The Buzz About Shooting Star

Shooting Star (Dodecatheon meadia) is an herbaceous perennial named for the shape of its flowers and the flowers’ curved stems, which together look a bit like a shooting star with a tail following it through the sky.

Shooting Star (Dodecatheon meadia)

Shooting Star blooms in spring over a period of several weeks. Each flower shoot produces multiple flowers, each flower with its own curved stem (or tail).  The flowers can be white or pink.

Shooting Star (Dodecatheon meadia)

Shooting Star (Dodecatheon meadia)

If the flowers are pollinated, fruit capsules take their place and along with the leaves remain visible for many weeks in the summer.

Shooting Star (Dodecatheon meadia) fruit capsule

Shooting Star requires a partner with special skill to help achieve successful pollination,  an insect with the athletic ability to hang from below the flower and vibrate its wing muscles without moving its wings, in order to shake pollen loose from the flower.  This is called buzz pollination, because the vibration makes a buzzing sound.  Queen Bumble Bees have this ability, and they are the perfect unsuspecting collaborator in Shooting Star’s pollination.

Queen Bumble Bee on Shooting Star (Dodecatheon meadia)

When a female Bumble Bee like the one shown here clings to a Shooting Star flower from below, her abdomen touches the plant’s stigma, the place on the pistil (female reproductive part) where pollen must be deposited if pollination is to take place.  If pollen is present on the bee when she arrives at a flower, it will be brushed from her abdomen onto the flower’s stigma, possibly with some assistance from static electriciy.  As the Bumble Bee clings to the flower she vibrates it, causing a dusting of pollen to be releases onto her abdomen.  She then carries the pollen to the next flower she visits.

Queen Bumble Bee on Shooting Star (Dodecatheon meadia). The flower’s stigma is touching the bee’s abdomen. Notice the dusting of pollen that is beginning to accumulate.

Honey bees don’t have this special skill. Only native bees like Bumble Bees and some others are able to buzz pollinate.  Blueberries, cranberries, tomatoes, eggplants and peppers also require buzz pollination.  If we didn’t have these bees, we wouldn’t have this food!

Shooting Star doesn’t produce nectar, so why would bees keep visiting these flowers?  They don’t do it altruistically, they need some incentive.  Bees visit the flowers for pollen, a food source high in the protein and lipids bees need. After she has visited enough flowers, the Bumble Bee will groom herself, eating some of the pollen and storing the rest on her legs to carry back to her nest to feed her larvae.

Queen Bumble Bee on Shooting Star (Dodecatheon meadia). She has collected pollen on her rear legs to take back to her nest to feed her larvae.

Other small bees may visit the flowers to harvest pollen, but because of the way these smaller bees handle the flowers, the chances are lower that they will encounter the stigma and deposit pollen.

Shooting Star is native in Manitoba in Canada, and much of the eastern half of the United States except the New England states, New Jersey and Delaware.  It is most commonly found in some of the mid-western states.  Shooting Star likes shade to part shade and can be found in open woods.

Resources

Spira, Timothy A.  Wildflowers & Plant Communities of the Southern Appalachian Mountains & Piedmont.  2011.

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

Willmer, Pat.  Pollination and Floral Ecology. 2011

Illinois Wildflowers

USDA Plant Database

 

 

Rue Anemone and a Bee Fly

Within the space of a day, Rue Anemone (Thalictrum thalictroides) grows from being invisible to attaining its full height.  Walk a trail one day and it is nowhere to be seen, the next day it’s up with its first flower opening, starting the race to reproduce. Rue Anemone blooms, produces fruit, then the above ground parts die back, all before the leaves in the trees above them finish opening for the season.

Rue Anemone (Thalictrum thalictroides)

Before opening, Rue Anemone’s flowers resemble tiny rose buds.  Pale pink sepals enclose the flowers’ reproductive organs, but quickly open for business.

Rue Anemone (Thalictrum thalictroides) in bud

There may be up to five flowers per plant, arranged in a whorl radiating from the main stem of the plant, with a whorl of leaves directly below the flowers.

