flowering plant

I inherited this plant from my mother who had a houseful of healthy plants. They all flowered profusely under her care but those in my house usually have to struggle with periods of neglect (I am trying to do better) and I thought this one (whose name I do not know) was not going to produce much till I realised it was probably not in the best place. It is now on the sunniest south-facing windowsill and seems much happier there.