STUDIES OF NEW ALBANY SHALE PLANTS. I. STENOKOLEOS SIMPLEX COMB. NOV.

Beck , Charles B. (U. Michigan, Ann Arbor.) Studies of New Albany shale plants. I. Stenokoleos simplex comb, nov. Amer. Jour. Bot. 47(2): 115—124. Illus. 1960.–A specimen of Stenokoleos from the Falling Run member of the Sanderson formation is described and shown to belong to the same species as Mesoneuron simplex (Read and Campbell, 1939). Among the distinctive features of this species are traces of triangular shape bearing 3 mesarch protoxylem areas, metaxylem tracheids with scalariform pitting, and the presence of fibers in the outer phloem. The new specimen indicates that Stenokoleos had a basically cruciform xylem strand which gave rise to pairs of traces, each trace supplying one of a pair of lateral appendages which occurred on opposite sides of the main axis, but at different levels. The fern-like nature of Stenokoleos is emphasized and it is suggested that this genus most closely resembles members of the Zygopteridaceae.