mil · wenty-four species of milkweeds are found in illinois. they grow in a variety of habitats....

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bluevine Ampelamus albidus sand milkweed Asclepias amplexicaulis poke milkweed Asclepias exaltata tall green milkweed Asclepias hirtella butterfly-weed Asclepias tuberosa swamp milkweed Asclepias incarnata oval milkweed Asclepias ovalifolia narrow-leaved green milkweed Asclepias stenophylla horsetail milkweed Asclepias verticillata green milkweed Asclepias viridiflora green-flowered milkweed Asclepias viridis variegated milkweed Asclepias variegata white swamp milkweed Asclepias perennis showy milkweed Asclepias speciosa This poster was made possible by: Illinois Department of Natural Resources Division of Education with assistance from the Division of Natural Heritage Plants are not shown in equal proportion to actual size. Classification and nomenclature are based on the follow- ing source. Other authors may differ on the classification and nomenclature associated with these plants. Mohlenbrock, R. H. 2014. Vascular flora of Illinois. Southern Illinois University Press, Carbondale. 544 pp. wenty-four species of milkweeds are found in Illinois. They grow in a variety of habitats. Most milkweeds have leaves in pairs or in whorls of four and sap that is white and milky. Milkweed flowers develop in an umbel at the stem tip or in the leaf axils in the upper part of the plant. Color varies with the species, but varieties include white, pink, red, orange, green, red-purple and purple-pink flowers. Each flower has five petals and five sepals that bend away from the other flower structures and a five-parted cup that supports five horns and hoods. Pollinators visit milkweed flowers for their nectar.The fruit that develops from the fertilized flower is a pod that contains seeds attached to floss. A close relationship exists between monarch butterflies ( Danaus plexippus) and milkweed plants. Monarch larvae only eat milkweed plants of the genera Asclepias and Ampelamus. If there are no milkweeds plants, there will be no monarchs. As of 2016, five species of milkweeds are listed as endangered in Illinois with one of those species also listed as threatened federally. Species List Kingdom Plantae Division Magnoliophyta Class Magnoliopsida Order Gentianales Family Asclepiadaceae bluevine Ampelamus albidus sand milkweed Asclepias amplexicaulis poke milkweed Asclepias exaltata tall green milkweed Asclepias hirtella swamp milkweed Asclepias incarnata woolly milkweed Asclepias lanuginosa Mead’s milkweed Asclepias meadii oval milkweed Asclepias ovalifolia white swamp milkweed Asclepias perennis purple milkweed Asclepias purpurascens whorled milkweed Asclepias quadrifolia endangered in Illinois endangered in Illinois, threatened federally showy milkweed Asclepias speciosa narrow-leaved green milkweed Asclepias stenophylla prairie milkweed Asclepias sullivantii common milkweed Asclepias syriaca butterfly-weed Asclepias tuberosa variegated milkweed Asclepias variegata horsetail milkweed Asclepias verticillata green milkweed Asclepias viridiflora green-flowered milkweed Asclepias viridis climbing milkweed Matelea decipiens * climbing milkweed Matelea gonocarpos * climbing milkweed Matelea obliqua * black swallow-wort Vincetoxicum nigrum * * Photo found on reverse side. Photo © Christopher D. Benda Photo © Christopher D. Benda Photo © Gerald D. Tang Photo © Gerald D. Tang Photo © Christopher D. Benda Photo © Christopher D. Benda Photo © Christopher D. Benda Photo © Christopher D. Benda purple milkweed Asclepias purpurascens Photo © Jan Sundberg Photo © Jan Sundberg whorled milkweed Asclepias quadrifolia Photo © Christopher D. Benda Photo © Christopher D. Benda Photo © Gerald D. Tang Photo © Gerald D. Tang Photo © Christopher D. Benda Photo © Christopher D. Benda Photo © Christopher D. Benda Photo © Christopher D. Benda Photo © Christopher D. Benda Photo © Christopher D. Benda Photo © Jan Sundberg Photo © Jan Sundberg Photo © Gerald D. Tang Photo © Gerald D. Tang prairie milkweed Asclepias sullivantii Photo © Joe Bauer, IDNR Photo © Joe Bauer, IDNR common milkweed Asclepias syriaca Photo © Jan Sundberg Photo © Jan Sundberg Photo © Jan Sundberg Photo © Jan Sundberg Photo © Adele Hodde, IDNR Photo © Adele Hodde, IDNR Photo © Adele Hodde, IDNR Photo © Adele Hodde, IDNR woolly milkweed Asclepias lanuginosa Photo © Gerald D. Tang Photo © Gerald D. Tang Mead’s milkweed Asclepias meadii Photo © Carol Freeman Photo © Carol Freeman Photo © Gerald D. Tang Photo © Gerald D. Tang T Illinois Milkweeds Milkweeds

