Hypericum antiquum
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| Hypericum antiquum Temporal range: | |
|---|---|
Scientific classification  | |
| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Clade: | Angiosperms |
| Clade: | Eudicots |
| Clade: | Rosids |
| Order: | Malpighiales |
| Family: | Hypericaceae |
| Genus: | Hypericum |
| Species: | †H. antiquum |
| Binomial name | |
| †Hypericum antiquum Balueva & Nikitin (2005) | |
Hypericum antiquum is an extinct species of the genus Hypericum that was present during the Eocene epoch. The species' fossils are the oldest collected of Hypericum, and it is believed that the species is the common ancestor of the tribe Hypericeae.[1] Fossil seeds have been found in Russia, and the predicted paleoregion of the species stretched across Eurasia.[2] It is theorized that one factor leading to the species' extinction is a global cooling at the end of the Eocene that removed much of its habitat.[3]
Because the only recovered fossils of the species are seeds, the only description available is of said seeds. The collected seeds were approximately 0.5 long by 0.3 mm wide in size and black in color.[4] They are anatropous, and either cylindrical or somewhat flattened in shape. The meshes of the surface are elongated and hexagonal, and are formed by the elongated cells of the testa. One end of the seed is rounded, while the other is slightly narrowed with a small tubercule. The case of the seed is rather thin, and is colored black.[5][6]