Moss pop-guns

It's not very often that I find bog moss (Sphagnum) bearing spore capsules. They are easy to overlook because they are not raised on a long stalk (seta) like the capsules of many other British mosses.

I found these on cushions of Sphagnum growing in a little hillside mire near Wolsingham in Weardale. I'm wondering whether it may have been the very dry spring followed by wet mild weather that triggered rapid growth and their formation.

The capsules remind me of small, round ginger jars.

They are unusual because, unlike most moss capsules that shake spores out through pores or peristome teeth, these literally explode.

As the capsules mature they lose water and the air inside them becomes pressurised. As the walls contract the capsules change shape, from spherical to cylindrical like the rearmost in this photograph. Eventually the lid blows off, sending a mushroom cloud of thousands of microscopic spores, in a vortex like a smoke ring, about ten centimetres into the airstream.

You can watch a high-speed film of the whole process by clicking here and here  

Johannes Hedwig, moss sexual reproduction and King Penguins

The King Penguin series of books began publication in 1939 and continued through 76 titles until 1959. These slim volumes covered a remarkably wide range of subjects, ranging from ballet to ballooning and from cricket to the crown jewels. You can read more about them here.

Number 57, published in 1950, was A Book of Mosses by Paul Richards.

King Penguins were noted for their beautifully designed covers and this title carried a pattern of stylised moss plants.

In addition to the well written text, this volume contained exquisite illustrations taken from Johannes Hedwig's Descriptio et adumbriato microscopico-analytica muscorum frondosorum, published between 1787 and 1797.

Hedwig's book contained ground-breaking researches on the structure of mosses, using the best microscopes that were available in the late 18th. century. In his day the details of the reproduction and life cycle of mosses was unknown, but his observations led him to speculate, accurately, that mosses carried male antheridia and female archegonia that were analogous to the pollen and ovules of higher plants.

Hedwig was a very acute observer and skilled artist. The plate above shows his observations on the peristome arrangements of moss capsules, Atrichum undulatum (top left); Grimmia apocarpa (bottom right); Tortula rigida (top right); Camptothecium sericeum (centre left); Fontinalis squamosa (bottom left)

Here is Rhacomitrium lanuginosum and ........

.... here's Camptothecium sericeum.

King Penguins cost one shilling each when they were first published and were very popular, so most titles aren't hard to find in second hand bookshops. Many of them cover natural history themes.

You can read an on-line version of Hedwig's original book by clicking here The text is in Latin. The illustrations are astonishingly good, especially when you zoom in on the detail.

Wildlife viewed through beer goggles: 6. Is this the world's first moss-themed beer?

Still in pursuit of wildlife-themed beers (click here for earlier examples), here's a complete novelty. I suspect that this must be the world's first moss-themed beer.

Old Sphagnum has been brewed by the Allendale Brewery to celebrate the tenth anniversary of the Peatland Restoration Scheme by the North Pennines Area of Outstanding Natural Beauty Partnership.



This is Sphagnum, the wonderful moss that grows from the top, dies from below and produced deep peat deposits that - amongst other attributes - lock away atmospheric carbon.



And here, high in the North Pennines in Weardale, is a peaty pool, partially full of Sphagnum, that is a superb habitat for all sorts of wildlife.



Sphagnum absorbs water like a sponge, thanks to these highly specialised leaves that are formed by a network of living cells separated by dead, empty cells that hold water.



Here they are under the microscope, showing that network of living cells (green) and the hollow dead cells in between that hold water.

The Peatlands Restoration project aims to reverse past damage from moorland drainage, that has killed the Sphagnum and led to rapid peat erosion. 

This is the only moss-themed beer that I've ever encountered and has instantly become an indispensable addition to any bryological field trip.

A moss with teeth

These are the ripe spore capsules of cypress-leaved plait moss Hypnum cupressiforme - a moss with teeth.