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Page 1: Mil · wenty-four species of milkweeds are found in Illinois. They grow in a variety of habitats. Most milkweeds have leaves in pairs or in whorls of four and sap that is white and

bluevine Ampelamus albidus

sand milkweed Asclepias amplexicaulis

poke milkweed Asclepias exaltatatall green milkweed Asclepias hirtella

butterfly-weed Asclepias tuberosa

swamp milkweed Asclepias incarnata

oval milkweed Asclepias ovalifolia

narrow-leaved green milkweed Asclepias stenophylla

horsetail milkweed Asclepias verticillata green milkweed Asclepias viridiflora green-flowered milkweed Asclepias viridisvariegated milkweed Asclepias variegata

white swamp milkweed Asclepias perennis showy milkweed Asclepias speciosa

This posterwas made possible by:

Illinois Department ofNatural Resources

Division of Educationwith assistance from theDivision of Natural Heritage

Plants are not shown in equal proportionto actual size.

Classification and nomenclature are based on the follow-ing source. Other authors may differ on the classificationand nomenclature associated with these plants.Mohlenbrock, R. H. 2014. Vascular flora of Illinois.Southern Illinois University Press, Carbondale. 544 pp.

wenty-four species of milkweeds are found in Illinois. They grow in avariety of habitats. Most milkweeds have leaves in pairs or in whorlsof four and sap that is white and milky. Milkweed flowers develop inan umbel at the stem tip or in the leaf axils in the upper part of theplant. Color varies with the species, but varieties include white, pink,red, orange, green, red-purple and purple-pink flowers. Each flower

has five petals and five sepals that bend away from the other flower structures and afive-parted cup that supports five horns and hoods. Pollinators visit milkweed flowers for their nectar. The fruit that develops from the fertilized flower is a pod thatcontains seeds attached to floss. A close relationship exists between monarch butterflies (Danaus plexippus) and milkweed plants. Monarch larvae only eat milkweedplants of the genera Asclepias and Ampelamus. If there are no milkweeds plants, therewill be no monarchs. As of 2016, five species of milkweeds are listed as endangeredin Illinois with one of those species also listed as threatened federally.

Species ListKingdom PlantaeDivision MagnoliophytaClass MagnoliopsidaOrder GentianalesFamily Asclepiadaceae bluevine Ampelamus albidussand milkweed Asclepias amplexicaulispoke milkweed Asclepias exaltatatall green milkweed Asclepias hirtellaswamp milkweed Asclepias incarnatawoolly milkweed Asclepias lanuginosaMead’s milkweed Asclepias meadiioval milkweed Asclepias ovalifoliawhite swamp milkweed Asclepias perennispurple milkweed Asclepias purpurascenswhorled milkweed Asclepias quadrifolia

■ endangered in Illinois■ endangered in Illinois, threatened federally

showy milkweed Asclepias speciosanarrow-leaved green milkweed Asclepias stenophyllaprairie milkweed Asclepias sullivantiicommon milkweed Asclepias syriacabutterfly-weed Asclepias tuberosavariegated milkweed Asclepias variegatahorsetail milkweed Asclepias verticillatagreen milkweed Asclepias viridifloragreen-flowered milkweed Asclepias viridisclimbing milkweed Matelea decipiens *climbing milkweed Matelea gonocarpos *climbing milkweed Matelea obliqua *black swallow-wort Vincetoxicum nigrum *

* Photo found on reverse side.

