Stems erect, 20–80 (–120) cm. Cauline leaf-blades lanceolate to linear, reduced distally (becoming bractlike near heads), margins usually serrate apically, rarely entire. Peduncles stipitate-glandular, sometimes hispid as well. Involucres campanulate, (3.5–) 5–8 (–10) mm diam. Ray-florets (10–) 13–21 (–29); corolla laminae 6–12 mm. Disc-florets (20–) 33–70 (–108). 2n = 10, 12, 14.

Distribution

• Generated Map
• Legacy Map

Ark., Kans., Okla., Tex.

Discussion

Varieties 3 (3 in the flora).

Morphologic differences among the three varieties are slight and they form a closely coherent group within the genus; corresponding differences in geography, habitat, and chromosome number provide a rationale for maintaining the taxonomic and nomenclatural distinctions. B. L. Turner et al. (2003, vol. 1) treated var. hookerianum as including var. graniticum. B chromosomes sometimes are present and appear to increase the number by a pair (E. B. Smith 1966).

Selected References

None.

Lower Taxa

Croptilon hookerianum var. graniticum, Croptilon hookerianum var. hookerianum, Croptilon hookerianum var. validum

Key

1	Peduncles long-stipitate-glandular (longest hairs 0.4–0.5 mm, including gland), often slightly hispid proximal to heads; ray laminae 1–2.5 mm wide	Croptilon hookerianum var. validum
1	Peduncles short-stipitate-glandular (longest hairs 0.2–0.3 mm, including gland), never hispid; ray laminae (1.2–)2–3(–4) mm wide	> 2
2	Peduncles densely stipitate-glandular; ray laminae 1.2–2.2 mm wide; sandy habitats	Croptilon hookerianum var. hookerianum
2	Peduncles sparsely stipitate-glandular; ray laminae (1.5–)2–3(–4) mm wide; granitic habitats	Croptilon hookerianum var. graniticum