XVI International Botanical Congess
Although twenty three species of Laurencia have been referred from Brazil, many of these have limited value, since only few species received appropriated taxonomical treatment. The circumscription of species in this genus is extremely difficult because of extensive morphological variation within and among species. This fact led us to use cytogenetical aspects and comparison of secondary metabolite content associated with morphological criteria to delimiting species each other. The sequence of meiotic division during the tetrasporogenesis revealed two patterns of cell behavior which distinguish Chondrophycus from Laurencia and reinforce the generic level of Chondrophycus, as recently proposed. The diversity of secondary metabolite evidenced through TLC suggests that chemotaxonomical studies should be stimulated.