Have you seen a massive round leaf on the forest floor, somewhere along the escarpment or in the dry rainforest of the Berkeley Hills? How about a huge assortment of juicy-looking, grape-like, purple-black fruit?
If so, you might have been in the vicinity of a Round Leaf Vine, a rainforest specialist, and overall quite an uncommon species locally. In the Illawarra region, Round Leaf Vine is particularly associated with our critically endangered Illawarra Subtropical Rainforest. So seeing a Round Leaf Vine is an indication you may be in a patch of this amazing rainforest, which is unique to the Illawarra.
It's fruiting late this year so you may be able to see the fruit if you take a walk on the escarpment, or pop into the Wollongong Botanic Garden, where a large specimen is rambling along the ground near the Administration Building.
As the vine itself generally grows up the tall rainforest trees, where its leaves mingle with the canopy, its presence can be hard to discern if a tell-tale leaf isn't present. The picture below shows healthy leaves on a living plant. More often the fallen leaves have lost a lot of their green colouration and are a mixture of browns and greys, perhaps with a yellow or green tinge if the leaf is fairly fresh.
As you can see the leaves are really large, and they're also very ornamental.
Growing the plant, as has been done at the Botanic Garden, as a clumping specimen on the ground, is one option. It could also be trained up a pergola or other structure, but I've never seen this tried. Ultimately, this is a pretty large vine and it's probably best appreciated at the BG or in natural areas. The image below shows fruit of Large Leaf Vine in a private property in Kiama, where it is growing up tall rainforest trees.
The fruit typically have a greyish-white bloom, similar to that seen on red grapes, although the species are not related and Round Leaf Vine fruit are not edible. (In fact, there are other local vines, in the genus Cissus, that are related to the grape (Vitis vinifera), which are technically edible, and which also look similar to grapes, and which also fruit in autumn. However, I've never met anyone who enjoyed eating them as they're both sour and astringent.)
