Coffee Beans come from cherries which grow on the coffee plant.
There are two main plant species of coffee used for consumption: Arabica (Coffea arabica) and Canephora (Coffea canephora). The Canephora species has a most famous variety named Robusta, commonly used as metonym for the species. Robusta is also known as Conilon in Brazil.
The Canephora species is considered to be an ancestor to the Arabica species, but there’s also evidence that the better flavor from Arabica was inherited from the Eugenioides species (Coffea eugenioides). It is believed that a single “interbreeding” event between Canephora and Eugenioides created the common ancestor of all existing Arabica coffee. Eugenioides is a wilder species and much harder to cultivate so it’s not widely available.
There’s also a species known as Liberian (Coffea liberica) which accounts for less than 2% the worldwide production, plus other species not significantly commercialized like the Racemosa (Coffea racemosa), a low-caffeine species, and the Charrier (Coffea charrieriana), completely caffeine-free, among others.
There are dozens of Arabica varieties. A few notable ones are the Typica (considered the first and grown extensively around the world), Bourbon (mutation of Typica with distinctive sweetness), Caturra (mutation of Bourbon that is high yield and low growing), Mundo Novo (hybrid of Typica and Bourbon with strength and disease resistance), Catuaí (hybrid of Caturra and Mundo Novo combining low growing and strength), Geisha (exceptionally floral aromatics).
Robusta is already a variety of Canephora, but there are a few others notable ones like Nganda and Sulu. Liberian has a famous Barako variety. These varieties arise from local selection and help indicating the beans origin and characteristics.
Arabica represents around 60% of production and is regarded as the higher quality beans due to extracting with more sweetness and less bitterness. Canephora, on the other hand, contains much more caffeine and is less susceptible to pests and diseases so cultivation tends to employ less pesticides. Liberian has the lowest amount of caffeine among the top three and is the most expensive mostly because there’s so little produced of it.
All of the hundreds of commercially available Grape Varieties for wine come from a single species, so there’s still room for a many more new coffee varieties to emerge.