Achillea
L.
Herbs or undershrubs, perennial, pilose or pubescent, often with thick woody
rootstock. Leaves alternate, serrulate, pinnatisect or pinnatipartite. Heads heterogamous,
radiate, peduncled or subsessile, small or medium sized, usually arranged in terminal
corymbs, rarely solitary, terminal. Involucral bracts few seriate, more or less scarious
margined, Receptacle flat or convex, paleaceus; paleae lanceolate or oblong. Ray florets
female; lingule white pink or yellow, short, more or less 3-dentate. Disc florets
hermaphrodite, fertile, tubular, compressed and 2-winged; limbs 5-toothed. Anther bases
obtuse. Style arms of disc florets with truncate and penicillate tips. Achenes glabrous,
smooth, compressed, not winged, oblong or obovate, tips rather broad. Pappus absent.
Temperate regions; ca 200 species, 2 in India.
Literature. ISSAR, R.K. (1984) Achillea millefolium L. floristic variability of morphological characters. Ind. For. 104(2): 90-95. THOMSON, J. (1978). Yarrow, herbs of Achillea. Vascular 63(2): 13. Achillea millifolium.
Temperate regions; ca 200 species, 2 in India.
Literature. ISSAR, R.K. (1984) Achillea millefolium L. floristic variability of morphological characters. Ind. For. 104(2): 90-95. THOMSON, J. (1978). Yarrow, herbs of Achillea. Vascular 63(2): 13. Achillea millifolium.
KEY TO THE SPECIES
1a. Herbs; leaves 3-pinnatisect; heads 6 mm in diam. | 2. Achillea millefolium |
b. Undershrubs; leaves pectinately-pinnati-partite; heads 9 - 12 mm in diam. | 1. Achillea alpina |