Wikipedia
Calcofluor-white is a special fluorescent stain that binds strongly to structures containing cellulose and chitin.
In plant cell biology research, it is used for the staining of cell walls of both algae and higher plants. It is also useful in medicine and animal biology for the identification of fungi in the tissue, (it binds to the chitin in the cell walls of the fungi).
In research, calcofluor-white is also used to stain bud scars of yeast cells because the bud scars have a higher content of chitin, which stains them more than the rest of the cell membrane. Due to this stain it is possible to count the bud scars which is an indication for the age of the cell. It shows similar staining patterns as Wheat Germ Agglutinin (WGA). It is especially useful for the identification of Candida albicans and the causative agents of zygomycosis. Calcofluor-white can be used to stain thecal plates in armoured dinoflagellates. Calcofluor is also used as the dye in white-colored clothing, and results in the characteristic appearance under "black-lighting".