A knifeful of cunonia wax, for rhyme or reason?

Dr Hai Ren, the Director of South China Botanical Garden in Guangzhou, about 100 km north-west of Hong Kong, peeled apart the spoon-shaped 'leaves' to reveal a waxy white substance. You can eat this he said. Raw or cooked, I asked. Straight from the leaf, he said.

I didn't try it. But a reference by someone else to this tree as the Butterspoon Tree reinforced its connection with food (although I commented at the time I didn't know what a butter spoon looked like). I was also curious about which species Dr Ren would have sampled in China given this species was, Cunonia capensis, was presumably from the Cape region of South Africa.

The Butterspoon Tree has a white, bottle-brush-like bloom in late summer, followed by horned capsules, none of which were present in August when I visited Harold Porter National Botanical Garden and Kirstensbosch National Botanical Garden in South Africa. The allegedly butterspoon-shaped leaves, actually 'stipules' protecting the growing tip, however, were present. As were the distinctive red stalks that contrast nicely the deep green leaves.

It's a fast-growing forest species, often found near steams, from the Western Cape through to Mozambique. It resprouts after fire and is likely to do quite well as a urban tree in Melbourne as our climate dries and warms.

As to what Dr Ren was eating in China, I'm not sure. The other 25 or so species of Cunonia come from New Caledonia, to Australia's east. They all have these spoon-shaped stipules, which are leaf-like appendages arising between the stem and the leaf stalk.

There are another 26 genera in the family Cunoniaceae, but these are almost all from the Southern Hemisphere (including another 65 or so species in New Caledonia), and none occur naturally in China.

I see that an antibacterial compound used in Chinese medicine called 'mallotinic acid' has been extracted from Cunonia macrophylla, a species from southern New Caledonia. The same species also contains other chemicals with antimicrobial properties and like most Cunonia species it is easy to cultivate. Maybe that was the species known to Dr Ren but as to the taste and use of the white waxy stuff, I don't know. Perhaps it was best I didn't try its African relative.

Wax aside, the African species does have its human uses. It is 'reportedly used for treating nervous complaints' and the timber is 'tough and hard', and milled for furniture. The Afrikaan common name is Rooiels, meaning Red Alder from the similarity of the wood with the genus Alnus. This (Red Alder) is the common name we give the couple of specimens we have growing in Melbourne Gardens.

When I returned home I tracked these plants down in the Melbourne Garden, pealing apart their 'butter spoons' to find only a very small amount of the waxy product. I tasted a little, which was tasteless but of a pleasant buttery texture. I also found some fruits in early green stage, and dried and open.

And some very nice 'butter spoons'. Now that I see them in my home town, I think perhaps they are shaped like what we might call a 'butter knife'.

Still, if you find no practical use or analogy for this plant where you live, there is a poetic connection of sorts. The genus Cunonia is named after John Christian Cuno, an eighteenth century writer of verse who used his own garden as muse. And here is Dr Hai Ren, pealing apart stipules back in South Africa.