Pseudocyphellaria haywardiorum has a more or less circular thallus measuring 30–80 mm in diameter, loosely attached from its edges to its centre, featuring rising wavy margins with rounded lobes that overlap in a complex pattern.

The upper surface varies in colour from dark grey-blue to brown-black, becoming darker at the lobe tips when moist, and displays a spectrum of colours including dark olive-brown to pale yellowish with greyish edges when dry, while the underside is either bubbly or unevenly wrinkled with a tomentum ranging from red-brown to black-brown, and white pseudocyphellae especially noticeable in the central region.

The species epithet honours Bruce and Glenys Hayward, "for their collections of, and researches into, lichens of the offshore islands of northern New Zealand".

They collected the type specimen in 1971 on Red Mercury Island, where it was growing on the bark of a tea tree (genus Leptospermum).

The soredia clusters, which can be up to 0.5 mm in diameter, can either be dispersed, densely packed, or even merge to form extensive sorediate to pseudoisidiate crusts.

The edges are a pale buff or brown shade with a smooth appearance, while the rest is densely covered in hair-like structures (tomentum) ranging in colour from red-brown to black-brown.

[2] On Raoul Island, it is known from fragmentary specimens collected from amongst the debris of Kermadec pōhutukawa that were toppled by a cyclone, suggesting that in that location it inhabits the upper tree canopy.