Liberica
A minor commercial species by global volume, native to West and Central Africa, grown on a notably larger tree with larger leaves and larger, irregularly shaped cherries and beans than arabica or robusta. Tolerant of heat and some lowland growing conditions unsuitable for arabica. Most significant today in parts of the Philippines (where it is known as kapeng barako) and Malaysia, rather than as a major share of world production. "Excelsa" coffee, once described as its own species, is generally classified in contemporary taxonomy as a variety of liberica (Coffea liberica var. dewevrei) rather than a separate species — sources and terminology have not been fully consistent on this over time, so both usages still appear in circulation.
Caffeine content
Less consistently documented than arabica or robusta; generally described as broadly comparable to or somewhat lower than robusta, though CoffeeHQ has not found a source precise enough to state a confident comparative figure.