On a new Cordaitean Stem, Cordaites Sahnii, from Central Shansi, China

Abstract

A silicified stem collected by F. L. Yuan from the Yang-Chu district (37º 8’: 112° 6’) of Central Shansi, China, is considered to be a new species of Cordaites. The pith is fairly large and discoid. The bark is represented by some layers of crushed tissues. The secondary wood consists only of tracheides and rays and is devoid of annual rings, resin canals and resin cells. Bordered pits are confined in the radial walls of tracheides and are generally uni- and biseriate, alternately arranged, and mostly flattened into hexagons. Triseriate pits are found only at the terminal part of racheides. The xylem rays are uni- to biseriate, about 1-10 cells high with bordered pits, confined in radial walls of ray cells. In each "cross field" there are one to four elliptical bordered pits. The geological age of this fossil is thought to be Upper Carboniferous or Lower Permian. The specific name Cordaites Sahnii sp. nov. is suggested in memory of the late Professor B. Sahni.