Protopteris STERNBERG, 1838

Greguš, Josef & Kvaček, Jiří, 2015, Revision Of Cenomanian Flora From The Maletín Sandstone, Acta Musei Nationalis Pragae Series B 71 (3 - 4), pp. 315-364 : 319

Protopteris STERNBERG, 1838

T y p e: Lepidodendron punctatum STERNBERG, 1820, p. 20 , 23, pl. 4, fig. 1 = Protopteris punctata (STERNBERG) C. PRESL in STERNBERG, 1838, p. 170, pl. 65, fig. 1–3.

D i s c u s s i o n. This genus was re-defined to accommodate casts of Mesozoic tree fern stems ( Greguš et al. 2013). The genus Protopteris has one uninterrupted vascular bundle scar, which distinguishes it from the genus Protocyathea O. FEISTMANTEL , where the vascular bundle scars are formed with a few small irregular pits. In this character, Protopteris is similar to the recent genus Cyathea J. E. SMITH. The genus Protopteris has leaf scars helically arranged, as opposed to the genus Oncopteris DORMITZER in KREJČÍ, in which leaf scars occur in longitudinal rows. Protopteris , in comparison with the Paleozoic genus Megaphyton ARTIS , has more than two lines of leaf scars on the stem. Another Paleozoic genus, Caulopteris LINDLEY et HUTTON also has helically arranged leaf scars ( Pfefferkorn 1976), just like Protopteris . Additionally, both Paleozoic genera have much larger leaf and vascular bundle scars, compared to the genera Oncopteris and Protopteris ( Greguš et al. 2013) .