Ambrosia

Contains 4 accepted taxa overall.

Characteristics
Ambrosia L.
ASTERACEAE
RAGWEED
View USF Herbarium specimens of this family
Classification
ASTERALES
Ambrosia
Citation
AMBROSIA Linnaeus, Sp. Pl. 987. 1753.
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TYPE: Ambrosia maritima Linnaeus Lectotypified by Britton & A. Brown, Ill. Fl. N. U.S., ed. 2. 3: 340. 1913.
Distribution Map Present

This species have been reported in the counties highlighted.

Species
Scientific Name Common Name Herbarium Specimens Status Photos
Ambrosia artemisiifolia COMMON RAGWEED Native FACU (NWPL) U (WAP)
Ambrosia hispida COASTAL RAGWEED Native
Ambrosia psilostachya WESTERN RAGWEED Native FAC (NWPL)
Ambrosia trifida GIANT RAGWEED Native FAC (NWPL)
Identification Key
1.  Leaf blade with 3-5 lobes or unlobed
A. trifida
1.  Leaf blade 1-3-pinnatified or 1-3-pinnately lobed
2
2.  Plant densely hispid or pilose, usually with a creeping, prostrate stem and erect offshoots; most leaves 2-3-pinnatifid or 2-3-pinnately lobed
A. hispida
2.  Plant sparsely to densely strigillose or hispid, stems erect; most leaves 1-pinnatifid or 1-pinnately lobed or the pinnae with sparse, few shallow lobes or teeth
3
3.  Annual, the taproot with copious fibrous roots; petioles mostly (3)15-40(65) mm long; fruit with
A. artemisiifolia
3.  Perennial, mostly stout roots near the surface, often clonal from horizontal roots; petioles 0-15(25) mm long
A. psilostachya
Genus Synonyms
Synonym Full Citation Basionym Type
Acanthambrosia Acanthambrosia Rydberg, in Britton, N. Amer. Fl. 33: 22. 1922. TYPE: Acanthambrosia bryantii (Curran) Rydberg (Franseria bryantii Curran)
Franseria Franseria Cavanilles, Icon. 2: 78, t. 200. 1793, nom. cons. TYPE: Franseria ambrosioides Cavanilles, nom. illegit. (Ambrosia arborescens Miller)
Gaertneria Gaertneria Medikus, Philos. Bot. 1: 45. 1789, non Gaertnera Schreber 1789. TYPE: Ambrosia fruticosa Medikus, nom. illegit. (Ambrosia arborescens Mill.) = Franseria Cavanilles 1793.
Hemiambrosia Hemiambrosia Delpino, Stud. Lign. Anemof. 16. 1871. TYPE: Hemiambrosia heterocephala Delpino, nom. illegit. (Franseria pumila Nuttall)
Hemixanthidium Hemixanthidium Delpino, Stud. Lign. Anemof. 17. 1871. TYPE: Hemixanthidium paradoxum Delpino, nom. illegit. (Franseria montana Nuttall)
Xanthidium Xanthidium Delpino, Stud. Lign. Anemof. 17. 1871, non Ehrenberg ex Ralfs 1848. TYPE: Non designatus.