Stephanomeria exigua

Nuttall

Trans. Amer. Philos. Soc., n. s. 7: 428. 1841.

Common names: Small wirelettuce skeletonplant
Illustrated
Treatment appears in FNA Volume 19. Treatment on page 353. Mentioned on page 350, 351, 352, 354, 355.

Annuals, 10–200 cm (taproots relatively large). Stems single, branches divaricately or freely spreading, glabrous or sparsely pubescent. Leaves withered at flowering; basal blades linear to oblanceolate, runcinate, 3–10 cm, margins pinnately lobed; cauline much reduced, bractlike. Heads borne singly or clustered along branches or in paniculiform arrays. Peduncles 2–10 mm (along branches), or 10–40 mm (in paniculiform arrays). Calyculi of appressed or reflexed bractlets (glabrous, pubescent, or stipitate-glandular). Involucres 5–7 mm (glabrous, puberulent, or densely stipitate-glandular). Florets 5–11. Cypselae light tan to dark brown, 2.1–6.8 mm, faces smooth to tuberculate, grooved; pappi of 5–24 tan or white bristles (falling or widened bases persistent, bases connate in groups of 2–4 distal portions breaking off), plumose on distal 50–85%. 2n = 16.

Distribution

V19-552-distribution-map.gif

Ariz., Calif., Colo., Idaho, N.Mex., Nev., Oreg., Tex., Utah, Wash., nw Mexico.

Discussion

Subspecies 5 (5 in the flora).

Selected References

None.

Key

1 Heads borne singly or clustered along branches; peduncles 2–10 mm > 2
1 Heads in paniculiform arrays; peduncles 10–40 mm > 3
2 Calyculus bractlets appressed; peduncles 2–5 mm Stephanomeria exigua subsp. coronaria
2 Calyculus bractlets reflexed; peduncles 5–10 mm Stephanomeria exigua subsp. macrocarpa
3 Calyculus bractlets reflexed Stephanomeria exigua subsp. carotifera
3 Calyculus bractlets appressed > 4
4 Peduncles and involucres densely glandular Stephanomeria exigua subsp. deanei
4 Peduncles and involucres glabrous or sparsely glandular Stephanomeria exigua subsp. exigua