BY WAYNE R. CARLSON AND JAMES A. BIRCHLER

THERE ARE MANY ways to characterize scientists. Some could be said to choose a problem and begin to apply various techniques to understand it. Others explore the field with open eyes and open mind, grasping the unexpected for investigation. Marcus M. Rhoades was the latter type. His oft-repeated entreaty to beginning graduate students, ''Just get in the lab and start work; you can't help but discover something," gave evidence of his belief in this approach. Certainly his own discoveries were a diverse group of seminal contributions to genetics.

Marcus M. Rhoades was born on July 24, 1903, in Graham, Missouri, and spent his childhood in Downs, Kansas. He developed a strong affinity for the Midwest and often boasted of the fertile fields and wide expanses of that part of the United States. Rhoades attended the University of Michigan, majoring in botany and mathematics. When he was a senior and uncertain of his interests, he was befriended by Prof. E. G. ("Andy") Anderson. Anderson introduced Rhoades to plant genetics and, when Rhoades later wrote a memorial resolution on Anderson, he praised him warmly. After receiving his B. S. and M. S. degrees at Michigan, Rhoades studied for his Ph.D. at Cornell University under