Fossil Plant Species

leaf with 2 pointed lobes, one smaller than other
Gyrocarpus FOBU10668 specimen

NPS Photo

Plants are major indicators of climate. Fossil leaves and plants act as ancient thermometers, allowing scientists to study the ancient climate of Fossil Lake. It is difficult to identify fossil leaf specimens from the Fossil Butte Member (FBM) at the species level.

non-lobed leaf with tiny bites out
Gyrocarpus FOBU13320 specimen

NPS Photo

Gyrocarpus species

Gyrocarpus specimens (pictured above and to the right) demonstrate the challenge of identifying fossil plant species.
This species produces:

  • non-lobed specimens (pictured right)
  • 2 lobed specimens (pictured above)
  • 3 lobed specimens
The same species of tree can produce different looking leaves.
Fossil of a palm frond from the Green River Formation
Palmites sp FOBU446 fossil

NPS Photo

Palm - Palmites species

Order Arecales, Family Aracacea
Palm inflorescences (a group of flowers arranged on a stem) and palm fronds (pictured here) are common fossil specimens from the FBM.
  • Variation in morphology of specimens indicates Fossil Lake may have been home to several palm species.
  • No FBM palm species have been described as of yet.
  • Abundance of large and complete palm frond specimens suggests there may have been palm trees near the shores of Fossil Lake.
There are over 2,000 living palm species, found naturally in tropical, sub-tropical, and humid environments. Palm specimens are indicators of a warm, sub-tropical environment at Fossil Lake.
2 long leaves forming v shape with small circular seed at the base
L. lacustris FOBU9835 specimen

NPS Photo

Winged Fruit Species - Lagokarpos Lacustris

Order unknown, Family unknown
"Hare-Fruit-Of Lakes"
Lagos - translating "hare" (referencing rabbit-head shape of seed and wings)
Karpos - translating "fruit"
Lacustris - translating "of lakes and ponds"
  • recognizable by its spherical shaped seed body and dual set of wings
  • wings characterized by V shape
  • wings indicate that fruit was wind dispersed (seeds carried by wind to new growing sites)
  • specimen wings range in size from 3 to 9 inches
  • known from fossil deposits in Wyoming, Utah, Colorado, Oregon, and British Columbia
  • found exclusively in lake deposits, indicating they were a near-shore species
No modern fruits are known to share the specific characteristics of L. lacustris, and the Lagokarpos genus is though to be extinct. Species of the living Gyrocarpus genus are, however, similar in form. This genus is found primarily in tropical and subtropical regions.
leaf with small crack with round seed in middle, on top of bug with outstretched wings
A. confucii RH-27 specimen

NPS Photo

Tree of Heaven - Ailanthus confucii

Order Sapindales, Family Simaroubaceae
There are about 100 modern species in the Simaroubaceae family, found primarily in tropical and subtropical regions. The Ailanthus genus has a disputed number of living species, somewhere between 5 and 10. They are commonly known as "Trees of Heaven."
A. confucii is:
  • a winged fruit
  • characterized by its centrally located seed
  • known from fossil deposits in North America, Asia, and Europe
  • found almost exclusively in lake and pond deposits
A. confucii specimens from the FBM are the oldest known representation of the Simaroubaceae family in North America, possibly the world.
leaf-like fossil with 3 off-shoots
Platycerium FOBU11465 specimen

NPS Photo

Staghorn Fern - Platycerium species

Order Polypodiales, Family Polypodiaceae
  • almost 20 living species in Platycerium genus
  • found primarily in tropical environments of Asia, South America, New Guinea, and Africa
2 cup like leaves with skinny roots hanging below
S. preauriculata FOBU11895 specimen

NPS Photo

Water Fern - Salvinia preauriculata

Order Salviniales, Family Salviniaceae
This aquatic species had 2 floating leaves and 1 root-like leaf which would hang below the water's surface.
Living members of the Salvinia genus:
  • include 15 modern species
  • found in tropical regions of Madagascar, Africa, West Indies, Europe, Asia, North and South America
  • only found in freshwater
  • spread rapidly in warm water
2 long skinny leaves in a v shape with small clump of seeds at the base
L. kaulfussi FOBU12018 specimen

NPS Photo

Climbing Fern - Lygodium kaulfussi

Order Schizaeales, Family Lygodiaceae
Living members of the Lygodium genus:
  • include 40 modern species
  • found primarily in the tropical regions of Asia
  • do not have a fixed growing season and will continue to grow throughout their life
  • growing cycle lead to common name, "climbing fern"
black circle with many smaller circles inside
Nelumbo FOBU11744 specimen

NPS Photo

Lotus - Nelumbo species

Order Proteales, Family Nelumbonaceae
The modern Nelumbo genus:
  • contains 2 living species
  • aquatic plants restricted to freshwater
  • found in Asia, North America, and the Caribbean
  • characterized by large flowers and leaves
Fossil Lake may have been home to multiple species of the Nelumbo genus. FBM specimens include:
  • lily pads (ranging from 4 - 20 inches)
  • root systems
  • characteristic seed pods (pictured here)
five petals surrounding small circular seed, crack through left side of rock
C. tenuis FOBU11466 specimen

NPS Photo

Flower-Like-Fruit - Chaneya tenuis

  • characterized by 5 petal-like wings
  • although resembling a flower, C. tenuis is actually a fruit
  • Chaneya genus known from fossil deposits in North America, Asia, and Europe
leaf fossil with mushroom shape
Birthwort FOBU1185

NPS Photo

Birthwort - species unknown

Order Piperales, Family Aristolochiaceae
Modern members of the Aristolochiaceae family:
  • found primarily in tropical regions
  • also commonly known as "pipe-vines"
  • perennial (lifecycle longer than 2 years)
  • working herbaceous plants (grow as non-woody shrubs or vines)
  • include about 400 living species
  • primarily pollinated by flies
The fossil plant pictured has not been described as a species.
feather shaped leaf with circular seed at bottom
D. wolfei FOBU11716 specimen

NPS Photo

Soapberry - Deviacer wolfei

Order Sapindales, Family Sapindaceae
Living members of the Sapindaceae family:
  • are found in temperate to tropical regions
  • includes over 1,800 modern species
  • modern species include maple and the tropical lychee tree
circular seed with visible vertical veins
Walnut FOBU13350 specimen

NPS Photo


This seed has the appearance of a walnut.

Last updated: November 17, 2022

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