Giant sea leaves near the lake

"With me tonight, to explain why this giant-leafed plant is almost incorruptible, is Green's spokesperson Ms Grandleaf Sea Grape...".

OK, not quite up the standard of our local television (ABC TV) darling Shaun Micallef, but the common name for Coccoloba pubescens - yes, Grandleaf Sea Grape - did set my mind wandering in this direction. Or was it to Middle Kingdom?

Back in Victoria, Australia, I doubt you will find this species in conversation or in reality. We don't grow this, or indeed any of its kind (Coccoloba) here in the Royal Botanic Gardens Victoria. We do grow other members of the buckwheat family, Polygonaceae, including a few I've blogged on here such as St Catherine's Lace and the Centipede Plant. We also employ one of the world's leading experts on the family, Dr Tanja Schuster.

Grandleaf Sea Grape, or Eve's Umbrella, though, is a plant I only recall seeing once, tucked inside the entrance of this glasshouse in Geneva's botanic garden, Conservatoire et Jardin Botaniques Genève. That's Geneva, Switzerland, is on the banks of Lac Léman but no where near the sea.

There are more than 150 species of Coccoloba, many of them producing clusters of grape-like fruits and quite a few growing by the coast. Hence Sea Grape, a common name applied to various species of Coccoloba. Other local names for this group of species stick with the marine viticulture theme: e.g. Little Beach Grape, Beach Grape Tree and Edge-of-sea Raisin Tree. Less obviously, some species are called Pigeon Wood, Big Potato and White Big Bed.

Nearly all Coccoloba species are from tropical America, with Coccoloba pubscens - our Grandleaf Sea Grape - native to Mexico, Guyana and the West Indies. Fittingly, it seems to have the biggest leaves in the genus, often half a metre wide and sometime bigger. The juvenile form of the plant, which is probably all we'll see in glasshouses, is larger leaved.

The eighteenth century Dutch botanist, Nikolaus von Jacquin, described the mature tree as inelegant but others focus on the beauty, or at least the function, within. The wood is said to be 'almost incorruptible' and when buried beneath the ground - as footing for fence posts for example - can become 'hard as stone'.

Like most of the buckwheat family, the Grandleaf Sea Grape has a distinctive sheath (an ocrea or ochrea) wrapped around the stem, extending upwards from where the leaf arises an. In the close-up below you can see blackish dry flaps which are part of this sheath.

While not in our glasshouses (yet), the Grandleaf Sea Grape has been grown in the conservatories of the UK since 1590, although not flowering until 1832. At that time, due to the 'bad condition of the hothouse' plants did not fruit or set seed.