers. Plants and animals have evolved together over centuries to depend on each other.  About 80% of flowering plants depend on animals to carry their pollen to other plants of the same species, helping them achieve successful cross-pollination.  In exchange, many animals depend exclusively, or for at least part of their diet, on plants.

The most common food enticements that plants offer to flower visitors are nectar and pollen. Many insects visit flowers for nectar, but some are also interested in eating pollen, and in the case of bees, harvesting it to bring back to their nests to feed their larvae.

Black Cohosh has evolved a strategy of offering pollen, but not nectar, to entice potential pollinators. Plants evolve to be as efficient as possible, trying not to expend unnecessary resources.  Black Cohosh is able to attract enough visitors to its flowers by offering them pollen only.

Insects want to eat pollen and plants want insects to transport their pollen to another plant of the same species. If this sounds like a potential conflict of interest, it is.  Only about 2% of pollen is actually used for pollination.  Potential pollinators or their offspring eat much of the remaining 98%.

In spite of the fact that another common name for Black Cohosh is Bugbane, many insects are more attracted than deterred by its fragrance. Bees, flies and beetles visit Black Cohosh flowers to eat or harvest pollen.  While I watched for just a few minutes, the activity at a small group of Black Cohosh plants included bees, flies and beetles.  Bumble Bees, Sweat Bees, and Leaf-cutter Bees, all worked the flowers.

Black Cohosh (Actaea racemosa, syn. Cimicifuga racemosa) with Leafcutter bee (Megachile species)

Black Cohosh (Actaea racemosa, syn. Cimicifuga racemosa) with Leafcutter bee (Megachile species)

Black Cohosh (Actaea racemosa, syn. Cimicifuga racemosa) with Sweat bee (Haictidae)

Black Cohosh (Actaea racemosa, syn. Cimicifuga racemosa) with Sweat bee (Haictidae)

Bumble Bee visits were the most brief. They stopped for just a few seconds per plant before moving on to another.  It may seem counterintuitive, but this may make Bumble Bees the most successful of Black Cohosh’s cross-pollinators, since they are the most likely to move the pollen to a different plant.

A Flower or Syrphid Fly (Toxomerus geminatus) dined on the flowers’ pollen.

Black Cohosh (Actaea racemosa, syn. Cimicifuga racemosa) with Flower Fly (Toxomerus geminatus)

Black Cohosh (Actaea racemosa, syn. Cimicifuga racemosa) with Flower Fly (Toxomerus geminatus)

At least two species of tiny Tumbling Flower Beetles (Falsomordellistena pubescens and Mordellistena fuscipennis) munched on the flowers’ tissues.    Tumbling Flower Beetles are named for their behavior when threatened; they bounce and tumble unpredictably and may fly away, carrying pollen to another plant, possibly helping to meet Black Cohosh’s pollination needs.

Black Cohosh (Actaea racemosa, syn. Cimicifuga racemosa) with Tumbling Flower Beetle (Falsomordellistena pubescens) in upper right

Black Cohosh (Actaea racemosa, syn. Cimicifuga racemosa) with Tumbling Flower Beetle (Falsomordellistena pubescens) in upper right

The Tumbling Flower Beetles were joined by at least three species of Longhorn Beetles, the Banded Longhorn Beetle (Typocerus velutinus), and two others, Metacmaeops vittata, and Analeptura lineola.

Black Cohosh (Actaea racemosa, syn. Cimicifuga racemosa) with Longhorn Beetle (Metacmaeops vittata), upper right, and Tumbling Flower Beetles (Mordellistena fuscipennis)

Black Cohosh (Actaea racemosa, syn. Cimicifuga racemosa) with Longhorn Beetle (Metacmaeops vittata), upper right, and Tumbling Flower Beetles (Mordellistena fuscipennis)

Black Cohosh (Actaea racemosa, syn. Cimicifuga racemosa) with Longhorn Beetle (Analeptura lineola), center, and Tumbling Flower Beetle (Mordellistena fuscipennis)

Black Cohosh (Actaea racemosa, syn. Cimicifuga racemosa) with Longhorn Beetle (Analeptura lineola), center, and Tumbling Flower Beetle (Mordellistena fuscipennis)

For an insect, visiting Black Cohosh flowers is not without its risks. Predators like the perfectly camouflaged Crab Spider in the photo below may be lurking in the shadows, waiting for an unwary victim.

