Allocasuarina stem galls (Cylindrococcus spiniferus)

An amazing flower-like structure is caused by a scale insect interfering with the chemistry of Allocasuarina stems. They look similar to the actual tree cones among which they are interspersed but also different (see inset). Found on Allocasuarina stems in a local nature reserve.
Likely female insects inside these. The scale insect uses chemistry to force the tree to grow this clever little flowery home for it. The details of the gall 'stem' are particularly fascinating. About 15mm long.
From Dr Lyn Cook...
"The galls are induced on new vegetative growth (new branchlets) rather than cones, and they can grow on male and female plants (many Allocasuarina species have separate sexes, and cones are only on females). One of the identifying features of the host plant species is the number of scale-like leaves around the nodes of branchlets, and the galls make them easy to count - the number of bracts in each ring on the gall is the same as the number of tiny leaves around a branch node."