How old is the tree? Sometimes young trees will make dry fruit. Most of the time it can be that the fruit is over ripe. I do not know enough about the nutrition aspect of trees to comment on whether or not it is a nutritional deficiency.

Amanda is right...it may be a young tree. The fruit may have been left too long on the tree and dried out?

I had to Google Clematine to find out what kind of citrus this was. Google suggested Clementine. Now I can say to let the tree put on a few years. Rootstock also affects juice levels in fruits.

Steve

Another very common cause of fruit dryness, is because the fruit is not picked in time. Fruit left hanging on the tree too long past its maturity is a major cause of dryness..