I've noticed there are several growers here that have this species and also that the issue of flowering has come up before. I have a specimen that is about to flower for the first time. I am pondering if there a way to determine the sex when they still are in bud. I have been searching the web and managed to find a couple photos of both male and female inflorescenses. From looking at them I've noticed that the males had markedly more flowers per inflorescence, but this could of course be coincidences. I've also read an article by C. Frazier in Clarke's Sumatra nep book and in which he writes that the male plants (gracilis, ampullaria and rafflesiana) have 1,7-2 times more flowers than the females.
My question now is; what are other peoples experience regarding number of flowers on male and female N. campanulata? I was thinking that maybe the number of developing buds might be a indicator to help determine the sexes of this species early on.