Burr Medic
Medicago polymorpha
Fabaceae
Forage, soil improvement and medicinal. Also reports of it being edible.
Burr medic is an annual herbaceous plant that is found in a variety of situtaions, from parks and gardens, lawns, bushland, cultivation, orchards, nurseries and bushland. It tolerates a range of soils. Burr medic has prostrate stems to 50 cm long, with leaves trifoliate. Leaves and stems are hairless. Small pea shaped flowers are yellow, while the pod is covered with slightly hooked spines. These spines attach to most things, enabling seed to be distributed over large areas. It has a taproot and nitrogen-fixing nodules. Germination and growth occur mostly in the cooler parts of the year. Burr medic produces hard coated dormant seeds, which can remain viable in the soil for many years.
Major pests of Burr medic include redlegged earth mite (Halotydeus destructor), lucerne flea (Sminthurus viridis), bluegreen aphid (Acyrthosiphon kondoi), cowpea aphid (Aphis craccivora), spotted alfalfa aphid (Therioaphis trifolii), sitona weevil (Sitona discoideus), root lesion nematode (Pratylenchus neglectus, Majorphoma black-stem (Phoma medicaginis), rhizoctonia bare-patch (Rhizoctonia solani), powdery mildew (Erysiphe trifolii), Uromyces ciceris-arietini (chickpea rust), U. pisi-sativi, and U. anthyllidis. The small yellow flowers are reported to attract small butterflies and other pollinating insects. In the publication, Honey and Pollen Flora by Alan Clemson, burr medic is described as having good pollen and nectar supplies.