Mosses: Is city Moss darker?

Hi all,

The moss I see in the city on north-facing roads and walls is darker than the lighter green moss you would see in the forest. Is this because the moss is a different type, or because city moss absorbs pollution and dirt?

Thanks

 

There are many different species of moss, much like there are different species of plants--and each has its own range of colour.

 

Thanks, so the moss that tends to grow in cities has a darker color?

 

Well lit moss tend to be lighter than poorly lit moss. Moss is especially dark in the night conditions, without any artificial lighting.

 

Heh.

The species of moss in cities, often Grimmia spp. in the most concrete-filled areas, are about the same colour green as the Grimmia species found in high alpine environments. I don't think there is a tendency here that one can draw a conclusion on.

 

Here is an example of moss I found on concrete next to my home

One part is dark and the other one is lighter. Any idea of why there are colour differences for the same moss plant?

Thanks

 

Two different species of moss, perhaps? One also looks like it is covered with sporophytes, which may be a different colour than the leaves below.

 

I assume, the light green is fresh growth. The dark green is old, maybe already dying moss.
The moss probably started at the side of the curbstone, where there was plenty of moisture and nutrients, washed there from the road. The moss shifted moist and nutrient rich environment away from the curbstone and invaded new positions towards the centre of the road. Now the new moss filters nutrients and the old one at the edge of the curbstone remains hungry and eventually dies. This way the moss is moving towards the road axis, until to the area, where wheels of the vehicles prevent it to move any further.