Inflorescence morphology of Loranthaceae – an evolutionary synthesis

A systematized survey of inflorescence structure is presented of Loranthaceae, s.s., on a world-wide basis, starting with New World taxa and continuing with Old World ones. In each case, material is arranged to reflect a presumed evolutionary sequence. This sequence uses as its starting point the solitary sessile flower subtended by a foliage leaf, leading to the evolution of a determinate inflorescence with ebracteolate lateral monads, and eventually to indeterminate inflorescence types successively bearing ebracteolate and bracteolate lateral monads and, in many groups, eventually triads. Various trends in condensation to umbels and capitula have emerged occasionally, as well as other reductional phenomena and other modifications. The unit inflorescence of Loranthaceae is thus regarded as a fundamentally axillary structure, and not a modified leafy branch.