Doubling of flowers — the development of extra petals — is a common mutation, and often beloved by gardeners. Sometimes double forms of flowers become so popular that gardeners hardly recognize the single flowered, wild-type. Wild roses, for example, have just 5 (or, in once case, 4) petals and look totally different than the extra petal flaunting varieties familiar from gardens.
![Rose rubrifolia, like other roses before human breeders got their hands on them, has only 5 petals](https://i2.wp.com/gardenprofessors.com/wp-content/uploads/2015/09/R.-rubrifolia.jpg?resize=660%2C495)
Doubling usually happens when gene expression gets mixed up and bits of cells that were destined to develop into anthers develop into extra petals instead. Sometimes a single mutation makes a dramatic change all in a go, but more often, the path to a double flowered cultivar starts with something like this:
![Iris x norrisii with three ugly little petaloids full of potential](https://i1.wp.com/gardenprofessors.com/wp-content/uploads/2015/09/irisnorrisiipetaloid.jpg?resize=660%2C440)
Here we have a flower of Iris xnorrisii (formerly known as x Pardancanda norrisii) with the usual six petals, and three “petaloids” — anthers that are stuck in an ugly transition between anther and petal. This is a seedling in my garden this year, and I’m going to grow out lots of seeds from it — hopefully some of them will get past the petaloid stage to full on extra petals and hey presto, a double flowered variety will be born!
Joseph Tychonievich
Thanks, I love checking out petaloids and trying to figure out what they were before they tried to be petals. But I’ve always wondered how badly losing the reproductive parts affects reproduction.
I guess as long as there is still an ovary and stigma they will produce seeds?