Pseudobornia is a genus of plants known only from fossils found from the Upper Devonian.[1] It contains a single species Pseudobornia ursina, and is the earliest fossil assigned with certainty to the Equisetopsida.
| Pseudobornia Temporal range: | |
|---|---|
 | |
| Pseudobornia ursina | |
Scientific classification  | |
| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Division: | Polypodiophyta |
| Class: | Polypodiopsida |
| Subclass: | Equisetidae |
| Order: | †Pseudoborniales |
| Genus: | †Pseudobornia Nathorst. |
| Species: | †P. ursina |
| Binomial name | |
| †Pseudobornia ursina Nathorst. | |
The first fossils of Pseudobornia were collected by Johan Gunnar Andersson on Bear Island in the 1890s.[2] Hans-Joachim Schweitzer, a paleobotanist, was the first to interpret the fossils as belonging to a large tree, based on additional fossils discovered in Alaska in the 1960s.[3][4]
The probable relationships within Equisetidae are shown in the cladogram below. The position where Ibyka would be has been added.[5]