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purple milkweed Asclepias purpurascens

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whorled milkweed Asclepias quadrifolia

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prairie milkweed Asclepias sullivantii

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common milkweed Asclepias syriaca

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woolly milkweed Asclepias lanuginosa

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Mead’s milkweed Asclepias meadii

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I l l i n o i s

MilkweedsMilkweeds

Page 2: Mil · wenty-four species of milkweeds are found in Illinois. They grow in a variety of habitats. Most milkweeds have leaves in pairs or in whorls of four and sap that is white and

What are Milkweeds?What are Milkweeds?

Many insects and some bats are pollinators. Hummingbirds, some monkeys, some rodents and otheranimals are pollinators, too. Humans can be pollinators as well! Not all plants need pollinators, but

about 85 percent of them do.These plants would not be able toproduce seeds without pollinators.

Pollen contains the malereproductive cells. For fertiliza-tion to occur, pollen must reachthe female reproductive cells ofthe plant. Animals that movepollen are called pollinators.They are important to bothnative plants and agriculturalcrops. In the United States, morethan 150 crop plants require pol-linators. Pollinators help insurethat we have food to eat. It isestimated that one of every threebites of food that we eat is relat-ed to the actions of pollinators.Pollinators provide more than $10 billion in economic value annually in the United States, but they arealso vital to the existence of native plants and all of the animals that feed on them.

Pollinators are in decline worldwide. Habitat loss, pesticide use, competition from nonnative speciesand diseases are killing pollinators. We can help pollinators by providing habitat in pollinator gardens.Native milkweeds are important components of pollinator habitats.• A good pollinator garden has native plants that attract and support native bees and other pollinators at

all stages of their life cycle. Included should be flowers that provide pollen and nectar from early springthrough late fall. Add flowering trees. Use plants with flowers of varying shapes. Add bunch grasses tothe planting for nest sites for ground-nesting bumble bees. Eliminate or minimize the use of pesticides.

• A butterfly garden is a massed planting of butterfly favorite plants in a sunny location that provides foodand shelter for all stages of butterfly life. Prairies are the original butterfly gardens. A prairie garden, usu-ally part of a home/school landscape, is of variable size and utilizes native wildflowers and grasses oftenorganized according to height, color, bloom time, etc.

• Prairie Establishment and Landscaping – This publication from the IDNR offers information about select-ing, establishing and maintaining a prairie. It also includes possible sources for native seeds and plants.You can order, view or download it at https://www.dnr.illinois.gov/publications. Other publicationssuch as the Butterfly Gardens brochure are also available through this Web site.

• Try to obtain plants or seeds that were developed within a 50-mile radius of where you live. If that is notpossible, select plants and seeds from a source in Illinois or one of Illinois’ border states.

• There is much information about developing gardens using native plants at https:// www. dnr. illinois.gov/ education/Pages/GrantsSHAG.aspx.

Pollinator GardensPollinator Gardens

Aclose relationship exists between monarch butterflies (Danaus plexippus) and milkweed plants.Monarchs have a life cycle that includes four stages: egg; larva; pupa; and adult. Monarch larvae feed

exclusively on milkweed plants of the genera Asclepias and Ampelamus. If there is no milkweed, there will be no monarchs. Female monarchs usually lay their eggs only on milkweed plants so that the larvae willhave an immediate food source when they hatch from the egg. They find milkweeds by using visual andchemical cues. Monarch adults often visit milkweed flowers for the nectar they produce, but they are notrestricted to these plants as the larvae are.

