Ray Callaway, a professor of plant ecology at the University of Montana, will speak at Wichita State University as part of the Watkins Visiting Professorship Lecture Series on biological sciences.

Callaway's public lecture is at 4 p.m. Monday, Sept. 21, in 209 Hubbard Hall. The topic is "Does Competition Run the World? Positive Interactions Among Plant Species."

It is free and open to the public.

Callaway studies interactions among plants and the implications of these interactions in nature. Most recently, his focus has shifted to exotic plant invaders, because these species appear to break many of the rules that are thought to operate in natural systems.

The Watkins Visiting Professorship was created in 1974 from the Watkins Foundation, which provides the university's biology, chemistry, geology and physics departments with one visiting professor each year as part of the series.