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April Fungi Focus -  Chaetosphaerella phaeostroma

April Fungi Focus –  Chaetosphaerella phaeostroma

by Jasper Sharp, 13 April, 2022, 2 comments

In my last post I wrote about inconspicuous ascomycetes – the kind of tiny species that hide in plain site, manifesting themselves as little black dots on dead plant matter such as woody stems. This time, I want to zero in on a species that is not quite so inconspicuous and which grows on dead deciduous wood. After spotting it for the first time this year, it then started popping up everywhere in my local woods and beyond. I’ve found it in three different sites over the past few weeks alone. And not only me, as I’ve seen numerous postings in various online mycological interest groups by people who’d stumbled across it just as perplexed as I initially was. Who knows, perhaps the conditions have been particular good for it this year, or perhaps it’s always been around and I’ve just never noticed it. It’s name is Chaetosphaerella phaeostroma, and though it doesn’t have a common name in English, I’d argue it probably should do, as it is a fairly distinctive species. From a distance, it manifests itself as black fuzzy patches. Up close however, one notices that nestling amongst the felty patches of hairs are dozens of tiny slightly rough textured dark bluey-grey to black spheres up to 0.5mm in diameter.  [caption id="attachment_37861" align="aligncenter" width="650"] Chaetosphaerella phaeostroma[/caption] These are the perithecia of this pyrenomycetous ascomycetes  – if you didn’t read last months post, these are the hard black spherical flasks that hold the asci sacs that in turn hold and release its spores of this particular group. Looking closely, you can see the top of many of them have broken away, like the tops of Easter eggs. There are many, many fungi species that consists of groups of tiny spherical perithecia like this (to name but a few, there are the various species in the genuses of Nischkia, Ruzenia and Rosellinia, if you care to Google them). But Chaetosphaerella phaeostroma is distinguishable from these due to the coarsely hairy mat its perithecia are immersed in, known as the ‘subiculum’ (defined as the net, felt, or crust-like growth that covers a substrate formed by a mat of hyphae from which fruiting bodies emerge). In fact, there was a time when scientists believe this was two separate species, the orb-like perithecia being one of them, the hairy subiculum being another. [caption id="attachment_37862" align="aligncenter" width="650"] The large distinctive spores of Chaetosphaerella phaeostroma.[/caption] Fungi are complex organisms that constantly seem intent on thwarting those whose attention they attract. So it’s perhaps no surprise to find out that there is actually another species, Acanthonitsckea tristis, that looks superficially much the same as Chaetosphaerella phaeostroma. Whether it is more or less prevalent in the UK, I don’t know, but as ever, the way to tell them apart is through microscopic examination of the spores – the fungi in focus has relatively large (20-25x6-9 microns) banana-shaped ones that are segmented into four with the end segments lighter than the middle two;  Acanthonitsckea tristis has much smaller single-celled ones about 6-9x1.5-2 microns. [caption id="attachment_37863" align="aligncenter" width="650"] No hairy subiculum and totally different spores point towards an entirely different genus of Nitschkia for this otherwise very similar looking specimen.[/caption] I duly set about looking for the evidence, laying my find, after removing it from the wood with a penknife, facedown on a microscope slide overnight. The next day, I put the slide under the microscope and found thin curved ones, about 10x2 microns, which fit neither species. I was perplexed for a while, until the ever-helpful Emma Williams of the British Mycological Society pointed out that not only did the spores look more like those of the Common Tarcrust (Diatrype stigma), which I covered in some detail a few years back, or those of a number of other species in the related Eutypa genus, but that Chaetosphaerella phaeostroma doesn’t actually grow on dead deciduous wood, but parasitises these Diatrype and Eutypa species. I had stray spores. [caption id="attachment_37864" align="aligncenter" width="650"] In the top left of this picture you can see Chaetosphaerella phaeostroma growing as a parasite on its host in the bottom right, a member of the Eutypa genus.