Rue Anemone (Thalictrum thalictroides) in bloom

The flowers open one at a time, beginning soon after the plant emerges.  The petal-like sepals form the outermost circle of each floral display.  They may be pure white or retain the hint of pink they showed before the flowers opened.  Moving toward the center of the flower, numerous stamens (the male reproductive parts), comprise the next ring in the floral structure. Starting from the outside of this ring and gradually moving inward, the anthers, located at the tips of the stamens, open a few at a time to release their pollen.  At the very center of the flower, there is a cluster of female reproductive parts called carpels, or collectively, pistils. The whitish stigmas at the tips of the carpels are receptive, advertising their availability for a pollen deposit.

Rue Anemone (Thalictrum thalictroides) in bloom. The petal like sepals form the outer ring of the floral display. The next ring are the stamens, with the anthers of the outermost beginning to open to release their pollen. A cluster of carpels forms the center of the floral display.

Within a few days, all of the flowers on the plant open, each at a slightly different stage of development as a result of their staggered opening.

Rue Anemone (Thalictrum thalictroides) in bloom

Rue Anemone partners with early flying bees and flies to assist with cross-pollination.  Like some other early spring wildflowers, including Hepaticas (Hepatica nobilis) and Bloodroot (Sanguinaria canadensis), Rue Anemone has evolved to provide only pollen as an enticement to these flower visitors.  Pollen is an important part of a bee’s diet, and female bees also harvest it to feed to their larvae.  Flies of many species also consume pollen; the females of some species require the protein in pollen to enable egg development.

I watched while a Greater Bee Fly (Bombylius major) darted in and out of a Rue Anemone flower.  Bee flies have a very long proboscis (mouth parts), perfectly suited to reach and sip nectar that might be out of range for some other flower visitors.  Knowing that Rue Anemone doesn’t offer nectar, I assumed the Bee Fly was harvesting pollen, and I was curious to see how she did it.

Greater Bee Fly (Bombylius major) visiting a Rue Anemone (Thalictrum thalictroides) flower. Note the long proboscis (mouth parts)

In the photos below, it appears that the Bee Fly is harvesting pollen with its proboscis.  Once pollen is at the tip of its proboscis, a bee fly then mixes the pollen with fluids and sucks it up through its straw-like mouth parts.

Greater Bee Fly (Bombylius major) visiting a Rue Anemone (Thalictrum thalictroides) flower. Note she is opening the tips of the proboscis, apparently to harvest some pollen.

In exchange for the meal, the Bee Fly’s hairy body may pick up pollen and deposit it on another Rue Anemone, enabling cross-pollination.

Greater Bee Fly (Bombylius major) visiting a Rue Anemone (Thalictrum thalictroides) flower. Note she is opening the tips of her proboscis to harvest some pollen.

After pollination occurs, fruits develop at the center of the flower.  Ants disperse the seeds, enticed by the nutritious food packet, called an elaiosome, that is attached.

Rue Anemone (Thalictrum thalictroides). Note the green fruit capsules beginning to develop at the center of the largest flower.

Rue Anemone (Thalictrum thalictroides) in fruit.

Rue Anemone is a delicate looking perennial of wooded understories, usually about 6-8 inches (1 – 2 dm) tall, but its height can range from 4 to almost 12 inches, depending on growing conditions.  It is a member of the Buttercup (Ranunculaceae) family, and like other members of this family, the foliage produces a burning sensation if eaten, a survival strategy that discourages herbivores from consuming the plant.

Rue Anemone is native in the eastern half of the United States, and in the province of Ontario in Canada.

Rue Anemone (Thalictrum thalictroides)

Related Posts

A Carpet of Spring Beauty, Woven by … Ants!

Bloodroot

Hepatica’s Survival Strategy

Resources

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

Hoffmann, David.  Medical Herbalism.  2003.

Marshall, Stephen A. Flies The Natural History and Diversity of Diptera. 2012.

Newcomb, Lawrence.  Newcomb’s Wildflower Guide.  1977.

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

Illinois Wildflowers

USDA NRCS Plant Database

 

 

Bloodroot

In spite of the weather whiplash we’ve experienced since late February, spring wildflowers are slowly, cautiously beginning to emerge and bloom.  One of the first spring blossoms I saw this season was Bloodroot (Sanguinaria canadensis).

Bloodroot (Sanguinaria canadensis)

The sight of this stunning white blossom holding its face up to the sun was especially welcome after a snowy, chilly March.

