AbstractThe seasonal variations of the carbohydrates in the leaf and stem of lucerne have been studied during two successive years' growth. During growth from seed in the first year, when the crop did not flower, there was a continuous accumulation of sucrose in the plant. In the second year, flower and seed formation influenced the soluble sugar content, which was highest when the flowers were in bloom. This substantiates field observations by other workers that the best hay and silage are obtained from material cut at this stage. In both years there was a continuous increase in the amount of cell wall polysaccharides.