In the pots on my deck lurk strange but tiny worlds. The garden you see above is just a few centimetres across and sits at the base of a clematis (that's the bigger stalks rising off the top of the frame). I didn't plant this miniature oasis – it just grew there, complete with minute 'palm trees'. I assume that these are mostly mosses and other primitive plants (or just small, young weeds in a few cases), but I find them fascinating up close, with some very strange structures.

Update: A bit of research prompted by a reader with similar things in his pots shows they are in fact Liverworts (not moss). These are are usually indicative of compacted soil or poor drainage, which sounds about right.