Pilostyles hamiltoniorum is a completely parasitic plant that lacks chlorophyll and therefore does not photosynthesise. It grows within the stems of its host, and only appears during flowering, when the flowers burst through the surface of the host’s bark a bit like the creature in the movie Alien.
Pilostyles is a genus of c. 18 species occurring in North and South America, the Middle East and south-western Australia. All species of Pilostyles grow only on genera within the family Fabaceae; the Western Australian species grow on Daviesia, Jacksonia or Gastrolobium. Flowers of P. hamiltoniorum appear on second year’s growth of Daviesia angulata, D. nudiflora and D. rhombifolia, from late January to March. Very little is known of the biology of Pilostyles hamiltoniorum, including how it infects its hosts, how its seeds are dispersed, and how it survives when its hosts are burnt by fires.
Photo: K. Thiele