Acer lincolnense facts for kids

Acer lincolnense is an extinct maple species that lived a long, long time ago. We know about it from fossils of its leaves and fruits. These fossils were found in rocks from the Eocene period in Montana, USA. Scientists think Acer lincolnense might be related to a group of living maples called Cissifolia.

Acer lincolnense: An Ancient Maple

Discovering a Fossil Maple

Fossils of Acer lincolnense were found in a place called the Beaver Creek flora in western Montana. This area has many plant fossils from the late Eocene period. Scientists believe these fossils are about 32 to 38 million years old.

The first people to study these fossils were paleobotanists Jack A. Wolfe and Toshimasa Tanai. They are scientists who study ancient plants. In 1987, they officially named this new maple species Acer lincolnense. The name "lincolnense" comes from Lincoln County, Montana, where the fossils were found.

The main fossil used to describe the species is called the holotype. It is kept at the University of California Museum of Paleontology. Other Acer species were also found in the same area.

How Acer lincolnense Relates to Other Maples

Scientists compared Acer lincolnense to other maple trees. Its leaves and fruits looked similar to two groups of maples: Acer section Negundo and Acer section Cissifolia.

One special thing about Acer lincolnense leaves is that they had three leaflets. These leaflets were attached directly to the main leaf vein, without little stalks (called petiolules). This is different from some modern maples.

The fruits of Acer lincolnense were also similar to the Cissifolia group. They had a curved shape. However, the veins on the fruit's wing were wavy. This wavy pattern is usually seen in another maple group called Acer section Indivisa. Scientists are still learning exactly where Acer lincolnense fits in the maple family tree.

What Did It Look Like?

Leaves of Acer lincolnense

The leaves of Acer lincolnense had three separate parts, called leaflets. The side leaflets were about 1.5 to 4.8 centimeters (0.6 to 1.9 inches) long. They sat right against the main vein of the leaf. This means they didn't have tiny stalks.

Each side leaflet had 5 to 7 smaller veins branching off. The edges of the leaflets had large, simple teeth. Some of the biggest teeth even had smaller teeth on them.

The main leaflet (at the end) was not fully preserved in the fossils. So, its exact size is unknown. The veins on the leaves formed a network of irregular shapes.

Fruits of Acer lincolnense

Like other maples, the fruits of Acer lincolnense were samaras. This means they had a seed part (called a nutlet) and a flat wing. The nutlet was about 1.0 centimeter (0.4 inches) long and 0.4 centimeters (0.16 inches) wide.

The wing of the fruit was about 1.2 centimeters (0.5 inches) long and 0.7 centimeters (0.3 inches) wide. Its outer edge was broadly curved. The veins on the wing were wavy. They spread out from each other at small angles.