This article was published in The Fringe, March 2016

Blue Berry, Turutu, Whistles.

As you wandered our bush tracks over the summer you may well have seen the clumps of gracefully drooping grassy foliage with a 1m long flower spike producing brightly-coloured blue berries.

Dianella is a peculiar genus of plants, and botanists are debating whether it is a lily or a flax. Some give it a common name of flax-lily which perhaps adds to the confusion while others want to put it in a family of plants called Xanthorrhoeaceae which surely doesn't help.

However, no matter which family it belongs in, since 2007 New Zealand has had three species of Dianella. Prior to that botanists were confused by the variation they could see in the one named species, Dianella nigra, and it wasn't until they considered the habitats the plants grew in that the picture became a little clearer. Dianella nigra is the name retained for the more common forest-dwelling form, while those plants preferring rocky bluffs were named Dianella latissima, and the form that tolerates damp swampy, acidic soils was named Dianella haematica. Of course, plant species that are so closely related can hybridise and the resulting hybrids are a confusion of forms. But in undisturbed habitat the species generally remain pure and distinct.

I doubt, during the time of the Roman Empire, that the Romans ever saw the plants named after their Goddess Diana because they are mostly southern hemisphere plants. Naming them Dianella was not unreasonable as Diana was the Goddess of hunting and forests and most species of Dianella prefer the gentle conditions of forests. There are more than 30 species growing overseas and many have been introduced into New Zealand which adds to the confusion as to which species you may find in gardens and nurseries.

Most Dianella develop underground rhizomes. They have long, strappy leaves up to 1 metre long, ranging from deep to pale green, to blue-green. Their flowers have 3 petals (frequently blue), 3 sepals, and prominent yellow stamens. Their shiny blue to purple berries are up to 1.5 centimetres in diameter, spherical or elongated with spongy pulp and shiny black seeds.

The New Zealand species, however, have white flowers and the fruit range from white/grey/porcelain to blue/dark blue/black.

The tantalising fruit hang just at grasping level for young children, and parents often express concern they may be poisonous. There is no record of the fruit causing illness but they are certainly unpleasant to eat so are best avoided - unlike that other exotic blueberry, Vaccinium corymbosum, which grows on shrubs, and is wondrous in muffins.

In case you are wondering why the plant is also called "whistles", pick a leaf, hold the lower end (where the two halves are folded closely together) between your parallel thumbs, and blow vigorously onto your knuckles. The vibrating leaf produces a shrill whistling sound.