candidus

Candidus is a Latin adjective meaning white, bright, or shining. In scientific naming, it is used as a species epithet to indicate pale coloration or purity of a feature, such as the color of a microorganism’s colonies or plant parts. The form candidus is masculine; feminine candida and neuter candidum exist to agree with the genus gender.

In English, candidus is the root of several familiar words. The adjective candid, meaning frank or sincere, and the noun candor derive from Latin candidus via Old French and Middle English, reflecting the historical association of whiteness with purity and openness.

In biology, several species bear candidus in their scientific names. Notable examples include Bacillus candidus, a Gram-positive bacterium that forms white colonies, and Staphylococcus candidus, another pale-colored bacterium. The epithet is commonly used for organisms with pale or light-colored features.

The modern taxonomic term Candidatus is a separate, formal designation used in microbiology. It denotes uncultured or incompletely described prokaryotes that have not yet been fully isolated or cultured, and thus cannot be given a complete formal description. Examples include Candidatus Carsonella rudii and related names used to document lineages known from genetic material or partial characterization rather than a pure culture.