Anyone who has spent much time in our lowland tropical rainforest will have seen stray banana plants and clumps growing, apparently, wild. But our cultivated bananas don’t reproduce from seed do they? So what’s going on? These questions have nagged me for a few years, especially since I took an active interest in trying non-standard varieties.
It’s true that our all our cultivated bananas – including Ducasse, Lady Finger, Red, Monkey, Blue Java and the all-too-common Cavendish – are grown from root stock, and it seems that getting a viable seed from any of them is almost impossible even with human assistance:
… although banana plants are clones, very occasionally they can be persuaded to produce seeds through a painstaking process of hand pollination. Only one fruit in three hundred will produce a seed, and of these seeds only one in three will have the correct chromosomal configuration to allow germination. The seeds are laboriously extracted by straining tons of mashed fruit through fine meshes …
That comes from this article, The Unfortunate Sex Life of the Banana (highly recommended – it’s both entertaining and informative) and after reading it I abandoned any thought that cultivated bananas grow from seed in the rainforest. It’s still possible that they occasionally grow wild when a plantation has been washed out by floods and a ball of roots lodges somewhere downstream and starts growing, but that must be rare and can’t account at all for plants growing high in the hills. So our wild bananas genuinely are wild, and can’t even have crossed with the cultivated ones.
I had been told of wild bananas – “so full of seeds you wouldn’t eat them” – years ago but didn’t really follow them up. Then, last weekend, I saw and photographed them in the rainforest near Sanctuary Resort above Bingil Bay (just north of Mission Beach), and was introduced by a fellow guest to a magnificent book, Cooper’s Fruits of the Australian Tropical Rainforest which depicts and describes our native species.
There are two, Musa banksii and Musa jackeyi, and clicking on those links will take you to CSIRO fact sheets about them. In short, Musa jackeyi is rare, even in coastal north Queensland; its stumpy reddish fruit are borne on a vertical stem. Musa banksii has a bigger range, from Cape York to just south of Townsville, and is more common across that range. The plant and its fruit are more like our cultivated bananas, but the fruit turn upwards from their stem, not down. Both species tend to grow in disturbed areas of rainforest, e.g. where a big tree has fallen and exposed earth to the sky, and both are eaten by feral pigs.
Sometime I will find a bunch of wild bananas ripe enough to try eating one, but my expectations are not high: Cooper’s picture of the fruit (on the CSIRO page) doesn’t look promising.
The last piece of the puzzle is the relationship between wild bananas and the fruit on our table. Its outline is simple enough: our wild bananas are just two of some 70 species worldwide, and all of our cultivated varieties are sterile hybrids of other “wild” species, mostly from SE Asia; some have human histories going back thousands of years. The details are very complicated indeed and I will merely recommend wikipedia’s article on the genus Musa as a starting point before beating a strategic retreat.