Dicotyledones. 119 



I. Anthemis Cdtula, L. (Gr., kotyle, a small measure or cup.) Mayweed 

 or Dog Fennel. Strong-scented and pungent annual, branched, i to 2 feet high. 

 Leaves finely 1-3 pinnately dissected. Rays white, 10-18, neutral or with an abor- 

 tive pistil. Pappus none. Receptacle with bristly chaff near the summit only. 

 By roadsides or in fields and waste places. 



IV. ACHILLEA. Yarrow. 



(Named for Achilles, who is supposed to have discovered its virtues.) 



Heads small, with both radiate and tubular flowers, in corymbose 

 clusters at the ends of the branches. Ray flowers white, few and 

 fertile. Disk flowers yellow. Bracts of the involucre imbricated in 

 a few rows, appressed. Receptacle chaffy, convex, or flattish. Pappus 

 none. Achenes flattened and somewhat margined. Perennial herbs, 

 with serrate, pinnatifid, or finely dissected, alternate leaves. 



I. Achillea Millefdlium, L. (L., mille, thousand; folium, leaf.) Common 

 Yarrow or Milfoil. Perennial, from a horizontal rootstock, becoming i to 2 

 feet high. Leaves twice pinnatifid into slender segments. Flowers in a compound, 

 flat-topped corymb. Heads small and numerous ; ray flowers 4-5, mostly white, 

 sometimes pink or purple ; bracts of the involucre oblong, acute. Habitat various. 



V. CHRYSa'nTHEMUM. Ox-eye Daisy. 



(Gr., chrysanthemon, golden flower.) 



Heads composed of both tubular and ray flowers ; the rays fertile, 

 white, rose-colored, or yellow. Disk flowers with flattened tubes, per- 

 fect. Scales of the involucre imbricated in several rows. Receptacle 

 flat or convex, without chaff". Biennial, perennial, or annual herbs, 

 with mostly large heads borne on long peduncles. 



I. Chrysanthemum LeuQdnthemum, L. (Gr., /<?«^oj, white ; anthemon,Roviex^ 

 Ox-eye or White Daisy. Perennial, i to 3 feet high. Branches terminated by 

 a single large head on a long peduncle. Rays white, 20-30. Pappus none. Basal 

 leaves petioled, spatulate, incised. Upper leaves spatulate to linear, cut-toothed, 

 clasping at the base. Scales of the involucre with scarious and brown margins. 

 In pastures, fields, and waste places. 



VI. SENECIO. Groundsel. 

 (L., senex, old man, from the hoariness of some species.) 



Heads usually consisting of both disk and ray flowers. Ray flowers, 

 when present, pistillate ; disk flowers perfect and fertile. Both disk and 

 ray flowers usually yellow. Pappus of numerous fine capillary bristles 



