Pentaclethra is a small genus of tropical trees in the family Fabaceae (order Fabales), placed within the mimosoid clade of the subfamily Caesalpinioideae. The genus comprises only three species and is considered phylogenetically basal to the mimosoid clade — a position that makes it of particular interest to botanists studying the evolution of the large mimosoid lineage.
The genus has a disjunct distribution spanning two tropical regions. One species, Pentaclethra macroloba, occurs in the American tropics, where it is a dominant canopy tree in seasonal swamp forests along the Atlantic coast of Panama and adjacent lowlands. The remaining two species — Pentaclethra macrophylla and Pentaclethra eetveldeana — are native to Africa.
Members of the genus are medium to large trees. The genus name references a distinctive floral character: flowers bear five imbricate sepals and five petals that are joined at the base, a morphology that gives the genus its name from the Ancient Greek penta ('five') and cleithro ('bolt' or 'bar').
Pentaclethra macrophylla, the African oil bean tree, is economically important across West and Central Africa. Its seeds — known as ugba in southeastern Nigeria — are rich in protein (36–42%), lipids (43–47%), and essential amino acids, and are widely consumed both raw and in fermented form as a flavoring and protein source in soups and stews.
Etymology
The genus name Pentaclethra derives from the Ancient Greek words penta ('five') and cleithro ('bolt' or 'bar'), referring to the characteristic floral structure of five imbricate sepals and five petals joined at their base.
Distribution
Pentaclethra has a disjunct tropical distribution: P. macroloba grows in the American tropics and is the dominant tree of certain seasonal swamp forests in coastal Atlantic Panama, while P. macrophylla and P. eetveldeana are native to Africa.
Ecology
Pentaclethra macroloba is a dominant canopy tree in seasonal swamp forests along the Atlantic coast of Panama, playing a key structural role in these waterlogged lowland ecosystems.
Cultural Uses
The African oil bean tree (Pentaclethra macrophylla), known as ugba in southeastern Nigeria, is an important food plant. Raw seeds contain 36–42% protein, 43–47% lipids, and significant levels of essential amino acids including glutamic acid. Fermented ugba is widely used as a protein-rich flavoring agent in soups and stews across West and Central Africa.
Taxonomy Notes
Pentaclethra is placed in the mimosoid clade of subfamily Caesalpinioideae (family Fabaceae) and is considered basal to this clade. The genus contains three species: P. macroloba, P. macrophylla, and P. eetveldeana.
