298 ASTER FAMILY 



(b) Pappus of the ray flower of scales and 



1-2 bristles; stems finally 4-10 in. high T.strigosa 

 b. Stems none, or less than an inch high at ma- 

 turity 



(1) Plants gray or white-hairy 



(a) Leaves linear, closely and finely gray- 



hairy; heads 12-20 mm. high T.exscapa 



(b) Leaves spatulate, densely woolly; heads 



7-10 mm. high T. spathuldta 



(2) Plants green, hairy to smooth 



(a) Heads 2-3 cm. high, without the rays T.Rothrockii 



(b) Heads 6-12 mm. high 



x. Leaf blades hairy; -heads 10-12 mm. 



high T. scapigera 



y. Leaf blades smooth ; heads 5-8 mm. 



high T. glabella 



TRAGOPOGON Linne 1753 SALSIFY, GOATSBEARD 



(Gr. tragos, goat, pogon, beard, from the pappus) 



PI. 37, fig. 5. 



Heads with yellow or purple perfect strap-flowers, achenes linear, 

 round or 5-angled, ribbed, with a long beak, pappus of brownish, plumy, 

 interwoven bristles ; receptacle flat, without chaff, involucre cylindric or bell- 

 shaped, the equal bracts in 1 row ; heads solitary ; leaves alternate, entire ; 

 biennial or perennial. 



1. Heads purple; bracts of the involucre much long- 



er than the flowers T. porrifolius 



2. Heads yellow ; bracts of the involucre equalling 



or shorter than the flowers T. pratensis 



VERNONIA Schreber 1791 IRON WEED 

 (Named for Vernon, an English botanist) 



Heads without rays, the tube-flowers usually purple, perfect, achenes 

 ovate to oblong, 8-10-ribbed, pappus mostly of hair-like bristles ; receptacle 

 flat, without chaff, involucre hemispheric to oblong, the bracts imbricated 

 in several to many rows ; heads in panicled cymes ; leaves usually alternate, 

 simple ; perennial. 

 Leaves linear to lance-oblong, spiny-toothed to nearly 



entire ; heads 6-10 mm. high V. fasciculdta 



