Can you post a picture in the Fern Gallery? Except for the height, it sounds like Lycopodium digitatum.

It's considered a fern ally, one of the clubmosses. Some people call it Ground Cedar. It does creep by rhizomes and can be very tricky to transplant.

If that's not it, look at other clubmosses and selaginella.

Here is a link that might be useful: Lycopodium digitatum

Thanks for the reply but it's definitely not Lycopodium. I spent all my money on plants, so I have no digital camera and cannot post a photo!

If you can scan it, you can post that as a photo.

After looking at some images of Davallia, I am pretty sure it's in that genus. Tomorrow I will detach part of a frond and scan it.

OK, I scanned a portion of a frond and posted in the Gallery.

Ok, I looked at the picture. Tell me this: is this fern a houseplant?

As far as I know, this is indeed a houseplant.