The results of an investigation of the cell
wall composition of Mougeotia have greatly aided our understanding
of the phylogenetic relationships within the Charophyceae. A
weakly crystalline cellulose fraction represented 13.5% of the
Mougeotia mechanically isolated wall preparation. Cellulose
I diffraction patterns were only evident following limited acid
hydrolysis of a hot alkali insoluble fraction. It was concluded
that the cellulose crystallites in the native state were too small
to be detected without extensive extraction of other cell wall
polysaccharides. Cellulose microfibril assembly in Mougeotia
was observed to be associated with solitary rosette/globule
terminal complexes. Similarities between the cell wall composition
of Mougeotia and Klebsormidium suggest that their
cellulose component is characteristic of cellulose soon after
its evolution in the cell walls of algae representing the direct
ancestors of vascular plants.