Weed of the Month – May 2016

BURR MEDIC

(Medicago polymorpha)

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(Photos: E. Cousins; habit, closer view of leaves and fruit.)

This small creeping plant from the pea family can be used as a pasture crop, but it can become a weed in some habitats. It is a prostrate (flat to the ground) annual, though it can climb slightly through nearby plants. The multiple stems are green to slightly red, and can be up to 50cm long. The leaves occur in groups of 3 leaflets at the end of short stalks. The centre leaflet has the longest stalk (an identification key used for distinguishing medics from similar plants). Leaflets can be heart or wedge-shaped, as seen above, with finely toothed margins near the tip. Pea-like yellow flowers appear in spring, to be followed by the fruits. These are like little coiled pods, disc or barrel-shaped, 3-4mm wide, with hooked spines (see second photo) all over.