Occurrence of nodulation in legume species in the Amazon region of Brazil

summary This paper reports the nodulation status of 172 legume species from different ecosystems within the Amazon region of Brazil. The nodulation ability of 98 species and eight genera was observed for the first time. Occurrence of nodulation is discussed in the context of the taxonomy of the family and the different ecosystems. The frequency of nodulation among tribes and genera was found to be higher in flooded (varzea and igapó) than in non‐flooded sites (terra firme); moreover, more plants had nodulated in nursery beds consisting of soil from flooded areas. The symbiosis may therefore be favoured in flooded areas.