Noisy signal from Australian bugle

If you wander to the end of the colourful cultivar beds in the Australian Garden at Royal Botanic Gardens Cranbourne, to the right past the water feature, you'll find yourself looking over the research display beds.

This is where we run scientific experiments out in the public space so you can what normally goes on behind the scenes. In recent times we have tested new plant selections for their tolerance of different soil and environmental conditions and trialed some iterations of woody meadows for use on roadsides around Victoria.

At the moment one bed (the one above) is occupied by collections of Ajuga australis from across Victoria. The Austral Bugle is a member of the mint family and the only one of the 40 or so species in the genus Ajuga found naturally in Australia. A close relative, Ajuga reptans, the Bugleweed, is a sometime weed on roadsides in the Dandenongs and few other places near Melbourne.

Compared to the weedy European species, Austral Bugle has more elongate leaves with usually long stiff hairs. It also lacks 'stolons', which you'd be familiar with from strawberries - they allow the plant to extend its distribution by dropping a stem to the ground and rooting a new rosette of leaves. 

Your typical Austral Bugle plant has a rosette of basal leaves and then a leafy flowering stem that may be erect or prostrate. I think some also have underground stems, called rhizomes, that extend an individual plant in a similar way to stolons.

Austral Bugle is scattered across Victoria, where it grows in all kinds of habitats: mallee sand, coastal plains, alpine grasslands, hillside forests and granite outcrops. It also extends extensively into South Australia, Queensland, New South Wales, Australian Capital Territory and Tasmania. 

If you look across its range, even within Victoria, you'll find, as they say in VicFlora, a 'very variable species in need of revision'. That variability is in the size of all parts of the vegetative plant, and shape, size and colour (pink to purple) of the flowers.

While on one of our two annual Jim Willis Studentships last summer, Amy Buckner studied the variation in this species using 80 preserved collections in the National Herbarium of Victoria. Her project was supervised by Royal Botanic Gardens Victoria botanists Liz James and Neville Walsh, and Sydney botanic garden botanist, Trevor Wilson

Amy confirmed that there was indeed great variation in all aspects of the plants from those different habitats in Australia. While there have been a few varieties and forms named since Robert Brown described the species in 1810, only one from the mallee, given a separate species name Ajuga grandflora in 1933, has some limited currency.

Amy found in her studies a distinct arid form, and distinct alpine form and then a couple of other interesting populations that may also warrant some recognition with a name as variety or even species level. At the end of her six week study, the results were included within a broader research project by Trevor Wilson on this species and other Australian members of the mint family across Australia.

Amy and her colleagues also collected living plants during her study and these are now on display in this research bed. I've illustrated this post with some of the plants growing there. Trevor, Amy and others are yet to decide which ones warrant their own names but you can take a look yourself and decide what you would do.

And thanks to Matt Henderson and others for encouraging me to take a look at the ajugas...