Two invasive milkweed species that are native to Europe have been growing in North America since the1800s. Black swallow-wort (Vincetoxicum nigrum) can be found in Illinois. Pale swallow-wort (Vincetoxicumrossicum) grows in Illinois’ neighboring states of Indiana, Wisconsin and Missouri and may also be present inIllinois. Problems occur when female monarchs lay eggs on these two species. They are known as “dead-end”hosts. Monarch larvae cannot eat them. The larvae hatched from eggs on these plants will die. Experimentshave shown that female monarchs will lay eggs on these nonnative plants even when native milkweeds arepresent in the same area. These two swallow-wort species also crowd out native milkweed plants, reducingnative plant biodiversity and biodiversity of the animals that depend upon the native milkweeds. Both ofthese swallow-wort species are herbaceous vines with clear sap and opposite leaves. Black swallow-wort flow-ers are dark purple to black. Pale swallow-wort flowers range from pink to burgundy. Their seedpods containseeds that are similar in appearance to those of common milkweed (Asclepias syriaca).

What can be done to stop the invasive swallow-worts? The first step is to successfully identify theplants. They are easiest to identify when they are blooming. Plants in full sun produce fruits sooner thanthose in shaded areas and should be eradicated first to reduce seed dispersal. When swallow-wort has beenremoved, it is important to plant the area with native plants quickly so that more invasive species do notmove in. Digging, cutting, mowing and seedpod removal can help control these plants. Cutting should beused in combination with other techniques, since cutting alone can lead to resprouting. Prescribed burnscan help to keep these plants out of an area after they have been removed by other methods. Appropriatedisposal of all roots, root parts and seeds is required to ensure that they do not grow. Bag them and eitherburn them or dispose of them in a landfill. Do not put them in a compost pile.

Milkweeds& MonarchsMilkweeds& Monarchs

BibliographyBibliography

Illinois MilkweedsIllinois Milkweedsbluevine Ampelamus albidusHeight/Length: up to 15 feet long Leaf Arrangement: oppositeSeedpod Length: up to four inchesFlower Position: leaf axilsFlower Color: white to pink-whiteFlowering Time: July through SeptemberIllinois Distribution: mainly in the southerntwo-thirds of the stateIllinois Conservation Status: commonOther: Bluevine, also known as sandvine andhoneyvine, is a vining milkweed that does nothave milky sap. It grows in moist woods,fields, thickets, roadsides and disturbed soil.

sand milkweed Asclepias amplexicaulisHeight/Length: one to three feetLeaf Arrangement: oppositeSeedpod Length: four to six and one-half inchesFlower Position: stem tipFlower Color: green with purple tintsFlowering Time: May through JulyIllinois Distribution: northern three-fourths ofIllinois and rarely in the rest of the stateIllinois Conservation Status: commonOther: Sand milkweed is also known as blunt-leaved milkweed. The leaves are wavyand clasp the stem. Both the stem and the leaf veins are pink to red. It grows in dry sand prairies.

poke milkweed Asclepias exaltataHeight/Length: three to six feetLeaf Arrangement: oppositeSeedpod Length: up to six inchesFlower Position: leaf axilsFlower Color: white flowers that may havepurple or green tintsFlowering Time: June through JulyIllinois Distribution: statewideIllinois Conservation Status: commonOther: Poke milkweed grows along the edges of woods. The flowers droop. The leaves of thisspecies are stalked and pointed at each end.

tall green milkweed Asclepias hirtellaHeight/Length: up to three feetLeaf Arrangement: alternateSeedpod Length: about four inchesFlower Position: leaf axils Flower Color: pale green with the petalswhite-edged or purple-spotted at the tipFlowering Time: May through AugustIllinois Distribution: statewideIllinois Conservation Status: commonOther: This species grows in prairies, especially sand prairies, and fields. The leaves are narrow, about three-fourths inchwide or less.

swamp milkweed Asclepias incarnataHeight/Length: up to five feetLeaf Arrangement: oppositeSeedpod Length: about five inches Flower Position: stem tipFlower Color: pink

Flowering Time: June through AugustIllinois Distribution: statewideIllinois Conservation Status: commonOther: The leaves are lance-shaped, up to four inches long and up to one inch wide.This species grows in swamps, wet ditches and wet meadows.

woolly milkweed Asclepias lanuginosa Height: less than one footLeaf Arrangement: alternateSeedpod Length: about four inchesFlower Position: stem tipFlower Color: pale green, sometimes withpurple on the backFlowering Time: May through JuneIllinois Distribution: northern one-sixthIllinois Conservation Status: endangered Other: Woolly milkweed grows in rocky orgravel prairies where it reaches its easternrange limit. Its populations have been reducedby overgrazing and gravel mining.

