Cratonia Rydin, B.A.R.Mohr et E.M.Friis

Plant Fossil Names Registry Number: PFN002846

Act LSID: urn:lsid:plantfossilnames.org:act:2846

Authors: C. Rydin, B. A. R. Mohr & E. M. Friis

Rank: genus

Reference: Rydin, C., Mohr, B. & Friis, E. M. (2003): Cratonia cotyledon gen. et sp. nov.: a unique Cretaceous seedling related to Welwitschia. – Proceedings of the Royal Society of London. Series B. Biological Sciences 270(Suppl.): S29–S32.

Page of description: S29

Type

Original diagnosis/description

The cotyledons are ovate and large, rounded at the base and apically convex. The leaf margins are entire. First-order veins are parallel and equidistant throughout the leaves. They fuse apically with a marginal vein. Vein dichotomies are not preserved. Second-order veins diverge at ca. 45° to the primary veins, and fuse with the opposite secondary veins in the middle of the area between the corresponding primaries to form a distinct pattern of irregularly fused, inverted ‘Y’s. The ‘Y’s are occasionally free ending. Epidermal cells are polygonal. The stomata are slightly sunken and distributed in a scattered pattern. Guard cells are longitudinally arranged, and the subsidiary cells are apparently paracytic or actinocytic. The hypocotyl region is inconspicuous. The root is laterally branched with a major, proximal branching. A thick, lateral feeder is positioned below the cotyledons.

Etymology

The generic name is adopted from the Crato Formation, Brazil.