Many mosses have teeth - peristome teeth - that surround the mouth of the capsule and regulate the dispersal of the spores. They're highly sensitive to changes in atmospheric humidity, so in dry air they curl back and allow the spores to be shaken out, just a few at a time, when the capsule vibrates on its stalk.

It's fascinating to watch the teeth uncurl and then curl under the microscope when you breath on them. They seem to be alive, although they're really formed from dead cell walls that react to changes in atmospheric moisture in the same way as the scales of a pine cone.

Elegant moss capsules

These elegant spore capsules belong to the common woodland moss called swan's neck thyme moss Mnium hornum and their presence is testament to the fact that the individual plants that bear them are female. Sometime back in the winter the egg cell inside a microscopically small flask-shaped structure called an archegonium, tucked away somewhere down amongst the leaves,  was fertilised by a swimming male cell called an antherozoid, that swam across the surface film of water on the moss plants, attracted by organic acids secreted from the neck of the archegonium. Countless similar sexual encounters between moss plants occur every day on the woodland floor on mild, wet days in winter and early spring.

And these are the structures that release the male sex cells. The glistening structures packed amongst the rosette of leaves on the shoot tips of these male plants are the antheridia - flasks full of male antherozoids, each equipped with a whip-like flagellum that propels it through the film of water. Sometimes rain-splash in the rosette of leaves will hurl water droplets laden with antherozoids towards surrounding female plants. Sometimes small soil animals may carry antherozoids on their bodies.  The odds against a successful fertilisation are long but the antherozoids are many and the net result is a fertilised egg cell, and ultimately a spore capsule full of spores that will be dispersed on the wind and grow into a new moss plant. Mosses have been reproducing like this for over half a billion years, surviving five great mass extinction events that have extinguished many other forms of life. 

Durable little plants, aren't they?

Redshank Captain, but not as we know it........

Historically, one of the reasons why so few naturalists take an interest in mosses as opposed to, say, birds, is that very few mosses have ever had colloquial names in English conferred on them. So anyone with an aversion to Latin names (and there are plenty of those) tended to steer well clear of these obscure groups with unpronounceable names; unless you are in the company of died-in-the-wool bryologists it has been difficult to have a friendly chat about mosses that you've seen recently, unlike birders who can happily converse in hides for hours about bar-tailed godwits or whatever, without worrying that they'll appear to be overly academic or natural history snobs. Latin names, though essential, are a great conversation killer unless you are in like-minded company.

So there has been a democratizing and very worthy trend in field guides for some of the less well-known forms of wildlife - fungi and mosses and liverworts, for example - to invent common names for everything, so that everyone in the English-speaking world is on the same linguistic wavelength. 

This little moss, with the striking red capsule stalks (setae) and caps (calyptras)  set at a jaunty angle on its capsules, which has been known as Ceratodon purpureus since it was first named, has now been given the English name redshank (logically enough) in the latest moss field guide. 

So, if you are a bryologist, that'll get your ornithologist mates' attention, when you tell them you've been clearing your garden path of redshank with a pressure-washer hose.

Mosses

Today's Guardian Country Diary focuses on mosses, which continue to grow in winter - even when most of the other vegetation in the countryside is dormant. This is really their season, when there's plenty of water, little shading from taller plants or woodland leaf canopies and when - on milder days - they can make rapid growth. 

With little else in the plant world to explore at the moment, this is a good time to appreciate these durable little plants which were amongst the first to colonise the land surface and have survived as a group for half a billion years.

These are a few species from my neck of the woods....

Thuidium tamariscinum (Common Tamarisk Moss), growing in woodland

Plagiomnium undulatum (Hart's tongue Thyme-moss), another woodland species

Homalothecium sericeum, Silky Wall Feather moss, common on shaded tops of dry stone walls 

Fissidens bryoides, Lesser Pocket-moss, often found on clay soils on ditch banks

Rhytidiadelphus triquetrus, Big Shaggy-moss, on a woodland edge

Hypnum cupressiforme,Cypress-leaved Plait-moss, with spore capsules, often on tree branches and rotting logs

Hypnum cupressiforme,Cypress-leaved Plait-moss - the leaves are curved inwards so the shoots look as though they're plaited.

