Biennials, 30-90 cm. Leaves: basal 2-pinnate, 6-15 cm, lobes 3-15(-20+) × 1-6 mm; cauline 10-50. Heads 15-100 per stem. Pedun-cles 1-6 cm. Phyllaries yellowish, 4-8 × 2-4 mm. Ray florets 0. Disc florets 20-40; corollas yellow, 2.5-3.5 mm, tubes 1.5-2 mm, throats campanulate, 0.8-1.5 mm, lengths 1-1.5 times lobes. Cypselae 3-4.5 mm, ± villous; pappi of 16-22 scales 0.5-1.5 mm.

Duration: Biennial

Nativity: Native

Lifeform: Forb/Herb

General: Biennial herbs, to 90 cm tall, from a taproot; stems solitary, branching above, glabrate to tomentose.

Leaves: Basal leaves usually present; cauline leaves at least 10 per stem, alternate, smaller than basal leaves; blades up to 15 cm long and 4 cm wide, bipinnately dissected, the lobes linear, 1-2 mm wide, evenly tomentose or cansescent on both sides.

Flowers: Flower heads yellowish, discoid, up to 100 per stem in corymbose arrays; involucres turbinate to campanulate, 5-6 mm high, the bracts (phyllaries) 2-4 mm wide, with yellow-membraneous tips; florets all discs, 30-90 per flower head, yellowish.

Fruits: Achenes 3-4 mm long, evenly pubescent with 1 mm long hairs; topped with a pappus of 16-22 linear oblong scales, these about 1 mm long.

Ecology: Found in gravelly, rocky, open, and disturbed sites, often on limestone or sandy soils, from 5,000-7,500 ft (1524-2286 m); flowers May-August.

Distribution: AZ, NM, CO, TX, OK, and KS

Notes: This species can be distinguished from H. filifolius based on its biennial duration, simple taproot, single stem, and abundance of cauline (stem) leaves. There are 2 recognized varieties; var. canotomentosus is the variety present in Arizona and New Mexico.

Ethnobotany: Unknown

Etymology: Hymenopappus comes from Greek hymen for membrane and pappos for pappus, for the chafflike pappus scales; flavescens is Latin for becoming yellow, which refers to the color of the florets.

Synonyms: Hymenopappus robusta

Editor: AHazelton 2017