[/caption] And so I went back to break open the tiny perithecia and tried to ease a new batch of spores out. I was relieved that these did indeed perfectly match the large segmented spores of the Chaetosphaerella phaeostroma I thought I’d discovered. A closer inspection of the original photos also showed that beneath the margins of the felty subiculum, one could see the distinctive pimples of a Eutypa species upon which this was growing.  Whereas the Common Tarcrust is fairly easy to identify, the various Eutypa species are not so much. Some grow as a crust with the perithecia embedded in a spreading hard black body (the stroma) on top of the wood, like the Common Tarcust, and some species grow with the stroma forming beneath the wood and the perithecia emerging through it as little black dots. Wikipedia notes this “widespread genus is estimated to contain 32 species”. Even my fairly specialist literature at hand notes only about four species in detail, and I found no records of which might be found in the UK. [caption id="attachment_37865" align="aligncenter" width="650"] This cross-section photo shows the perithecia of this Eutypa species growing beneath the surface of the wood.[/caption] To be fair, such widespread but generally unremarkable types as Eutypa, of which we can find many more examples within the vast understudied field of ascomycetes, are not likely to be of much interest to anyone beyond those who have dedicated their life to the study of such things right down to the level of molecular genetics. I quickly decided it wasn’t worth my losing much sleep over narrowing it down to a species level.  However, that they themselves play host to more interesting species like our focus species, Chaetosphaerella phaeostroma, and therefore provide vital clues as to their identification, is more of interest to the amateur mycologist, and points to the complex and little understood interconnectedness of our woodland ecosystems. (I have covered several such examples of fungi-on-fungi relationships previously in these postings, including the Yellow Brain, the Silky Piggyback and the Bolete Eater). The other purpose of this month’s post is also to remind ourselves how surface features of many fungi only get us so far, and that how the complex and unusually-shaped spores of many of the otherwise nondescript ascomycetes can be a handy guiding feature.  [caption id="attachment_37866" align="aligncenter" width="650"] The lack of the fuzzy subiculum, the vestiges of white downy hair on the perithecia and in particular the long, worm-like spores guide us to an identification of Woolly Woodwart.[/caption] As an example, I just want to quickly mention another species I found recently beneath a damp, well-rotted deciduous log, the Woolly Woodwart (Lasiosphaeria ovina). The one has an english name, and one that reflects its appearance. While it too grows as tiny spherical perithecia that match the size of those of Chaetosphaerella phaeostroma, these are not immersed in the same black felty subiculum but are typically covered in the woolly white hairs that give it its common name. Except, however, that in the case of the specimen I found, these hairs had worn away, leaving distinctly un-woolly little black balls with little to identify them from without diving into the microscopic realm. Fortunately this was another one with highly unusual looking spores; large, long and worm-like, with dimensions around 40x5 microns, and singled celled – indeed, I initially thought I’d chanced upon a stray nematode on the microscope slide.  There are dozens of pages of tiny non-stromatic pyrenometous species listed in my go-to guide Fungi of Temperate Europe (vol 2., to be precise), and many many more unlisted. I hope that the example of Chaetosphaerella phaeostroma shows that not all need a microscope for identification, and that its not worth being too daunted by this group. [caption id="attachment_37867" align="aligncenter" width="650"] Chaetosphaerella phaeostroma[/caption]
Of owls and dormice

