annuus

Annus is Latin for year, and annuus is the adjectival form used in taxonomic Latin to indicate annual habit. In binomial nomenclature, annuus is a species epithet that signals the organism completes its life cycle within a single growing season, though not all taxa with this epithet are strictly annual in cultivation. The epithet agrees in gender with the genus: annuus (masculine), annua (feminine), annuum (neuter). The most familiar example is Helianthus annuus, the common sunflower, an annual plant widely cultivated for seeds and oil. Other examples include Capsicum annuum, a widely cultivated species of peppers, including bell and chili peppers; the epithet implies annual habit and has become part of the formal name rather than a strict description of the plant’s ecological range in cultivation. In general, annuus is common across many plant genera, used to distinguish annual species from biennial or perennial relatives within the same genus. The term reflects a historical naming convention in taxonomy where life cycle traits are encoded in species epithets, and it remains a standard descriptive element in botanical nomenclature.