Anthemis arvensis, L.

Tutin, T. G., Heywood, V. H., Burges, N. A., Moore, D. M., Valentine, D. H., Walters, S. M. & Webb, D. A., 1976, Flora Europaea. Volume 4. Plantaginaceae to Compositae (and Rubiaceae), Cambridge University Press : 153

27. A. arvensis L. , Sp. Pl. 894 (1753).

Sparsely hairy to densely pubescent annual or biennial, perhaps sometimes perennating. Stem (4-5-)10-50(-80) cm, usually more or less branched, often from the base, the basal branches as long as or longer than the main stem. Leaves obovate-oblong to obovate, 1 - to 3-pinnatipartite or pinnatisect, not glandular-punctate, more or less hairy; lobes acute, mucronate. Involucral bracts hairy, oblong or oblong-obovate, obtuse, with hyaline to brown scarious margin and apex. Receptacular scales acuminate. Achenes turbinate, (9-)10(-ll)-ribbed; ribs obtuse, separated by narrow, deep furrows, smooth. Most of Europe except the extreme north. All except Az Fa Sb.

Probably native only in S. Europe, but so long established elsewhere as a cornfield weed that the original limits of distribution cannot be ascertained.

1 Biennial or perennial; achenes with ribs and rim not or slightly

thickened; peduncles not davate in fruit (d) subsp. sphacelata 1 Annual; at least the achenes of the outer tubular florets with

rather thickened ribs and wide, obtuse rim 2 Pedunclesusuallydistinctlydavatein fruit(b) subsp. incrassata 2 Peduncles not or slightly davate in fruit 3 Capitula 20-40 mm in diameter; receptacle 5-7 x 3-4 mm,

attenuate to the apex; achenes l-5-2-5(-3) x 0-7-l- 5 mm;

pappusabsent (a) subsp. arvensis 3 Capitula up to c. 20 mm in diameter; receptacle 3-5- 5 x 2-3

mm, ±contracted to a very acute apex; achenes up to

1 -75 mm, the peripheral nearly as long as wide, sometimes

with a lacerate hyaline auricle up to 0-5 mm

(c) subsp. cyllenea