Capsicum annuum, bell, sweet, or chili pepper—with cultivated varieties including bell, sweet, chili, and paprika peppers—is a perennial herbaceous plants in the Solanaceae (nightshade family), which originated in Central and South America and the Caribbean and was domesticated over 5,000 years ago. Peppers from C. annuum have been developed into numerous varieties that are now cultivated around the world for sweet and hot varieties of green and red bell peppers and chili peppers, that are one of the world’s most widely used spices, with dried forms including paprika, chili powder, and cayenne.

Capsicum annuum, which is perennial but often cultivated as an annual in temperate climates, is a many-branched plant, growing up to 75 cm (30 in) in cultivated varieties, often shrubby in appearance. The leaves are simple and alternate, elliptical to lanceolate, with smooth margins (entire). The small flowers (around 1.5 cm, or 1 in, in diameter), re borne singly or, rarely, in pairs in the axils (where leaves join stems); they are white or occasionally purple, campanulate (bell-shaped), often with 5 lobes, and contain 5 bluish stamens. The fruits are many-seeded berries--pod-like, but with no sutures—that vary considerably in size and shape, ripening to green, yellow, orange, red, or purple.

The numerous varieties that have been developed are categorized in five major groups: 1) Cerasiforme (cherry peppers); 2) Conoides (cone peppers); 3) Fasciculatum (red cone peppers); 4) Grossum (bell or sweet peppers); and 5) Longum (chili or cayenne peppers). These varieties include well-known Mexican peppers such as jalapeños, serranos, and poblanos. However, some pepper varieties known as chili and cayenne peppers come from the closely related species, C. frutescens, including the Tabasco varieties used in Tabasco sauce, and the intensely spicy Habanero peppers.

Peppers are used fresh, cooked, or dried in an enormous variety of dishes characteristic of different regional cuisines. They are high in vitamins A and C. Some varieties have been developed to use as ornamentals, often for indoor pots; these often have small, brightly-colored, persistent fruits.

Capsaicin, which is obtained from C. annuum and other Capsicum species, is an intense skin and eye irritant, and is the ingredient used in pepper sprays sold for self-defense. However, it also has numerous medical uses, including topical pain relief for muscle soreness, shingles, skin irritations, and rheumatism, and as an anti-inflammatory. Recent medical research has also documented antimicrobial and antifungal activity of capsaicin obtained from several Capsicum species, and on-going studies are exploring its use in cancer treatment.

Although known as pepper, Capsicum annuum is not closely related to the spice known as black pepper (Piper nigrum, in the Piperaceae), which was prominent in the spice trade of the Middle Ages, and for which Christopher Columbus may have been searching when he brought Capsicum annuum to Europe and referred to it by the same common name.

(Bailey et al. 1976, Chowdhury et al. 1996, Cichewicza and Thorpe 1996, Hedrick 1919, van Wyk 2005, Wikipedia 2012.)