SLENDER THISTLE

(Carduus tenuiflorus)

(Photos: E. Cousins; a patch at Cape Jervis, flower head.)

This weed has been appearing on the foreshores at Cape Jervis over spring-early summer. As you can see from the photos, the plant stems sit upright, with the flower heads held high. The flowers are small (2-3cm), purple, and are around from September to December. They always occur at the end of a flowering stem, not along its length. Note the spiny bracts at the lower outside edge of these flowers. Later the flower produces two types of seeds: inner (about 85% of the seeds) and outer. These all have plumes for spreading by wind. Leaves are a dull green on top, paler underneath and hairy there. There’s a rosette of leaves at the base, but other leaves along the stems as well, forming ‘wings’. There can be multiple stems, ribbed and a bit hairy; these might be seen still standing long after the plant dies off in summer.