Mayweed Tribe 435 



57. ACHZLLEA 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- 

 branous, subtending the disk-flowers. Ray-flowers white 

 or pink, pistillate. Disk-flowers perfect, fertile, yellow. 

 Achenes oblong or obovate, slightly compressed. Pappus 

 none. 



1. A. lanulosa Nutt. Pubescent or nearly glabrous, simple or 

 corymbosely branched above, 3-6 dm. high; basal leaves and 

 those of the sterile shoots petioled, those of the stem sessile, all 

 narrowly oblong or lanceolate in outline, finely dissected into 

 narrow pinnatifid segments; heads numerous, 4-6 mm. broad, in 

 terminal compound dense corymbs; rays 4-6, white. 



Rather common in the pine belt of the San Gabriel and San Bernardino 

 Mountains. 



58. MATBICABIA L. 



Annual or perennial herbs with alternate leaves dis- 

 sected into filiform or narrowly linear segments, and 

 discoid or radiate peduncled heads. Involucre hemi- 

 spheric, its bracts imbricated in few series. Receptacle 

 conic or elongated, naked. Rays in ours wanting. 

 Disk-flowers yellow, perfect, fertile, 4-5-toothed. Achenes 

 3-5-ribbed. Pappus a coroniform border or none. 



1. M. matricariodes (Less.) Porter. Annual, glabrous; stems 

 leafy, becoming much branched, often more or less decumbent, 

 1-3 dm. high; leaves 2-3-pinnately dissected into linear acute 

 lobes; heads numerous, 6-8 mm. broad; involucral bracts oval 

 or oblong, green with broad white scarious margins, much shorter 

 than the ovoid disk ; achenes oblong, faintly nerved ; pappus an 

 obscure crown. (M. discoidea DC.) 



Frequent along roadsides and in waste places. May-July. 



