Plant of the Week AAAnnngggoooppphhhooorrraaa cccooossstttaaatttaaa SSSyyydddnnneeeyyy RRReeeddd GGGuuummm,,, SSSmmmoooooottthhh BBBaaarrrkkkeeeddd AAAppppppllleee
So why isn’t the Sydney Red Gum a eucalypt? Well, it is closely related but there are some important differences. Eucalyptus and Angophora both belong to the plant family Myrtaceae which includes trees and shrubs with leaves liberally studded with oil glands. You can see these if you hold a leaf up to the light. Most species come from tropical and temperate parts of the world, including South America, Australia and Malesia. In Australia there are 1,400 species in 70 genera1. Many of these are eucalypts or their close relations! Here it gets a bit more complex. Both Eucalyptus and Angophora have an abundance of stamens and both produce woody fruits but in Eucalyptus (and in the closely related genus Corymbia) the perianth (sepals and petals) is fused to form a cap or lid (calyptra or operculum) which covers the flower buds. In contrast, if you look closely at the Angophora flowers, you can see that sepals and petals are clearly visible and never fused into a cap. There are some other obvious differences too. Eucalyptus leaves are usually arranged alternately on the stem whereas those of Angophora are always opposite. The woody fruits of Angophora are ridged and shed soon after the seed matures whereas those of Eucalyptus can be retained on the tree for a considerable length of time, sometimes for many years.
Angophora costata is variously known as Sydney Red Gum or Smooth Barked Apple and is widely distributed along the coast, ranges and tablelands of New South Wales and Queensland through into south and central western Queensland2. The richly patterned red and orange bark is highly distinctive and the name Apple refers to the seasonally bright green leaves. However, Angophora does have its dark side and its propensity to drop branches without warning has earned it the name Widow Maker. Firefighters give the trees a wide berth after bushfires, as fire scarred hollows in trunks and branches make them even more likely to fall, sometimes many days after the fire has passed.
1 Plantnet: http://plantnet.rbgsyd.nsw.gov.au/cgi-bin/NSWfl.pl?page=nswfl&lvl=sp&name=Angophora~costata 2 Map modified from Australia’s Virtual Herbarium http://www.chah.gov.au/avh/avhServlet
Text and photography by Alison Downing & Kevin Downing, 5.12.2011 Downing Herbarium, Department of Biological Sciences