ASTERACEAE. 397 



Tribe 8. ANTHEM IDEAE. Mayweed Tribe. 



Strong-scented or aromatic herbs, with alternate, 

 mostly dissected, pinnately parted or pinnatifid leaves. 

 Involucral bracts imbricated, commonly dry and scari- 

 ous or with scarious margins. Receptacle naked or with 

 chaff-like bracts. Rays present or none. Pappus none 

 or a short scarious crown. 



Receptacle chaffy; rays present. 



Heads solitary; rays 14-20. 57. Anthemis. 



Heads in a terminal corymb; rays 4-5. 58. Achillea. 



Receptacle naked; rays none. 



Marginal flowers destitute of corollas, 60. Cotula. 



Marginal flowers not apetalous. 



Heads solitary, terminating leafy branches. 59. Matricaria. 

 Heads small, in panicled racemes or spikes. 61. Artemisia. 



57. ANTHEMIS L. 



Annual or perennial ill-scented branching herbs, with 

 finely dissected alternate leaves, and radiate heads soli- 

 tary on terminal peduncles. Involucre hemispheric, its 

 bracts imbricated in several series, scarious-margined, 

 appressed, the outer shorter. Receptacle convex or 

 conical, chaffy at least toward the summit; the chaff 

 subtending the disk-flowers. Ray-flowers pistillate, fer- 

 tile or neutral, white or yellow. Disk-flowers perfect, 

 yellow, the limb 5-cleft. Achenes oblong, ribbed or 

 striate. Pappus none. 



1. A. cotula L. (Mayweed.) Annual, glabrous or sometimes 

 pubescent above, glandular, much branched, 2-6 dm. high; leaves 

 mostly sessile, finely 1-3-pinnately dissected into narrow acute 

 lobes; heads about 2 cm. broad, including the rays; these 10-18, 

 white, neutral, mostly 3-toothed; receptacle conic, its chaff bristly, 

 subtending the central flowers; achenes 10-ribbed, rugose or glandu- 

 lar-tuberculate. 



Common in moist places in all the valleys. Native of Europe. 

 April-June. 



58. ACHILLEA L. (Yarrow, Milfoil.) 



Perennial herbs, with finely dissected leaves, and small 

 heads of both tubular and ligulate flowers corymbose at 

 the ends of the stem and branches. Involucre ovoid or 

 campanulate, its bracts compressed, imbricated in few 

 series. Receptacle flat or convex, chaffy; chaff mem- 



