Silphium radula

Nuttall
Trans. Amer. Philos. Soc., n. s. 7: 341. 1840.
Common names: Roughleaf rosinweed
Endemic
Treatment appears in FNA Volume 21. Treatment on page 80. Mentioned on page 78, 82.

Plants caulescent, 30–250 cm; fibrous rooted. Stems terete, scabrous, hispid, or hirsute. Leaves: basal persistent or caducous, petiolate; cauline alternate or opposite, petiolate or sessile; blades lanceolate to ovate, 2–22 × 0.5–8 cm, bases attenuate to round, margins coarsely dentate or entire, apices acuminate to acute, faces scabrous, hispid, or hirsute. Phyllaries 18–37 in 2–4 series, outer appressed or reflexed, apices acute, abaxial faces scabrous. Ray florets 12–30+; corollas yellow. Disc florets 100–175; corollas yellow. Cypselae 10–17 × 7–15 mm; pappi 2–5 mm.

Distribution

V21-182-distribution-map.gif

Ark., Kans., La., Mo., Okla., Tex.

Discussion

Varieties 2 (2 in the flora).

Selected References

None.

Key

1 Basal leaves caducous; ray florets 20–30+ Silphium radula var. radula
1 Basal leaves persistent; ray florets 12–18 Silphium radula var. gracile
... more about "Silphium radula"
Jennifer A. Clevinger +
Nuttall +
Roughleaf rosinweed +
Ark. +, Kans. +, La. +, Mo. +, Okla. +  and Tex. +
Trans. Amer. Philos. Soc., n. s. +
Undefined (tribe Undefined) subtribe Enceliinae +, Undefined (tribe Undefined) subtribe Engelmanniinae +, Undefined (tribe Undefined) subtribe Spilanthinae +, Undefined (tribe Undefined) subtribe Verbesininae +  and Undefined (tribe Undefined) subtribe Zinniinae +
Silphium radula +
Silphium +
species +