STUDIES OF THE ROOT NODULE ORGANISMS OF CERTAIN WILD LEGUMES

Abstract

As to morph. and cultural characteristics, the organisms causing nodules on Amphi-carpa bracteata, Baptisia tinctoria, Cassia nictitans, Cro-talaria sagittalis, Desmodium paniculatum, Dolichos lablab, Genista tinctoria, Lespedeza hirta, and L. frutes-cens were essentially the same as the cowpea and soybean organisms. Nearly all strains formed nodules on cowpeas, and certain strains on soybeans. Irregularities in these crosses, however, prevent definitely placing all of the aforementioned host plants in either the cowpea or soybean inoculation group at present. The organisms causing nodules on Lathyrus latifolius and L. japonicus bore a close morph. and cultural relation to the strains previously described from garden pea, sweet pea, and vetch. L. latifolius appeared by cross-inoculation tests to belong in the pea group, but irregularities in nodula-tion of garden pea and vetch by the L. japonicus strain prevent placing the latter legume in the garden pea inoculation group without certain reservations. The cultural characteristics of the wild legumes studied were extended to include results of tests on amino acid media, media containing numerous carbohydrates, and media containing varying concns. of certain salts and of dibrom-oxymercuri fluorescein.