Sonchus - Sow-thistle family

Sonchus arvensis Perennial Sow-Thistle Seen in grassy roadside verges, attractive, tall plant with capitula that droop over sideways. Spreads by rhizomes so in loose clumps. Like Sonchus asper, taller with larger wide leaves and bigger capitula. The flower stalks and phyllaries are covered in yellowish glandular hairs which become darker. The flattened achenes dark brown and ridged.

Sonchus asper - Rough or Prickly Sow-thistle Common annual street weed. Branched stem to 1.2m can be reddish-purple. Leaves shiny green, wavy, pinnately lobed, spiny with basal ‘wheels’ appressed to the stem. Glabrous including the phyllaries which can have very fine spikes down the midline. The flattened achenes are ridged and smooth between the ridges.

Sonchus oleraceus - Smooth Sow-thistle Common annual street weed. Branched stem (to 1.5m) and leaves can be reddish-purple. Leaves dull, grey-green, pinnately lobed, less spiny with end lobes pointed and straight on both sides of the stem. Glabrous including the phyllaries. The flattened achenes are ridged with horizontal wrinkles between the ridges.

Sonchus tenerrimus Slender Sow-thistle This is a rare casual which resembles S. oleraceus in its rugs achenes and leaves with pointed auricles, but the leaf lobes are narrower and contracted at the base. These are pictures of the first Scottish sighting in Glasgow made by Malcolm Macneill.