showy milkweed

(Asclepias speciosa)

Conservation Status
showy milkweed
  IUCN Red List

not listed

     
  NatureServe

NNR - Unranked

SNR - Unranked

     
  Minnesota

not listed

     
           
Wetland Indicator Status
     
  Great Plains

FAC - Facultative

     
  Midwest

FAC - Facultative

     
  Northcentral & Northeast

FAC - Facultative

     
           
 
Description
 
 

Showy milkweed is an erect, perennial forb that rises from a deep rhizome. It often forms colonies. The leaves and stems are velvety and contain a milky juice.

The stems are erect, usually unbranched, and hairy.

The leaves are opposite, untoothed, 2½ to 8 long, up to 4 wide, and egg-shaped. They have pointed tips and rounded bases. They are attached to the stem on short leaf stalks. There are conspicuous veins running from the midrib to the edge. The lower surface is hairy.

The inflorescence is one or more loose, umbrella-shaped clusters (umbels) rising from the upper leaf axils and at the end of the stem. The clusters are 2 to 3 in diameter and are on a 1 to 3 long, woolly, stalk. They typically have 10 to 20 flowers.

The structure of the typical milkweed flower is unique and instantly recognizable. There are 5 petals bent backward at the base and hanging downward. Subtending the petals are 5 much shorter, light green, lance-shaped sepals. There are 5 stamens. Formed from the filament of each stamen is a petal-like appendage. The appendage consists of a tubular hood surrounding an awl-shaped horn in the center of the hood. The stamens and the stigma are fused together into a crown-like structure (gynostegium). Each stigma has a long slit designed to catch the legs of a pollinating insect. A small, dark, sticky gland above this slit is attached to pollen sacs from adjacent anthers. These glands are designed to break off as an insect pulls its leg free of the slit, and remain attached to the insects leg. The flowers are pollinated by larger insects strong enough to lift off with the pollen sacs attached. Smaller insects are caught in a death trap or leave behind their detached legs.

The flowers of this plant are shaped like the typical milkweed flower but are larger than those of any other milkweed. They are ¾ to 1½ tall, ½ to 1 wide, and are attached on ⅜ to 1⅛ long stalks. The petals are pink or reddish purple. They bend backward at the base, hang downward, then curl upward near the tip. They are attached directly below the hoods without a separating column. The hoods are to long and abruptly narrowed below the middle to an linear to oblong tip, and are taller than the gynostegium. Collectively, the hoods are in the shape of a 5-pointed star. They are white or the same color as the petals but much paler. The horns are shorter than the hoods. They project from the hoods and are curved inwards. There is little or no fragrance.

The fruit is a fat, spindle-shaped pod. It is 2¾to 4¾long and ¾ to 1½ thick. It is densely warty and densely covered with white, wooly hairs. It is held erect or ascending on an erect stalk. It opens on one side exposing the seeds to spreading by the wind. The seeds have a tuft of hairs at the tip that are whitish and about 1 long.

 
     
 

Height

 
 

12 to 36

 
     
 

Flower Color

 
 

Pink or reddish purple

 
     
 

Similar Species

 
 

 

 
     
 
Habitat
 
 

Moist. Prairies. Full sun.

 
     
 
Ecology
 
 

Flowering

 
 

June to August

 
     
 
Use
 
 

Faunal Associations

 
 

Milkweeds are the only plants that Monarchs lay their eggs on. The eggs are laid on the underside of healthy young leaves.

 
     
 

Toxicity

 
 

This and other milkweeds contain cardiac glycosides and may be poisonous to both humans and livestock.

 
     
 
Distribution
 
 

Distribution Map

 

Sources

2, 3, 4, 5, 7, 24, 28.

 
  12/26/2011      
         
 

Nativity

 
 

Native

 
         
 

Occurrence

 
 

Locally common but not abundamt

 
         
 
Taxonomy
 
  Kingdom Plantae (green algae and land plants)  
  Subkingdom Viridiplantae (green plants)  
  Infrakingdom Streptophyta (land plants and green algae)  
  Superdivision Embryophyta (land plants)  
  Division Tracheophyta (vascular plants)  
  Subdivision Spermatophytina (seed plants)  
  Class Magnoliopsida (dicots)  
  Superorder Asteranae  
 

Order

Gentianales (gentians, dogbanes, madders, and allies)  
 

Family

Apocynaceae (dogbane)  
  Subfamily Asclepiadoideae (milkweed)  
  Tribe Asclepiadeae  
  Subtribe Asclepiadinae  
 

Genus

Asclepias (milkweed)  
       
 

Subordinate Taxa

 
 

 

 
       
 

Synonyms

 
 

Asclepias douglasii

Asclepias giffordii

 
       
 

Common Names

 
 

greek milkweed

showy milkweed

 
       

 

 

 

 

 

 

 

 

Glossary

Axil

The upper angle where the leaf stalk meets the stem.

 

Gynostegium

A crown-like structure of plants of the genus Asclepias formed by the fusion of the anthers with the stigmas.

 

Linear

Long, straight, and narrow, with more or less parallel sides, like a blade of grass.

 

Rhizome

A horizontal, usually underground stem. It serves as a reproductive structure, producing roots below and shoots above at the nodes.

 

Umbel

A flat-topped or convex, umbrella-shaped cluster of flowers or buds arising from more or less a single point.

       
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Dan W. Andree
       

Blooming Milkweed....Sandpiper Prairie SNA...

  showy milkweed    
       
MinnesotaSeasons.com Photos
   

Plant

  showy milkweed   showy milkweed
       
  showy milkweed    
       

Inflorescence

  showy milkweed   showy milkweed
       
  showy milkweed   showy milkweed
       

Flowers

  showy milkweed    
       
       

 

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Other Videos
 
  Showy Milkweed.mp4
gnwyfdn
 
   
 
About

Uploaded on Sep 1, 2011

This video is part of the Upstream hiking series that can be read in the Greenway Foundation's monthly newsletter. Read the original article here:

http://www.gnwy.org/web/index.php?cID=116

   
       
  Bee pollinators on Showy Milkweed (Asclepias specosia)
GrowMilkweedPlants.com
 
   
 
About

Published on Jun 8, 2014

This video is about Bee pollinators on Showy Milkweed (Asclepias specosia). Filmed at Mayberry Park Reno Nevada June 8th 2014. www.growmilkweedplants.com

   
       

 

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