Perforatocarpum echinatum was an icacinaceous plant whose fruit contained a hard, strongly pitted endocarp. The surviving London Clay stone is pointed-obovate in side view and lenticular in cross-section. Its dense small pits are not merely surface decoration: they continue inward as channels associated with small projections into the seed cavity, giving the fruit wall a highly distinctive three-dimensional construction.

Micro-CT shows characters that place the fossil within the Phytocreneae branch of Icacinaceae, but its combination of pit structure, vascular anatomy and apical canals does not fit any known living or fossil genus closely enough. The 2016 revision therefore created Perforatocarpum for it. No leaves or stems are attached to the fruit, so the precise growth form is unknown; any comparison with the climbing habits common in living relatives is ecological inference rather than direct evidence.