Mead’s milkweed Asclepias meadii Height: less than two feet Leaf Arrangement: oppositeSeedpod Length: about four inchesFlower Position: stem tipFlower Color: white to pale greenFlowering Time: May through JuneIllinois Distribution: southern, northeasternand central sections Illinois Conservation Status: endangered inIllinois and threatened federallyOther: Mead’s milkweed can be found atsome mesic prairies and sandstone bluffs, butit is not common anywhere in the state or inits national range. The flower cluster nodsdownward.

oval milkweed Asclepias ovalifolia Height: about 20 inches Leaf Arrangement: oppositeSeedpod Length: up to three inchesFlower Position: stem tip and leaf axilsFlower Color: white, green-white or pale purple-whiteFlowering Time: May through JuneIllinois Distribution: northeastern one-fourthIllinois Conservation Status: endangeredOther: Also known as dwarf milkweed, thisspecies grows in hill and sand prairies, savan-nas and dry woods. Oval milkweed reaches itssoutheastern range limit in Illinois.

white swamp milkweed Asclepias perennis Height: about two feet Leaf Arrangement: oppositeSeedpod Length: up to two and one-half inchesFlower Position: leaf axilsFlower Color: white or pinkFlowering Time: May through SeptemberIllinois Distribution: southern one-fourth, alongthe Wabash River and in Richland CountyIllinois Conservation Status: commonOther: Also known as aquatic milkweed or

thin-leaved milkweed, this species grows inwet woods, swamps, ditches and on pond andstream banks. Its habitats must be shaded andwet. Seeds do not have tufts of hairs as thoseof other milkweeds and are dependent onwater for dispersal.

purple milkweed Asclepias purpurascens Height: about three feet Leaf Arrangement: oppositeSeedpod Length: up to six inchesFlower Position: stem tip and leaf axilsFlower Color: pink-red or purpleFlowering Time: May through JulyIllinois Distribution: statewideIllinois Conservation Status: commonOther: Purple milkweed grows in woodlandborders and prairies. A single leaf may be upto eight inches long.

whorled milkweed Asclepias quadrifoliaHeight: about two feet Leaf Arrangement: some whorled, some oppositeSeedpod Length: three to five and one-halfinchesFlower Position: stem tipFlower Color: pink, purple or whiteFlowering Time: May through JulyIllinois Distribution: southern two-thirdsIllinois Conservation Status: commonOther: Whorled milkweed, also known asfour-leaved milkweed, has leaves in whorls offour in the middle section of the stem. Upperstem leaves may be in pairs. This speciesgrows in rocky, open woods.

showy milkweed Asclepias speciosa Height: up to three feet Leaf Arrangement: oppositeSeedpod Length: up to three inchesFlower Position: leaf axilsFlower Color: red-purple petals with pinkhoodsFlowering Time: June through AugustIllinois Distribution: a few counties in northern IllinoisIllinois Conservation Status: commonOther: Showy milkweed grows along railroads and in moist areas. This species wasintroduced from the western United States.The flowers are larger than those of othermilkweeds in Illinois.

narrow-leaved green milkweed Asclepiasstenophylla Height: up to three feet Leaf Arrangement: oppositeSeedpod Length: up to five inchesFlower Position: leaf axilsFlower Color: whiteFlowering Time: June through JulyIllinois Distribution: west central Illinois Conservation Status: endangeredOther: This species grows in a few counties in west central Illinois in hill prairies andupland woods along the Mississippi River.Narrow-leaved green milkweed reaches itsnortheastern range limit in Illinois.

prairie milkweed Asclepias sullivantiiHeight: about four feet Leaf Arrangement: oppositeSeedpod Length: three to four inchesFlower Position: stem tipFlower Color: purpleFlowering Time: June through JulyIllinois Distribution: statewideIllinois Conservation Status: commonOther: Although found statewide, prairiemilkweed is much more common in thenorthern two-thirds of the state. It grows inmoist to wet prairies.

