Some fascinating information by Dr Glenda Vaughton whose research interests include: evolution and ecology of plant mating systems gender strategies in plants pollination biology and floral evolution the evolution of selfing from outcrossing Plants change their sexuality depending on their environment. Populations growing in dry areas where there isn't an assured lot of pollinators, whether insects or birds, are different from ones in wet areas. There are a few interesting pictures on this website http://www.une.edu.au/esnrm/staff/gvaughto.php Diane Whitehead