Plagiomnium affine, Many-fruited Thyme-moss, has unusually large leaves. Growing here on the shady banks of an beck running through Hamsterley Forest.

Polytrichum commune,Common Haircap, growing in a wet hollow on open moorland.

Rhytidiadelphus squarrosus, Springy-turf moss, often in poorly drained grassland

Pseudoscleropodium purum, Neat Feather-moss, grows in grassland and has stout shoots that look as though they've been inflated.

Sphagnum sp., Bog moss, which forms peat bogs

Syntrichia ruralis subsp. ruraliformis, Sand-hill Screw-moss, forms extensive mats on the surface of sand dunes between Warkworth and Alnmouth on the Northumberland coast.

The Mosses and Liverworts of Britain and Ireland: a Field Guide, published by the British Bryological Society  is an excellent guide to identifying our moss flora.

For more mosses, click here

Where the Bodies are Buried ...

Today's Guardian Country Diary describes a field excursion with some Durham University biology students to Chapel Fell, between Weardale and Teesdale in Co. Durham 


We were lucky from the weather and the views were stunning, although there were still patches of snow on the ground so it was pretty bracing up there. This is just about the last place in the local landscape to show signs of spring but if you take your eyes off the view and look at the ground under your feet there are plenty of signs of growth in the upland mosses. Some beautiful lichens thrive here too.

Bogs like this are deep pools filled with Sphagnum moss and are a potential death trap. Stroll onto this fine green 'lawn' and you'd instantly disappear up to your neck (at least) in ice-cold water. 

Sphagnum moss is a living sponge that retains vast amounts of water, thanks to its unique leaf structure which you can see by clicking here. Once you get about a metre down from the surface it's pretty anaerobic and preserves biological materials (like drowned bodies) extremely well. You can read about some fine examples of corpses exhumed from peat bogs by clicking here.

In more open patches of water the moss takes on this very attractive starry appearance.

Sphagnum species identification is a specialist skill (there are around 36 species listed in the latest field guide) that I've never mastered and there are several species up here that would keep dedicated bryologists occupied for some time, including ...

.... this delightful claret-coloured example.

One day I'll learn to identify them, using his excellent key.

Polytrichum species thrive on the drier banks ....

.... and  this one,  which I think is Hylocomium splendens, has intensely red stems bearing yellowish leaves and does well amongst the heather stems that have yet to show much sign of new growth. 

This is also home to some fine lichens (mostly Cladonia species) .....

I think this may be Cladonia diversa

Troglodyte moss, slowing turning to stone ...

When I was mooching around in the entrance to this old ironstone mine near Port Mulgrave on the North Yorkshire coast yesterday I found this ....

..... unusual Whorled tufa-moss Eucladium verticillatum, lurking in the gloom ....

... in a zone where there was just enough light for it to grow into these dense cushions. As the common name suggests, this species is associated with places where tufa forms, where mineral-laden (usually calcareous) water, slowly percolating through it, gradually turns the moss to stone. If you double-click on his image and look at plants on the right-hand edge  you can see that some are almost completely 'petrified' in mineral pillars with the moss inside. I guess that those further from the entrance that grow more slowly tend to become engulfed first, while those nearer the light grow faster and survive.


 The usual tufa mineral deposit is calcium carbonate but these ironstone cliffs are famous for their alum deposits which is mined a couple of miles away at Boulby, so I think that in this case that's what the petrifying mineral is.

You can see the crystalline deposits here ......

..... here ....

..... and here at increasing levels of magnification. 

The densely-packed individual moss leaves are extremely long and narrow, with a distinct mid-rib and minute teeth along the leaf edge.


You can read more about plant life in cave entrances by clicking here.