ERIGERON 269 



like bristles; receptacle flat, hairy or bristly, involucre hemispheric to 

 cylindric, the bracts in 1 series, more or less united ; heads solitary or some- 

 what panicled ; leaves alternate or opposite, pinnately parted or dissected ; 

 annual. 



1. Leaves mostly opposite, strong-scented; rays us- 



ually 2-5, 3-4 mm. long D. papposa 



2. Leaves mostly alternate, not strong-scented ; rays 



about 12, 6 mm. long D. a urea 



Erigerox Linne 1753 Daisy 

 (Gr. cr, spring, geron, old man, from the woolly heads and time of blooming) 



(Wyomingia Nelson) 

 PL 38, fig. 3. 

 Heads with white, violet or purple pistillate ray-flowers, disk-flowers 

 yellow, perfect, achenes flattened, usually 2-nerved, pappus of hair-like 

 bristles in 1-2 rows; receptacle flat, without chaff, involucre hemispheric 

 to bell-shaped, the bracts nearly equal in 1-2, rarely 3-4 rows; heads soli- 

 tary or in corymbs or panicles ; leaves alternate or basal, entire to pinnatifid ; 

 annual or perennial. 



1. Rays inconspicuous, short or wanting, usually 



erect; leaves entire 



a. Heads in a flat-topped corymb or panicle E. acris 



b. Heads in a narrow raceme E. a. racemosus 



2. Rays conspicuous, spreading or flat ; leaves vari- 



ous 

 a. Bracts of the involucre in 1-2 nearly equal 

 rows 

 (1) Perennial, as shown by old stems, runners, 

 rootstocks, caudexes, etc. 



(a) Stems spreading by runners. 2-10 in. 



high ; leaves linear to spatulate ; rays 

 • white, rose or purplish E. flagellaris 



(b) Stems without runners 



x. Leaves basal, deeply divided or cleft 

 1-3-ternate. 3-5-fid or pinnatifid ; stems 

 tufted, 2-8 in. high; heads 1-1.5 cm. 

 wide; rays white to blue-purple E. compdsifus 



y. Leaves entire or toothed 



(x) Involucres copiously white or black 

 cobwebby-woolly, especially at 

 base 



