A 3.5 years'' study was made of the vegetative and reproductive development of over 200 K. tubiflora plants which were X-radiated when they were tiny plantlets. For the first 17 months the irradiated plants exceeded the controls in number of plantlet-bearing leaves, number of plantlets, and in height. Most of the induced branching which occurred in 20% of the treated plants became evident between the 8th and 11th months; while many of the plants branched dichotomously near the base, a higher percentage forked at a height between 10 and 20 cm. The earliest blossoming of this short-day species occurred in an irradiated plant 724 days after treatment. 23% of the treated plants which blossomed during the 2d winter of the expt., came into bloom in less than 2 yrs. as contrasted with but 11% of the controls. Small-leaved shoots develop in the inflorescence region of this species as the flowers fade and drop off. The exptl. group had 37% increased shoot development in this region 7 weeks after the first blossoms appeared; this increase gives additional proof of the earlier maturation of the irradiated group. Evidence is presented to show that vegetative growth and reproduction, as well as branching, are increased when very young plants and those up to and including ones in the 8-leaved stage are irradiated.