Peat moss
![](http://www.den-uijl.nl/photography/stored/KikkerMetVeenmos.jpg)
*Olympus XZ-1, 112mm, ISO100, f5.6, 1/125*

This little plant is responsible for much of the formation of peat bogs. It can hold huge quantities of water, in the order of 20 times its weight. It also acidifies its surroundings. The bottom parts die off and form peat, while the top keeps on growing. See also https://en.wikipedia.org/wiki/Sphagnum.

You can sometimes find floating islands of the stuff with other plants growing on top. These floating masses can become so thick and strong you can walk over them, but, um, just don't. Here's some round-leaf sundew on top of peat moss:

![](http://www.den-uijl.nl/photography/stored/ZonnedauwOpVeenmos.jpg)

Peat moss is just a modest little plant, but it is vital in the formation of peat bogs, which serve as a habitat for many species.