Allocasuarina is a
genus of trees in the
flowering plant family
Casuarinaceae. They are
endemic to
Australia, occurring primarily in the south. Like the closely related genus
Casuarina, they are commonly called
sheoaks or
she-oaks, they are notable for their long, segmented branchlets that function as leaves. Formally termed , these branchlets somewhat resemble
pine needles, although sheoaks are actually
flowering plants. The
leaves are reduced to minute scales encircling each joint. Fallen cladodes form a dense, soft mat beneath sheoaks, preventing the development of undergrowth (a phenomenon known as
allelopathy) and making sheoak woods remarkably quiet.