With each sunny day more flower shoots make their way through their winter blanket of fallen leaves.  As Bloodroot emerges, it leads with a flower stem, each one wrapped by a single leaf.

Bloodroot (Sanguinaria canadensis) emerging from its winter blanket of leaves

The flowers open as the temperatures warm, advertising their presence to early flying pollinators.  The veins in the pure white petals, contrasted with the yellow stamens surrounding the pistil in the center of the flower make a perfect target for foraging pollinators.  The stamens are the male reproductive parts, the pistils are the female reproductive parts.

Bloodroot (Sanguinaria canadensis)

The most likely flower visitors are early flying bees or flies that can tolerate low temperatures.

Bloodroot (Sanguinaria canadensis) with Bee

Each plant species evolves to utilize its energy to maximize the chances of survival and reproduction.  Like Hepatica and some other early spring flowers, Bloodroot’s strategy is to produce an enticing floral display whose only reward is pollen;  the flowers don’t produce nectar.  This works, because pollen is an important food source for many of the insects active at this time of year.  Bees consume pollen, and female bees also collect it to feed their larvae.  Flies and beetles visit flowers for their nutritious pollen.  Not many of the insects that prefer nectar, like butterflies, are active at the time Bloodroot is blooming, so there would be little added benefit in offering it.

As unpredictable as spring weather is, even the hardiest insects may not always be available in the short window of time a Bloodroot flower is open for business.  Each flower remains open for about three days, closing at night and on rainy days to protect its pollen when insects are unlikely to be active.

When a Bloodroot flower opens, its stigma, located at the tip of the pistil, is receptive.  Pollen must be deposited on the stigma in order for pollination to occur. At this time, the stamens are curved away from the stigma to clear the way for an insect’s access to the receptive stigma, hopefully bringing pollen.

Newly open Bloodroot (Sanguinaria canadensis) flower, in the female phase

After a few hours, some of the anthers, located at the tips of the stamens, begin to dehisce, or open, making pollen available.  The remaining anthers open gradually over the three-day period that Bloodroot flowers are typically open. The continuing separation of the anthers from the stigma helps minimize the likelihood of self-pollination.

Bloodroot (Sanguinaria canadensis) flower with some of the anthers open to make pollen available

Bloodroot (Sanguinaria canadensis) flower. Notice the pollen around the edges of the anthers where they have opened to make pollen available.

If after three days the flower has not been pollinated with the assistance of an insect, the stamens will begin to curve inward toward the center of the flower. The anthers touch the stigma, depositing the pollen.  In Bloodroot’s world, it’s better to self-pollinate to ensure reproduction than not to reproduce at all.  The flower drops its petals within hours of pollination.

Bloodroot (Sanguinaria canadensis) flower with some of the anthers beginning to curve back towards the stigma to enable self-pollination

After pollination, the thick, almost succulent leaves that protected the flower stem gradually open, expand, and capture energy from the sun for several more weeks.

Bloodroot (Sanguinaria canadensis) leaf in late spring. the leaf will continue to photosynthesize for much of the summer.

Pollinated flowers produce a fruit capsule that develops under the protection of the expanding leaves.  The capsule splits open when it’s ripe, making the seeds inside available for dispersal.  Like many early spring blooming wildflowers, Bloodroot has evolved to partner with animals, in this case ants, to disperse its seeds.  Each seed has  a packet of food called an elaiosome attached.  The elaiosome’s chemical make-up mimics the nutrition of insects, a preferred food for ants.  The ants take the seeds to their homes, where they eat the elaiosome and discard the seed, effectively planting it.

Both the common name, Bloodroot, and the genus, Sanguinaria, refer to the color of the sap found in the plants’ foliage and rhizomes (the plants’ underground parts).  This sap contains chemicals with a narcotic effect that Bloodroot produces to protect itself from herbivores. This is a common and highly effective strategy of the Poppy (Paperaceae) family, of which Bloodroot is a member.  As a result, Bloodroot does well even where there is serious deer pressure.

Native Americans have used Bloodroot for many medicinal purposes.  One of the chemical constituents of Bloodroot, sanguinarine, has also been used commercially in toothpaste and mouthwash to help prevent gingivitis. The red sap is also used as a dye.

