CPC Plant Profile: Mead's Milkweed
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Plant Profile

Mead's Milkweed (Asclepias meadii)

This closeup shows the flower heads of Mead's milkweed. Photo Credit: Marlin Bowles
Description
  • Global Rank: N/A
  • Legal Status: N/A
  • Family: Apocynaceae
  • State: IA, IL, IN, KS, MO, WI
  • Nature Serve ID: 129673
  • Date Inducted in National Collection: 03/05/1993

A. meadii is a rare, attractive species of Midwestern tallgrass prairies and glades. Today, all of the tallgrass prairie populations of this species in Wisconsin, Illinois, and Indiana have been destroyed by agriculture, and the only remaining native eastern populations occupy glade habitat in southeastern Missouri and southern Illinois. However, following federal and state recovery planning, populations are being restored in Illinois, Indiana, and Wisconsin. It now persists in about 150 populations, many of which are located on privately-owned land that is mowed each year. This mowing unfortunately often coincides with the flowering of this species, thus preventing sexual reproduction, and perpetuating the rarity of the species (Bowles et al. 2001). This species of milkweed differs from most other milkweeds by producing an unbranched stem that terminates in a single inflorescence projected above the top pair of leaves. Mature Mead's milkweed plants can reach up to 20 inches high. They have 4-8 pairs of smooth blue-green leaves with a distinctive herringbone leaf-vein pattern. The nodding inflorescence contains about 12 flowers, which change from green to ivory as they mature, finally fading to a pale cream-color. The flowers produce large amounts of nectar and are pollinated by small bees (USFWS 2005).

Participating Institutions
Updates
Center for Plant Conservation
  • 11/25/2021
  • Reintroduction

The Morton Arboretum has designed a restoration that will meet federal recovery plan criteria by restoring genetically diverse populations in the eastern part of this species range.

  • 08/19/2020
  • Genetic Research

Tecic et al. (1998) studied the genetic diversity of the species.

  • 08/19/2020
  • Demographic Research

Current demographic monitoring is being used to help understand whether the few larger preserved populations of Mead's milkweed are viable. The great longevity of adult plants could be masking slow long term demographic declines if rates of seedling establishment are below a threshold of viability. Related research is also seeking to learn whether viable populations can be restored. There are about 150 remaining populations of Mead's milkweed. (Bowles et al. 2001) Most populations are in privately owned prairie haymeadows in Kansas, where mowing removes developing seed pods and prevents sexual reproduction. Only one Kansas population may be viable, where about 200 or more plants occur in a protected and fire-managed tallgrass prairie. Fewer than 20 former haymeadow populations are preserved on public prairies in Missouri, and only one site contains a large population. A second large, apparently viable, population occurs in fire-managed igneous glade habitat in southeastern Missouri, where several hundred or more plants are present. The southern Iowa populations occupy prairie remnants and several haymeadows, and seed production has occurred at only one of these sites. The southern Illinois population comprises four small colonies, each of which appears to be a single clone.

Nature Serve Biotics
  • 05/02/2017

A formerly widespread species - historically it ranged over much of the native tallgrass prairie region of the Midwest - that has declined due to the extensive destruction and fragmentation of its habitat. Where habitat remains, inadequate management (loss of fire regime; frequent mowing prior to seed set) has threatened the species. There are about 212 remaining occurrences and the species' overall range has shrunk dramatically. It is thought to have disappeared entirely from Wisconsin and Indiana.? Continuing threats include urbanization, conversion to agricultural land, habitat fragmentation, invasive species expansion, lack of prescribed fire, annual hay mowing before completion of reproduction, feral hog habitat destruction, herbicide/pesticide application, predation by weevils, deer, voles, and cattle, and climate change.

