Wildflower Fruits: Diversity of Dispersal

Many of our showy summer flowers are forming fruits.  Now and into fall is a fascinating time to watch how plants disperse their seeds. Many birds, small rodents, even ants depend on them for food: eating them on the spot or stashing them for later, often leaving some behind to sprout. Look at the designs of the flying fruits or how others stick to animals or float away.  There are so many ways plants have evolved to give their off-spring a chance to grow in the future.

For beginning plant enthusiasts, here is a bit botany to help explain what exactly are fruits and seeds. To start, fruits mature from pollinated flowers.


Image from: (http://stickrathbiology.yolasite.com/resources/28%20Plant%20Anatomy%20Lab.pdf)

The ovary is nestled inside the petals, protects the eggs/ovules, and transforms in shape, size, color, and texture to form a fruit. The fertilized eggs/ovules become seeds which include a seed coat surrounding a tiny embryo and extra stored food—think about a bean seed as an example.

Bean seed embryo — Science Learning Hub

(Bean seed diagram from: https://www.sciencelearn.org.nz/)

Fruits enable the seeds to move beyond the shadow of their parents—literally.  Fruits are dispersed by wind, water, animal, expulsion, and gravity using all sorts of mechanisms.

Sticky GeraniumGeranium viscossissimum – catapult their seeds. A geranium fruit has five compartments (carpels) – each with a seed. As each carpel dries, it will spring upright ejecting the seed.


Parsley FamilyApiaceae – One key characteristic of this family is that the flowers, then fruits, are arranged in umbels with all branches coming from a central point like ribs of an umbrella. Members of this family are often called umbellifers.  Relatives include parsley, celery, dill, anise, coriander and more.


The seeds are “schizocarps”—meaning split fruits.

Glossary | FNWD

(Schizocarp Diagram from: https://idtools.org/id/fnw/glossary.php)

Watch over the next few weeks to see how the fruits dry and divide.  Birds, mammals, gravity, and wind can all play a part in dispersal.

Cow ParsnipHeracleum sphondylium/maximum – is the largest member of this family in the U.S. and is found along streams and moist meadows.


Its schizocarps enlarge and flatten and develops a beautiful pattern before they break apart.


A tourist asked if Cow Parsnip gave a rash like Giant Hogweed (Heracleum mantegazzianum), which is invading the East Coast. I did some research. The genus Heracleum contains compounds (flurocoumarins) in the hairs and sap that make our skin very sensitive to ultraviolet light. If we brush against the plants, get the oils on us, and then we are exposed to sun, we can get a nasty sunburn or blisters (phytophotodermatitis).  While each person reacts differently, it seems our native Cow Parsnip is not as toxic as Giant hogweed, which is native to the Caucasus Mountains bordering Southern Russia and Georgia and can grow well over 8’ tall. I have not gotten a rash from this plant.


The 3-4’ Sharptooth AngelicaAngelica arguta – was still blooming the third-week in August in moist higher elevations. The variety and number of pollinators on different umbels was impressive: flies, hornets, bees.


Various insect species can easily land and crawl about spreading pollen and sucking up nectar. Angelica fruits are ribbed, vs. flattened, and will also split in two.


YampahPerideridia montana – is still producing its lacey umbels of flowers in some locations, such as sage flats and burned-over areas at low elevations around the valley. Stems are about 1-2 1/2′ high with mostly linear withered leaves.


Some plants are forming tiny schizocarps.

PeriMont_frcu_DtcCrkRd_91713_1_5x5_200Yampah will also begin to store starches into their taproots, which will provide food for grizzly bears. People like to forage on the tasty roots, as well. (Carrots are in the Parsley Family, too).

Western SweetrootOsmorhiza occidentalis – grows 2-3′ high. The elongate fruits are held up to waist high.


It is easy to sample the 3/4-1″ fruits, which while still green taste like licorice or anise.


The fruit of its less robust relative – Sweet CicelyOsmorhiza berteroi – has a sharp point and hairs to attach to passing socks or fur.


Colorful Berries:

Clasping TwistedstalkStreptopus amplexicaulis – has branched stems that typically arch 2-3′ high over streams or in wet sites. Leaves have parallel veins and clasp the stalks which zig-zag slightly. At each leaf node, formerly a yellow flower hung from a curled pedicel.  Now a single red, ovoid fruit hangs from the same kinked stem. Who knows why the pedicels do this?


False Solomon’s sealMaianthemum racemosum – had a spray (technically a panicle) of small white flowers at the end of the arching branches in June. Now each flower has produced speckled fruits that can be scarfed up by robins, thrushes, chipmunks, and such.


