Faboidea crassicutis was an early Eocene member of Icacinaceae known from a remarkably robust fruit stone. The preserved endocarp is squat and broader than long, with a very thick woody wall and an irregularly corrugated exterior. It enclosed a single pendulous seed; a groove on one side of the seed marks the course of the raphe. These characters show that the fossil represents the hard inner part of a one-seeded drupaceous fruit rather than an isolated seed.

The whole plant is not preserved, so its precise growth form cannot be demonstrated. Icacinaceae are woody plants, and the family includes trees, shrubs and climbers, making a woody habit a reasonable family-level inference but not a Species-level fact. Faboidea is retained as a distinct fossil genus because its unusually squat form and heavy endocarp differ from the more lenticular, ridged stones assigned to Iodes. The London Clay specimens are especially valuable because internal anatomy — including a marginal vascular bundle embedded in the wall and a papillate locule lining — confirms the family placement.