Hello, those little green balls are seeds. some Lilies grow these on the stem, usually at the stem / leaf junction. If you leave them on to grow they will usually get a single small green leaf. You can plant those and in 3-4 years they will bloom as a mature LIly. You can watch for a short root to grow downward from the bulbils and plant at that time. I've done this many times and have thousands of lilies. if you leave them on the stem until it dies they will seed themselves. Which you do it will take 3 seasons to bloom, 2 if you get lucky weather.
sorry Philomena but you are slightly wrong. Leaving the seeds on to mature WILL NOT harm the parent bulb. If we were talking Tulips i'd agree but LILIES really don't care what you do with them.
Q