ANTHEMIS COMPOSITE 361 



ACHILLEA 



rigid wings or callous margins, sessile. 



--*--- Heads slender-peduncled, discoid, heterogamous : pistillate 

 flowers apetalous : style deciduous. 



76 COTULA Rays wanting : receptacle flat or convex : achenes raised on 

 pedicels. 



*---*- Heads discoid, heterogamous, the few pistillate flowers 

 with tubular 2-3-toothed or lobed corolla, or sometimes homogamous : 

 style deciduous. 



76 Tanacetum Heads corymbosely cymose or glomerate, many-flowered : 



achenes 5-ribbed or 3-5 angled, with broad truncate summit : anther- 

 tips broad and mostly obtuse. 



77 Artemisia Heads paniculately disposed, small : achenes obovate or 

 oblong, mostly with a small epigynous disk : anther-tips pointed. 



70 ANTHEMIS L. Sp. 893. 



Annual or perennial herbs with pinnatifid or dissected alter- 

 nate leaves and usually large heads of both tubular and ligulate 

 flowers on peducles terminating the branches. Involucre hem- 

 ispherical, many-flowered, of comparatively small imbricated 

 bracts the outer successively shorter. Receptacle convex to ob- 

 long, chaffy at least toward the summit . Bays pistillate and 

 fertile or neutral. Disk-flowers perfect, fertile, yellow, their 

 corollas with 5-cleft limb. Anthers obtuse and entire at base. 

 Achenes terete, 4-10-angled or ribbed, glabrous, the truncate 

 summit naked, or with a very short coroniform or dentiform 

 pappus. 



A. COTULA L. Sp. 894. Unpleasant-scented annual, 1-2 feet high, diffu- 

 sely branched : leaves finely tri-pinnately dissected : receptacle conical, 

 with bristly bracts only near the centre : rays mostly neutral, white : 

 achenes 10-ribbed, rugose or tuberculate* Common along roadsides and 

 waste places. Naturalized from Europe. 



A ARVENSIS L. Sp. 894. Annual or sometimes biennial, not fetid: stems 

 usually much branched, about a foot high, the branches decumbent at base : 

 leaves once or twice p nnately parted into linear-lanceolate acute lobes : 

 heads rather long-peduncled : bracts of the involucre obtuse, whitish-scari- 

 ous: receptacle conical, its bracts acuminate-lanceolate: rays white: 

 achenes oblong, obtusely 4-angled : pappus a mere crown. In fields and 

 waste places. Naturalized from Europe. 



71 ACHILLEA L. Sp. 898, 



Perennial herbs with erect leafy stems, alternate leaves and 

 small radiate heads corymbose at the ends of the stem and 

 branches. Involucre campanulate or obovoid, of small imbri- 

 cated bracts, the outer shortest. Receptacle conical to oblong; 

 chaffy. Ray-flowers pistillate, fertile, short and broad. Style- 

 branches truncate. Anthers obtuse and entire at base Achenes 

 oblong or obovate, obcompressed, callous-margined, glabrous. 

 Pappus none. 



A. Millefolium L. Sp. 899. From villous-lanate to glabrate: stems 

 simple or corymbosely branched above, 1-2 feet high : leaves narrowly 



