As the common name of this magnificent tree suggests, Albizia adianthifolia var. adianthifolia has a conspicuous flat crown, which makes it unmistakable in the coastal and low-altitude forest, forest margins, open forest and ravines where it occurs in South Africa. It can reach a height of over 40 m. The bark is grey to reddish brown and rough. Branchlets and peduncles have grey to brown hairs with the young tips tinged pinkish red.

Leaves are very characteristic; the 4-8 pairs of pinnae bear 6-12 pairs of leaflets each. Every leaflet is obliquely rhombic-quadrate (rectangular) with the midrib diagonally across it. The petiole has a gland at the base.

The flowers are striking, forming relatively large, half-spherical heads. Petals are white or greenish white and joined for at least two thirds of their length. Stamens are fused partly to form a tube and reddish pink or green at the tips. These lax inflorescences appear in different months of the year, but in South Africa the tree flowers in spring during the months of September-November.

The fruit is a thin pod with a conspicuous margin and veins. As the pod dehisces and opens up, the margins often persist as the centre parts fall off. The seeds are flat and brown.