Polygamy in Atriplex halimus L. (Chenopodiaceae)

It appears that up to now the inflorescence and flower morphologies of Atriplex halimus have been described incompletly. This species has been classified as monoecious or dioecious. Numerous observations and ontogenic studies have pointed to types of flowers morphologically and functionally hermaphroditic, never described until now. One specimen of this species presents both unisexual, male and female flowers and bisexual flowers, so Atriplex halimus is polygam and more precisely trimonoecious. Observation of inflorescences reveals a structure based on the spike and the dichasium. The sex distribution along the inflorescence axis was studied and the existence of a physiological gradient controlling its expression is discussed. (C) 2001 Academie des sciences, Editions scientifiques et medicales Elsevier SAS.