part of stem stem nodule BTO:0001816 BrendaTissueOBO Rhizobia interact symbiotically with leguminous plants by inducing nitrogen-fixing nodules on the roots. Some plants of the genus Aeschynomene, encountered in waterlogged soils or riverbanks, have the peculiar property of forming stem nodules. This very unusual behavior among leguminous plants is shared only with a few species of the genera Sesbania, Neptunia, and Discolobium.