CARDUACEAE 1297 



1. Anthemis Cotula L. Annual, often finely pubescent, heavy-scented. Stems 1-8 

 dm. "tall, more or less branched : leaf-blades finely thrice pinnately dissected : involucres 

 flattish : bracts linear to oblong, pubescent, 3-5 mm. long : ray-flowers mostly neutral ; 

 ligules white, linear or oblong, 1-2 cm. long : disk yellow : receptacle conic : achenes 

 about 1 mm. long, 10-ribbed, rugose or tuberculate. 



In various situations, nearly throughout North America, except the extreme north. Naturalized 

 from Europe. Spring to fall. Mayweed. Dog's Camomile. Dog Fennel. 



131. ACHILLEA L. 



Perennial caulescent strong-scented herbs. Leaves alternate : blades toothed, pinnatifid 

 or dissected. Heads radiate, in corymbs. Involucres short, several-flowered : bracts ap- 

 pressed, in several series, distinct. Receptacle more or less convex : bractlets membranous. 

 Ray-flowers pistillate, fruit-producing : ligules white or pink. Disk-flowers perfect, fruit- 

 producing. Anthers obtuse and entire at the base. Stigmas of the disk-flowers obtuse. 

 Achenes slightly flattened, more or less broadened upward. Pappus wanting. 



1. Achillea Millefolium L. Foliage villous and cottony, bright green. Stems 2-9 

 dm. tall, sometimes branched, angled : leaf-blades twice or thrice pinnately parted, 5-20 

 cm. long, mostly oblong in outline, the lower ones petioled : corymbs many-flowered, 

 compound, 2-10 cm. broad : involucres 4-5 mm. high ; bracts oblong to lanceolate, in 3-4 

 series, with transparent margins : ray-flowers 4-5 ; ligules white, suborbicular, crenate. 



In dry or stony soil, nearly throughout temperate North America, especially eastward. Natural- 

 ized from Europe and Asia. Summer and fall. Yarrow. Milfoil. 



132. CHRYSANTHEMUM L. 



Annual or perennial caulescent herbs, often heavy-scented. Leaves alternate : blades 

 toothed, incised or dissected, the segments coarse. Heads usually radiate. Involucres flat 

 or hemispheric : bracts in several series, the inner longer than the outer. Receptacle flat 

 or hemispheric, naked. Ray-flowers pistillate, fruit-producing : ligules white, pink or 

 yellow. Disk-flowers perfect, fruit-producing : corollas with terete or winged tubes. An- 

 thers entire and obtuse at the base. Stigmas of the disk-flowers truncate, brush-like. 

 Achenes terete or angled. Pappus a scaly cup, or wanting. 



1. ChryBanthemum Leucdnthemum L. Perennial, glabrous or nearly so. Stems 

 2-9 dm. tall, usually simple : leaf-blades spatulate to linear, 2-10 cm. long, serrate or pin- 

 natifid : heads showy, long-peduncled : involucre flattish ; bracts linear-lanceolate to linear, 

 4-7 mm. long, obtuse : ray -flowers numerous ; ligules white or pink, 1-2.5 cm. long, rarely 

 tubular : disk light yellow, 1-2 cm. broad : pappus wanting. 



In fields, meadows and waste grounds, nearly throughout North America. Naturalized from 

 Europe and Asia. Spring to fall. Daisy. 



133. MATRICARIA L. 



Annual or perennial caulescent odorous herbs. Leaves alternate : blades 1-3-dissected, 

 the segments filiform or narrowly linear. Heads radiate or rarely discoid. Involucres 

 hemispheric : bracts in few series, appressed, the inner longer than the outer. Receptacle 

 conic or more elongated, or ovoid, naked. Ray-flowers pistillate, fruit-producing : ligules 

 white. Disk-flowers perfect, fruit-producing : corollas yellow. Anthers obtuse and entire 

 at the base. Stigmas of the disk-flowers truncate, brush-like. Achenes 3-5-ribbed or 3- 

 5-nerved. Pappus wanting or a mere border, sometimes slightly toothed. Camomile. 



1. Matricaria Chamomilla L. Annual, aromatic, resembling Anthemis Cotula. 

 Foliage glabrous or nearly so : stems 2-4 dm. tall, sometimes branched at the base, and the 

 branches decumbent : leaf-blades 2-8 cm. long, twice or thrice pinnately-parted : heads 5-6 

 mm. high : involucral bracts oblong, 2-2.5 mm. long: ray-flowers 15-21 ; ligules white, lin- 

 ear or linear-oblong, 5-7 mm. long: disk ovoid or conic: achenes 1.5-2 mm. long, the 

 inner face unequally 5-ribbed : pappus an obscure border or wanting. 



In waste places and fields. New York t« Georgia. Spring and summer.— 3/. Chamomilla coi-ondta 

 Gay, has a scarious, cleft, toothed or one-sided pappus surmounting the achenes of the ray and most of 

 those of the disk, it occurs in southern Texas and adjacent Mexico. Like the species, native of Europe. 



134. TANACETUM L. 



Perennial or sometimes annual caulescent often strongly aromatic herbs. Leaves 

 alternate : blades 1-3-pinnately dissected or divided. Heads discoid or rarelv slightly 



82 



