XVI International Botanical Congess

SEM-based floral ontogenies of 30 representative taxa show two possibly significant sets of characters for caesalpinioid tribe Detarieae or its segregate groups. First, ring-meristem activity is limited to Brachystegieae among Caesalpinioideae. Second, a character assemblage, centered on contrasting states in bracteole size at initiation, appears significant. In one assemblage, initiatory bracteoles are small, the post-bracteole floral apex is circular and initiates five sepals helically. This assemblage occurs in Leonard's Amherstia, Brownea, Crudia, Cynometra pr.p., and Hymenostegia groups. In the second character assemblage (in taxa of Brachystegia, Berlinia, Detarium, Cynometra pr.p., and Macrolobium groups), initiatory bracteoles are massive, the post-bracteole floral apex is sagittally elongate, and the perianth may be reduced to one sepal and one petal.