Prairie Groundsel

Packera plattensis is abundant, widespread, and almost weedy. Putative hybrids with other species are known. Plants in mesic, remnant prairies in the east are sometimes stoloniferous.

Biennials or perennials, 20–60+ cm; rhizomatous and/or fibrous-rooted (bases erect to suberect), sometimes stoloniferous (mostly eastern populations). Stems 1 or 2–3, clustered, floccose-tomentose proximally and in leaf axils, otherwise sparsely tomentose or glabrescent. Basal leaves (and proximal cauline) petiolate; blades narrowly elliptic to elliptic-ovate or oblanceolate to suborbiculate or sublyrate, 20–70+ × 10–30+ mm, bases tapering to rounded or abruptly contracted, margins subentire to crenate, serrate-dentate, or pinnately lobed (abaxial faces floccose-tomentose, especially along midribs, ± glabrescent). Cauline leaves gradually reduced (petiolate, sublyrate or pinnatisect, abaxial faces sparsely hairy; distals sessile, subentire to irregularly dissected). Heads 6–20+ in open or congested, corymbiform arrays. Peduncles conspicuously bracteate, sparsely to densely tomentose. Calyculi inconspicuous. Phyllaries 13 or 21, green (tips sometimes cyanic), 5–6+ mm, densely tomentose proximally, glabrescent distally. Ray florets 8–10; corolla laminae 9–10 mm. Disc florets 60–70+; corolla tubes 2.5–3.5 mm, limbs 3.5–4.5 mm. Cypselae 1.5–2.5 mm, usually hirtellous, sometimes glabrous; pappi 6.5–7.5 mm. 2n = 46, 92.

Senecio plattensis Nuttall, Trans. Amer. Philos. Soc., n. s. 7: 413. 1841; S. pseudotomentosus Mackenzie & Bush

Packera plattensis, commonly known as prairie ragwort or prairie groundsel, is a species of the genus Packera and family Asteraceae. It used to be placed in the genus Senecio.

Prairie groundsel is found throughout the tallgrass prairie region. It blooms fairly early for a prairie wildflower: from April to July depending on the climate.

It is easily confused with golden ragwort (Packera aurea) which has a hairless stem and heart-shaped basal leaves, and Senecio integerrimus, which has leaves that are mostly entire instead of fern-like, and much larger basal leaves.