The Fabaceae family (known also as Leguminosae), represents one of the most significant plant families on Earth.
With around 20,000 species distributed across tropical and temperate regions, the family is particularly well represented in the Neotropics and Africa, whilst Australia boasts remarkable diversity.
You’ll recognise familiar members: peas, beans, lentils, clover, and vetch. The family encompasses herbs, shrubs, vines, and trees, most bearing compound leaves of multiple leaflets.
Their flowers range from the classic “pea flower” form—five petals arranged with the standard overlapping the others—to small, fluffy clusters in some subfamilies. The fruits are those distinctive pods, dehiscing along their sutures to release seeds.
What makes these plants truly remarkable, though ancient farmers recognised it long before understanding the mechanism, is their partnership with soil bacteria.
Living in small nodules on the roots, these bacteria capture atmospheric nitrogen, converting it into plant food. Each year, according to Graham and Vance (2003), agricultural legumes fix 40 to 60 metric tons of nitrogen worldwide.
For humanity, the importance of legumes rivals that of grasses. They provide 33% of our dietary protein and over 35% of processed vegetable oil.
Beyond food (chickpeas, lentils, soya beans, peanuts) they’ve given us timber, dyes (including true indigo), medicines, gums, and oils.
Ancient cultures cultivated legumes for millennia. Today, grain and forage legumes occupy roughly 180 million hectares globally, accounting for 27% of the world’s primary crop production. They underpin dairy and meat production whilst enriching pastures, a service farmers have valued since antiquity.
Some species, of course, have become invasive when introduced beyond their native ranges, having escaped their natural pests and diseases.