Branch length mediates flower production and inflorescence architecture of Fouquieria splendens (ocotillo)

The capacity of individual branches to store water and fix carbon can have profound effects on inflorescence size and architecture, thus on floral display, pollination, and fecundity. Mixed regression was used to investigate the relation between branch length, a proxy for plant resources, and floral display of Fouquieria splendens (ocotillo), a woody, candelabraform shrub of wide distribution in arid North America. Long branches produced three times as many flowers as short branches, regardless of overall plant size. Long branches also had more complex panicles with more cymes and cyme types than short branches; thus, branch length also influenced inflorescence architecture. Within panicles, increasing the number of cymes by one unit added about two flowers, whereas increasing the number of cyme types by one unit added about 21 flowers. Because flower production is mediated by branch length, and because most plants have branches of various lengths, the floral display of individual plants necessarily encompasses a wide range of inflorescence size and structure. ?? Springer 2006.