Yarrow, Milfoil

Achillea millefolium L. Sp. PI. 899. 1753
Alitubus Millefolium Dulac, Fl. Hautes-Pyr. 500. 1867.
A perennial, with a creeping rootstock; stem 3-6 dm. high, simple or branched above, sparingly villous, striate; leaves sparingly villous, bior tri-pinnatifid, the lower oblanceolate in outline, 1-2 dm. long, 2-4 mm. wide, petioled, the upper sessile, linear, oblong, 1-2.5 cm. wide; primary divisions ovate in outline, divaricate; rachis winged, 1-2 mm. broad; ultimate divisions linear-lanceolate, spinulose-tipped; heads many, in corymbiform panicles; involucre 4-5 mm. high, 3-5 ram. broad, villous; bracts about 20, in 4 series, the outer ovate, obtuse, about half as long as the innermost; inner bracts oblong, obtuse; margins light-brown, rarely dark-brown; ray-flowers mostly 5; ligules white or rarely pink or rose-colored, orbicular, 2.5-3 tnm. long; disk-flowers 20-25; corollas 2.5-3 mm. long, yellowish-white; achenes 2 mm. long, with thick wing-margins.
Type umtality: Europe.
Distribution: Naturalized or native (?) from Nova Scotia and Quebec to New Jersey and Pennsylvania, occasionally found as far as Florida, Illinois, and Alberta; Yukon; Bermudas; native of Euroi>e and Asia.