Eostangeria

Eostangeria is a genus of fossil foliage belonging to the Cycadales.

Eostangeria
Temporal range: Paleocene to Middle Miocene
Scientific classification
Kingdom:
Plantae
(unranked):
Cycadophyta
(unranked):
Cycadopsida
Order:
Cycadales
Family:
Zamiaceae
Genus:
Eostangeria

Barthel 1976[1]
Species

Taxonomy

Some leaflets of Eostangeria had previously described as ferns such as Angiopteris.

Distribution

This genus was first erected based on material from the Eocene of the Geisel valley,[2] but other species have been later retrieved from the Paleocene of Wyoming and Eocene of Oregon[3] and the Miocene of Bulgaria.[4] Affinities have been suggested with either Stangeria or the Colombian Zamia restrepoi.

Description

Leaflets of Eostangeria have a notable midrib from which parallel veins diverge fusing only rarely in the margin of the leaflet. Dispersed leaflets are often retrieved, suggesting the presence of an abscission layer at the base.[3] Cuticles have isodiametrical to elongated cells, with dark-staining and light-staining pavement cells and sunken stomata. If the cuticle is not preserved, leaflets of Eostangeria can be confused with fern leaflets of the genus Allantodiopsis.

References
  1. Barthel, M (1976). Eozäne Floren des Geiseltales: Farne und Cycadeen. Abhandlungen des Zentralen Geologischen Institutes. Paläontol Ab-handl.
  2. Barthel, M (1976). Eozäne Floren des Geiseltales: Farne und Cycadeen. Abhandlungen des Zentralen Geologischen Institutes. Paläontol Ab-handl.
  3. Kvaček, Zlatko; Manchester, Steven R. (1999-05-01). "Eostangeria Barthel (Extinct Cycadales) from the Paleogene of Western North America and Europe". International Journal of Plant Sciences. 160 (3): 621–629. doi:10.1086/314152. ISSN 1058-5893. S2CID 83978433.
  4. Uzunova, K., Palamarev, E.. and Kvacek, Z., 2002. Eostangeria ruzinciniana (Zamiaceae) from the Middle Miocene of Bulgaria and its relationship to similar taxa of fossil Eostangeria, and extant Chigua and Stangeria (Cycadales). Acta Palaeobotanica-Krakow-, 41(2), pp.177-194.
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