Icacinicarya minima

Icacinicarya minima

Reid et Chandler

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

Summary

Icacinicarya minima was a minute early Eocene icacinaceous plant known from its small, rather inflated fruit stone. The thick endocarp protected the seed, while a marginal vascular pathway connected the seed region towards an apical placenta. The inner surface of the fruit stone was finely papillate.

The surviving material is commonly abraded, pyritised or preserved only as locule casts and seeds, so some of the original fruit surface has been lost. These fossils preserve useful reproductive anatomy, but no attached leaves or stems are known and the whole-plant growth form remains uncertain.

Quick Identification

Look for: a tiny, inflated subglobose-to-ovoid fruit stone around 7.5 × 6 × 6 mm, with a relatively thick wall and a strong marginal funicular/vascular feature. Fine papillae on the locule lining require good preservation and usually magnification.

Diagnostic Features

  • Endocarp is minute, subglobose to ovoid and relatively inflated.
  • Holotype dimensions are about 7.5 × 6 × 6 mm.
  • Wall is comparatively thick for such a small fruit stone.
  • Marginal funicular/vascular pathway produces a longitudinal ridge or corresponding deep marginal depression on locule casts.
  • Locule lining is finely papillate.

Fossil Details

Typical size
Holotype about 7.5 × 6 × 6 mm.
Fossil material
Seed, Fruit
Preservation
All surviving endocarps in the modern collection are abraded or pyritised; additional material includes locule casts and seeds. Loss of the wall can remove the marginal ridge while coarse pyrite can mask the fine papillation.

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