Of owls and dormice

by Judy, 8 April, 2022, 1 comments

Dave and I bought our lovely wood in Kent in 2019 because we wanted to surround ourselves in nature and have somewhere our children could visit to decompress from their busy lives.  In due course, we hope our as-yet-unborn grandchildren can come and explore amongst the trees to root them firmly in the natural world. One day, we wish them to become the custodians of this beautiful space. But it was more than that for us. Dismayed by on-going news of threatened wild spaces, we wanted to play our small part to protect, cherish and encourage the biodiversity that calls our wood its home. Understanding how the wood ticks throughout the year was a steep learning curve for us and one that we shall still be climbing for many years to come. We have dug several small ponds, put up bird feeders and a large number of bird boxes, as well as clearing some glades and coppicing the hazel through the winter. Trail cameras have been sprinkled liberally around, all the better to find out what the wildlife is up to when we are away. We have found that there is a thriving population of Hazel Dormice in our wood and there are several badger holes and fox dens. [caption id="attachment_37873" align="aligncenter" width="640"] A Hazel Dormouse that has made a nest in a bird box[/caption] Green Woodpecker nest in the same hole in a cherry tree every year and this spring we have the thrill of a pair of Tawny Owls setting up home in one of our owl boxes. [caption id="attachment_37874" align="aligncenter" width="623"] A Tawny Owl hunting for worms on the woodland floor[/caption] White Admiral and Silver-washed Fritillary butterflies glide majestically through the woodland glades in August and Woodcock and Redwing fly in from distant lands to spend their winters here with us. We feel that the wood has given us so much - the joy of a deeper understanding of the woodland habitat, a space to clear our heads, bountiful aerobic exercise, and, in a small way, the opportunity to give a little bit back to the world.  
Tree Planting Spades

Tree Planting Spades

by Anton, 7 April, 2022, 0 comments

So, you’ve decided to plant some trees and are wondering what tools you’ll need for the job.  Whether you’re planting a select group of ornamental species, a bountiful orchard of fruit and nut trees or a new broadleaved woodland, there is one key aide which will take you a long way – the humble tree planting spade.  This is a short guide to what you might find on the market and the differences between various spades. Spade or Spear? Most tree planting tools will fall into one of two categories: Spades - those shaped like a traditional spade with a curved head and a flat cutting edge at the bottom.  They will look similar to a normal garden spade but much smaller.   Spears – those with a flat face and a point at the end, designed to create a slot in the ground when pressure is applied to the tread by foot. Spades can be used to dig holes for planting and move soil around, making them more versatile tools, whilst spears are excellent for planting cell-grown* or bare root* stock, but are somewhat limited to this sole function.  If planting larger trees with established root systems (root-ball* trees), then a spade is definitely the tool for you, as the slot created by a spear would not be sufficient to house the root system without causing crushing. In contrast, for those looking for an efficient method to plant lots of small trees quickly, for example when establishing new woodland for carbon offsetting purposes, then a spear should definitely be considered.  Comfort is key Like many things, it often comes down to personal preference and what you feel most comfortable with.  There is no right or wrong tool to use, as long as the tree is planted in a way that does not damage it (for example by burying the root collar) then you’re on the right track.  Planting trees is a wonderful thing to do and as much as possible, you should work with tools that make the process a pleasure, which hopefully means you’ll spend more time doing it! Other factors to consider An often-overlooked detail is the length of the shaft and handle, which for those who are slightly taller or have the odd back pain, can make a big difference!  A nice long handle will take the strain off those sensitive back muscles, as well as offering a bit more leverage which can be of assistance when planting in heavier soil types.  The materials and quality of construction is also important; try wherever budget allows to buy once and buy well!  Some cheaper tools made from inferior parts may not stand the test of time, or worse still let you down when you’re out in the field with a bag full of whips.  A solid wooden handle (or better still stainless steel) with a galvanised steel head is a good option, ideally with a double-riveted socket which will provide greater strength.  Where to buy and how much? Tree planting spades are available to buy at most garden centres and agricultural supply stores, such as Mole Valley.  They are also widely available to buy online from specialist tool suppliers.  Whilst you could pick one up from as little as £20, and pay up to £100 for the very best, you will be able to buy an excellent spade for around £30-£35. Bulldog Tools are a reliable supplier and would be a good option to consider. Do what works for you! Planting trees is good fun and of benefit to the planter, the wider community and the environment.  A communal activity and a great form of exercise, the more trees we can all plant, the better!  This means that you should use a planting spade (or spear) which is comfortable to use and gets the job done.  If possible, try out a couple of different designs and manufacturers (borrow from a friend or neighbour where possible) before making the decision, but always remember they are in essence doing the same thing – making a home for a tree where it will live for many years to come. *Tree types Bare root trees – Produced by sowing seeds into outdoor beds.  During development, seedlings are undercut to encourage a healthy root system.  When ready, the trees are lifted and shaken by a machine to remove the soil, revealing the ‘bare’ roots of the tree.  They can only be lifted and planted during the winter months when they are in a state of dormancy. A cost-effective option. Cell grown stock – These trees are developed in a compost ‘cell’ or ‘plug’ and can be seen as an intermediate option between bare root and pot grown.  When removed from the cell, the fibrous root system is contained with the compost which remains on the roots.  More expensive than bare root but generally has a higher success rate and can be planted all year round. Root ball or pot grown – These trees are the most developed and largest of the three options and are delivered with a significant ball of soil surrounding an advanced root system.  The root ball will be encased in a biodegradable material.  Great for those who want more established trees from the offset, although there is a price to be paid for this benefit.
Woodlands web update 15.

