Tuesday, 25 November 2014

Deane's Wattle not so high on a hill top


Climbing The Hill at Pyramid Hill earlier this year (in March), I was reminded of the first time I sighted the nearby Mount Witchyproof. At 43 metres, Mount Witchyproof is reputedly the smallest registered mountain, and it doesn't live up to any altitudinal expectation. At least The Hill, at much the same height I think, is just called a hill.

The vegetation is a bit clapped out (that's the technical term) but it has few interesting specimens. Wattle season, sprinter, is now well finished but I thought I'd feature an Acacia. In this case the wattle was in full flower in March so it's one of the many that flowers outside sprinter - sprinter just happens to be the peak wattle flowering season for much of Australia.


Acacia deanei, or Deane's Wattle to its friends, is one of the feathery leaved wattles. Most wattles have what are called phyllodes, flat blades that are actually modified leaf stalks rather than true leaves. They start off with feathery leaves when young but the mature plant has only phyllodes (think Golden Wattle, Acacia pycnantha).

A Deane's Wattle plant starts and finishes with feathery leaves. Each leaf consists of 2-8 pairs of what are called pinnae, and each pinna (singular) has 10-30 pinnules (littler pinnae...). You find this kind of structure in some ferns and in other wattles, like the common Black and Silver Wattle.


But Deane's Wattle is not so common, at least in Victoria. There are two subspecies, one called deanii (like the species, name after Mr Deane who first collected the species from Gilgandra in New South Wales) and one paucijuga (meaning fewer of the pinna or pinnules, but in this case also a reference to the smaller pinnules).

In Victoria, the first subspecies is only found near Chiltern, on the Murray River. It is more common in New South Wales and into southern Queensland. The paucijuga subspecies is scattered around the State but primarily in the north-central parts, and extending up into New South Wales. This is the one we saw on and near Pyramid Hill.

At first glance both subspecies might look like the Black Wattle, Acacia mearnsii, but that species has more pinnae and more pinnules, and the pinnules are smaller.Their ranges overlap a bit but Deane's Wattle is the only one you'll find growing naturally up towards the Murray.

We have preserved collections in the National Herbarium of Victoria from plants in flower (of both subspecies) pretty much anytime of the year, although mostly in summer. Which is a good thing. Apart from a few salt-bushes and a weed or two, it was one of the few colourful plants in flower at that time of year in the hills and mountains of northern Victoria.

As we enter the final week of sprummer, there is plenty in flower at the moment in our gardens and in the bush. The purple haze of jacaranda flowering has at last made its way to Melbourne and the Cape Chestnut is pretty in pink. The Sydney Red Gum, Angophora costata, is particularly stunning in nature and in nature-strips. 

The 4-month long summer that I favour for much of southern Australia is about to begin. This is 'down time' for many of our Australian plants, with notable exceptions such as the Hyacinth Orchid (Dipodium). By the time we get to March there will be little in flower so we need to savour the likes of Deane's Wattle.


No comments: