Cirsium acaule

Cirsium acaule, the stemless or dwarf thistle, is a low-growing herbaceous perennial in the Asteraceae forming a flat basal rosette pressed close to the ground from a thick, deep taproot. The leaves are oblanceolate in outline, 8–20 cm long, deeply pinnately lobed with triangular, undulate, spiny-toothed lobes; the upper surface is dark green and glossy and the lower surface paler, with stout yellow spines along the margins and at the tips of the lobes. The plant typically has no, or only a very short, stem so that one to several flower heads sit directly within the rosette; occasional plants from the southern part of the range develop a short leafy stem up to 30 cm tall. Flower heads are solitary or in small clusters, 3–5 cm across, with reddish-purple tubular florets and an ovoid involucre of imbricate, lanceolate, spine-tipped phyllaries. Fruits are oblong, pale brown achenes 4–5 mm long crowned with a long feathery pappus. It grows on dry calcareous grasslands and chalk downs across western and central Europe.