Protea comptonii is a medium-sized evergreen tree that grows to 4-8 m high. The tree has grey, corky, thick bark about 20 mm thick on the main stem, which reaches up to 450 mm in diameter. The branches are stout, 10-20 mm in diameter. The leaves are oblanceolate to elliptic, large, 120-250 mm long, 25-50 mm wide, dark green, hairless, thick, leathery, with a red margin. A large number of red new leaves appear at the beginning of the growing season.

Fig. 2. New leaves of Protea comptonii.

Protea comptonii produces stalkless, ovate inflorescences that are 80-120 mm in diameter. The involucral bracts are 15 mm long and 15-20 mm wide; the outer series is hairless and triangular, clearly visible before the bracts open. The inner series is approximately 50-60 mm long and 10-20 mm wide. When the involucral bracts open, they form a flattened saucer-like structure that holds the floral parts. Initially, the flowers are creamy white, but as the perianth fades, they develop a light pinkish blush.

Fig. 3. Involucral bracts of Protea comptonii when the inflorescence is closed (left) and open (right).

There are male and female elements present in the same flower; the male consists of stamens and anthers, and the female consists of stigma and pollen presenter. Styles are white, 65-80 mm long and curved inwards; pollen presenters are thread-like and knee-bent at the base. This species blooms from autumn (May), through winter to spring (September), but its peak occurs in early winter, between May and July, and the fruits are released in early summer, between October and November.

Fig. 4. A closer view of the inflorescence of Protea comptonii showing the flowers, stick-like stigma with the pollen presenter at the tip and the thread-like perianth with the anthers attached.