Marlin L. Bowles
  • 01/01/2010

Haymeadow populations in Kansas are threatened by urban development and agricultural expansion. Haymowing of private or preserved prairies prevents seed production and leads to loss of genetic diversity. Inbreeding and loss of genetic diversity app

Marlin L. Bowles
  • 01/01/2010

There are about 150 remaining populations of Mead's milkweed. (Bowles et al. 2001) Most populations are in privately owned prairie haymeadows in Kansas, where mowing removes developing seed pods and prevents sexual reproduction. Only one Kansas population may be viable, where about 200 or more plants occur in a protected and fire-managed tallgrass prairie. Fewer than 20 former haymeadow populations are preserved on public prairies in Missouri, and only one site contains a large population. A second large, apparently viable, population occurs in fire-managed igneous glade habitat in southeastern Missouri, where several hundred or more plants are present. The southern Iowa populations occupy prairie remnants and several haymeadows, and seed production has occurred at only one of these sites. The southern Illinois population comprises four small colonies, each of which appears to be a single clone.

Marlin L. Bowles
  • 01/01/2010

Current demographic monitoring is being used to help understand whether the few larger preserved populations of Mead's milkweed are viable. The great longevity of adult plants could be masking slow long term demographic declines if rates of seedling establishment are below a threshold of viability. Related research is also seeking to learn whether viable populations can be restored. Tecic et al. (1998) studied the genetic diversity of the species.

Marlin L. Bowles
  • 01/01/2010

The Missouri Department of Conservation has management guidelines established for this species. (Smith 1997) Populations of this species are being monitored in Illinois.

Marlin L. Bowles
  • 01/01/2010

Research is needed to determine whether practices such as haymowing and grazing can be compatible management schemes for viable milkweed populations. Prescribed burning appears to be the most important management need for this species, as it promotes flowering and maintains tallgrass prairie habitat. In smaller populations, supplemental cross-pollination or introduction of compatible genotypes may be needed to promote seed production.

Marlin L. Bowles
  • 01/01/2010

The most important ex situ need is the maintenance of genetically diverse garden populations, as well as seed banks, that can serve as a resource for propagules used in population restoration.

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Nomenclature
Taxon Asclepias meadii
Authority Torr. ex Gray
Family Apocynaceae
CPC Number 308
ITIS 30285
USDA ASME
Common Names Mead's Milkweed
Associated Scientific Names Asclepias meadii
Distribution Mead's milkweed is restricted to the tallgrass prairie region of the central United States (Harrison 1988, Betz 1989). It formerly ranged from northwestern Indiana, southwestern Wisconsin, and southern Iowa to southern Illinois, southern Missouri, and east Kansas (USFWS 2012).
State Rank
State State Rank
Iowa S1
Illinois S2
Indiana SX
Kansas S2
Missouri S2
Wisconsin SX
Habitat

Mead's milkweed has two habitats. Most populations occur in virgin tallgrass prairies or unplowed native prairie haymeadows that have well-drained, or dry-mesic, soils. Plants also occur in igneous glades in the Missouri Ozarks and in limestone glades in the Shawnee Hills of southern Illinois. Soil conditions in these habitats range from acid and nutrient poor in Missouri and southern Illinois to calcareous nutrient rich in Iowa and northern Illinois (Bowles et al. 1998, USFWS 2003).

Ecological Relationships

Mead's milkweed is a rhizomatous perennial, and individual plants may persist for decades or longer. This species is genetically diverse, and has a strongly enforced outcrossing breeding system (Tecic et al. 1998).

Self-pollination rarely produces viable seeds, either due to self-incompatibility or severe inbreeding depression. As a result, small fragmented populations that persist by rhizomatous spread of a single clone do not produce seeds. Mowing for hay, which prevents sexual reproduction, also appears to cause vegetative spread and loss of genetic diversity within populations (Tecic et al. 1998).

Dormant season fire has been found to promote flowering and seed production in this species, and relatively high levels of spring rainfall enhance seed germination and seedling establishment. Successful seedling establishment may occur infrequently and growth to flowering size may require ten or more years. As a result, population maintenance may depend upon extreme longevity of adult plants (Bowles et al. 1998).

Pollinators
Common Name Name in Text Association Type Source InteractionID
Bees
Anthophorine bees Anthophora abrupta Confirmed Pollinator Link
Anthophorine bees Anthophoridae Confirmed Pollinator Link
Honey bees Apis mellifera Confirmed Pollinator Link
Bumble bees Bombus affinis Confirmed Pollinator Link
Bumble bees Bombus griseocollis Confirmed Pollinator Link

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