flowering a little earlier than G. urbanum, so early pollinations will be within the gene-pool of the single species. The seeds of Water Avens are burr-like, and are distributed after being caught in the coats of rabbits and other small mammals, and by rhizomal growth. Geum rivale is parasitised by Podosphaera aphanis – a conidial powdery mildew. Yellow spots on the living leaf may be caused by Peronospora gei – a downy mildew. Hybrids Geum urbanum hybridises fairly regularly with Geum rivale as they are closely related and occur together. In North America it is known to hybridise with Geum aleppicum (the hybrid being named Geum × aurantiacum ), with Geum macrophyllum var. perincisum (as Geum × pervale), and with Geum macrophyllum var. macrophyllum (as Geum × pulchrum). References External links Video and commentary on Geum urbanum and Geum rivale rivale Plants described in 1753 Taxa named by Carl Linnaeus