Spermatophytes (seed plants): Angiosperms (flowering plants): Eudicots: Core Eudicots: Asterids: Campanulids: Asterales
WEAKLEY'S FLORA OF THE SOUTHEASTERN US (4/24/22):
Ambrosia trifida var. trifida
FAMILY
Asteraceae__
Go to FSUS key
Dig deeper at SERNEC, a consortium of southeastern herbaria.
Read more about Ambrosia at Vascular Plants of North Carolina.
INCLUDED WITHIN
PLANTS NATIONAL DATABASE:
Ambrosia trifida var. trifida
FAMILY
Asteraceae__
INCLUDED WITHIN Flora of North America north of Mexico, vol. 19-20-21 (2006)
Ambrosia trifida
INCLUDED WITHIN VASCULAR FLORA OF THE CAROLINAS (Radford, Ahles, & Bell, 1968) 179-02-002:
Ambrosia trifida FAMILY Asteraceae__
SYNONYMOUS WITH Manual of the Southeastern Flora (Small, 1933, 1938)
Ambrosia trifida
COMMON NAME:
Giant Ragweed, Great Ragweed
To see larger pictures, click or hover over the thumbnails.
)
USDA / Selected Weeds of the US. 1970 swus_page_369
)
JK Marlow jkm250521_0443
May Greenville County SC
Poinsett Bridge Heritage Preserve
)
JK Marlow jkm140623_235
June Greenville County SC
Swamp Rabbit Trail
)
JK Marlow s060617_b
June Greenville County SC
Roadside/creekside
Leaves 3(5)-lobed or unlobed, tips acuminate, margins evenly serrate, per Vascular Flora of the Carolinas (Radford, Ahles, & Bell, 1968).
COMPARE
leaves of Giant Ragweed and Sassafras
)
Gill Newberry gn08_a_trifida_plant
August
)
JK Marlow jkm130823_485
August Greenville County SC
Swamp Rabbit Trail
Leaves usually with 3-5 deep lobes, per Newcomb's Wildflower Guide (Newcomb, 1977).
)
Keith Bradley kab_ambrosia_trifida_2776
August Swain County NC
Great Smoky Mountains National Park
)
Roxanna Martin rlm83010_171
August Spartanburg County SC
Staminate heads 3-5mm broad, peduncles 2-7mm long, per Vascular Flora of the Carolinas (Radford, Ahles, & Bell, 1968).
)
JK Marlow jkm0309f_23
September Greenville County SC
Roadside
)
JK Marlow jkm110925_622
September Greenville County SC
)
JK Marlow jkm190903_1208
September Greenville County SC
Tall Pines Wildlife Management Area
)
JK Marlow jkm210905_3367
September Greenville County SC
Swamp Rabbit Trail
)
JK Marlow jkm210905_3372
September Greenville County SC
Swamp Rabbit Trail
Stems erect, from 0.3 to 1.5 (to 4) meters tall, per Flora of North America.
)
Richard and Teresa Ware rtw_ambrosia_trifida_2
September
)
JK Marlow jkm0310e_06
October Jackson County NC
Roadside
)
JK Marlow jkm0310e_09
October Jackson County NC
Roadside
)
JK Marlow jkm121024_677
October Cherokee County NC
Murphy River Walk
)
JK Marlow jkm121024_684
October Cherokee County NC
Murphy River Walk
WEAKLEY'S FLORA OF THE SOUTHEASTERN US (4/24/22):
Ambrosia trifida var. trifida
FAMILY
Asteraceae__
INCLUDED WITHIN
PLANTS NATIONAL DATABASE:
Ambrosia trifida var. trifida
FAMILY
Asteraceae__
INCLUDED WITHIN
Flora of North America north of Mexico, vol. 19-20-21
Ambrosia trifida
INCLUDED WITHIN
VASCULAR FLORA OF THE CAROLINAS (Radford, Ahles, & Bell, 1968) 179-02-002:
Ambrosia trifida
FAMILY
Asteraceae__
SYNONYMOUS WITH
Manual of the Southeastern Flora (Small, 1933, 1938)
Ambrosia trifida
65
Forb
Annual
Habitat: floodplains, moist pastures, disturbed ground, per Weakley's Flora
Native to the Carolinas & Georgia
Common (rare in Coastal Plain)
CLICK HERE to see a map, notes, and images from Weakley's Flora of the Southeastern US.
LEAVES:
Simple
Lower opposite, upper alternate
FLOWER:
Summer/Fall
Disc: Greenish ?
Rays: Absent
Inferior ovary
FRUIT:
Summer/Fall
Black
Achene
TO LEARN MORE about this plant, look it up in a good book!
- Forest Plants of the Southeast and Their Wildlife Uses (Miller & Miller, 2005) p010
- Guide to the Wildflowers of SC, 1st ed. (Porcher & Rayner, 2001) p403
- Guide to the Wildflowers of SC, 2nd ed. (McMillan, Porcher, Rayner, & White; 2022) p551
- Newcomb's Wildflower Guide (Newcomb, 1977) p438
- Wildflowers of the Atlantic Southeast (Cotterman, Waitt, & Weakley, 2019) p461
- Wildflowers of the Eastern United States (Duncan & Duncan, 1999) p120
- Field Guide to the Wildflowers of Georgia (Chafin, 2016) p057
- Wildflowers of Tennessee (Carman, 2005) p273
- Wildflowers of Tennessee, the Ohio Valley, and the Southern Appalachians (Horn, Cathcart, Hemmerly, & Duhl, 2005) p321
If a search such as "Carex leptalea var. leptalea" doesn't deliver the results you want, try "Carex leptalea".
Or, to minimize chances of a misspelling, try just "Carex le".
Less is more: If "pencil flower" doesn't deliver the results you want, try "pencil".