Morphology of Bennettitalean fructifications

Abstract

The Bennettitales dominated the vegetation throughout the world during Mesozoic Era. In external morphology they were cycad-like, but had distinct type of fertile parts. Fructifications were monosporangiate or bisporangiate. In seed-bearing fructifications a compact layer of fertile and sterile scales surrounded the conical/hemispherical receptacle. On the basis of ontogeny and anatomy, both types of scales are described as appendicular structures and derived the fructification from Cordaianthus. Bisexual fructifications resemble  cycadeoideas. Male fructifications are unique and can be correlated neither with any known extinct nor extant plant. Bennettitales originated independently from protoseminales, a plexus which also gave rise to cordaitales and pteridosperms, Bennettitales ended abruptly.