Pseudobornia

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: Late Devonian[1] PreꞒ Ꞓ O S D C P T J K Pg N ↓
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]

	†Ibyka(?) †Pseudobornia ursina †Sphenophyllales †Archaeocalamitaceae †Calamitaceae Equisetaceae

References

1. Taylor, Thomas N.; Edith L. Taylor. (1993). The Biology and Evolution of Fossil Plants. Englewood Cliffs, NJ: Prentice Hall. pp. 305–307. ISBN 0-13-651589-4.
2. "Paleontology: World's First Tall Tree". Time. June 16, 1967.
3. Schweitzer, H.-J. (1967). "Die Oberdevon-Flora der Bäreninsel I. Pseudobornia ursina Nathorst". Palaeontographica. 120B: 116–137.
4. Schweitzer, H.-J. (1967). "Ein Riesenschachtelhalm aus dem Oberdevon, Pseudobornia ursina". Umschau in Wissenschaft und Technik. 6: 196.
5. "Introduction to the Sphenophyta". University of California Museum of Paleontology. Retrieved 31 July 2011.