COMPOSITAE 197 



abnndant in low woods, especially along the Missouri Eiver. September- 

 October. 



17. A. lateriflonis (L.) Britton. l°-3° high, glabrate : branches 

 puberulent : leaves lanceolate to oblanceolate, 3' long, sparingly serrate, 

 sessile or nearly so : heads %"-i." broad, one-sided on the branches of a 

 large panicle: rays white, X"-\Y' long.— BlufE woods near Sibley. 

 September-October. 



12. ERIGBRON L. Fleabanb. 

 Ours are herbs with corymbose-paniculate, long-peduncled heads of 

 flowers. Leaves alternate. Involuoral scales subequal, in one or two 

 series. Eay flowers pistillate. Disk flowers fertile. Achenes flattened, 

 2-nerved. 



Stem leaves clasping, thin. 1. E. Philadelphicus. 

 Stem leaves not clasping. 



Leaves ovate-lanceolate, toothed. 2. E. annuus. 



Leaves linear-lanceolate, entire. 3. E. ramosus. 



1. B. Philadelphicus L. Perennial, l°-2° high, hairy : leaves spatu- 

 late to obovate, toothed : heads not numerous : rays 100-150, light rose- 

 purple : pappus simple. — Rather common in moist woods. May-June. 



2. B. annuus (L. ) Pers. Annual, l°-4° high, closely pubescent: 

 leads numerous : rays 40-70, white : pappus double. — Very abundant in 

 fields. May-August. 



3. E. ramosus ( Walt. ) B.S.P. Resembles the last, but pubescence 

 more appressed and leaves narrower and usually entire. — Abundant in 

 dry fields. May-August. 



14. LEPTILON Raf. 

 Annual herbs with alternate leaves. Involucre in 1-2 series. Ray 

 flowers pistillate. Disk flowers fertile. Achenes flattened. Pappus 

 simple. 



Plants tall and erect. 1. L. Canadense. 



Plants diffusely spreading. 2. L. divaricatum. 



1. L. Canadense (L. ) Britton. HoESB Wbbd. 1°-8° high, pubes- 

 cent : lower leaves spatulate, sparingly toothed, the upper linear, entire : 

 heads numerous, panioled, small : rays whitish. — A very common weed. 

 June-October. 



2. L. divaricatum (Michx. ) Raf. Low Horse Weed. 3'-12' high, 

 strigose- pubescent : leaves linear to awl-shaped : heads corymbose : rays 

 purplish-white. — Occurs locally in sandy fields throughout the county. 

 June-October. 



15. ANTBNNARIA Gaertn. Everlasting. Indian Tobacco. 

 Woolly perennial herbs with clustered, basal leaves and alternate 

 caaline leaves, and capitate or corymbose dioecious heads of flowers. 

 Involuoral bracts imbricated, scarious margined. 