FairybellsProsartes trachycarpa – also bloomed in June with usually two pale yellow, lily-like flowers at the tips of the branches. The three-parted ovary has swelled into a somewhat lumpy, brilliant-red, velvet-like fruit which stands out above the bright green leaves. This arrangement is a clear advertisement to birds and mammals to come and get it.


Our local members of the Pea Family – Fabaceae – have typical pea-like flowers and pod-like fruits. The pod was the ovary deep inside the bright petals, and the seeds were the eggs inside the ovary (see diagrams above). While we think of string beans and snap peas as vegetables, they are fruits botanically speaking.

The blue pea-like flowers of Lupines Lupinus sp. – are still blooming in some sites, but most have already formed thick, hairy pods–technically a “legume”. (For botany nerds: legumes are single carpels that split down two sides–compare to “follicle” below.) Many pods have dried, twisted, and propelled their seeds – some up to 10’! Plants and seeds contain poisonous alkaloids in varying amounts, and while most wildlife can eat the plants and seeds, they are toxic to domestic livestock, especially sheep, and to people.


For those who wish to propagate lupine from seed, it is easiest to plant ripe seed in place and let nature breakdown the tough seed coat over the winter.  It is best not to transplant the young or older plants as they have long taproots that get broken, setting the plant back.  One helpful link: https://www.blogs.nrcs.usda.gov/Internet/FSE_PLANTMATERIALS/publications/wapmcmt7129.pdf

If pollinated, each magenta pea-like flower of Western SweetvetchHedysarum occidentale – will produce a string of loments: essentially flattened pods. The winged segments–each with one seed–split off and are likely caught upon the wind to be transported to new ground.



The Buttercup Family has several variations:

Colorado ColumbineAquiligia coerulea – has 5 separate dry “follicles” each containing numerous seeds. Follicles split down one side. These follicles derive from separate carpels, typical of some members of the Buttercup Family.


The blue flowers on the 5-6′ stalks of  Tall DelphiniumDelphinium occidentale – bloom from bottom to top and out the side branches.  So the fruits ripen from bottom to top as well. It is interesting to observe that not all the flowers are pollinated–some just fade away.


After the blue tubular flowers are pollinated, the 3 distinct carpels enlarge to form 3 distinct follicles with many seeds inside. It is easy to see the similarity of these fruits to Columbine.


A third member of the family, Fendler Meadow Rue – Thalictrum fendleri – is usually found in the forest. Meadow Rue plants are male and female and are wind pollinated.  The “achenes” form only on female plants and likely just fall to the ground or perhaps a Junco or other bird comes and gets the fruits.


Its relative Sugar Bowls  – Clematis hirsutissima – has individual achenes that are attached to long hairy stigmas that help them fly off on the wind.  This plant is often called the Dr. Seuss or Phyllis Diller plant in the summer when it is in its “bad hair day” fruiting phase.


Other dry fruits:

Fern-leaf LousewortsPedicularis bracteosa – sported spires of beaked yellow flowers in early summer. Now the spikes are drying and dry capsules (formed from more than one carpel) are splitting open. Dark seeds are sifting out as the wind waves the stems about.


Bladder Campion –  Silene latifolia – has cups filled with seeds that shake out over time.SileLati_frCalyx_TrCkTr_8.26.18_3_Q2_crp_3x4_200

Leopard LilyFritillaria atropurpurea – has squarrish capsules that shake out seeds:


And perhaps the most pesky dry fruits that catch a ride on our pant legs and socks, as well as our dog’s fur, is Western StickseedHackelia micrantha.  The sharply pronged green to brown small nutlets are often passed unseen but are soon felt as they hitchhike down the trail and even home.


Composites get around:

While many composites or members of the Aster Family produce one-seeded fruits with fluffy parachutes like a dandelion, others have fruits nestled tight in heads.  For instance, Western ConeflowerRudbeckia occidentalis – has its fruits (achenes) standing firm on cone-shaped receptacles waiting for birds, such as Pine Siskins and American Goldfinches, to find them.


As birds avidly eat the fruits, they often dislodge some that fall to the ground. (photo by Susan Marsh):

PISI on RUOC 3 copy_crp_5x5_235

The same dispersal mechanism likely happens in Arrowleaf BalsamrootBalsamorhiza saggitata – with birds prying out the elongate achenes held within sharp protective scales.


