Colon contains

Mucous glands: Cell of mucous acini are tall with flat nuclei at their bases. The lumen of these acini is larger than the serous acini. In mucous glands the secretion contains mucopolysaccharides. The secretion collects in the apical pas of the cells. As a result nuclei are pushed to the base of the cell, and may be flattened. In classroom slides stained with haematoxylin and eosin, the secretion within mucous cells remains unstained so that they have an 'empty' look. However, the stored secretion can be brightly stained using a special procedure called the periodic acid Schiff (PAS) method. Unicellular cells secreting mucus are numerous in the intestines, they are called goblet cells because of their peculiar shape. REF : Inderbir Singh's Textbook of Human Histology, Seventh edition,pg.no.,56.