Acacia oxycedrus or Spike Wattle
I must admit that I had never seen one of these before (perhaps I was not looking very hard) . At first I thought it was a white callistemon , but a quick search corrected me. This acacia is a prickly, dense shrub up to 3 meters. The flowers are in cream spikes which occur in winter and spring. It is found in Australia in SA, Vic., NSW. This is from a local inner city Sydney area of land which , over the last few years, has been cleared of introduced species and weeds, and replanted with indigenous plant by our Landcare group, http://www.pyrmontultimolandcare.org.au/
I picked this from a shrub and put it in a glass of water at home. I sketched a bit on Sunday night and returned to it on Monday night to discover the flower spikes were beginning to blossum. This is truly a work in progress.