OF THE CAROLINAS & GEORGIA

Spermatophytes (seed plants): Angiosperms (flowering plants): Eudicots: Core Eudicots: Asterids: Campanulids: Asterales

WEAKLEY'S FLORA OF THE SOUTHEASTERN US (4/24/22):
Erigeron canadensis   FAMILY Asteraceae   Go to FSUS key



SYNONYMOUS WITH PLANTS NATIONAL DATABASE:
Conyza canadensis var. canadensis   FAMILY Asteraceae

INCLUDED WITHIN Flora of North America north of Mexico, vol. 19-20-21 (2006)

Conyza canadensis

SYNONYMOUS WITH VASCULAR FLORA OF THE CAROLINAS (Radford, Ahles, & Bell, 1968) 179-44-008a:

Erigeron canadensis var. canadensis   FAMILY Asteraceae

SYNONYMOUS WITH Britton & Brown Illus Flora of Northeast US & adjacent Canada (Gleason, 1952)

Conyza canadensis var. canadensis

SYNONYMOUS WITH Gray's Manual of Botany (Fernald, 1950)

Erigeron canadensis

SYNONYMOUS WITH Manual of the Southeastern Flora (Small, 1933, 1938)

Leptilon canadense

 

COMMON NAME:
Common Horseweed


         To see larger pictures, click or hover over the thumbnails.

image of Erigeron canadensis, Common Horseweed

USDA-NRCS PLANTS Database / Britton, N.L., and A. Brown. 1913    pnd_leca16_001_lvd

        

image of Erigeron canadensis, Common Horseweed

USDA / Selected Weeds of the US. 1970    swus_page_401

        

image of Erigeron canadensis, Common Horseweed

JK Marlow    jkm120727_828

July    Spartanburg County    SC

Leaves alternately spiraling, numerous and crowded along stem, per Forest Plants of the Southeast and Their Wildlife Uses (Miller & Miller, 2005).

image of Erigeron canadensis, Common Horseweed

JK Marlow    jkm120727_831

July    Spartanburg County    SC

Pappus bristles white to tan, capillary, 2-2.3mm long, per Vascular Flora of the Carolinas (Radford, Ahles, & Bell, 1968).

image of Erigeron canadensis, Common Horseweed

JK Marlow    jkm120727_835

July    Spartanburg County    SC

Stem coarsely spreading-hirsute (vs E. pusillus stem glabrous or widely scattered appressed hairs), per Weakley's Flora.

image of Erigeron canadensis, Common Horseweed

JK Marlow    jkm120727_837

July    Spartanburg County    SC

The inflorescence is a large open panicle bearing a great many small heads, per Wildflowers of the Southern Mountains (Smith, 1998).

image of Erigeron canadensis, Common Horseweed

JK Marlow    jkm120727_839

July    Spartanburg County    SC

Stem leaves sessile, long-ciliate particularly toward base, base attenuate, per Vascular Flora of the Carolinas (Radford, Ahles, & Bell, 1968).

image of Erigeron canadensis, Common Horseweed

JK Marlow    jkm120727_858

July    Spartanburg County    SC

The involucre is 1/8" high, and the whitish rays are narrow, short and erect, per Wildflowers of the Southern Mountains (Smith, 1998).

image of Erigeron canadensis, Common Horseweed

JK Marlow    jkm220722_9269

July    Greenville County    SC

Tall Pines Wildlife Management Area

E. pusillus on the left, E. canadensis on the right.

image of Erigeron canadensis, Common Horseweed

Gill Newberry    gn08_c_canadensis_inf

August        

image of Erigeron canadensis, Common Horseweed

Gill Newberry    gn08_c_canadensis_plant

August        

image of Erigeron canadensis, Common Horseweed

Gill Newberry    gn08_e_conyza_canadensis

August        

image of Erigeron canadensis, Common Horseweed

Gill Newberry    gn08_e_conyza_inf

August        

image of Erigeron canadensis, Common Horseweed

JK Marlow    jkm130824_548

August    Spartanburg County    SC

Stem spreading pubescent, rarely glabrous (whereas var. pusillus is glabrous), per Vascular Flora of the Carolinas (Radford, Ahles, & Bell, 1968).

image of Erigeron canadensis, Common Horseweed

JK Marlow    jkm230808_4881

August    Pickens County    SC

Glassy Mountain Heritage Preserve

image of Erigeron canadensis, Common Horseweed

JK Marlow    jkm230808_4881b

August    Pickens County    SC

Glassy Mountain Heritage Preserve

Phyllaries green-tipped or white-tipped (vs. those of E. pusillus purple-tipped), per Weakley's Flora (2022).

image of Erigeron canadensis, Common Horseweed

Gill Newberry    gn09_e_conyza_habitat

September        

 

 

WEAKLEY'S FLORA OF THE SOUTHEASTERN US (4/24/22):
Erigeron canadensis   FAMILY Asteraceae

SYNONYMOUS WITH PLANTS NATIONAL DATABASE:
Conyza canadensis var. canadensis   FAMILY Asteraceae

INCLUDED WITHIN Flora of North America north of Mexico, vol. 19-20-21
Conyza canadensis

SYNONYMOUS WITH VASCULAR FLORA OF THE CAROLINAS (Radford, Ahles, & Bell, 1968) 179-44-008a:
Erigeron canadensis var. canadensis   FAMILY Asteraceae

SYNONYMOUS WITH Britton & Brown Illus Flora of Northeast US & adjacent Canada (Gleason, 1952)
Conyza canadensis var. canadensis

SYNONYMOUS WITH Gray's Manual of Botany (Fernald, 1950)
Erigeron canadensis

SYNONYMOUS WITH Manual of the Southeastern Flora (Small, 1933, 1938)
Leptilon canadense

 

Find by SCIENTIFIC NAME:

526

Forb
Annual

Habitat: Old fields, disturbed areas, roadsides, gardens, per Weakley's Flora

Native to the Carolinas & Georgia

Common

map
CLICK HERE to see a map, notes, and images from Weakley's Flora of the Southeastern US.

Click here to see a map showing all occurrences known to SERNEC, a consortium of southeastern herbaria. (Zoom in to see more detail.)

LEAVES:
Simple
Alternate (basal leaves usually absent or withered at flowering)

FLOWER:
Summer/Fall
Rays: White/Lavender (few, 1-2mm long)
Disc: Yellow/Yellowish
Inferior ovary
Disc flowers bisexual & fertile/ Ray flowers pistillate & fertile

FRUIT:
Summer/Fall
Yellowish
Achene

 

TO LEARN MORE about this plant, look it up in a good book!



 


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