Isotropis cuneifolia Granny's Bonnet
There are large numbers of "pea" plants in Western Australia and this one looks a little larger than normal but unremarkable until you see the back of the standard. The veins are very striking - it must be one of the very few plants which have evolved to have flowers which look even better (to humans) from the back than the front.
This plant is also known locally as Lamb's Poison because it is said to have caused the death of lambs in the past. This is not quite so unlikely as it sounds as many of the plants here contain high concentrations of Sodium fluroacetate which is poisonous.
Wireless Hill Park, Perth, Australia, August 24th 2007
Added on 12th October 2007, updated 4th February 2010, updated 13th April 2010