This is the “Fossil Friday” post #332. Expect this to be a regular feature of the website. We will post fossil pictures you send in to esconi.info@gmail.com. Please include a short description or story. Check the #FossilFriday Bluesky/Twitter hash tag for contributions from around the world!

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Today, we have a largish plate of Crossotheca sagittata. Crossotheca sagittata is the fertile form of Pecopteris fontainei (see Mazon Monday #129). Remember, paleobotany specifies separate species for different plant parts, which is why we have two names for the same plant. This concept is known as form genera.

Both species were named by Leo Lesquereux in 1880 as Pecopteris abbreviata, the sterile form, and Sorocladus sagittatus, the fertile form. In 1889, he realized his P. abbreviata form was unlike P. abbreviata as originally erected by Brongniart and changed the name to Pecopteris fontainei.