Woodlands web update 15.

by The blog at woodlands.co.uk, 6 April, 2022, 0 comments

Lichens losing ? Sitting on the bark of many trees and on the surfaces of fences and walls, there will be lichens.  They are there in summer, winter, spring and autumn.  Lichens come in an amazing variety of shapes, sizes and colours.  Some can grow in extreme environments such as the rocky summits of mountains. Such lichens grow slowly and may live for hundreds of years. Lichens are rather unusual in that they are an amalgam of two (or occasionally three) organisms : a fungus and algae. They are symbiotic systems, where the partners of the association work together for mutual benefit.  The fungus makes up the bulk of the lichen’s structure (known as the thallus), but the algae (green algae or cyanobacteria) are essential as they can photosynthesise and provide the organism with carbohydrates.   Lichen covered tree One of the most common algae found in lichens is a species known as Trebouxia.  It can exist in association with a fungus to form a lichen,  or as a free living organism.  If the Earth’s warming continues at the present rate, it may well be too hot for certain species of Trebouxia to survive (in their normal range). Dr M Nelson of the Field Museum (Chicago) has looked at the adaptability of Trebouxia species and suggests that it could take hundreds or thousands of years for Trebouxia species to cope with the temperature changes that we are currently experiencing.   These algae may well lose out in the evolutionary race to cope with climate change. This would, in turn, affect many different species of lichen. Lichens are important in arctic tundra ecosystems, where they together with mosses and liverworts make up the majority of the ground flora. They contribute to food chains, for example, reindeer moss is not a moss but a lichen.  Lichens are also pioneer species - they can colonise bare rock and contribute to its weathering (their exudates chemically degrade and physically disrupt the minerals).  Lichens may be used by birds as nesting material. Hedgehogs. Rural hedgehog populations are still in decline, dropping by 30 to 75%, this is in contrast to urban populations that are ‘steady’.  Though urban populations suffer mortalities on the roads, well managed urban areas, parks and wildlife-friendly gardens provide refuges for hedgehogs.  The loss of hedgerows and diminishing field margins is contributing to the decline of rural populations. Land of Plenty report The WWF-UK has produced a report entitled “Land of Plenty”, which addresses some of the problems that the UK faces now and in the coming decades. There are many reports relating to the loss of plant and animal species and the degradation of particular ecosystems (flower-rich meadows, peatlands, salt marshes etc).   Sadly, much of this  damage has been associated with the expansion of our farming / food production systems; indeed some 70% of the land is involved in agriculture.  The WWF report outlines how a move towards regenerative farming / agriculture can significantly reduce CO2 and methane emissions, reduce pollution (from fertilisers) and help with biodiversity and resilience.  Such changes would (in time) help limit farmers’ exposure to extreme weather events that affect crops / harvests.   One of the many suggestions in the report is the expansion of ‘woodland creation programmes, focussing on potential for broadleaf and native species’. The focus would be on natural regeneration in the first instance, but supported by active tree planting. Full details of the report available in PDF format here. Drought, bark Beetles and fires. Woodland recovering from a fire The Cameron Peak Fire in the Rocky Mountains of Colorado and the Creek Fire in the Sierra Nevada of California burned through forests where large number of the trees had been killed by bark beetles. Warmth favours the bark beetles.  Mountain pine beetles had killed millions of lodgepole pines.  A dead tree does not take up water, it dries out.  The drying out was ‘helped’ by the drought that the West Coast has experienced in recent years.  The fires burned with incredible ferocity.  In the case of the Creek Fire, the plume reached some 50,000 feet up into the air.  The fires were the result of Drought / climate change Bark beetle infestation Large numbers of dead, dry trees Consequently, large amounts of energy-rich dry biomass Full details of the factors behind the forest fires here. Drought is a major ‘stressor’ affecting many ecosystem across the globe.  To understand how drought affects different ecosystems, DroughtNet is working with a number of existing projects and the International Drought Experiment (IDE).  A recent experiment at the University of Florida demonstrated how drought-stressed pines did not grow as well, and when faced with an invasive species and fire - they were much likely to succumb than a healthy tree.
Pollinator preferences

