Winter Bark not so old

May 23, 2023

Winter Bark not so old

Finally from Tasmania, a garden plant you'll find in cooler climate gardens throughout the world - Winter Bark, Drimys winteri, at Crawleighwood, near Hobart. This public garden and nursery is packed with plants from all over the world, but particularly those with a Gondwanan connection (mostly southern hemisphere).

The Winter Bark has that connection through South America and is often - inaccurately - described as 'primitive' because the flowers have very simple whorls of male, female and display parts, and the wood lacks specialised water-carrying cells called vessels. It shares all these features with other members of the plant family Wintereaceae, which branches off early in your typical flowering plant tree of life.

Calling the genus or the family primitive is no longer considered either helpful or accurate. That's because all flowering plants in existence today are just as old, or young, as all other species of flowering plant. Even saying they are 'basal' is misleading because all that means is that their branch has less diversity, so we show it as an off-shoot rather than the main shoot - we like our trees of life to be symmetrical or at least taller than wide it seems.

What we were trying to convey with that term 'primitive' or 'basal' is they have not changed as much as other flowering plants, perhaps displaying features we consider to be early innovations for the group. For example, the lack of xylem vessels found in most other woody flowering plants has been interpreted as a kind of evolutionary dead-end. Even this is probably incorrect, and it can be argued that the Winteraceae 'lost' those xylem vessels from an earlier ancestor rather than failing to take them up as an evolutionary advantage.

Species and genera alive today are all of the same age and if we want to search for ancestral character states (such as absence of vessels) we need to look across the whole tree for shared and derived features. A complicated business.

We can still contemplate Winter Bark for what it is today. Drimys is - today at least - a small genus of about eight species. All species are woody evergreens, with that wood of course lacking vessels. Originally a Gondwana family, they are now restricted to Central and South America. There were some species originally referred to this genus from Australia and further north - such as the Pepperbush or Mountain Pepper - but these are now considered to be a separate genus called Tasmannia.

Drimys winteri is from Chile and Argentina. I gave it a passing mention when I posted with great excitement about visiting the Monkey Puzzle Tree in one of its natural locations, the Huerquehue National Park near Pucon, in southern Chile. I also saw it further north, near where with nearly equal enthusiasm I reported on seeing Chilean Wine Palms in their habitat.

In Chile Drimys winteri is called Canelo. In English-speaking countries, it's mostly known as Winter Bark; that bark was once used to treat scurvy, as well as stomachache, toothache and other internal and external irritations. Like all members of the Winteraceae, this is an aromatic plant - from the leaves to the bark - with a peppery aftertaste.

To finish up, here are a few pictures I took in Chile back in 2015.