Allocasuarina grampiana is known as the Grampian’s Sheoak and is a tall shrub, growing to 4 metres. It has distinctive blue-grey foliage, due to a waxy bloom.
Allocasuarina spp. are flowering plants (not pine trees – a mistake made by some). Their closest relatives are plants such as birch trees and alders (not known for their showy flowers).
In common with many Sheoaks, this species is dioecious (male and female flowers on separate plants). The male flowers are carried in spikes on the ends of branches. The spikes are typically very narrow (2-3 mm across) and around 40 mm long, consisting of very small flowers. When the flowers mature, pollen is released and spread by the wind.
Female flowers are in globular heads on short stalks along branches and are usually arranged in leafy-clusters. These flowers are highly modified – lacking obvious petals and sepals. The globular heads consist mainly of female styles.
Pollinated female flowers develop into persistent, woody, globular “cones” – a cluster of woody valves (bracteoles) that function individually like follicles to release the seed. Each cone contains many small, winged seeds or samaras. In Allocasuarina spp., the seeds are usually black and shiny. The appearance of the fruit differs between species. In this species, the cone is 35 mm long by 10 mm wide, round and with a point shaped like a pyramid on the top and with the woody valves pointy (acute).
Allocasuarina grampiana is confined to the Grampian National Park in central Victoria on sandstone. The species is classified as rare and threatened although protected in a reserve. Frequent bushfires could pose a threat to the species.
The Grampian’s Sheoak has great horticultural potential. The foliage colour is similar to that of the Blue Spruce. Allocasuarina grampiana could be grown as a substitute for this expensive and slow growing exotic.
Propagate from seed and possibly cuttings.
The type specimen was collected in the Grampians in 1969 and formally described in 1989.
The main image is of a specimen growing in Canberra’s National Botanic Gardens and the thumbnail is from a plant in our garden.
Allocasuarina spp. can regenerate from seed after fire. They can also exhibit suckering from root zones.
Allocasuarina is a genus of about 62 species – all endemic to Australia. There are currently 19 species recognised in NSW.
Allocasuarina – Greek – Allo – meaning “other” – referring to this genus and its species being considered different to Casuarina. This genus was only established in 1982, by L.A.S Johnson (1925-1997).
grampiana – Latin – referring to the Grampians Mountains in Victoria where it is found.
This species is considered as being threatened with extinction in the wild in Victoria with the category of Vulnerable.
VICFlora (Flora of Victoria Online) – Allocasuarina grampiana profile page https://vicflora.rbg.vic.gov.au/flora/taxon/a6e7e2b5-57a1-4b3d-9cb5-bdcd22d46700
Wikipedia – Allocasuarina grampiana profile page https://en.wikipedia.org/wiki/Allocasuarina_grampiana