A Hairy Vetch
Here a leguminous plant, cousin to the peas and beans, is shown with both top and root, to illustrate the luxuriant growth of the foliage, and the nodules on the roots that enable the plant, thanks to the nitrifying bacilli that inhabit them, to take up a supply of nitrogen from the air. These plants may have the most luxuriant foliage, even when growing on leached and barren soil, that will scarcely support other types of vegetation.
This image is from: Luther Burbank: his methods and discoveries and their practical application. Volume 7 Chapter 3