Paullinia cupana is a scandent shrub or woody liana. Leaves compound alternate with five folioles and, when tendrils exist, they are axillary. Inflorescences on axillary racemes or originate on the tendrils. Flowers yellow, male and female, zygomorphous and have five petals and sepals, eight stamens and a trilocular ovary with a glandular semi-disc at the base. The fruit pear shaped, orange-red, and 3 sided with three-celled capsules, partially open when ripe, revealing 1-3 black or greenish seeds which are covered at the base with a white aril. There are two varieties of P. cupana; var. cupana differs from var. sorbilis in that it has no tendrils, its folioles are more strongly lobed and its flowers and fruit are bigger. There is no information on the genetic variability of var. cupana, which is little known and studied, var. sorbilis shows a high degree of variability. The name 'Guaraná' comes from Guaranis, a tribe of South American Indians. The genus name, Paullinia was taken from a German medical botanist, C.F. Paullini, who 'discovered' the plant.
Sapindaceae - World Agroforestry Centre, http://www.worldagroforestry.org/treedb/AFTPDFS/Paullinia_cupana.PDF (accessed January 26, 2017).