SOME INFECTION EXPERIMENTS WITH LOOSE AND COVERED SMUTS OF OATS WHICH INDICATE THE EXISTENCE IN THEM OF BIOLOGICAL SPECIES

SUMMARY. 1. Infection experiments are described with two spore collections of U. avenae (Pers.) Jens. and U. levis (K. and S.) Magn. obtained from Missouri and from Wales. 2. The results with U. levis indicate that the spore collections under test represent two distinct biological species, thus confirming the conclusion arrived at by Dr Reed(4), working with the same material at Missouri. 3. Forms highly susceptible and resistant to U. levis appear to exist in the sub‐species glabrescens of A. strigosa .