Gama Medic
Medicago rugosa Desr.

Synonyms -

Family: - Fabaceae

Names:

Other Names:

Medic

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.

Description:

Cotyledons:

Two. Large, elongated, oval to curved. Tip rounded. Sides convex. Base tapered to squarish. No petiole.

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.

Second and later leaves trifoliate.

Leaves:

Three leaflets (trifoliate) with the stalk of the central leaflet longer than those of the side leaflets.

Stipules - Broad with large teeth.

Petiole - Long.

Blade - Of leaflets round to oval or diamond shaped. Tip rounded. Edges toothed. Base tapered to squarish. Hairy on the lower surface, hairless on the upper surface.

Stems:

Low lying, branched, running, 100-500 mm long. Hairy.

Flower stem -

Flower head:

Flowers in clusters of 2-5 on stalks in leaf axils.

Flowers:

Yellow pea type

Ovary -

Sepals -

Petals - Pea type.

Stamens -

Anthers -

Fruit:

Coiled pod forming a flat round disk to compressed cylindrical burr with an anticlockwise spiral. Burr is 7-9 mm diameter by 5 mm tall. Surface of pod with prominent radiating veins. Spineless.

Seeds:

Yellow shiny, hooked kidney shaped. 3-5 mm long by 2.5 mm thick. Tip rounded. Edges concave or convex. Base rounded. Surface hairless.

Roots:

Taproot with nitrogen fixing nodules.

Key Characters:

Biology:

Life cycle:

Annual herb. Seeds germinate from autumn to spring.

Physiology:

Has an association with Rhizobia in root nodules that fix atmospheric nitrogen.

Reproduction:

By seed.

Flowering times:

Spring.

Seed Biology and Germination:

Vegetative Propagules:

Hybrids:

Allelopathy:

Population Dynamics and Dispersal:

Spread by seed and intentional planting.

Origin and History:

Europe, North Africa, Middle East.

Distribution:

VIC, WA.

Habitats:

Climate:

Temperate.

Soil:

Prefers alkaline soils.

Plant Associations:

Significance:

Beneficial:

Fodder. Introduced pasture species.

Detrimental:

Weed of crops.

Toxicity:

Not recorded as toxic.

Symptoms:

Treatment:

Legislation:

None.

Management and Control:

Chlorsulfuron, metsulfuron or triasulfuron herbicides provide high levels of control in cereal crops. Clopyralid can be used in Canola.

Tolerant to grazing.

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.

Biological Control:

None.

Related plants:

Barrel Medic. (Medicago truncatula)

Black Medic (Medicago lupulina)

Burr Medic (Medicago polymorpha, Medicago hispida)

Button Medic (Medicago orbicularis)

Calvary Medic (Medicago intertexta)

Cutleaf Medic (Medicago laciniata)

Disc Medic (Medicago tornata)

Gama Medic (Medicago rugosa)

Lucerne (Medicago falcata ssp. sativa)

Lucerne (Medicago sativa)

Murex Medic (Medicago murex)

Small leaved Burr Medic (Medicago praecox)

Snail Medic (Medicago scutellata)

Spotted Medic (Medicago arabica)

Strand Medic (Medicago littoralis)

Woolly Burr Medic (Medicago minima)

Yellow Lucerne (Medicago falcata)

Plants of similar appearance:

Clovers (Trifolium species) usually have the central leaflet on a stalk the same length as the side leaflets.

Melilotus species

Oxalis species usually have a bitter taste.

Trefoils

References:

Bodkin, F. (1986). Encyclopaedia Botanica. (Angus and Robertson, Australia).

Everist, S.L. (1974). Poisonous Plants of Australia. (Angus and Robertson, Sydney).

Harden, Gwen J. (1991). Flora of NSW. (Royal Botanic Gardens, Sydney). Volume . P. Diagram.

Lamp, C. and Collet, F. (1990). A Field Guide to Weeds in Australia. (Inkata Press, Melbourne).

Lazarides, M. and Cowley, K. and Hohnen, P. (1997). CSIRO handbook of Australian Weeds. (CSIRO, Melbourne). #638.15.

Moerkerk, M.R. and Barnett, A.G. (1998). More Crop Weeds. R.G. and F.J. Richardson, Melbourne. P89. Diagrams. Photos.

Acknowledgments:

Collated by HerbiGuide. Phone 08 98444064 or www.herbiguide.com.au for more information.