common milkweed Asclepias syriaca Height: three to five feet Leaf Arrangement: oppositeSeedpod Length: three to four inchesFlower Position: leaf axils

Flower Color: rose, lavender or purple-brownFlowering Time: May through AugustIllinois Distribution: statewideIllinois Conservation Status: commonOther: The seedpod has a warty, outer cover-ing. Common milkweed grows in prairies,fields and roadsides. It is the milkweed speciesthat many people consider to be a “weed,” asit is familiar and frequently observed.

butterfly-weed Asclepias tuberosa Height: up to three feet Leaf Arrangement: alternateSeedpod Length: up to five inchesFlower Position: stem tipFlower Color: yellow or orangeFlowering Time: May through SeptemberIllinois Distribution: statewideIllinois Conservation Status: commonOther: Unlike most milkweeds, the sap of thisspecies is not milky. Butterfly-weed grows inwoods, fields and dry-to-moist prairies.

variegated milkweed Asclepias variegata Height: up to three feet Leaf Arrangement: oppositeSeedpod Length: up to five inchesFlower Position: stem tip and leaf axilsFlower Color: white with purple centersFlowering Time: May through JulyIllinois Distribution: southern one-fourthIllinois Conservation Status: commonOther: This species grows in rocky woods. It is also known as red-ring milkweed.

horsetail milkweed Asclepias verticillataHeight/Length: one to two feetLeaf Arrangement: whorls ofthree to seven leavesSeedpod Length: three to fourinchesFlower Position: leaf axilsFlower Color: green-whiteFlowering Time: May throughSeptemberIllinois Distribution: statewideIllinois Conservation Status: commonOther: The leaf margins may beslightly rolled. This species grows in dry, rockywoods, dry prairies and fields.

green milkweed Asclepias viridifloraHeight: up to two feet Leaf Arrangement: oppositeSeedpod Length: up to six inchesFlower Position: leaf axils Flower Color: greenFlowering Time: May through AugustIllinois Distribution: statewideIllinois Conservation Status: commonOther: Green milkweed can be found inprairies, sandy soil, gravelly soil and fields.The leaves are often folded up and in along

their edge with a wavy margin. The flowerclusters nod.

green-flowered milkweed Asclepias viridis Height: one to three feet Leaf Arrangement: alternateSeedpod Length: three and one-half to five inchesFlower Position: stem tipFlower Color: green-violetFlowering Time: May through JulyIllinois Distribution: southern one-thirdIllinois Conservation Status: commonOther: Green-flowered milkweed grows inprairies, dry woods and fields.

climbing milkweed Matelea decipiensLength: up to 10 feetLeaf Arrangement: opposite Seedpod Length: up to four inchesFlower Position: leaf axilsFlower Color: maroonFlowering Time: May through JuneIllinois Distribution: Jackson, Saline andWilliamson countiesIllinois Conservation Status: endangeredOther: Also known as oldfield milkvine, thishairy, vining species grows in floodplain forests.

climbing milkweed Matelea gonocarposLength: up to 20 feetLeaf Arrangement: oppositeSeedpod Length: up to five inchesFlower Position: leaf axilsFlower Color: green with purple centerFlowering Time: July through AugustIllinois Distribution: southern one-sixth andWabash County Illinois Conservation Status: commonOther: This species, also known as anglepod,grows in rocky woods. It is a vine.

climbing milkweed Matelea obliquaLength: 10 feet or moreLeaf Arrangement: oppositeSeedpod Length: up to three inchesFlower Position: leaf axilsFlower Color: maroonFlowering Time: May through JuneIllinois Distribution: Hardin, Massac andPope countiesIllinois Conservation Status: commonOther: This vining milkweed is also known asoblique milkvine. It grows in rocky woods.The seedpods have scattered projections.

black swallow-wort Vincetoxicum nigrumLength: up to 6.5 feet Leaf Arrangement: oppositeSeedpod Length: up to three and one-fourthinchesFlower Position: leaf axilsFlower Color: dark purple to blackFlowering Time: June through September Illinois Distribution: northern two-thirds of IllinoisIllinois Conservation Status: commonOther: This species is native to Europe. It is a vining milkweed that grows in a variety of habitats.

