From the colour of the flower it might be Desmodium varians. I thought it was possible to distinguish Desmodium and Glycine clandestina and G. tabacina by the leaves but now I am not sure.
You got me thinking, Mike. In Desmodium varians, the stalk of 5he middle leaflet is more than twice as long as those of the other two leaflets. This rules out Glycine clandestina and Glycine microphylla. There is still the possibility that it is Glycine tabacina, which according to Vicflra can have narrow leaves. Though every other sighting of it on CNM has quite broad leaves. The pods will clinch it - straight in Glycine, constricted between each seed in Desmodium.