ON THE CHEMICAL COMPOSITION OF THE BROWN ALGA. HIMANTHALIA ELONGATA (L.) S. F. GRAY

¹ Botany Department, King's College, Newcastle-upon-Tyne, England

1. The qualitative determination of amino acids, sugars and organic acids in Himanthalia elongata has been carried out.

2. Mature vegetative tissues were found to be lower in nitrogen content than actively growing reproductive tissues.

3. The high nitrogen content of the male receptacles was correlated with the higher protein nitrogen content of the male gametes.

4. Vertical gradients of organic constituents were found to occur along the length of the individual plant. The mature button was lower in nitrogen and mannitol but higher in alginic acid and laminarin than the receptacles of the same plant. The apical regions of the receptacles were high in mannitol and nitrogen content, particularly protein. The basal sterile region of the receptacle was similarly high in mannitol, but was lower in nitrogen than the uppermost region.