Caldwell, W. 2016. Personal communication. Monarch Larva Monitoring Project, University of MinnesotaMonarch Lab, St. Paul, Minnesota.

Herkert, J. E. and J. E. Ebinger, editors. 2002. Endangered and threatened species of Illinois: status and distribution, volume I – plants. Illinois Endangered Species Protection Board, Springfield, Illinois. 161 pp.

Hilty, John. 2002-2016. Illinois wildflowers Web page. http://www.illinoiswildflowers.info/

Illinois Department of Natural Resources. 2010. Biodiversity of Illinois, volume I: aquatic habitats CD-ROM.Illinois Department of Natural Resources, Springfield, Illinois.

Illinois Department of Natural Resources. 2010. Biodiversity of Illinois, volume III: prairie and edge habitatsCD-ROM. Illinois Department of Natural Resources, Springfield, Illinois.

Kirt, R. R. 2000. Prairie plants of the Midwest: identification and ecology. Stipes Publishing L.L.C.,Champaign, Illinois. 137 pp.

Ladd, D. and F. Oberle. 2005. Tallgrass prairie wildflowers. Falcon Press, Guilford, Connecticut. 264 pp.

Mader, E., M. Shepherd, M. Vaughan, S. Hofman Black, and G. LeBuhn. 2011. Attracting native pollinators. Storey Publishing, North Adams, Massachusetts. 372 pages.

Missouri Botanical Garden. 2016. Plant finder Web page http:// www. missouri botanical garden. org/ PlantFinder/.

Mohlenbrock, R. H. 2014. Vascular flora of Illinois. Southern Illinois University Press, Carbondale. 544 pp.

Peterson, R. T. and M. McKenny. 1987. A field guide to wildflowers of northeastern and northcentral NorthAmerica. Houghton Mifflin Company, Boston. 420 pp.

Runkel, S. T. and D. M. Roosa. 2009. Wildflowers of the tallgrass prairie: the upper Midwest. University ofIowa Press, Iowa City. 286 pp.

State of Pennsylvania. 2016. Natural heritage Web page http://www.naturalheritage.state.pa.us/factsheets/12958.pdf.

United States Department of Agriculture, Natural Resources Conservation Service. 2016. Plants databaseWeb page. http://plants.usda.gov/java/

University of Kansas. 2016. Monarch Watch Web page. http://monarchwatch.org

Equal opportunity to participate in programs of the Illinois Department of Natural Resources (IDNR) and those funded by the U.S. Fish andWildlife Service and other agencies is available to all individuals regardless of race, sex, national origin, disability, age, religion or other non-merit factors. If you believe you have been discriminated against, contact the funding source’s civil rights office and/or the Equal EmploymentOpportunity Officer, IDNR, One Natural Resources Way, Springfield, IL 62702-1271; 217/785-0067; TTY 217/782-9175.

Printed by the authority of the State of Illinois 10M - 11/16 IOCI 0200-17

Milkweeds are herbaceous, perennial plants, meaning that they are soft-stemmed plants that die toground level at the end of each growing season but grow back from the roots the next spring. Most

have leaves that are paired on the stem or in whorls of four on thestem, but there are also milkweed plants with leaves alternating on the stem, and those that have so many leaves that it is hard to see apattern. Most of them have sap that is white and milky. Milkweedplants contain cardiac glycosides. These chemicals are poisonous andaffect birds and mammals. Many grazing mammals will not eat milkweeds. The toxicity of milkweeds varies by species, though, andtends to be greater in milkweeds in the southern United States. A fewanimal species have adapted to eating milkweeds and thrive on them.Monarch larvae feed exclusively on milkweeds of the Asclepias andAmpelamus genera. The poisons accumulate in the body of the larvalmonarchs and are retained by the monarch in its transformation tothe adult. They make monarchs unpalatable to many predators.

