A friend received roses, and on the back are these mysterious things. It's not everywhere, but it's behind the back of many of the leaves. Anyone know what they are?
It is not a rose, but a fern. Fern usually have sori (https://en.wikipedia.org/wiki/Sorus), which are used to disperse spores.
Ferns have no flowers, so no seeds.
Note the white flowers come from a different plant, which is also not a rose, but I cannot identify it.