In the Arboretum
By: Alfredo Chiri
PACAY - Inga feuillei - Fabaceae
Donated by: CRFG/Barkman and planted in 1998 (r.f.-06)
Common names: Ice-cream beans, Pacae, Guarma, Guamo, Rabo de Mico
The Andean "Pacay" is widely grown in highland valleys as well as in coastal lowlands of Perú and Ecuador. The tree pods have been favorite snacks for their sweet, mealy pulp and are eaten as fruit. The species has also been
introduced across most of tropical South America, Panama and Costa Rica. The tree is most widespread in areas without a dry season (Andean South America, western Brazil) or with a dry season of 3 to 4 months and minimum rainfall around 1200 mm.
In South America this tree is often employed as a shade tree in the coffee and cacao plantations.
The Pacay pods have been called in English the "ice-cream beans" because they are reminiscent of cotton candy.
The Pacay tree grows up to 51 feet tall, with broad spreading crown. The bark is pale gray, and the trunk is cylindrical to 12 inches in diameter. Branch-ing starts at 3 to 6 feet from base, forming a broad, flat, moderately dense canopy. Leaves are once pinnate, up 4 to 12 inches long, with 4-6 pairs of opposite oval leaflets. Between each pair of leaflets they are separated by a winged rhachis.
Flowers are fragrant, solitary, arranged at the tips of stems or solitary in upper axils. Corolla is silky. The tree may flower throughout the year, but in regions with a short dry season it is most likely to flower at the beginning of the wet season.
The fruits are ribbed, cylindrical pods, straight or spirally twisted, up to a yard long, occasionally even longer, and 1 to 2 inches in diameter. The fruits contain fleshy green seeds (1 inch long) in a sweet, white, cottony pulp. Seeds sometimes begin to germin-ate in the pod. The pods do not ship well. The seed storage is very poor.
The Pacay tree can tolerate short droughts. The tree is tolerant of acid soils, outgrowing many other leguminous trees under such conditions. It is a forest gap generator, and although seedlings often establish themselves in the shade of other trees, it needs light to grow and flower. In the forest it becomes a canopy tree, but it is also common in secondary forest.
Like most legumes, the Pacay trees fix nitrogen and improve the soil around them. The litter is high in organic nitrogen, lignins and polyphenols. It is slow to decompose but provides a long-term build-up of organic nitrogen.