ИСТИНА

Presence or absence of terminal flowers is used as one of the major distinguishing features of inflorescence morphology. Occasional flower-like terminal structures similar to those described in lab-induced homeotic mutants of model organisms can also be found in natural populations of different angiosperms. Triglochin maritima is a good example of this phenomenon. Typically, its inflorescence is terminated by a flower, but sometimes a flower-like terminal structure is formed, or neither a flower nor a flower-like structure is inserted in an unequivocally terminal position. At least some terminal structures could be interpreted as fusion products of uppermost lateral flowers (i.e. terminal pseudanthia), though other interpretations are possible. This study presents data on the vasculature of inflorescence tips with free and united flowers and those with terminal flower present or absent. The vascular system of an inflorescence with a terminal pseudanthium is similar to that of one with a terminal flower. Sometimes a terminal flower and one or several uppermost lateral flowers share the same vascular supply that is distinct from that of other lateral flowers; formation of this type of inflorescence resembles the phenomenon of fasciation.