Many plants can have more than one dispersal mechanism.  For instance, thistles–both native and introduced–can attract seed eaters which pluck out and therefore loosen fruits which then fly off upon the wind.


Keep on watching.  There are many more fruits and seeds to come, each with fascinating dispersal strategies!

Frances Clark, Wilson, WY

P.S. As alwasy we appreciate corrections and comments sent to us at tetonplants@gmail.com.  Also, look at the recent posting “Culmination of Composites–August 2020” for flowers that will soon be shedding wind-blown seeds.

A Culmination of Composites–August 2020

A variety of composites – members of the Aster Family (Asteraceae) – have been in bloom since the beginning of August, and many continue to bloom into the end of the month. Composites are at their flowering peak when most insects are also at the climax of their annual life cycles.  For instance, butterflies have developed from eggs to larvae to chrysalises to beautiful adults over the course of the summer.  They depend on nectar in their final days. These and many other insects are laying eggs in host plants for another year. August is a great time to look at both flowers and insects!

Ai_ButFly_Frit on Rabbitbrush_bySMarsh_8.23.20_5x5_250_Q1.jpg

(Photo of Fritillary on Rubber Rabbitbrush by Susan Marsh)

As some of you already know, the Aster family is one of the largest plant families in the world. The basic characteristic of the family is that many individual flowers are gathered together on a platform and surrounded by protective bracts to form a “head” that looks like a single flower—a “composite” flower.


(Image from: https://cronodon.com/BioTech/asteraceae.html)

From this simple flower “plan”, the variations multiply.  The 5-parted flowers can be “ray” flowers with their petals fused into a single showy petal-like structure, or less obvious “disc” flowers with the petals fused into a tube.  Heads can have a combination of both ray flowers and disc flowers, or all disc or all ray flowers and come in various sizes and colors.  The surrounding protective bracts are helpful ID features and fruits have distinctive dispersal mechanisms, as well.


Ecologically, members of the Aster Family offer an abundance of nectar and pollen in one location over an extended period of time: individual flowers boom and fade sequentially.  Also, the often wide-open arrangement enables many different insects to land and probe, dab, lap, and suck nectar and gather pollen accidentally or on purpose before they seek more rewards on the next similar flower. Insects munch on developing or ripened seeds, lay their eggs in flowers or stems, and otherwise make use of these often abundant plants.  Birds and small rodents are common dispersers of the fruits.

With this introduction, here are some common composites that have been blooming for the past couple of weeks.  We have provided some ID tips to help you look more closely.

Showy GoldeneyeVigueria multiflora – has several cheerful yellow flower heads waving about on thin 2-3’ stems adorned with oblong opposite leaves. If you look, you will see that there is a shift in hue from a lighter yellow to a darker tone toward the center of the “golden eye”.  Insects with their UV vision likely see this as a distinct bulls-eye.  Showy Goldeneyes are common along park roadsides and into dry meadows.


Curleycup GumweedsGrindelia squarrosa – are sturdy, dense, foot-high plants found along park roads.  The bright-yellow, almost glowing, flower heads have distinctive sticky bracts which curl under.


You are likely to smell TarweedMadia gomerata – before you see it.  An acrid odor arises from around your feet where you have stepped on it. You may wonder. “Where are they paving the road?”  Usually only a few inches high (although I have seen it 18” tall), these resinous plants have tiny oily hairs and small linear leaves. Heads have only a couple of ray flowers. This annual is mostly in disturbed sites and is considered a native weed.


Western ConeflowerRudbeckia occidentalis – grows to 4-6’ high.  The large oval to triangular leaves can reach 10” long and alternate up sturdy straight stems.  At the top are brown-black “cones” surrounded by a collar of green bracts.  The “cone” is the “receptacle” or platform for the many tiny disc flowers. Flowers start blooming from bottom—look for the yellow pollen, and spiral up over a couple of weeks to the top. These tiny flowers attract dozens of pollinators! In one large meadow with thousands of coneflowers, I witnessed bees on one-in-20 cones, often more than 1 bee/flower head, and myriad Milbert’s Tortoiseshell butterflies, all gathering pollen and nectar from these abundant “disc” flowers. Later Pine Siskins and other birds will pluck out the seeds. Again, it is likely the flowers project a UV signal that our human eyes cannot detect.


Rayless ArnicaArnica parryi – is also composed of only “disc” flowers, unlike its much more admired relatives which have showy heads of both ray and disc flowers.  Note the bracts are even in size and the leaves are opposites, as in all arnicas.


