An annual herb with sprawling stems to 60 cm native to the southern parts of the USA and to Mexico. It has small bright yellow daisy-like flowers. A common weed of tended areas such as gardens, parks and footpaths. The stems are thin and weak, tending to sprawl over the ground. They are green or reddish in colour and rough to touch, growing upright at first but falling to the ground as they lengthen. Adventitious roots are formed at the stem joints (nodes). Leaves are oppositely arranged with stalks (petioles) 5-11 mm long. Leaf blades are egg-shaped (ovate) to triangular (15-40 × 8-25 mm in size) with an acute tip. They have short hairs and margins that are notched with small, forward-pointing teeth. Flower heads are small bright yellow daisy-like flowers (5-10 mm across). They are produced at the tips of the stems and have several toothed petals (ray florets) about 3 mm long. The seeds are three or four-angled and warty in texture (3-4 mm in length).
Photo: Robert Whyte