Selaginella kraussiana Krauss's Clubmoss I
This vascular plant really does look a bit like a moss - which is of course why it is called a Clubmoss. Other so-called Clubmosses like Diaphasiastrum alpinum (Alpine Clubmoss) or Huperzia selago (Fir Clubmoss) have some upright habit and to me anyway don't look too much like the mosses which surround them in the wild. I have to admit I never noticed it until it was pointed out. It is an African introduction used in gardens for ground cover in shady, damp places.
It does seem a touch weird though - just leave your dark and damp places alone and good old English mosses will quickly establish themselves and surely provide with very similar looking ground cover. Gardeners though tend to favour the exotic plant over the native.
Selaginella kraussiana has escaped to some extent mostly in the south of England and Ireland with a good few records in north Wales but is only rarely found in the west of Scotland.
Warley Place, Essex 12th February 2008
Added on 22nd February 2008, updated 3rd February 2012