Originally Posted by Andre Yew
It looks like a carnation to me. The problem I have with carnations is that their base (the green leaves that hold the flower together) is too thick to fit through the buttonhole so the flower points up instead of out. But if you strip the leaves, then the flower kind of falls apart. I haven't yet tried using string to hold the flower together, or maybe it works best only with SR-style long lapel holes (I haven't tried it on anything but my Zegna suits).
The proper way would to get a Malmaison carnation which is two flowers done up in one. A smaller bloom is inserted into the center of a larger one with a wire stem.