Allocasuarina decussata

Location & distribution maps

Phylogeny & links to associated information

Wikipedia links:       Angiosperms > Eudicots > Rosids  > Fagales > Casuarinaceae > Allocasuarina  decussata

Other links:     

Plant  information

Common name:               Karri Oak 

• Also, karri she-oak  

Conservation status:   unknown

Etymology:   

• The specific epithet (decussata) is a Latin word meaning "like the letter X" or "the Roman numeral ten

Flowers:                  

• Separate male and female flowers form on the same individual plant

Fruit:                         

• The fruiting structure is a woody cone, shaped like a short cylinder

• Its diameter roughly equal to or slightly greater than its length

• The fruit is a winged samara 7–9 mm long

Leaves:         

• The foliage consists of wiry green branchlets called cladodes with rings of minute leaf scales

• The branchlets are about 140 mm long, roughly square or X-shaped in cross section, with four scale-teeth in each ring

• The rings of scale-leaves are 7–9 mm apart

Stem & branches:       

Roots:         

Habit:        

• A medium-sized tree, or more rarely a shrub

• Karri oak usually grows as a medium tree 8–15 m high

• In harsh, exposed situations in places like the top of Bluff Knoll it is a stunted shrub or poorly-formed tree in shrubland

Habitat:   

• It is an understory tree in karri forest where it grows on loam

• It also found on much poorer soils in the Stirling Range

• It occurs as a stunted shrub in places like Bluff Knoll in the Stirling Range

• It often grows in association with Acacia pentadenia and Asplenium aethiopicum often grows as an epiphyte on its branches

Distribution:                  

• Endemic to the south west of Western Australia

• It is restricted to the southwest of Western Australia in the Esperance Plains, Jarrah Forest and Warren biogeographical regions

Additional notes:     

• Taxonomy

  • This species was first formally described in 1873 by George Bentham Flora Australiensis from specimens collected by James Drummond near Cape Riche, Western Australia

  • Bentham gave it the name Casuarina decussata

  • In 1982, Lawrie Johnson moved it to its current genus Allocasuarina in his revision of the she-oaks

  • It is closely related to A. torulosa of NSW and Queensland

• Cultivation and uses

  • Karri oak is not known in cultivation and there is only limited availability of timber because most trees are in national parks 

  • Its pale reddish-brown heartwood has distinctive rays that potentially make it useful as a craft wood

Sources of information:

• https://en.wikipedia.org/wiki/Allocasuarina_decussata (2023)