Most plants are, to some extent or another, capable of vegetative reproduction. With a bit of rooting hormone and a bit of luck, the careful gardener can clone almost anything she'd care to grow. Some species are decidedly less difficult than others, though. Moth orchids (Phalaenopsis), for instance, take -- at best -- a lot of careful coaxing before they'll bud; but strawberries send out runners in all directions if the conditions are even halfway agreeable, and sometimes even when they're not. There's also the question of which parts of the plant are most readily reproductive. It's very difficult to grow a new moth orchid from anything other than the small plantlets ("keikis" to orchid fanciers) that it can occasionally produce from a flowering stem, but virtually any old leaf from an African violet will root readily if placed in soil, and willow branches will sprout new roots from either end if water so much as looks at them funny.
Strawberries, willows, and African violets all look like amateurs next to mosses, though. Most temperate moss species are so flexible and so reproductive that just about any part of them will root if separated from the whole. Chop them into tiny bits, and each part will simply grow into a new plant. Part of a leaf, or a millimeter-long bit of bare stem, can be enough.
This tendency is so strong that many mosses can quite literally recover from five rounds in a blender. If you put a chunk of dry moss in an ordinary kitchen blender with some room-temperature water and buttermilk, then spritz the resulting suspension over a rock and keep it moist, each tiny fragment will take root and grow into a whole new moss plant! Given enough time, you'll end up with a rock densely coated in the green stuff. The "moss milkshake" technique is widely-used among gardeners interested in these tiny plants, and you can even buy commercially-prepared milkshake starters if you don't want to get dirt in your only blender.