Eucommia jeffersonensis facts for kids

Eucommia jeffersonensis is an extinct flowering plant. It was part of the family Eucommiaceae. Scientists know about this plant from a fossil fruit. This fruit was found in Oregon, United States. It dates back to the very end of the Eocene time period.

E. jeffersonensis is one of five fossil species from North America. These species are all grouped under the modern plant genus Eucommia. Other related fossil species include E. constans, E. eocenica, E. montana, and E. rolandii.

Discovery and Classification

Scientists know Eucommia jeffersonensis from just one fossil. This special fossil is called the holotype. It is kept at the Florida Museum of Natural History. The fossil is a fruit that is not fully complete. It is preserved as a compression fossil. This means it was flattened and pressed into shale rock.

The fossil was found in a place called the Gray Butte flora in Oregon. This area is near Gray Butte. The Gray Butte flora has plants from both the Clarno Formation and the John Day Formation. These are different layers of rock that tell us about ancient times.

Two paleobotanists, Victor B. Call and David L. Dilcher, first studied this fossil. They were both from the University of Florida. In 1997, they officially described the new species. Their description was published in the American Journal of Botany journal.

The name jeffersonensis was chosen for the plant. It refers to Jefferson County, Oregon. This is the county where the Gray Butte flora is located. It is also where the fossil was found.

What the Fruit Looked Like

The fossil fruit of E. jeffersonensis is not complete. Even so, scientists can tell it was about 12.7 millimetres (0.50 in) long. This measurement does not include the missing tip or the stem part. The fruit was about 7.1 millimetres (0.28 in) wide. The stem, called a stipe, was about 7.9 millimetres (0.31 in) long.

The stipe is the small stem that connected the fruit to the tree. It was at the base of the fruit. The fruit body became narrower as it reached the stipe. The stipe then became even narrower. Scientists think the tip of the fruit was pointed, even though it is missing.

Like other Eucommia plants, this fruit was a samara. A samara is a type of winged fruit. It had two flattened parts called carpels. These were surrounded by a narrow wing. Usually, only one of the two carpels fully grew. The other carpel stayed small along the edge of the mature fruit. This made the fruit look a bit uneven.

A special feature of E. jeffersonensis is its infertile carpel. It had two strands, not just one. These strands are like veins that start at the stipe. They curve around the edge of the fruit wing. Then they join together at the tip of the fruit. These two strands ran side-by-side for a short distance before merging.

Other Eucommia species have different fruit sizes. For example, E. montana fruits are shorter than E. jeffersonensis fruits. Most E. eocenica fruits are longer than E. jeffersonensis. E. constans fruits are larger and have a longer stipe. E. eocenica is also larger than E. constans. Its fruit tip is pointed, unlike the rounded tip of E. constans.