Description of Acacia terminalis
Plants seen south of the Harbour and around North Head are usually the endangered Acacia terminalis subsp. Eastern Sydney.
Acacia terminalis subsp. Eastern Sydney can be distinguished from other subspecies by having hairy branchlets and rachises, as well as a large number of flowers per inflorescence (>10). Pictures of the the endangered subspecies are shown below.
A detailed description of Acacia terminalis and the various subspecies can be found on Plantnet.
Photos of Acacia terminalis

Inflorescence of Acacia terminalis subsp. Eastern Sydney, Nielsen Park

Hairy branchlets, rachis and leaflets on Acacia terminalis subsp. Eastern Sydney, Nielsen Park

Seed pod of Acacia terminalis subsp. Eastern Sydney, Nielsen Park