Milkweed flowers develop in an umbel at the stem tip or in theleaf axils in the upper part of the plant. An umbel has a centralpoint from which a group of flowers all develop. In some milkweedspecies the flowers are arranged in a spherical shape, while in otherspecies the flowers droop. Color varies by species, but milkweedscan be found with white, pink, red, orange, green, red-purple and purple-pink flowers. The flowers are often described as having an hourglass shape. Each flower has fivepetals and five sepals that bend away from the other flower structures. A five-parted cup supports fivesmall horns and hoods. The hoods contain nectar and are arranged around the central flower column. The

flower column has slits in it. Inside each slit is an opening where pollen (containing male reproductivecells) must be delivered to fertilize the egg and start the development of a new milkweed plant. Also in

each slit is the pollinarium that contains the pollen in packets.Pollinators, including adult monarch butterflies (Danaus

plexippus), visit milkweeds for their nectar. Nectar is a sweet solutionproduced by flowers to attract pollinators. Milkweeds have a uniquesystem for pollen transfer. When an insect visits a milkweed flower todrink nectar, its leg, antennae or bristles can slip into the slit in theflower where the pollen is stored. The pollen-containing structureclips onto the insect part. When the insect pulls away from the flower,this pollen packet goes, too. The same insect body part may slipinside a slit in the flower column of a different flower. If the pollenpacket is placed precisely where it needs to be, that flower will be pollinated. If the pollen packet is not deposited in the exact positionrequired, fertilization will not occur. The amount of precisionrequired may be the reason that milkweeds produce so few fruits.Pollinator populations are declining. As their numbers continue todecrease, the amount of viable seeds from milkweeds will also besmaller, leading to fewer milkweed plants, fewer milkweed flowers andless pollen and nectar for pollinators.

The fruit that develops from the fertilized flower is a pod that contains seeds attached to floss. Seeds with floss are easily dispersed by wind. An exception, though, is provided by the white swamp milkweed (Asclepias perennis). This species’ seeds are dispersed by water insteadof wind, and they do not have floss.

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The Illinois Department of Natural Resources’ Division of Education provides the following resources for educators.

• The ENTICE (Environment and Nature Training Institute for Conservation Education) training programfor teachers and other educators provides participants with background information in the topic, the opportunity to work with resources professionals, participation in hands-on activities and supplemental, educational resources that allow for instant implementation of the topic into the curriculum. ProfessionalDevelopment Hours from the Illinois State Board of Education are available at all ENTICE workshops.Workshops on native bees, pollinators and developing schoolyard wildlife habitat are offered regularly. Visit https:// www. entice workshops. com for the ENTICE workshop schedule and to register.

• The Schoolyard Wildlife Habitat Action Grant provides funding for teachers and youth-group leaders to implement or enhance a wildlife habitat area on the school grounds or other public place. https:// www. dnr.illinois. gov/ education/Pages/grants.aspx

• The Illinois Biodiversity Field Trip Grant can pro-vide funds to allow teachers to take their studentson a field trip to study native bees/pollinators.https:// www. dnr. illinois. gov/ education/ Pages/grants.aspx

• The Illinois Insects and Spiders resources trunks areavailable for loan from locations statewide. https://www. dnr. illinois. gov/ education/ Pages/ Items ForLoan. aspx

• IDNR publications may be accessed at https://www. dnr. illinois. gov/publications.

Educational ResourcesEducational Resources

black swallow-wort Vincetoxicum nigrumPhoto © Leslie J. Mehrhoff, University of Connecticut, Bugwood.org

climbing milkweed Matelea obliquaPhoto © Christopher D. Benda

climbing milkweed Matelea gonocarposPhoto © Christopher D. Benda

climbing milkweed Matelea decipiensendangered in Illinois Photo © Jeff McMillian/almostedenplants.com

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Adele

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IDNR

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Adele

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IDNR

I l l i n o i s

MilkweedsMilkweeds