Pollinator preferences

by The blog at woodlands.co.uk, 4 April, 2022, 0 comments

It would seem that pollinators have ‘favourite plants’.  Research centred on the National Botanic Garden of Wales has looked in some detail at the foraging habits of bees, bumblebees, hover flies and solitary bees - our most important pollinators. Dr Abigail Lowe identified the plants that the insects were visiting by analysing the DNA from pollen grains on their bodies (a process known as DNA barcoding). It is clear that the ‘preferences’ of the insects change with the seasons and indeed the availability of particular flowers.  In Spring, nearly all the pollinators frequent buttercups, lesser celandines and dandelions (all brightly coloured yellow flowers).  Come the summer, honey bees and bumblebees tend to favour thistles, knapweeds and brambles, whilst hover flies may be seen on hogweeds and angelica plus thistles and knapweeds.  In autumn, the bumblebees can be see visiting asters (Daisy family flowers) and brambles. Full details of her work can be found here : https://botanicgarden.wales/press/plants-for-pollinators-new-dna-research-reveals-fascinating-insights-into-the-plants-used-by-bees-and-hoverflies/ There are also suggestions on how to help pollinators in your garden, such as encourage buttercups and dandelions by reducing mowing (in the Spring) plant late flowering daisy type flowers encourage some bramble (you might get some blackberries, in return) reduce the use of chemicals (especially pesticides and herbicides) hoverflies can be encouraged by damp, wet areas and rotting wood and these suggestions would also work in a woodland.   [caption id="attachment_38320" align="aligncenter" width="700"] Marmalade hover fly[/caption]
Sorry, you’ve bought a woodland?

Sorry, you’ve bought a woodland?

by Jethro, 30 March, 2022, 2 comments

That’s the most common reaction among friends, family and colleagues when mentioning our latest project. So I thought it would be fun to share a little about why we have in the hope it will help others who may be considering it.    We’ve always had a love for the outdoors; I grew up practising my Scout skills on Dartmoor and Exmoor and my wife hiking and living on the North York Moors.  Fast forward 19 years and with boys of 8 and 11 we had spent days and days during Co#%d outside. We’d chat about the environment, ecology, camping and escapism amongst other things. I’d dreamt of owning a woodland for years and we could now think about making it a reality. I must confess that it’s taken a year or so of convincing my wife that rather than having money sat doing nothing in savings, thinking about a camper-van or extending the house -  it would be much more prudent to leave something for future generations and critically much more fun to learn about and apply our ideas from those Co#%d chats in our own woodland and more so to share some of that with our family and friends.   What blew me away in the process was how much the boys would help. The ideas were flowing; camping, hammocks, making fires Bear Grylls style, bird/owl/bat box making and installing, planting new trees, wildlife trail cameras, dens, bird hides, benches, swings, obstacle courses, tree houses, a pond, a zip line, a zip line over a pond! You get the idea. The boys’ ideas have spurred us into investigating and learning about the interconnectivity of many of these ideas; bracken control by digging a pond to encourage a new natural wetland habitat, new wildlife, opening an area above for bats and birds, the potential for new mammals, creating an area for relaxation and quiet reflection. We might also be creating entrepreneurs as the boys have realised they could earn some pocket money by selling poles or netting kindling or even one day carving spoons. They’ll keep us on our toes that’s for sure. And how about something for me? Apart from the gadgets I’ve been secretly buying, the latest project is a compost loo with a view - made from  old pallets. Ticks off the categories of environment, sustainability, ecology and escapism all in one hit. And we’re only at the beginning, what else might come in the future?   Four weeks have rolled by since the purchase, many of those same friends and family now say things like “it’s so great how much the boys are into it!”. Isn’t it just?!…and in reflecting on the title of this post; no, we’re not sorry at all! Far from it! To track our progress and time as a woodland owning family please follow us on Instagram @grange_close_wood.   Jethro.  
March Fungi Focus: Bracken Map and other Little Black Dots and Smudges

