Thanks for your information Mimi.
I don't think it is P. ionidiflorum as it has an upright habit. Looking
at my Latin dictionary I would guess the name is meant to be P.
peliniflorum, which would probably meant something like "leathery
flowered" (although my Latin is pretty rusty). The best thing will
probably be to photograph it when it flowers and post the picture for
identification. It may be just some old and outdated name for a
commonly grown plant.