"Perilous Plan of the Plant-Master" and "Fury of the Floronic Man!" by Denny O'Neil (in English)

art by Dick Dilin and Terry Austin.

"Perilous Plan of the Plant-Master" - The Flash #245 - DC Comics, November 1976.
"Fury of the Floronic Man!" - The Flash #246 - DC Comics, January 1977.