Canada:The maple leaf is the symbol of the nature in Canada. The red bands would represent the Pacific and the Atlantic Ocean, and the white Arctic snows.

Australie:In the corner top-left we find the Jack union, the direct reference to the flag of United Kingdom.
The big lower left white star calls back by her 7 branches all the states and the territories of Australia.
On the right part, 5 small white stars show the Cross of the South.