Thursday, 2 February 2012

More on mosses

Mosses have a complex and very interesting reproductive cycle: individual plant specimens are either male or female (although some have both male and female portions). The male plants produce gametes in the antheridium, which looks rather like a pepper-pot lid:
Antheridium on male moss plant
These male gametes swim towards the female gametes, which are held in the archegonium on the female plants. Fertilisation takes place and the offspring grows upwards, forming the seta ('stem') and eventually the spore-bearing capsule. This sporophyte looks like it is part of the original plant, but is actually parasitic on it, so when you see a spore capsule forming like the one below, it isn't one plant with green leaves and a spore capsule, it's the mother (leaves) and child (spore-producing sporophyte).

Emerging spore capsule on Polytrichum moss
Here's a shot of last year's capsules:

Old capsules of Polytrichum commune
The specimens I used for these photographs are Polytrichum commune, which is one of our larger mosses. The setae regularly reach over 8 cm. long, which makes them an ideal subject to use for initial moss studies, since everything is large enough to be seen with the naked eye.

The fact that the male gametes swim towards the females gives us one reason that mosses flourish in damp places.

4 comments:

Toffeeapple said...

Thank you, I have learned something new again!

Gill said...

I love that little holly fungus - though I've never found it here in NE Yorkshire, despite searching carefully. I wonder what its distribution is?

Stuart said...

Gill, the distribution is general, but very thinly scattered. The Fungal Records Database has 190+ records, a few of which are in your area.

http://www.fieldmycology.net/FRDBI/FRDBIrecord.asp?intGBNum=2280

It's classified as rare in the red book but I suspect it's overlooked. This specimen was under a Holly on my local hedgerow, so it's a new dot on the map.

Dulantha said...

Nice images of fungus, I love nature..........