9. Artemisia stelleriana Besser (beach wormwood, dusty miller)

Map 949

Plants perennial herbs, with long, thin rhizomes, not or only slightly aromatic when bruised. Stems 30–70 cm long, erect or ascending, densely silky- or woolly-hairy and minutely glandular. Leaves 2–10 cm long, the basal and lower to median leaves short- to long-petiolate, the upper leaves short-petiolate to sessile, lacking stipulelike lobes or teeth at the base but sometimes slightly expanded around the stem. Leaf blades mostly 1 or 2 times pinnately or ternately shallowly to deeply lobed, mostly obovate to oblanceolate in outline, the 3 or 5 primary lobes (1–)2–9 mm wide, oblong-triangular to narrowly oblong or less commonly linear but not threadlike, sometimes with a few coarse teeth toward the tip (the lowermost sometimes shallowly lobed a third time), mostly rounded to bluntly pointed at the tip, the margins flat or those of the uppermost leaves slightly curled under, both surfaces densely pubescent with woolly to felty, white or grayish white hairs and minutely glandular. Inflorescences appearing as relatively narrow, mostly leafless panicles, the branches spicate or narrowly racemose with relatively densely spaced heads. Heads with the central florets perfect and the marginal florets pistillate, thus all of the florets potentially producing fruits. Involucre 6.0–7.5 mm long, the bracts in 2 or 3 overlapping rows, the main body indistinguishable, hidden by the densely woolly to cobwebby hairs, also minutely glandular, at least the innermost with narrow to somewhat broader, thin, transparent margins and tip, these glabrous. Receptacle naked. Corollas 3.2–4.0 mm long. Fruits 3–4 mm long, more or less obovoid, slightly flattened, smooth, yellowish brown to dark brown. 2n=18. June–September.

Introduced, known thus far from a single historical collection from Butler County (native of Alaska, Europe, Asia; introduced widely but sporadically in the U.S. and Canada, mostly in coastal areas). Habitat unknown, but presumably disturbed areas.

This species was first noted as occurring in Missouri by Ling Yeou-ruenn in 1993 during research at the Missouri Botanical Garden herbarium. It is sometimes cultivated for its attractive white foliage under the name dusty miller. This vernacular name has been applied to various Asteraceae with felty, white foliage that are grown as bedding plants, including selected species of Artemisia, Centaurea, Senecio, and Tanacetum. The most commonly grown of these is Senecio cineraria DC., a native of the Mediterranean region that has a number of cultivars in the horticultural trade.