Bloodroot can be found in rich, deciduous woods throughout much of the eastern two-thirds of the United States and Canada.  Look for it and other spring wildflowers along a wooded trail near you!

Bloodroot (Sanguinaria canadensis)

Related Posts

Hepatica’s Survival Strategy

A Carpet of Spring Beauty, Woven by… Ants!

A Tale of Two Spring Beauties

Dutchman’s Breeches and Squirrel Corn

Resources

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

Gracie, Carol.  Spring Wildflowers of the Northeast. 2012.

Hoffmann, David.  Medical Herbalism.  2003.

Illinois Wildflowers

Lady Bird Johnson Wildflower Center

Native American Ethnobotany Database

 

 

 

A Winter Show-off

My first encounter with Round-headed Bush Clover (Lespedeza capitata) was in late fall when the warm brown seed heads caught my eye.

Round-headed Bush Clover (Lespedeza capitata)

Throughout fall through winter, this plant is at its most dramatic, easily compelling attention away from nearby vegetation.

Round-headed Bush Clover (Lespedeza capitata)

When in bloom, Round-headed Bush Clover’s appearance is much more subtle, blending in with the grasses, Mountain Mints, asters, goldenrods and other plants that may share its territory.

Round-headed Bush Clover (Lespedeza capitata)

Round-headed Bush Clover has dense clusters, or heads, of small white flowers.  ‘Capitata’ in the scientific name means ‘growing in a dense head’, reflecting this arrangement.  The upper petal of each flower has a bit of an art deco vibe – they’re smudged with pink at the throat with ray-like veins radiating above.  This display may look delicately pretty to us, but to the many bees that visit the flowers it’s a beacon advertising food availability.

Round-headed Bush Clover (Lespedeza capitata)

The flower petals are protected by hairy sepals, green when the flowers are in bloom, then turning deep brown for fall and winter.  It’s these brown sepals that provide the eye-catching winter display.   If Round-headed Bush Clover’s strategy for enticing pollinators to visit is successful, dry (not fleshy) fruits will be tucked inside the dried sepals.

Hairs on plants are often an adaptation to protect the plant from being eaten, or too discourage free-loaders from stealing nectar when the flowers are blooming.  For example, ants visit flowers for nectar but rarely help with pollination because they are not a good anatomical match for the flowers’ reproductive structures, nor do the ants have the type of surface to which pollen might adhere.  The hairy sepals surrounding the flowers are likely to discourage ants from foraging the flowers, preserving the nectar for more effective flower visitors.

Round-headed Bush Clover (Lespedeza capitata)

Round-headed Bush Clover has three-part compound leaves, an arrangement that is common with clovers. It grows to a height of two to five feet (.6 – 1.5 meters).  Although the plant is somewhat shrubby-looking, it is herbaceous, that is, its above ground parts die back in the winter, and new shoots emerge from its roots for the next growing season.

In addition to offering food for pollinators, Round-headed Bush Clover is a food plant for the caterpillars of several butterflies, including the Silver-spotted Skipper,

Silver-spotted Skipper ovipositing (laying an egg) on Pokeweed (Phytolacca americana). Silver-spotted Skippers have the unusual habit of laying their eggs on plants near their caterpillar food plants.

Eastern-tailed Blue,

Eastern-tailed Blue on Butterflyweed (Asclepias tuberosa)

Gray Hairstreak,

Gray Hairstreak on White Clover (Trifolium repens)

Southern Cloudywing, Northern Cloudywing, Confused Cloudywing, Hoary Edge, and the Io Moth.

Dark-eyed Juncos, Mourning Doves, Bobwhites and Wild Turkeys are among the birds that may eat the seeds when they are available.

Dark-eyed Junco

Round-headed Bush Clover is native in most of the eastern two-thirds of the United States, and in Ontario and New Brunswick in Canada.  Searching for it in a meadow near you gives you a reason to go out for a winter walk!

Round-headed Bush Clover (Lespedeza capitata)

Resources

Beadle, David; Leckie, Seabrooke. Peterson Field Guide to Moths of Northeastern North America. 2012.

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

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

Stearn, William T. Stearn’s Dictionary of Plant Names.  1996

Illinois Wildflowers

Natural History Museum Hosts Database

USDA NRCS Plants Database