Marsh Ragwort - Senecio congestus
Fibrous-rooted annual to short-lived perennial. Stems hollow, erect, 15–80 cm. Herbage villous to sparsely tomentose. Leaves short-petiolate below, mainly cauline at flowering; blades oblanceolate to spatulate, dentate to shallowly lobed, 5–15 cm long, not much reduced but becoming sessile above. Inflorescence corymbiform with 6 to 20 heads, somewhat congested. Heads radiate; involucres 5–10 mm high; phyllaries ca. 21, pale, sometimes pink-tipped. Rays ca. 21; ligules 5–9 mm long. Disk corollas 6–10 mm long. Achenes glabrous (Lesica 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX)
Slightly brackish seasonal wetland margins and wet meadows.