I recently travelled to eastern Gippsland in search of a. obtusifolia. I'm unsure as to whether this specimen is a. longifolia or obtusifolia. My strategy to distinguish the two apart was from flowering. I was under the impression that obtusifolia flowers in summer, whereas longifolia in spring. Unfortunately this specimen and other phyllode acacias in the region weren't in flower. The population seemed young (tallest was ~3m with a stem diameter of ~15cm) and there were no apparent fruits on or around the plants. I've read that the primary difference is resinous glands on the margins of obtusifolia leaves, crinked/uneven like margins and blunter tips.
Any help is much appreciated.
Cheeser