420 Karl M. Wiegand and Arthur J. Eames 



21. Helenium L. 

 1. H. autumnale L. (Including H. latifolium Mill.) Sneezeweed. 



Along streams and the borders of marshes and along the lake shore, in sandy 

 or gravelly calcareous soils; frequent. Aug. 20-Oct. 



Especially abundant on the gravel bars in the creeks of the basin, about the Cayuga 

 Marshes, and on the calcareous sandy shore of Cayuga Lake at Farley Point. 



W. Que. and w. Mass. to Man. and Oreg., southw. to Fla. and Ariz. ; infrequent 

 on the Atlantic Coastal Plain except in the maritime sands. 



22. Achillea (Vaill.) L. 



a. Leaves linear-lanceolate, serrate. [A. Ptarniica] 



a. Leaves bipinnately dissected into fine divisions. 1. A. Millefolium 



[A. Ptarmica L. Sneezeweed. 



Escaped from cultivation to roadsides and fields ; rare. July-Aug. 

 Highland Ave., Cayuga Heights, by roadside in shaded gully, 1913 (E. L. Palmer). 

 Probably not established. 

 Newf. to Mich, and Mass.; local. Introduced from Eu.] 



1. A. Millefolium L. Common Yarrow. 



A weed in fields and by roadsides, in various soils ; very common. June 10-Sept., 

 rarely later. 



General throughout most of N. A. Possibly introduced in cent. N. Y. Found also 

 in Eurasia. 



A form with rose-purple rays, forma roseum Rand & Redfield (Fl. Mt. Desert), 

 occurs occasionally, as : n. w. of Enfield Falls ; between Etna and Ringwood ; Ball 

 Hill, Danby (D.) ; Forest Home; and elsewhere. 



Some authors consider the yarrow adventive in N. Y. ; others believe it to be native ; 

 and some consider it both native and adventive. 



23. Anthemis (Mich.) L. 

 a. Rays white. 



b. Rays neutral ; achenes warty, 1.2-1.5 mm. long ; receptacle without chaff near 

 the margin; plant strong-scented; leaves finely 3-pinnately dissected. 



1. A. Cotula 



b. Rays pistillate; achenes not warty, about 2 mm. long; receptacle chaffy through- 

 out; plant not strong-scented; leaves 1-2-pinnately, and more coarsely, divided. 



2. A. arvensis, var. agrestis 

 a. Rays yellow; leaf divisions broader. [A. tinctorial 



1. A. Cotula L. May- weed. Dog Fennel. 



A weed on dry roadsides and in waste places, mostly in rather rich gravelly soils ; 

 very common. July-Nov. 



Generally distributed in N. A. except in the extreme North. Naturalized from the 

 Old World. 



2. A. arvensis L., var. agrestis (Wallr.) DC. Corn Chamomile. 



A weed in situations similar to the preceding but in heavier soil ; common. May 

 15-Aug. 



N. S. to Mich., southw. to Va. and Mo. ; also on the Pacific coast. Naturalized 

 from Eu. 



[A. tinctoria L. Yellow Chamomile. 



Found along Cayuga Heights Road in 1915, but not established. Common in 

 cultivation.] 



