Summary:A low lying to ascending, annual medic with trifoliate leaves with oval to diamond shaped, toothed leaflets with black markings and the central leaflet on a longer stalk. The burr is a coiled spineless pod with radiating veins produced from yellow, pea type flowers.
First leaves:First leaf single, egg shaped to oval, small irregular red blotches on upper and lower surface. Tip indented with a tiny point. Edges toothed. Base squarish to tapered. Hairy on the lower surface. Petiole long and hairy.
Leaves:Three leaflets (trifoliate) with the stalk of the central leaflet longer than those of the side leaflets.
Stems:Low lying, branched, running, 100-500 mm long. Hairy.
Flower head:Flowers in clusters of 2-5 on stalks in leaf axils.
Flowers:Yellow pea type
Fruit:Coiled pod forming a flat round disk to compressed cylindrical burr with an anticlockwise spiral. Burr is 7-9 mm diameter x 5 mm tall. Surface of pod with prominent radiating veins. Spineless.
Seeds:Yellow shiny, hooked kidney shaped. 3-5 mm long x 2.5 mm thick. Tip rounded. Edges concave or convex. Base rounded. Surface hairless.
Roots:Taproot with nitrogen fixing nodules.
Key Characters:Cotyledons oval to curved shaped.
Physiology:Has an association with Rhizobia in root nodules that fix atmospheric nitrogen.
Seed Biology and Germination:Vegetative Propagules:
Origin and History:Europe, North Africa, Middle East.
Soil:Prefers alkaline soils.
Detrimental:Weed of crops.
Toxicity:Not recorded as toxic.
Management and Control:Chlorsulfuron, metsulfuron or triasulfuron herbicides provide high levels of control in cereal crops. Clopyralid can be used in Canola.
Thresholds:More than 20 plants/m2 is usually worth controlling in cereal crops.
Eradication strategies:In bushland situations, Logran® at 40g/ha provides reasonably selective control.
Herbicide resistance:None reported. It is relatively tolerant to glyphosate.
Related plants:Barrel Medic. (Medicago truncatula)
Plants of similar appearance:Clovers (Trifolium species) usually have the central leaflet on a stalk the same length as the side leaflets.
References:Bodkin, F. (1986). Encyclopaedia Botanica. (Angus and Robertson, Australia).