Cyathea cranhamii

Cladus: Eukaryota
Regnum: Plantae
Divisio: Pteridophyta
Subdivisio: Pterophyta
Classis: Pteridopsida
Ordo: Cyatheales
Familia: Cyatheaceae
Genus: Cyathea
Subgenus: Unassigned
Species:†C. cranhamii

Name

Cyathea cranhamii Smith, Rothwell, & Stockey 2003

Type locality

Early Cretaceous (Barremian); Longarm Formation equivalents; Apple Bay, Vancouver Island, British Columbia, Canada.

Type material

* Holotype: University of Alberta Paleobotanical Collections UAPC-ALTA P13021 Hbot b
* Paratypes: University of Alberta Paleobotanical Collections UAPC-ALTA P13018 Dbot a, P13021 Hbot c, and P13023 Abot

References

* Smith, Selena Y., Rothwell, Gar W., & Stockey, Ruth A. (2003) "Cyathea cranhamii sp. nov. (Cyatheaceae), anatomically preserved tree fern sori from the Lower Cretaceous of Vancouver Island, British Columbia" 90:755-760

Cyathea cranhamii is an extinct species of tree fern. It was described based on permineralised sori from the Early Cretaceous deposits of Apple Bay in Vancouver Island, British Columbia.

C. cranhamii has sori arranged in two rows on narrow pinnules. They are covered by globose indusia which resemble those of Sphaeropteris species in morphology. Sporangia are circinate (ring-shaped) and bear multicellular stalks. They diverge from a basal, vascular receptacle. The sporangia contain 64 trilete spores which bear sculpturing on their outer covering (perispore) ranging from irregular granulate or echinate to prominent rodlets. The annulus is nearly vertical and arranged in a single series. It is not interrupted by the stalk.

The specimens used to describe C. cranhamii are the first anatomically preserved tree fern sori known from the fossil record. Smith, Rothwell and Stockey (2003) state that "they represent the most ancient evidence for fertile structures of the Cyatheaceae and demonstrate that essentially modern species of cyatheaceous tree ferns had evolved by the Early Cretaceous".

Numerous Cyathea species are present today in the Americas, especially the Greater Antilles, the Caribbean, and Central and South America.

C. cranhamii is named after Gerald Cranham of Parksville, British Columbia, who provided plant specimens for study at the University of Alberta.

References

* Smith, Selena Y., Gar W. Rothwell & Ruth A. Stockey 2003. Cyathea cranhamii sp. nov. (Cyatheaceae), anatomically preserved tree fern sori from the Lower Cretaceous of Vancouver Island, British Columbia. American Journal of Botany 90: 755-760.