Nasturtium officinale W.T.Aiton

• a herbaceous plant that grow in or near water, with low-growing or semi-upright stems 10-80 cm long.
• its green stems are hollow, hairless and often produce roots at their lower joints.
• its leaves (2-12 cm long) are either deeply-lobed or once-compound with 1-5 pairs of lobes or leaflets.
• its small white flowers are arranged in loose elongated clusters, each flower with four white petals (3-6 mm long).
• its straight or slightly curved fruit (10-20 mm long and 2-2.5 mm wide) are hairless and almost cylindrical in shape.

[From: Environmental Weeds of Australia]