BAIKALOPHYLLUM LOBATUM AND REHEZAMITES ANISOLOBUS: TWO SEED PLANTS WITH CYCADOPHYTE FOLIAGE FROM THE EARLY CRETACEOUS OF EASTERN ASIA

Two fossil seed plants with cycadophyte foliage, Baikalophyllum lobatum and Rehezamites anisolobus, are reinvestigated and described on the basis of new material from Lower Cretaceous strata of Liaoning and Inner Mongolia, China, and previously published material from China and Transbaikalia, Russia. The new fossils demonstrate that the Baikalophyllum plants were slender-stemmed, loosely branched, and shrublike. Yixianophyllum jinjiagouensis, described from the Zhuanchengzi beds of the Yixian Formation, Liaoning, is determined to be a junior synonym of B. lobatum. Rehezamites anisolobus, informally described from the Lower Cretaceous Yixian Formation in previous studies, is validated here, and its foliage is compared with that of Baikalophyllum. Baikalophyllum and Rehezamites have leaf morphologies and venation patterns that, in terms of general architecture, resemble those of leaves traditionally assigned to extinct members of Cycadales, Bennettitales, and Pentoxylales, but because of ambiguous circumscription and the need for thorough revisions of these groups, leaves of Baikalophyllum and Rehezamites are retained unassigned.