Inga edulis, known as ice-cream bean, ice-cream-bean, joaquiniquil, cuaniquil (both from Nahuatl: cuahuxinicuile combining cuahuitl "tree"; icxitl "feet" and necuilli "crooked") guama or guaba, is a fruit native to South America. It is in the mimosoid tribe of the legume family Fabaceae. It is widely grown, especially by Indigenous Amazonians, for shade, food, timber, medicine, and production of the alcoholic beverage cachiri. It is popular in Peru, Ecuador, Pernambuco-Brazil, Venezuela and Colombia. The taxonomic name Inga is derived from its name with the Tupí people of South America (ingá) while the species name edulis is Latin for "edible". The common name "ice-cream bean" alludes to the sweet flavor and smooth texture of the pulp.
Biology
Mature trees of Inga edulis reach 30 m (98 ft) high and 60 cm (2.0 ft) diameter at breast height, usually branching from below 3 m (9.8 ft). The branches form a broad, flat, moderately dense canopy. Inga edulis can be evergreen in tropical regions or deciduous when planted in colder regions. The tree has a pale grey coloured trunk. The stems and young twigs can be sparsely to densely haired. The leaves are alternate, evenly pinnate, 10–30 cm long with 4–6 pairs of opposite, dark-green, membranous, slightly pubescent, oval leaflets. The terminal leaflets can grow up to 18 cm long by 11 cm wide in comparison to the basal ones. Extrafloral nectaries are placed on petioles and stipules can be either inconspicuous, absent, or caducus.
Inga species are in symbiosis with ants (e.g., Pheidoles spp.), which get the nectar of the extrafloral nectaries. In exchange the ants will patrol over the Inga plant to protect it against herbivores. There are certain insects such as Riodinid caterpillars which excrete sugary honeydew from their tentacle nectaries. The ants will form a symbiosis with the caterpillars by letting them feed on the tree and in favour of getting sugary honeydew from them. Flowers are fragrant, sessile, pentamerous and are arranged in dense axillary spikes. The flower has a calyx tube with five puberulent, striate lobes, corolla with five silky, villous petals. These are around 14–20 mm long and contain numerous white stamens. The fruits are longitudinally ribbed, cylindrical indehiscent leguminous pods which can be straight, curved or often spirally twisted up. They are pendant and up to 1 m long and yellowish brown to greenly coloured. The amount of ovoid seeds can vary from 10 to 20, which are purplish-black to olive colored. These are embedded in the sweet, cottony, white arillus which gives it the name Icecream bean, since they taste sweet.
Symbiosis The Inga plant can also form symbiotic relationships where nitrogen gas can be fixated by rhizobial bacteria and mycorrhiza as other legumes can. Surveys have shown that Inga edulis undergo a mutualistic relationships with the bacterial strain of Bradyrhizobium.
Synonyms
This plant has a convoluted history of synonymy with Inga vera. The plants discussed under that name by Brenan and Kunth are actually I. edulis, whereas that based on the writings of Carl Ludwig Willdenow refers to the actual I. vera. Inga edulis in works referring back to authorities other than von Martius usually refers to Inga feuilleei.
Synonyms of Inga edulis Mart.: Feuilleea edulis (Mart.) Kuntze Inga benthamiana Meisn. Inga edulis var. grenadensis Urb. Inga minutula (Schery) T.S.Elias Inga scabriuscula Benth. Inga vera Kunth Inga vera sensu Brenan Inga ynga (Vell.) J.W.Moore Mimosa inga L. Mimosa ynga Vell.