5.
Psilostrophe tagetina
(Nuttall) Greene, Pittonia. 2: 176. 1891.
Riddellia tagetina
Nuttall, Trans. Amer. Philos. Soc., n. s. 7: 371. 1841 (as tagetinae);
Psilostrophe tagetina
var.
grandiflora
(Rydberg) Heiser;
P. tagetina
var.
lanata
A. Nelson
Biennials or perennials
(rarely flowering first year), 10—30(—60+) cm.
Stems
arachno-villous (gray to gray-green).
Heads
in ± loose to crowded, corymbiform arrays.
Peduncles
(3—)12—20(—40) mm.
Involucres
4—8 mm.
Rays
3—4(—6); laminae (3—)7—14+ mm, spreading in fruit.
Disc florets
6—9(—12).
Cypselae
usually glabrous, sometimes hirtellous and/or gland-dotted;
pappi
of (4—)6—8 elliptic or lanceolate to lance-subulate scales 2—3+ mm.
2
n
= 32.
Flowering (Apr—)May—Sep(—Dec). Desert scrub, grasslands, limestone soils, saline flats, sandy soils; (300—)600—2400 m; Ariz., N.Mex., Tex., Utah; Mexico (Chihuahua, Coahuila).
See comments under 6.
Psilostrophe villosa
.
