Artemisia porteri
Artemisia biennis
Porter mugwort, Porter's wormwood
armoise bisannuelle, biennial sagewort, biennial wormwood
5–8, silver-gray, densely tomentose.
1, erect, often reddish, simple (finely striate), glabrous.
persistent, silver-green, mostly basal;
proximalmost blades 3–4 × 1–1.5 cm, 1-pinnately lobed, lobes mostly 2–3 mm wide;
blades of flowering stems somewhat reduced, (1–)2–3(–5) × 0.15 cm, mostly entire;
apices rounded, faces densely hairy.
cauline, green or yellow-green (sessile);
blades broadly lanceolate to ovate, 4–10(–13) × 1.5–4 cm, 1–2-pinnately lobed (ultimate lobes coarsely toothed), faces glabrous.
broadly campanulate, 4–5(–7) × 2–3 mm.
globose, 2–4 × (1.5–)2–4 mm.
pistillate 8–10 (2–2.8 mm); functionally staminate 22–32;
corollas pale yellow, 2.2–4.5 mm, glandular.
pistillate 6–25;
bisexual 15–40;
corollas pale yellow, ca. 2 mm, glabrous.
(ovate, margins broadly scarious) densely tomentose.
(green) broadly elliptic to obovate, glabrous.
borne singly or (clustered in 2s and 3s on lateral branches; peduncles 0 or to 5 mm) in paniculiform arrays, (2–)4–9 × 1–1.5(–2) cm.
(erect, subsessile) in (leafy) paniculiform to spiciform arrays 12–35(–40) × 2–4 cm (lateral branches relatively short).
(light brown) ellipsoid, flattened (faintly nerved), 1.5–2 mm, sparsely hairy, glabrous or resinous.
ellipsoid (4–5-nerved), 0.2–0.9 mm, glabrous.
= 18.
Artemisia porteri
Artemisia biennis
Although Cronquist observed that Artemisia porteri may be an autopolyploid derivative of A. pedatifida, morphologic similarities to northerly cespitose taxa suggest a more complex origin.
Artemisia porteri is in the Center for Plant Conservation’s National Collection of Endangered Plants.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Artemisia biennis is naturalized and weedy in the eastern portion of its range. It is morphologically similar to A. annua, differing primarily in the coarser leaf lobes and larger heads that are sessile in axils of leaflike bracts. Artemisia biennis is considered native to the northwest United States; it may be introduced in other parts of its range. The type specimen is a horticultural specimen from New Zealand.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
- Local floras:
BC, 
CA, 
OR, 
WA - Local Web sites: CalFlora, CalPhotos,
Flora NW, 
Go Botany, 
IL Wildflowers, 
KS Wildflowers, 
MD Biodiversity, 
MI Flora, 
MN Wildflowers, 
MO Plants, 
PNW Herbaria 
WildflowerSearch
iNaturalist (observations)
USDA Plants Database- LBJ Wildflower Center
- SEINet
- Plants of the World Online
- Encyclopedia of Life
- Wikipedia
- Google Image Search
