356 IOWA ACADEMY OF SCIENCE 



116. Prenanthes alba L. "White Lettuce, Rattlesnake-root. 

 L., 4. — 6.2 mm. W., .8 — 1.4 mm. C, rich dark brown. S., 

 linear oblong, contracted at the base but not at the apex ; some- 

 what four-angled with seventeen to twenty long striations ; pap- 

 pus rusty brown. 0., quite common. Native. 



117. Hieraciiim aurantiafiim L. Orange Hawkweed, Devil's 

 Paint-brush. L., 1.8 — 2.4 mm. W., about .3 mm. C, dead 

 black. S., fluted cylindrical with ten longitudinal ridges which 

 dilate slightly at the apical end; with very fine hairs about 15 

 io 20 mm. arranged on the ridges and pointing towards the apical 

 end. 0., very common in grass seed. Naturalized from Europei. 



118. Hieraciiim scabrum. Michx. L., 2. — 2.8 mm. W., 

 .2 — .4 mm. Color, dead black. S., fluted cylindrical, expanded 

 at the extreme apex and more attenuate at the base than 

 Uieracium aurantiacam; hairs on the ridges also slightly more 

 numerous. 0., fairly common in pastures. Native. 



