Stenoosids

Stenoosids are an extinct family of flowering plants belonging to the order Apiales. They are known exclusively from fossilized remains, primarily found in Cretaceous and Paleogene deposits. The most distinctive feature of stenoosids is their unusual seed structure, which is characterized by a hard, woody pericarp and a highly lignified endosperm. This characteristic seed morphology is what gives the family its name, derived from the Greek words "stenos" meaning narrow and "oos" meaning egg, referring to the elongated, egg-like shape of their seeds.

Fossil evidence suggests that stenoosids were relatively widespread during the early Cenozoic, with fossils discovered in various parts of the world, including North America, Europe, and Asia. Their ecological role is not fully understood, but their seed structure indicates adaptation to dispersal through water or by animals capable of processing tough seed coats. While direct ancestors are difficult to pinpoint, stenoosids are thought to be related to modern families within Apiales, such as Araliaceae (the ivy family) or Apiaceae (the carrot family), though their exact phylogenetic position remains a subject of ongoing research. The extinction of stenoosids is likely due to a combination of environmental changes and competition from more successful plant lineages.