Contents

08 June 2007
Vol 316, Issue 5830

About The Cover

Cover image expansion

COVER Flowers of monkshood, Aconitum napellus, extend laterally from a main stem and open successively toward the apex. This arrangement is one of only three basic flowering structures observed in nature, reflecting the way developmental mechanisms and natural selection interact to constrain biological form, as described on page 1452. Photo: Karen Lee