spotted Joe Pye weed

(Eutrochium maculatum var. maculatum)

Conservation Status

 

No image available

 
  IUCN Red List

not listed

     
  NatureServe

NNR - Unranked

SNR - Unranked

     
  Minnesota

not listed

     
           
Wetland Indicator Status
     
  Great Plains

OBL - Obligate wetland

     
  Midwest

OBL - Obligate wetland

     
  Northcentral & Northeast

OBL - Obligate wetland

     
           
 
Description
 
 

Spotted Joe Pye weed (var.maculatum) is a 24 to 80 tall, erect, perennial forb that rises from a fibrous roots and sometimes rhizomes.

The stems are erect and usually light green with purple spots but are sometimes more evenly purple. They are usually solid but are sometimes hollow near the base. They are usually not covered with a whitish, waxy coating (glaucous). They are hairless except for a covering of minute, short hairs near the top.

Most of the leaves are usually in whorls of 4 or 5, sometimes in whorls of 3 or 6. They do not have a tight bundle of small leaves in the leaf axils. They are on hairless, 1 16 to 1 long leaf stalks. The leaf blades are relatively thin, lance-shaped to elliptic or egg-shaped, 3 to 10 long, and 1 to 3½ wide. They are tapered to a sharp point at the tip and tapered gradually to the leaf stalk at the base. There is a single main vein. The upper surface is dull and hairless. The lower surface is paler green and usually hairless. The margins are toothed with sharp, forward-pointing teeth. The uppermost whorl of leaves, the whorl directly subtending the inflorescence, is not broader than the inflorescence. The leaf blades of this whorl are to 1 long and 1 16 to 3 16 wide.

The inflorescence is a branched, elongated, flat-topped or nearly flat-topped array of numerous flower heads at the top of the stem.

Each flower head has 8 to 22, usually 10 to 16, pale purple to pink disk florets and no ray florets.

The fruit is a to 3 16 long achene with a fluffy tuft of hairs attached.

 
     
 

Height

 
 

24 to 80

 
     
 

Flower Color

 
 

Pale purple to pink

 
     
 

Similar Species

 
 

Holzinger’s eupatorium (Eupatorium purpureum var. holzingeri) stems are mostly green, purple only at the leaf nodes, and are rarely hollow near the base. The leaf undersurface is densely hairy. The inflorescence is dome-shaped, not flat-topped. The flower heads have 4 to 7 disk florets per head.

Bruner’s spotted Joe Pye weed (Eutrochium maculatum var. bruneri) stems are densely covered from the base to the inflorescence with minute, short hairs. The leaves are relatively thick. The leaf undersurface is densely hairy.

Spotted Joe Pye weed (Eutrochium maculatum var. foliosum) uppermost whorl of leaves is much larger, as broad or broader than the inflorescence. The leaf blades of this whorl are 3 to 8 long and ¾ to 1½ wide. It has been reported only in Cook County.

Sweet Joe Pye weed (Eupatorium purpureum var. purpureum) stems are mostly green, purple only at the leaf nodes, and are rarely hollow near the base. The inflorescence is dome-shaped, not flat-topped. The flower heads have 4 to 7 disk florets per head. The flowers are pale pink to purplish.

 
     
 
Habitat
 
 

Wet to moist. Meadows, marshes, lakeshores. Full sun or partial shade.

 
     
 
Ecology
 
 

Flowering

 
 

July to September

 
     
 

Pests and Diseases

 
 

 

 
     
 
Use
 
 

 

 
     
 
Distribution
 
 

Distribution Map

 

Sources

3, 4, 7, 29, 30.

 
  6/21/2023      
         
 

Nativity

 
 

Native

 
         
 

Occurrence

 
 

Common

 
         
 
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 (flowering plants)  
  Superorder Asteranae  
 

Order

Asterales (sunflowers, bellflowers, fanflowers, and allies)  
 

Family

Asteraceae (sunflowers, daisies, asters, and allies)  
  Subfamily Asteroideae  
  Supertribe Helianthodae  
  Tribe Eupatorieae (bonesets, blazingstars, and allies)  
  Subtribe Eupatoriinae  
  Genus Eutrochium (Joe Pye weeds)  
  Species Eutrochium maculatum (spotted Joe Pye weed)  
       
 

Joe Pye weeds were originally assigned to the genus Eupatorium. In 1836 a French botanist (Rafinesque) separated Joe Pye weeds from that genus and proposed assigning them to the genus Eutrochium. Unaware of Rafinesque’s work, in 1970 researchers at the Smithsonian Institution (King and Robinson) proposed the genus Eupatoriadelphus for Joe Pye weeds, and it was widely adopted. In 1987, further study by the same researchers convinced them to return Joe Pye weeds to Eupatorium. In 1999 and 2000, DNA studies at the University of Tennessee (Schilling) concluded yet again that Joe Pye weeds did not belong to Eupatorium, and they were returned to the genus Eupatoriadelphus. In 2004, a contributor to the Flora of North America (Lamont), recognizing the precedence of earlier-established names, transfered the species to Eutrochium.

 
       
 

Subordinate Taxa

 
 

 

 
       
 

Synonyms

 
 

Eupatorium maculatum

Eupatorium maculatum var. maculatum

Eupatoriadelphus maculatus

Eupatorium purpureum var. maculatum

 
       
 

Common Names

 
 

spotted Joe Pye weed

spotted Joe-pye-weed

spotted joepyeweed

spotted trumpetweed

 

 

 

 

 

 

 

 

 

 

Glossary

Achene

A dry, one-chambered, single-seeded fruit, formed from a single carpel, with the seed attached to the membranous outer layer (wall) only by the seed stalk; the wall, formed entirely from the wall of the superior ovary, does not split open at maturity, but relies on decay or predation to release the contents.

 

Glaucous

Pale green or bluish gray due to a whitish, powdery or waxy film, as on a plum or a grape.

 

Node

The small swelling of the stem from which one or more leaves, branches, or buds originate.

 

Rhizome

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

 
 
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