HallCompositae of Southern California. 211 



1. A. Cotula L., Sp. PL 894 (1753). MAYWEED. 



Annual, 2 to 6 dm. high, nearly glabrous: leaves mostly 

 sessile, finely and pinnately dissected into linear acute lobes: 

 involucre about 7 mm. broad, shorter than the disk, its bracts 

 imbricated in several series : rays 10 to 20, white, 8 to 10 mm. 

 long, at length reflexed : chaff of the receptacle narrow and acute 

 or bristle-like : achenes rugose, 10-ribbed. 



Pastures and waste ground. Naturalized from Europe. 



84. ACHILLEA L. 



Ours an erect strongly scented perennial herb with finely 

 dissected alternate leaves. Heads radiate, cymose at the ends of 

 the stem and branches. Kay-flowers few, pistillate, fertile. In- 

 volucral bracts appressed, imbricated in few series, the outer 

 shorter. Receptacle nearly flat, the chaff membranous and sub- 

 tending fertile disk-flowers. Achenes linear or oblong to obovate. 

 obcompressed. Pappus none. 



1. A. Millefolium L., Sp. PL 899 (1753). COMMON YARROW. 

 MILFOIL. 



Perennial from horizontal rootstocks, the stems simple, 3 to 9 

 dm. high: herbage glabrate or sparsely villous to lanate-pubes- 

 cent: leaves linear-lanceolate in outline, the petiole with dilated 

 base, the ultimate segments linear and generally with setaceous 

 callous tips : cyme compound, mostly flat-topped : involucre ovoid, 

 about 5 mm. high : rays 4 to 6, white or pink, about 3 mm. broad : 

 achenes linear, with a more or less obvious wing or margin. 



Widely distributed in Europe, Asia, and North America. In 

 Southern California we have two forms, as follows : 



f. Calif ornica (Pollard) Hall, comb. nov. A. Calif ornica 

 Pollard, Bull. Torr. Club xxvi. 369 (1899). Plant robust, the 

 lower branches of the inflorescence elongated : stems sparsely pu- 

 bescent, the foliage green and glabrate : tips of the ultimate leaf- 

 segments harsh and spinulose : achenes narrowly margined. The 

 type of A. Calif ornica was "collected by Mr. H. W. Henshaw on 

 the Calif ornian sea coast at Santa Ysabel, May, 1893," ace. to 

 Pollard ; Santa Ysabel, at the western base of Cuyamaca Mt., San 

 Diego Co., and about 20 kilometers inland, being probably in- 



