Atlantic Alibertia

Herbarium ledgers and modern occurrence maps show Alibertia atlantica hugging the humid Atlantic rim: it runs from Nicaragua's Río San Juan basin through Sarapiquí, Boca Tapada, the Cabécar highlands, and even Bahía Chal in Osa before leaping south to Panama's Colón ridges.

Up close it looks very much like its Colombian cousin, the cultivated borojó: leaves 12–25 centimeters long carry eight to nine arcuate lateral veins with tufted domatia, the lower surface turning minutely velutinous along the midrib, and male shoots end in two-to-six-flowered cymes whose white, sericeous corollas sit beneath persistent, stipule-like bracts.

The fruits that follow have the same architecture that made Chocó's borojó famous: solitary globes approximately four to five centimeters wide with walls 8 to 12 millimeters thick and dozens of flattened seeds set in dense pulp, a design that protects ripening drupes along lowland streams even when canopy openings dry out.

Identification

Habit and Bark

Alibertia atlantica grows as an evergreen understory tree reaching 8 to 10 meters tall. Its branches form horizontal tiers that catch filtered light beneath the forest canopy. The green-brown branchlets are round in cross-section and smooth (hairless), with widely spaced leaf scars. Triangular stipules (small leafy appendages) up to 13 millimeters long persist as sheaths around the growing tips.

Leaves

The leaves are large, 12 to 25 centimeters long and 6 to 13 centimeters wide, with an elliptic to broadly spoon-shaped outline that tapers to a short pointed tip. The upper surface is mostly hairless and somewhat glossy, while the midrib and side veins develop a fine velvety lining (about 0.5 millimeters) beneath. Eight to nine curved side veins arc toward the leaf margin.

A key identification feature: each vein axil (where secondary veins meet the midrib) carries a small tufted pocket called a domatium. These tiny shelters house beneficial mites that help protect the leaf from herbivores. The tufted domatia separate A. atlantica from glossier species like Genipa that lack them.

Flowers

The species is dioecious, meaning male and female flowers grow on separate trees. Male flowers cluster in small cymes (branched flower clusters) of two to six blooms. Each flower has a tubular calyx 8 to 10 millimeters high and five fleshy, silky-textured white petals that reach 12 to 15 millimeters. Persistent bracts (6 to 16 millimeters) sit beneath the flower clusters like small leafy collars.

Female flowers remain poorly documented in Costa Rica. Male flowering peaks in July and August, while fruiting specimens have been collected in June, suggesting that female flowers are pollinated earlier in the wet season.

Fruits

The fruits are solitary berries approximately 4 to 5 centimeters in diameter, with thick walls (8 to 12 millimeters). When dried, faint lengthwise grooves appear on the surface. Inside, dozens of flattened seeds sit embedded in sticky, mucilaginous pulp within a persistent calyx cup at the base. This architecture mirrors the famous borojó of Colombia's Chocó region (Alibertia patinoi), a close relative whose fruit is prized for its complex sweet-tart flavor—described as plum with hints of vanilla and tamarind—and used in juices, marmalades, and the traditional "jugo de amor." Whether A. atlantica shares this palatability remains undocumented; its rarity and remote habitat mean no traditional culinary use has been recorded.

Distribution

Kew’s checklist and La Selva’s digital flora agree on a range from southeastern Nicaragua’s Río San Juan through Costa Rica to central Panama, with Costa Rican records spanning the Caribbean slope (La Selva station, Selva Verde, La Tirimbina, Cerro Negro) and southward to Bahía Chal on the Golfo Dulce coast.

GBIF adds dozens of herbarium and photo observations from Boca Tapada, San Carlos (including plots inside the Crucitas mining concession), Sarapiquí village mosaics, the Cabécar corridor between San Miguel and Cerro Mirador, and the Colón mining cordillera in Panama, highlighting how the species occupies both protected ridges and human-altered corridors within the wet lowlands.

Ecology & Phenology

La Selva field crews consider the species “ocasional” but easiest to locate on steep, primary-forest ridges where the canopy opens just enough for the tiered crowns to photosynthesize; they also record it along remnant thickets in Selva Verde, La Virgen, and Cerro Negro, showing tolerance for secondary edges so long as moisture stays high.

Plants are dioecious: male inflorescences appear in July and August, while fruiting samples at La Selva and in Burger & Taylor’s Flora Costaricensis were collected in June, suggesting that female flowers ripen shortly after the rainy-season peak.

Recent Pl@ntNet submissions corroborate those phenological windows with close-ups of staminate flowers from Sarapiquí (2013–2014) and vegetative shoots from Boca Tapada (2023), but no Costa Rican photographer has yet documented a receptive stigma or a ripe fruit section—data that would clarify pollination and dispersal.

Taxonomic History

John Dwyer described the species in 1980 as Borojoa atlantica, distinguishing it from B. panamensis by its more numerous lateral veins and thicker fruit walls, yet noting how the berries mirrored those of B. patinoi, the cultivated borojó of Colombia.

Thirty years later, Delprete and C.H. Persson transferred the Atlantic material into Alibertia when molecular and morphological evidence showed that Borojoa was nested in that broader genus—a change quickly adopted by Kew's Plants of the World Online and regional floras.

Conservation Outlook

The species never received a formal IUCN assessment, but it already appeared in the World List of Threatened Trees in 1998 and now registers as “threatened” (albeit with low confidence) in the Angiosperm Extinction Risk Predictions model, reflecting its narrow distribution and dependence on intact wet forest ridges.

GBIF records underscore those concerns: multiple vouchers were collected along the Placer-Dome/Crucitas mining roads, the Teck Cominco concession in Panama, and Bahía Chal cattle clearings—the very frontiers where forest loss could erase the dioecious populations that still persist in Sarapiquí reserves and Cabécar-managed corridors.

Maintaining riparian buffers across San Carlos and Sarapiquí, supporting community monitoring in Cabécar territory, and documenting the still-unknown female flowers are immediate steps that would keep this Atlantic alibertia visible to both science and regenerative agroforestry efforts.