Artemisia annua
Artemisia tridentata
annual wormwood, armoise annuelle, sweet annie, sweet sagewort
big sagebrush, blue sagebrush, common sagebrush, mountain sagebrush, sagebrush
mostly 1, erect, green, turning to reddish brown with age, simple (smooth or ribbed), glabrous or sparsely hairy.
gray-brown, glabrate (bark gray, exfoliating in strips).
cauline, bright green;
blades triangular to broadly ovate, 2–5(–10) × 2–4 cm, 2–3-pinnatifid (lobes relatively narrow, ± toothed), faces glabrous, gland-dotted.
persistent, gray-green;
blades usually cuneate, (0.4–)0.5–3.5 × 0.1–0.7 cm, 3-lobed (lobes to 1/3 blade lengths, 1.5+ mm wide, rounded), faces densely hairy.
globose, 1.5–2.5 × 1.5–2.5 mm.
lanceolate, (1–)1.5–4 × 1–3 mm.
pistillate (0–)10–20;
bisexual 18–24;
corollas pale yellow (broadly campanulate), 0.5–1 mm, glabrous.
3–8;
corollas 1.5–2.5 mm, glabrous.
(green) lanceolate, glabrous.
oblanceolate to widely obovate, densely tomentose.
(nodding, peduncles 2–5 mm) in open, (diffusely branched, leafy) arrays 15–30(–40) × 10–20 cm.
(usually erect, on slender peduncles) in paniculiform arrays 5–30 × 1–6 cm.
oblong (flattened), 0.3–0.8 mm, glabrous.
1–2 mm, hairy or glabrous, glandular.
= 18.
Artemisia annua
Artemisia tridentata
Widely cultivated for aromatic oils, Artemisia annua often persists in gardens, becoming naturalized in moist-temperate areas (especially in eastern United States). Reports of naturalization may be exaggerated (reported for Prince Edward Island, but not established).
The systematic placement of this species appears to align most closely with species of the Eurasian subg. Seriphidium (L. E. Watson et al. 2002). Molecular evidence suggests that the Artemisia annua lineage may be ancestral to woody species in the Old World.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Subspecies 4 (4 in the flora).
Artemisia tridentata has undergone considerable taxonomic revision in the past century and circumscription of subspecies remains a topic of considerable controversy. Workers in the field should be aware of the morphologic variation within the subspecies across the range of the species (i.e., approximately from the Sierra Nevada in the west to the plains of the Rocky Mountains in the east). Because rangeland managers and conservationists can often identify local morphologic and chemical races based on grazing or habitat preferences of wildlife and domestic animals, some impetus exists to further subdivide the subspecies within A. tridentata at the varietal level. This treatment of the species complex remains conservative in light of the need for further study. As to chemical differences among the subspecies, aroma is often used to distinguish subspecies in the field. Volatile resins in the plants are strongly aromatic and, when crushed, leaves have very distinctive (although not easily described) aromas.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
1. Shrubs 100–200(–300) cm (leaf blades: lengths usually 3+ times widths); heads in relatively broad, paniculiform arrays | → 2 |
1. Shrubs 30–150 cm (leaf blades: lengths usually less than 3 times widths); heads in relatively narrow, paniculiform arrays | → 3 |
2. Involucres 1.5–2.5 × 1–2 mm; deep, well drained (usually sandy) soils in valley bottoms, lower montane slopes along drainages | subsp. tridentata |
2. Involucres 2–4 × 1–2 mm; loose, sandy soils of valleys and foothills | subsp. parishii |
3. Shrubs, 60–80(–150) cm (crowns flat-topped); heads in arrays 10–15 cm; involucres 2–3 × 1.5–3 mm; mountains | subsp. vaseyana |
3. Shrubs, 30–50(–150) cm (crowns rounded); heads in arrays 2–6(–8) cm; involucres (1–)1.5–2 × 1.5–2 mm; usually cold-desert basins and high plateaus, sometimes foothills | subsp. wyomingensis |
- Local floras:
BC, 
CA, 
WA - Local Web sites: CalFlora, CalPhotos,
Flora NW, 
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KS Wildflowers, 
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WildflowerSearch
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- Local floras: BC, CA,
OR, WA - Local Web sites: CalFlora, CalPhotos, Flora NW, PNW Herbaria, Turner Photog.
- WildflowerSearch
- iNaturalist (observations)
- USDA Plants Database
- LBJ Wildflower Center
- SEINet
- Plants of the World Online
- Encyclopedia of Life
- Wikipedia
- Google Image Search
