Photo: National Park Service, Fossil Butte National Monument
- Order
- Unknown
- Family
- Unknown
- Size
- Wings about 3–9 inches
A wind-dispersed winged fruit known only from lake deposits — and with no modern counterpart.
The name means "hare-fruit-of-lakes": Lagos (Greek for hare, referencing the rabbit-head shape of the seed and wings), karpos (Greek for fruit), and lacustris (Latin for of lakes and ponds).
L. lacustris is recognizable by its spherical seed body and dual set of wings characterized by a V shape. The wings indicate that fruit was wind dispersed. It is known from fossil deposits in Wyoming, Utah, Colorado, Oregon, and British Columbia, and is found exclusively in lake deposits. No modern fruits share its specific characteristics; living Gyrocarpus species are similar in form.
Species text: National Park Service, Fossil Butte National Monument — Fossil Plant Species.