Genus Brosimum in Family Moraceae

Genus Description

Brosimum Sw. (Moraceae, tribe Artocarpeae) comprises about twenty accepted species of evergreen trees and shrubs confined to the American tropics, from southern Mexico through Central America to Amazonian South America and into the Atlantic forest of Brazil. Brosimum guianense has long served as the type species, anchoring the generic concept in the family. The plants are monoecious trees or robust shrubs, typically bearing simple, entire leaves with a hard, domatium-bearing stipule that often forms a protective cap over the apical bud. The indumentum ranges from glabrous to variously hairy; papillary or colliculate laminar surfaces occur in some taxa. The inflorescences are unisexual heads or glomerules, those of the females usually subtended by an involucre of bracts and frequently fused into a capitate syconium-like structure; the flowers are tiny and embedded within the receptacle. The ovary is typically bicarpellate and inferior; fruit development produces a drupe within a fleshy, often brightly coloured receptacle, and the exocarp is usually smooth or tuberculate. Seeds are arillate or sarcotestate in several species.

The center of diversity lies in lowland tropical rainforests, with outlying diversity in swamp and seasonally dry forests; many species are canopy or subcanopy trees of lowland terra firme, riverine forests, and coastal swamps. Endemism is pronounced at regional and river-basin scales (e.g., Guiana Shield, Amazon basin), and elevational distributions are typically from sea level to about 1,000 m. Phytogeographically, the genus is Neotropical with restricted coastal mangrove associates in B. congestum.

Pollination is typically by small flies or thrips associated with enclosed inflorescences, and dispersal is largely by birds, bats, or primates attracted to the fleshy receptacles; arillate seeds facilitate secondary dispersal. Chromosome counts are sparse, but Brosimum alicastrum (2n=28) and B. guianense (2n=56) have been reported, suggesting a base number of x=14 for the genus. Growth rings are generally indistinct, though some species show diffuse porosity in wood anatomy.

Recent molecular work has clarified that Brosimum s.l. is not monophyletic. Data from Artocarpeae phylogenies show that the genus should be narrowed to include species such as B. alicastrum, B. dariense, B. utile, and B. bernadetteae in a core clade (Datwyler & Weiblen, 2004; Clement &tron, 2017; Zerega et al., 2015). Species historically placed in Brosimum but now treated in Helianthophyll (e.g., B. spruceanum) have been reinstated by recent phylogenetic synthesis (Clement & Tron, 2017). The tribal placement within Artocarpeae is uncontroversial. Species limits and synonymy have been stabilized using integrative taxonomic approaches (Berg, 2001), but some Amazonian taxa remain under revision (WFO, 2024; POWO, 2024; GBIF, 2024).

Several species provide useful timbers (e.g., B. utile, “cow tree”) and locally important food plants; B. alicastrum is cultivated as an ornamental and used in ethnobotany. No species are widely invasive, and most are unthreatened where forest remains extensive, although localized declines accompany deforestation.

Conservation priorities center on continued documentation of Amazonian taxa; climate change and forest loss pose risks to riverine and coastal populations. Ongoing taxonomy and phylogenetics will refine species boundaries and improve conservation assessments (WFO, 2024; POWO, 2024; Berg, 2001; Datwyler & Weiblen, 2004).

• Brosimum acutifolium (Huber)
• Brosimum alicastrum (Sw.)
• Brosimum costaricanum (Liebm.)
• Brosimum gaudichaudii (Trécul)
• Brosimum glaucum (Taub.)
• Brosimum glaziovii (Taub.)
• Brosimum guianense (Huber ex Ducke)
• Brosimum lactescens ((S.Moore) C.C.Berg)
• Brosimum longifolium (Ducke)
• Brosimum melanopotamicum (C.C.Berg)
• Brosimum multinervium (C.C.Berg)
• Brosimum parinarioides (Ducke)
• Brosimum potabile (Ducke)
• Brosimum rubescens (Taub.)
• Brosimum utile ((Kunth) Oken)