MORPHOLOGY AND HALOGENATED SECONDARY METABOLITES OF 3 GRAN-CANARIA SPECIES OF LAURENCIA (CERAMIALES, RHODOPHYTA)

Laurencia majuscula (Harvey) Lucas is characterised by the production of four periaxial cells from each vegetative axial segment and of two tetrasporangium-bearing (the third and fourth) periaxial cells per fer tile segment in tetrasporangial branches, in addition to other feature s. Major halogenated secondary metabolites of this species are sesquit erpenoids, isoobtusol and elatol. Laurencia intricata Lamouroux is cha racterised by the presence of 2-4 corps en cerise per superficial cort ical cell, in addition to other features. A major halogenated compound of this alga is a sesquiterpenoid, caespitol. Laurencia perforata (Bo ry) Montagne is characterised by the production of two periaxial cells from each vegetative axial segment, tetrasporangia formed on two (the second and additional third) periaxial cells from each axial segment in tetrasporangial branches, and the absence of corps en cerise, in ad dition to other features. Halogenated secondary metabolites were not d etected in this alga, although some characteristic sesquiterpenoids ha ve been reported from material collected from Fuerteventura, the Canar y Islands. This strongly suggests that the Fuerteventuran alga was not properly identified.