Within the plant family Boraginaceae, Heliotropium, plus Tournefortia and Heliotropium (section Orthostachys) exhibit great variation in many features of general biological interest, including habitat preference, physiognomy, photosynthetic carbon fixation system, breeding system and many morphological features. Previous studies of morphology suggest that unexpected evolutionary changes may have occurred; in particular, C4 photosynthesis may have been lost in one or two species and the "Axillaria" growth habit, in which the plant consists mostly of scorpioid cymes with bracts fulfilling the functions of leaves, may have evolved more than once within the group. Additional data are needed to test these conjectures. Dr. Michael W. Frohlich, of Union College in Schenectady, New York, will conduct a molecular systematic study of selected species of Heliotropium (section Orthostachys) to test the conclusions he derived from morphological studies by examining chloroplast restriction fragment length polymorphisms. This study could confirm the evolutionary changes that seem to have occurred in this genus. The research will be performed primarily at Cornell University's Bailey Hortorium, over the course of 13 months of Mid-Career Fellowship in Environmental Biology tenure beginning in August 1989.
