Red, or Pink, Ironbark, from New South Wales and Victoria; a common street tree in San Francisco. I've pointed them out to you many times.
The sideroxylon can be quickly distinguished from other common eucalypts in California by its thick, dark, crusty bark--nearly black, with orange highlights in inch(es)-deep crevices--from which sometimes seeps a rust-colored exudate. Ascending main branches taper off in long, weeping red stems that bear green, glabrous, lanceolate leaves, 2-5 inches long, alternate and simple.
Depending on the authority, the Myrtaceae contains 80-160+ genera, several of which are commonly found as imported ornamentals (and/or weeds; often noxious) in California: Agonis, Acacia, Callistemon, Eugenia, Leptospermum, Melaleuca, Metrosideros, Myrtus, Tristania, others. California has at least one native genus, Myrica, as in Myrica californica, the Pacific Wax Myrtle.
As San Francisco street trees, E. sideroxylon commonly grows 40-60 feet high, so the pink/magenta flowers are often too far overhead to see. The specimen in the picture is growing at the bottom of a slope behind my office's elevated parking lot.
Many eucalypts have unremarkable flowers, but these are lovely. Many stamens, no petals. I see nectar in the circular groove that separates the stamens from the central pistil.
I tasted it; really nice--sweet and herbal.