Saturday, 16 October 2010
Tree ivy not ivy tree*
*From the Radio Archive. Although I tried to restore a little balance in an recent posting about its insulation properties, ivy is not well loved in Australia. In most parts of the country it smothers trees and native vegetation, and overwhelms fences and buildings. This story from December in 2006 was about one of its more attractive relatives, the Tree Ivy, and few other family members.
Most members of the ivy family are tropical shrubs and trees. The common climbing ivy is an exception.
But like all its relatives in the family Araliaceae, ivy has flowers arranged like the spokes of an umbrella. In this respect it is similar to the carrot, parsnips and others in the closely related Apiaceae family.
Its leaves, however, give a hit to its true ancestry. Like many in the ivy family the leaves are lobed, often a bit like a hand – which we call ‘palmate’. Sometimes the leaflets are quite free, and entire leaf looks like a cluster of leaves attached to a central stalk.
Ginseng, produced from the roots of various Panax species, is a well known product of this family. The leaves of Panax are divided into a handful of radiating leaflets.
Around Sydney, the two most common ivy relatives you are likely to see are the woolly native shrub, Astrolochia (looking nothing like ivy and confusingly, without lobed leaves) and emergent Umbrella Trees. The latter are more likely to be the weedy garden plant, Schefflera actinophylla, with radiating leaflets, rather than the native Polyscias murrayi, with large fern-like leaves.
In flower in the Royal Botanic Gardens in December is the impressive Trevesia sundaica from Java and Sumatera. It has large leaves, each divided and incised like a fancy paper doily (a kind of botanical scherenschnitte). Its flowers, of course, are arranged like an umbrella.
You may even have a Trevesia at home – I have one in a pot under the eaves at my back door. It came with the house.
Image: The intricately divided leaf of Trevesia sundaica, in Sydney's Royal Botanic Gardens