Couma macrocarpa

Barca (Couma macrocarpa)
Couma macrocarpa tree and trunk
Scientific name	Couma macrocarpa [1]
Family	Apocynaceae [1]
Order	Gentianales [1]
Genus	Couma [1]
Native range	Amazonian lowland forest [2]
Habit	Evergreen forest tree, about 8–28 m in the examined accounts [2] [3]
Fruit	Rounded berry with sweet edible pulp and flattened seeds [2]

Couma macrocarpa is an evergreen Amazonian tree in the dogbane family, known as barca. It grows in humid lowland forest, including terra-firme forest, and produces rounded berries with sweet pulp and abundant white latex. ^{[1] [2]}

Older leaf of Couma macrocarpa, Rio Caura, Venezuela

Older leaf of Couma macrocarpa, Rio Caura, Venezuela

Description

The species is an evergreen tree recorded at about 8–22 m in a Manaus botanical study; a broader specialist account gives about 12–28 m and notes that taller trees occur. It is associated with humid lowland or terra-firme forest on clayey or sandy soils. The bark is rough and the tree produces abundant white latex. ^{[2] [3]}

The fruit is a rounded berry with sweet, edible pulp and flattened ellipsoid seeds. The specialist account describes a yellow-green fruit of roughly 6 cm with a few seeds; fruit size and ripening varied among trees in the Colombian germplasm observations, so that measurement should not be treated as a fixed value for every tree. ^{[2] [4]}

Cultivation

Soil and water

In its native setting, Couma macrocarpa occurs in humid lowland forest and terra-firme forest on clayey or sandy soils. A planting site should therefore combine reliable moisture with drainage appropriate to the local texture rather than remain stagnant after irrigation. These are habitat-based cultivation implications, not a tested soil recipe. ^[2]

The Colombian germplasm work grew plants at named sites in Caquetá and recorded regeneration and growth under those local conditions. Its results are site- and accession-specific; they do not establish a universal irrigation schedule or tolerance limit. ^[4]

Sun and humidity

The species is associated with wet mixed forest and is described as preferring shade. Begin young plants with filtered or partial light and high atmospheric humidity, then adjust exposure only as root establishment and local drying conditions allow. The shade recommendation is a habitat-based inference, not a controlled light trial for this species. ^[3]

Seasonal changes

The Manaus study records flowering from June to September and fruiting from November to March. Those months describe the observed Amazonian locality rather than a universal calendar; in cultivation, the wet and dry rhythm of the planting site may shift the timing. ^[2]

Propagation

Fresh seed is the documented propagation route. The Colombian germplasm record describes washing seed for 24 hours to remove sticky latex and sugars before sowing. Asexual propagation was reported as difficult in that work. ^[4]

Germination varied substantially with accession and substrate. In one nursery comparison, average germination was 30.5% in one shaded substrate and 44.4% in a forest-litter/soil substrate; across six accessions it ranged from 8.9% to 94.3%. Emergence began after about 17 days and continued for as long as 46–48 days in the reported trials. These figures are specific to the Colombian sites, accessions, and substrates. ^[4]

Use fresh seed rather than relying on routine storage. In a one-month storage test reported in the same germplasm record, seeds lost viability completely. That result is a storage observation from the tested material, not a universal shelf-life experiment for all seed lots. ^[4]

Flowering, fruiting, and harvest

Flowering was recorded from June through September and fruiting from November through March at Manaus. The Colombian observations describe gradual ripening and marked variation in fruit size among trees. Harvest timing should therefore follow fruit color and texture on the individual tree rather than a fixed calendar alone. ^{[2] [4]}

Fruit and uses

The ripe fruit has sweet edible pulp. The latex is abundant and is separately described in the botanical and ethnobotanical accounts; fruit use should not be treated as evidence that concentrated latex is safe to consume. The specialist account also records local uses of the latex, but no medicinal effects or general safety are inferred from those reports. ^{[2] [3]}

Photos

Historical botanical illustration identified by Wikimedia Commons as Couma macrocarpa

References

• ↑ [1] GBIF species record: Couma macrocarpa.

• ↑ [2] Contribuição ao conhecimento de Couma macrocarpa Barb. Rodr. e C. utilis (Mart.) M. Arg. (Apocynaceae) da Amazônia.

• ↑ [3] Couma macrocarpa - Useful Tropical Plants.

• ↑ [4] Juansoco (Couma macrocarpa) in Especies promisorias de la Amazonia, conservación, manejo y utilización del germoplasma.

Image credits

• Couma macrocarpa tree and trunk: Candre A., Wikimedia Commons file page, Creative Commons Attribution-ShareAlike 3.0 (CC BY-SA 3.0).

• Older leaf of Couma macrocarpa, Rio Caura, Venezuela: Vojtěch Zavadil, Wikimedia Commons file page, Creative Commons Attribution-ShareAlike 4.0 (CC BY-SA 4.0).

• Historical botanical illustration identified as Couma macrocarpa: Brasiliana Iconográfica, Wikimedia Commons file page, public domain.