Crab Spider with a fly victim (upper left), bee and Tumbling Flower Beetle on Black Cohosh (Actaea racemosa, syn. Cimicifuga racemosa)

Crab Spider with a fly victim (upper left) on Black Cohosh (Actaea racemosa, syn. Cimicifuga racemosa) with bee and Tumbling Flower Beetle

Black Cohosh is the only food Appalachian Azure butterfly caterpillars can eat. Female butterflies lay their eggs on flower buds.  When the caterpillars hatch, they begin eating the buds and flowers, moving on to leaves if no flowers remain.  Like the other Azure butterfly caterpillars, the Appalachian Azure caterpillars are protected by ants in exchange for the delicious honeydew the caterpillars excrete.  Depending on the species, ants have different forms of defensive weapons; they may bite, sting, or spray an acid at their enemy targets, deterring even birds from their prey.

Appalachian Azure caterpillar being tended by ants, on Black Cohosh (Actaea racemosa) flower buds

Appalachian Azure caterpillar being tended by ants, on Black Cohosh (Actaea racemosa) flower buds

Although I have seen Appalachian Azure caterpillars, I’ve never seen the butterfly. The Appalachian Azure closely resembles the Summer Azure, pictured below.

Summer Azure

Summer Azure

People use Black Cohosh, primarily the root, for medicinal purposes. Black Cohosh contains chemical compounds that are anti-inflammatory, antirheumatic, and that have efficacy in managing female reproductive system problems.  Black Cohosh is approved in Germany for treating menopausal symptoms.  Several indigenous Native American tribes also used Black Cohosh to treat rheumatism and other ailments.

Black Cohosh is native primarily in the eastern United States and the Canadian provinces of Quebec and Ontario. It grows in rich, moist woods, in ravines and on slopes.  Its height can range from just over two feet (.7 meters) to as much as eight feet (2.5 meters).  Black Cohosh will light up a shade garden, blooming from late June through early August.

Black Cohosh (Actaea racemosa, syn. Cimicifuga racemosa)

Black Cohosh (Actaea racemosa, syn. Cimicifuga racemosa)

Who uses Black Cohosh? Insects do, including bees, flies, beetles, ants, and butterflies; spiders and other predators of the insects feeding there do, and even people use it, for medicinal purposes and for the beauty it brings to a garden.

Related Posts

Spring Azures

Resources

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

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

Eisner, Thomas. For Love of Insects.  2003.

Evans, Arthur V. Beetles of Eastern North America.  2014.

Foster, Steven; Duke, James A. A Field Guide to Medicinal Plants and Herbs of Eastern and Central North America.  2000.

Hoffmann, David. Medical Herbalism.  2003.

Marshall, Stephen A. Insects Their Natural History and Diversity. 2006.

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

Willmer, Pat. Pollination and Floral Ecology. 2011

USDA NRCS Plant Database

 

 

White Beardtongue for Pollinators

White or Foxglove Beardtongue (Penstemon digitalis) blooms in late spring to early summer, offering nectar and pollen to flower visitors.  It’s easy to recognize in fields and along roadsides by its upright habit and its inflorescence of many whitish flowers, all positioned perpendicularly to the stem.  The name Penstemon reflects the fact that these flowers each have five male flower parts, called stamens.  ‘Foxglove’ and ‘digitalis’ both refer to the shape of the flowers, which resemble those of Foxglove (Digitalis purpurea).

White or Foxglove Beardtongue (Penstemon digitalis)

White or Foxglove Beardtongue (Penstemon digitalis)

The white flowers beckon to a variety of bees who are enticed by the possibility of a meal of nectar and pollen, with the purple lines (nectar guides) on the throat of the flower showing them the way.

Bufflehead Mason Bee (Osmia bucephala) on White Beardtongue (Penstemon digitalis)

Bufflehead Mason Bee (Osmia bucephala) on White Beardtongue (Penstemon digitalis)

Sweat Bee on White Beardtongue (Penstemon digitalis)

Sweat Bee on White Beardtongue (Penstemon digitalis)

Bee on White Beardtongue (Penstemon digitalis)

Bee on White Beardtongue (Penstemon digitalis)

In addition to feeding themselves, female bees also harvest pollen and nectar to provision their nests for their larvae. But if bees are eating and harvesting the pollen, how will the flowers be pollinated?  Will there be any pollen left to fulfill the plant’s goal of reproduction?

Female Bumble Bee on White Beardtongue (Penstemon digitalis). Note the harvested food on her hind leg.

Female Bumble Bee on White Beardtongue (Penstemon digitalis). Note the harvested food on her hind leg.

