1.
Helenium amarum
(Rafinesque) H. Rock, Rhodora. 59: 131. 1957.
Yellowdicks, fiveleaf sneezeweed
Gaillardia amara
Rafinesque, Fl. Ludov., 69. 1817 (as Galardia);
Helenium
tenuifolium
Nuttall
Annuals,
10—100 cm.
Stems
1—3(—15), usually branched distally, not winged, glabrous or sparsely hairy.
Leaves
glabrous or sparsely hairy; basal blades linear to ovate, entire or pinnately toothed or lobed to pinnatifid; mid and distal blades linear, entire.
Heads
(1—)10—150(—250+) per plant, in paniculiform arrays.
Peduncles
3—11 cm, sparsely hairy.
Involucres
hemispheric to globose or globoid, 5—9 × 6—10 mm.
Phyllaries
moderately to densely hairy.
Ray florets
8—10, pistillate, fertile; corollas yellow, 4.5—14 × 2—10 mm.
Disc florets
75—250+; corollas yellow proximally, yellow to yellow-brown or purple distally, 1.6—2.7 × 0.8—1.2 mm, lobes 5.
Cypselae
0.7—1.3 mm, moderately to densely hairy;
pappi
of 6—8 entire, aristate scales 1—1.8 mm.
Varieties 2 (2 in the flora): se United States, n Mexico.
