What is a yellow, globular, fluffy flower?

Acacia (scientific name: Acacia farnesiana? (Linn.) Willd.), alias: duck soap tree, prickly bulbous flower, message tree, etc.

Shrub or small tree, bark rough, brown, multi-branched, branchlets often "zig-zag" curved, with small lenticels. Stipules needle-like, born on the branchlets shorter. Leaves bipinnately compound, leaf rachis dreary, gray-white pilose, pinnae 4-8 pairs. Flowers yellow, fragrant; ovary terete, puberulent. Pods swollen, subterete, brown, glabrous, strongly straight or curved; seeds many, brown, ovate, flowering March-June; fruiting July-November.

The species of multi-branched, thorny, can be planted as hedges; wood hard, can be valuable equipment; roots and pods contain tannin, can be black dye, medicine can astringent, clearing heat; flowers are very fragrant, can mention the flavor; stems flow out of the resin can be used for aesthetic and medicinal purposes, the quality of more than the gum arabic is excellent.