Canada GoldenrodSolidago canadensis – is perhaps one of the most important flowers for biodiversity in the U.S. according to Dr. Doug Tallamy of the University of Delaware*.  Abundant from East to West, the 2-3’ flowers colonize large areas. Here they spread best in relatively moist soils.  By mid-August, they produce hundreds of tiny yellow flower heads that attract pollinators of all sorts. Other insects burrow into the stems to over-winter or lay eggs. Many birds depend on the bugs for their nutrition.


Goldenrod is not responsible for our allergies: Their showy flowers have evolved to attract insects to deliver the heavy pollen. However, often unseen nearby are plants that rely on wind to disperse pollen—such as grasses and soon sagebrush. Wind-dispersed pollen is much lighter and can lodge in nostrils and eyes.

Oregon DaisyErigeron speciosus – is one of a few showy blue daisies (vs asters below) that bloom into late summer. Typically, Erigerons have many, often narrow, ray flowers surrounding many yellow disc flowers. Even-sized bracts ring the flower heads like a palisade fence. One- to three-inch oval leaves alternate up the stem. These plants are showy and sturdy enough to be good garden plants!


Leafybract AsterSymphyotrichum foliaceum/cusickii – is 1-3’ tall, has large alternate leaves which can be 4-6” long near the base, smaller near the top.  The blue flower heads are surrounded by “leafy” bracts of different sizes which are arranged roughly like shingles on a roof. This species comes in various varieties, but here we group them as one.


Pacific AsterSymphyotrichum ascendens – is a tough 1-2’ plant that seems to thrive along roadsides.


The light-blue flower heads have tidy bracts that look like well-placed shingles. The narrow leaves have veins that form elongate patterns which help determine this particular species.


Engelmann AsterEucephalus engelmannii – is readily identified by its 4-5′ stems cloaked by alternating 4-6” leaves that retain their size as they spiral up the stem.


The large white flower heads are surrounded by a distinctive set of bracts. This is a very common plant in aspen groves and higher elevation meadows.


Thickstem AsterEurybia integrifolia – thrives from sagebrush flats in the valley floor up to 9,000’ subalpine meadows. Stems are not only thick and sticky but have a bit of a zig-zag at the nodes where each leaf alternates up the stem. Deep purplish-blue flowers are protected by hefty protruding bracts covered by sticky hairs. All sorts of insects come in to pollinate them and others try to eat them…sometimes getting stuck in the forest of glutinous hairs.


Musk Thistle – Carduus nutans – is a monster of a composite.  This invasive exotic can grow up to 7’ tall sporting multiple stems with elongate lobed leaves, all armed with ferocious spines. However, it is hard not to admire the 2+” flower heads for their gorgeous color. Insects galore come to gather pollen and nectar. And recently I have witnessed pine siskins and a downy woodpecker relish the fruits.


Each fruit (technically an “achene”–a dry case with one seed inside – like a sunflower seed) is attached to a sail of fluff. Hundreds, thousands, of fruits are dispersed by the wind, seeding into pastures and along trail edges, where new plants sprout up quickly to outcompete our natives. USDA has designated  musk thistle a noxious weed. Our local Teton County Weed and Pest https://www.tcweed.org/ can help land owners control it on their property.


Rabbitbrushes lure myriad butterflies, bees, and flies at the end of the growing season when nectar and pollen supplies are shriveling up.  Both species do well on dry, often disturbed sites such as roadsides, construction sites, and cliff edges.

Rubber RabbitbrushEricameria nauseosa – has a white sticky sap that has been investigated as a form of rubber—hence its common name. “Nauseosa” likely comes from the very strong fragrance and taste of  broken twigs. Twigs are typically covered in a layer of fine white hairs – tomentum – and are rather flexible. Leaves are very narrow up to 4” long on shrubs that can be 2-4’ high and wide. The many elongate disc flowers attract a hubbub of late summer pollinators.


Douglas RabbitbrushChrysothamus viscidifolus – is best identified by its twisted leaves with resinous or “viscid” glands.


The stems do not have hairs. It comes in several varieties, but this is the most common one I have seen. Typically shrubs are only a foot or so high.


While most of these flowers will be fading in color, another composite is just beginning to bloom–Sagebrush!  However, their flowers are wind-pollinated and, therefore, often go unnoticed.

Many of these same flowers and more are featured on past Teton Plants posts.  Look into the TetonPlants.org archives for more images and info.

Enjoy botanizing!

Frances Clark, Wilson, WY

P.S. As always we appreciate any corrections or suggestions.  Email us at tetonplants.org for your comments and to be placed on our email list.