A Study of the Vegetative Anatomy of the Genus Sphenophyllum from American Coal Balls

Abstract

Although the genus Sphenophyllum has been described in some of the earliest paleobotanical works and Seward (1898) lists it as one of the best-known fossil plants, the rich source of petrified specimens in the American coal balls has been very largely ignored. The works of Renault and Williamson (1878) did much to make known the inner structure of the stems, roots and leaves of the English and European forms, although gaps were left concerning our knowledge of branching, the attachment of roots, and other anatomical points. It was with the hope, therefore, of contributing to our knowledge of the internal structure of the plants, as well as the desire to make better known the American fossils and to correlate them in so far as possible with the English and French species, that this study was undertaken. The material on which this study was based was obtained from two sources as follows: The Pyramid mine, two miles south of Pinckneyville, Perry County, Illinois, this horizon being at the base of the McLeansboro series (coal No. 6) and of upper-middle Pennsylvanian age; and The What Cheer Clay Products Co. coal mine, one-half mile west of What Cheer, Iowa. This horizon lies in the Des Moines series of the Pennsylvanian.