(108) 



49. Achillea L. Yarrow. 



Superflua. Head co-flowerad; ray-flowers 6 

 to 6, ligulate, ovate. Involucre ovate; scales 

 imbricate, those of the receptacle hyaline. 

 Akenes marginate; pappus 0. U- 



1. A. MILLEFOLIUM L. Kay-flowors and disc 

 pale. — Common. Summer. - 



50. Matricaria L' Chamomile. 



Superflua. ^qualis. Scales of the invo- 

 lucre imbricate. Keceptacle conical, naked. 

 Akenes angulate. Pappus coroniform or 0. 

 Disc yellow; flowers of the ray white. — 



1. M. DiscoiDEA DC. Pappus 0; areola of 

 akene merely surrounded by a rim ; ray-flowers 

 white, depauperate.— Summer. Common. 



2. M. occiDENTALis Greene. Pappus coro- 

 niform, unequal, the side toward the ray con- 

 siderably developed, the inner side reduced to 

 a rim. — Contra Costa. Summer. 



51. Chrysanthemum L. 



Superflua. Involucre hemispherical, spread- 

 ing. Scales oo-seriate, imbricate, appressed. 

 Receptacle not conical, naked. Akenes short, 

 somewhat terete, costate, truncate at the apex; 

 pappus 0. 



1. C. SEGETUM L. Ray-flowers yellow. — 0. 

 Has been found near Oakland. Summer. 



