Each legume has its own type of nodule-forming bacteria.
"A Living from the Land"
William B. Duryee
She had a small tubercular nodule upon her upper arm, according to him.
"Round the Red Lamp Being Facts and Fancies of Medical Life"
Arthur Conan Doyle
The bacilli are stained red and appear as small straight rods within the cells of the nodule or tubercle.
"Special Report on Diseases of Cattle"
U.S. Department of Agriculture J.R. Mohler