Spiny Sowthistle
Rosette.
Leaves and stems. Key characteristics: leaf margins are wavy and contain prickly spines. Both leaves and stems have milky sap.
Flowers. Key characteristics: yellow and approximately 1 inch in diameter.
Seed. Seed are ribbed, have a feathery pappus attached to one terminal and the length is slightly greater than 2.0 mm (without the pappus).
Life cycle: winter annual.