Sphagnum Under the Microscope

As part of a bryology course at the University of British Columbia, I looked at some of the sphagnum mosses in Camosun Bog. I'd like to show you one of the mosses, Sphagnum palustre, magnified up close. This is what is looks like fresh.

If I were to pull out one individual and dry it, this is what it would look like:

Its hard to see, but there are two kind of "leaves" on this moss, ones that go down the stem and ones that come off on horizontal branches.

From Crum, Howard. 1984. North American Flora. Series II. Part 11. Sphagnopsida. Sphagnaceae. Published by the New York Botanical Garden, Bronx, NY.

This is what a stem leaf looks like and what the stem leaf cells look like:

 There are two types of cells. One type is green and undergoes photosynthesis. The other type is clear and allows the plant to take up water as a storage reservoir.

This is what a divergent leaf looks like under the microscope. In this case, there are holes where water can enter the cell.

 Now if we did a cross-section of the leaf, what would it look like?

 The leaf is only one cell thick! Here you can really see how photosynthetic cells are squeezed between transparent cells. Next is a cross-section of the stem.

The big clear cells are designed to store water. The closely packed cells in the middle are designed to move water from the bottom of the plant, to the top. There are no photosynthetic cells.  Some sphagnums in the bog can be identified by the eye, like the bright red S. capillifolium, while others require comparing structures under the microscope, like I've just shown. Sphagnum is very pretty both to the naked eye, as well as under a microscope.

Sphagnum: "just add water"

The dried out sphagnum comes back to life when it is hydrated.  Can you see the colour difference?

before wetting

after pouring water on the area:  note the colour change.

Summer bog, dormant sphagnum

Sphagnum turns yellow during the summer drought but after a rain, the bog becomes green quickly

Sphagnum Moss from Camosun Bog

All photos copyright Gerry Mignault,  CBRG

The keystone species in Camosun bog is Sphagnum moss, sometimes called peat moss.  Without Sphagnum , the bog would not exist. Sphagnum maintains the wet and acidic conditions favoured by bog plants.  It has the incredible ability to absorb water like a super sponge and it pumps hydrogen ions into its surroundings, thus creating a very acidic environment. 


Sphagnum moss is a Bryophyte, one of the earliest plants to colonize land in evolutionary history. It doesn't have many of the adaptations shared by more recent land plants:   Lacks a cuticle (no shiny waxy protective covering - lip balm for plants!) Has no vascular system, the xylem and phloem (the "arteries and veins" of later land plants - maple syrup is tree "blood" drizzled on our pancakes!).


Sphagnum shares many characteristics with its close relatives, the aquatic plants.  like seaweed, it has swimming sperm. Thus sphagnum requires constant water for sexual reproduction.  Observe Gerry's  photos of Camosun bog's range of Sphagnum moss varieties.

more pictures below