Icacinicarya ovalis

Icacinicarya ovalis

Reid et Chandler

Fossil group Plants
Order Icacinales
Family Icacinaceae
Genus Icacinicarya
Taxonomic status Accepted
Geological age Ypresian

Summary

Icacinicarya ovalis was an icacinaceous plant producing a compact, oval fruit stone with a patterned exterior. Low rounded ridges encircle small depressions across the endocarp, while a more substantial ridge follows the plane of symmetry. Internally, the wall is built from interlocking, digitate cells and the locule lining lacks the papillae seen in Iodes and several other London Clay icacinaceous fruits.

Those structural differences matter more than a broad resemblance in outline. The marginal vascular bundle appears to have run outside the wall, which helps separate the species from Iodes, where the bundle is characteristically embedded. Its exact parent-plant architecture remains unknown because only reproductive material is available, so the fossil is best understood as a securely icacinaceous one-seeded fruit whose precise living lineage cannot yet be named.

Quick Identification

Look for: an oval, lenticular fruit stone with low rounded ridges enclosing small shallow depressions and a stronger ridge around the symmetry plane. Microscopy/CT should show a non-papillate locule lining and an external rather than embedded marginal vascular bundle.

Diagnostic Features

  • Endocarp is oval in lateral view and lenticular in transverse section.
  • Low rounded ridges encircle small concavities on the surface.
  • A conspicuously thick smooth ridge follows the plane of symmetry.
  • Endocarp wall contains interlocking digitate cells.
  • Locule lining is non-papillate and the marginal vascular bundle lies outside the wall.

Fossil Details

Typical size
Roughly 14–15 mm long and about 12 mm wide; thickness is incompletely documented.
Fossil material
Seed, Fruit
Preservation
Surface ridges can be reduced by abrasion, while internal cellular structure normally requires sectioning or CT-quality preservation. Worn specimens without the symmetry ridge or internal characters should remain tentative.

Similar Species

Recorded Fossil Sites

No fossil-site occurrences have yet been recorded for this species.

References

  • Eleanor Mary Reid; Marjorie Elizabeth Jane Chandler. (1933). The London Clay Flora. . British Museum (Natural History), London View reference
  • Gregory W. Stull; Neil F. Adams; Steven R. Manchester; Dan Sykes; Margaret E. Collinson. (2016). Revision of Icacinaceae from the Early Eocene London Clay flora based on X-ray micro-CT. Botany, 94(9), 713–745 View reference
  • Kathleen B. Pigg; Steven R. Manchester; Melanie L. DeVore. (2008). Fruits of Icacinaceae (Tribe Iodeae) from the Late Paleocene of western North America. American Journal of Botany, 95(7), 824–832 View reference
  • Margaret E. Collinson; Neil F. Adams; Steven R. Manchester; Gregory W. Stull; Fabiany Herrera; Selena Y. Smith; Mary J. Andrew; Paul Kenrick; Dan Sykes. (2016). X-ray micro-computed tomography (micro-CT) of pyrite-permineralized fruits and seeds from the London Clay Formation (Ypresian) conserved in silicone oil: a critical evaluation. Botany, 94(9), 697–711 View reference
Last Reviewed
26 August 2026 Reviewed by Sam Harris