Pleasant surprise, my 11 month old plant is producing bulbils, I don't find anything in the literature about this plant, mentioning this, so I am guessing it is under some kind of stress.
Where do the bulbils develop on your iridescens? At the nodes like grandis or a tiger lily? I have not checked mine for such an occurrence but it has really grown from one small leaf - about 1.5 years old.
My plant, from a single strong seedling, grows in a glass terr. about 3x5 x 6"tall, it is badly overgrown. I was trying to clip out the green leaves to see if they would color up in another location and saw at the base of the rhizome the largest bulbil next to which was growing a slender bare stem about the circumference of a round toothpick, with nodes from which were one and two bulbils and at its growing tip were some small leaves, not in a cluster, but growing separately. I suspect these might be produced from bulbils. Does your plant produce the green leaves? Rekha has mentioned this but I didn't realize they all came from one single plant (Begonia, 2012, p. 210).
Whoops, that should be The Begonian, 2009, not 2012.
I guess I need to give mine a closer inspection. Mine stays in a small pot but inside two acrylic bowls (one as the top). I water every few weeks but I hate it when the top bowl is not sitting exactly on the bottom allowing all moisture to escape.
I found some older pics of it so I guess I was off on its age - it is 3 years old. Here it is after it finally produced some and I had it in a small drinking cup with a much larger one as the lid.
A photo of a bulbil, a lost a couple trying to straighten the growth.
Photo of bulbil.