Although much of its pollen is used to entice and reward insect visitors, White Beardtongue’s strategy is to deposit pollen on its flower visitors’ bodies in a place that can’t be easily reached for grooming.

The flowers have both male and female parts, but they are sequentially unisexual. The male flower parts, or stamens, mature first, with the anthers at their tips opening up to release pollen. Although White Beardtongue has five stamens, only four are capable of producing fertile pollen. These four stamens are all positioned just below the ‘roof’ of the flower tube, or corolla.  The dark brown anthers, which contain the pollen, are at the tips of the stamens, clustering above the center of the entrance to the flower.

White Beardtongue (Penstemon digitalis) in the male phase. The dark brown anthers are clustered just below the center of the ‘roof’ of the flower.

White Beardtongue (Penstemon digitalis) in the male phase. The dark brown anthers are clustered just below the center of the ‘roof’ of the flower.

When the flowers are in this phase, a visitor like the Bumble Bee in the photo below may enter the flower, and be brushed with pollen on the top of its head, thorax or even its tongue (proboscis).

Bumble Bee on White Beardtongue (Penstemon digitalis).

Bumble Bee on White Beardtongue (Penstemon digitalis).

After a day or so, the anthers begin to wither and the female flower part begins to mature, the sticky stigma at its tip becoming receptive to pollen. The style extends and curves downward, taking the same position that the anthers once held.

White Beardtongue (Penstemon digitalis) in the female phase. The stigma has replaced the anthers just below the center of the ‘roof’ of the flower.

White Beardtongue (Penstemon digitalis) in the female phase. The stigma has replaced the anthers just below the center of the ‘roof’ of the flower.

If a bee carries the pollen to a flower in the female phase, it will generally enter the flower in the same way, depositing the pollen on the receptive stigma. Success!  White Beardtongue’s pollination strategy has worked.

Bumble Bee depositing pollen on stigma of a White Beardtongue (Penstemon digitalis) in the female phase.

Bumble Bee depositing pollen on stigma of a White Beardtongue (Penstemon digitalis) in the female phase.

Some pollen may fall on the ‘floor’ of the flower, where the fifth stamen is positioned. This stamen is sterile; it does not produce its own pollen.  It is somewhat hairy, giving the plant its common name ‘beardtongue’.  This hairy stamen may catch some of the fallen pollen and deposit it on an insect visitor as it brushes past, a secondary means of pollen dispersal.  Some smaller bees may cling upside down while foraging for pollen.

Bee visiting White Beardtongue (Penstemon digitalis), possibly harvesting pollen

Bee visiting White Beardtongue (Penstemon digitalis), possibly harvesting pollen

Butterflies and even hummingbirds may stop by for nectar. They may not be as effective in pollinating White Beardtongue as the bees are if their anatomy and behavior is not as good a match for the anatomy of the flower.  On the plus side, neither butterflies nor hummingbirds harvest pollen, so any that does adhere to them has the possibility of being deposited on another flower.

Hobomok Skipper butterfly visiting White Beardtongue (Penstemon digitalis) for nectar. It may be just the right size to pick up or deliver pollen on its head.

Hobomok Skipper butterfly visiting White Beardtongue (Penstemon digitalis) for nectar. It may be just the right size to pick up or deliver pollen on its head.

White Beardtongue blooms for a period of about a month in June to early July. It is native in the eastern two-thirds of the United States, and is found in several Canadian provinces.  It can tolerate sun to part shade in dry to somewhat moist, well-drained soil, and grows to a height of 2-5 feet (6 – 15 decimeters).  It’s a good addition to a natural area or a pollinator garden.

Bumble Bee visiting White Beardtongue (Penstemon digitalis)

Bumble Bee visiting White Beardtongue (Penstemon digitalis)

Here are some other early summer blooming plants that are important for pollinators:

Milkweed – It’s Not Just for Monarchs

What Good is Dogbane?

Resources

Eastman, John. The Book of Field and Roadside.  2003.

Holm, Heather. Pollinators of Native Plants.  2014.

Willmer, Pat. Pollination and Floral Ecology. 2011

Illinois Wildflowers

Lady Bird Johnson Wildflower Center Plant Database

Ontario Wildflowers

USDA NRCS Plant Database

 

 

 

Cut-leaved Toothwort

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)

Bloodroot (Sanguinaria canadensis)

and Trout Lily (Erythronium americanum).

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)

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

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)

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)

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

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)

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 (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

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