This is one of a series of blogs written by Anthony Hall who beginning a three-month project to explore the secret life of historical moss specimens in our natural history collection in April 2021.

I find myself doing strange things in the name of research; for this project, I am spending a long time on the streets of Oldham examining tree bark and brick walls in fine detail. Last week a man came out of his house and confronted me;

Man: “What you doing, mate?” 

Me: “Umm, I’m doing a project about moss; I’m just looking at this moss here on this tree….” 

Man: “Oh right”, looking at me strangely. “So, can you tell me how I can get rid of it? I got loads of it on my lawn. It’s on the roof too. I think it’s damaging the roof.”

The man preceded to gesture towards his garden. Sadly I didn’t have any helpful advice to offer him. I didn’t want to tell him that I have been trying to cultivate moss on my lawn for years (with limited success). Or admit to admiring the incidental moss gardens that grow on rooftops and walls. So, if you are looking for ways to kill moss, this post is not for you. However, if you are interested in knowing more about these fantastic resilient miniature plants clinging to rocks and walls all around us, then please read on.

As a keen amateur naturalist, I am obsessed with exploring the natural world, often using my close up macro-lens to explore otherwise invisible worlds. Clumps of moss are of interest to me because they provide habitats for a range of microscopic life forms, insect larvae and, and the illusive Moss-Bear or Tardigrade [1] but more about these later. I must emphasise I am very much an amateur, and I am rapidly realising how little I know about moss. Through the course of the project, I will be collecting mosses which will then be formally identified and later become part of the natural history collection at Gallery Oldham. Along the way, I will be learning about mosses, what they are, why they are essential and how to collect, cultivate and protect moss in the natural environment. I will be sharing this through these blog posts and workshops later in the year.

Moss (Bryophyta) belongs to an ancient group of plants called ‘Bryophytes’, which also include, Hornworts (Anthocerotophyta) and Liverworts (Marchantiophyta). Liverworts [Image 6]  look very different from moss with leathery lizard-like leaves. Liverworts also like damp, shady areas, often near riverbanks or under bridges. Hornworts are less common look similar to liverworts, only with elongated horn-like structures on the leaves. Bryophytes are ‘non-vascular’ plants which means they don’t conduct water through roots, instead, they have hairlike ‘rhizoids’, which help them cling to surfaces. The rhizoids help the plant extract and store water like a sponge, which is absorbed directly into the plant through leaf-like structures called ‘phyllids’. Bryophytes are flowerless and seedless plants; sometimes, you will notice stalks with capsules called ‘sporophytes’ that generate spores which are released during dry conditions [2].

Moss exploits even the most hostile environments; it happily envelops concrete and tarmac, brick walls, and discarded clothing items. Even my car has slowly become a site for several happy moss communities. Moss tends to prefer damp environments, but, unlike most other plants, it can survive being completely dried out. One species can be revived after 19 years in its dehydrated dormant state [3]. Moss is also very tolerant to frost; Scientists recently revived a frozen moss discovered in the Arctic ice cap believed to be 400 years old [4].

I have quickly learned that identifying the exact moss species is not as straightforward as it might seem. The identification of moss takes years of experience. It often requires looking at minute microscopic details of the leaves and spore heads. Here are some images of common mosses I have found on walls lawns and trees near Gallery Oldham. I have made a guess at the species, but I hope to meet with some experts who will help identify these accurately soon. 

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Find more information on identifying common moss at britishbryologicalsociety.org.uk [https://www.britishbryologicalsociety.org.uk/learning/some-common-bryophytes/common-mosses-on-walls/ ] The next post will be about the Bryophyte specimens in the natural history collection and how collecting and scientifically recording moss samples has changed my perceptions of the natural world.

Thanks to Patricia Francis (curator of natural history) for continued her assistance with this research. 

Antony Hall is an artist and amateur scientist. You can find can his other blogs by visit our Blog Page. You can also follow his moss specific Instagram profile @moss_bothering or find out more about his work here.

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NOTES:

[1] I will be writing about Moss bears (Tardigrades) and how to find them in a later post.

[2] More detail about moss reproduction can be found here: http://www.hiddenforest.co.nz/bryophytes/mosses/reproduction.htm and Life Cycle of a Moss – Infographic: https://stemlounge.com/life-cycle-of-a-moss-infographic/ . In this video, you can see the detail of a sporophyte closing to protect spores during wet conditions. Thanks to @transbotanica https://www.instagram.com/p/CNmef7rKhFN/

[3] The moss Anoectangium compactum can survive up to 19 years in a dehydrated state, The Bryologist Vol. 25, No. 2 (March, 1922) https://www.jstor.org/stable/3237570?seq=1#metadata_info_tab_contents

[4] “Four-hundred-year-old moss frozen in Little Ice Age revived in ground-breaking experiment. The plant’s resilience suggests such cells may be ideal as trial balloons for researchers exploring survival beyond earth and travel to Mars” https://nationalpost.com/news/four-hundred-year-old-frozen-moss-re-animated-in-study-that-shakes-up-plant-science

Gallery Oldham