This section is from the book "An Illustrated Flora Of The Northern United States, Canada And The British Possessions Vol3", by Nathaniel Lord Britton, Addison Brown. Also available from Amazon: An Illustrated Flora of the Northern United States, Canada and the British Possessions. 3 Volume Set..
Similar to the preceding species, perennial by rootstocks, 1°-2 1/2° high, densely silky-woolly nearly all over. Leaves deeply bipinnatifid into narrow lobes and segments, those of the stem mostly sessile; inflorescence convex, 2'-4'broad; involucre oblong-cylindric, its bracts greenish-yellow, with brownish margins; rays 1"2 1/2"ad, white.
In dry soil, Quebec and Ontario to Michigan, Yukon, south to Oklahoma, Mexico and California. June-Sept. Locally naturalized eastward.
Achillea ligustica All., differing from A. Millefolium by being stouter with loosely corymbose heads, native of Europe, has been found in cultivated ground near Tannersville, New York.
Achillea borealis Bongard, Veg. Sitch. 149. 1831.
More or less silky-woolly; stem erect, 16' high or less. Leaves deeply bipinnatifid into narrow crowded lobes and segments, those of the stem few, sessile or nearly so, the ultimate divisions very small; corymb dense, strongly convex, 2 1/2' broad , or less; involucre about 3" high, its bracts with broad black or blackish margins; rays 10-20, white or pink, broadly oblong or suborbicular, often 2i" broad.
In wet places, on hillsides and rocks, Newfoundland to Quebec and Alaska. Summer. Rocky Mountain plants referred to this species appear to be distinct from it.
go. ANTHEMIS [Micheli] L. Sp. Pl. 893. 1753. Annual or perennial herbs, with pinnatifid or dissected, alternate leaves, and usually large peduncled heads of both tubular and radiate flowers, terminating the branches, or heads rarely rayless. Involucre hemispheric, its bracts imbricated in several series, scarious-margined, appressed, the outer shorter. Receptacle convex, conic or oblong, chaffy at least toward the summit, the chaff subtending the disk-flowers. Ray-flowers pistillate and fertile, or neutral, the tube terete or 2-winged, the ray white or yellow, entire or 2-3-toothed. Disk-flowers perfect, fertile, yellow, their corollas with 5-cleft limbs. Anthers obtuse and entire at the base. Style-branches of the disk-flowers truncate. Achenes oblong, angled, ribbed or striate. Pappus none, or a short coroniform border. [Greek name of Camomile.]
About 60 species, natives of Europe, Asia and Africa. Type species: Anthemis maritima L.
Rays neutral; plant glabrous, or nearly so, fetid.
1. A. Cotula.
Rays pistillate; plants pubescent.
Annual; chaff of the receptacle acute.
2. A. arvensis.
Perennial; chaff of the receptacle obtuse.
3. A. nobilis.
Rays yellow; plant pubescent, or tomentose.
4. A. tinctoria.