March Fungi Focus: Bracken Map and other Little Black Dots and Smudges

by Jasper Sharp, 28 March, 2022, 0 comments

There are times when one does begin to wonder whether one has tumbled too far down the rabbit hole of mycological obsession. Though the Spring months might seem something like a drought period for many in search of curious fungi, they are all around us and all year round. For the hardcore few, the next few months in particular are a time of rummaging through hedgerows and peering at dried twigs, grasses and herbaceous stems in search of what effectively appear as little more than black dots. From then on, it is a just a small step away from the full-blown insanity of lichenology. This month’s focus is on the more common and recognisable of these obscure types, which all fall within the category of ascomycetes: these are the spore-shooter types that develop their spores internally, typically in tube or flask-like sacs and in batches of eight, as opposed to the basidiomycetes, where the spores grow externally on cell-like structures known as basidia, typically in groups of four, which drop off as they mature.  Patellaria atrata, growing as inconspicuous black dots on a dead fennel stem, with the spores arguable more interesting looking than the fungus itself. I’ve written quite lengthily about various groups of ascomycetes in previous posts, but despite the fact that they far outnumber the basidiomycetes in terms of prevalence and the proliferating number and variability of species – which include the colourful goblet-shaped Green and Turquoise Elfcups, the hard black woodwarts and tarcrusts, and other less noticeable things like Sycamore Tar Spots and Holly Speckle) – many consider them a no-go area due to the inedibility of the majority of them, not to mention the fact most are very difficult to even see, unless one is looking specifically for them, yet alone identify.  Few have common names, and even the Latin names change with alarming regularity as individual species find themselves reclassified or split up into numerous subspecies. The obvious exception here is that prized edible, the Morel (Morchellan esculenta, although there are a few other lookalike species), one of the few that make it into spotters guides and foragers handbooks.  The spores of Bracken Map developing within its ascus, with their characteristic crescent shape, relatively large size and multiple segments. To really get to grips with the subject would take the kind of life-long fanaticism and fastidiousness displayed by the likes of Peter Thompson, the author of Ascomycetes in Colour (2013), who has evidently spent years driving around the country in search of photographic examples of the numerous nondescript specimens that can be found on specific hosts such as dead grasses, leaves and other organic material. It took literally a lifetime of research before the husband and wife team of Martin B. and J. Pamela Ellis devoted their retirement from teaching to put pen to paper for their landmark Microfungi on Land Plants: An Identification Handbook, first published in 1985 with a revised and enlarged edition appearing in 1997. Though it’s technically been out of print for years, the book remains a must-have for serious mycologists, giving an exhaustive list with detailed illustrations of the type of species one might find on a wide array of specific hosts, and secondhand copies are accordingly pricey. There’s also been more recent scholarly books such as Bjorn Wegen’s up-to-date and even more comprehensive Handbook of Ascomycota (2017), but again, this is a specialist publication intended for an academic readership and priced beyond the range of all but the most curious of amateur naturalists. The foreword of the revised 1997 edition of Ellis and Ellis refer to microfungi as “ones which require the use of a microscope to see their variety”. Nevertheless, a microscope isn’t always necessary for the identification of a number of common types if you can ascertain their host. For example, over the next few months, if one looks closely at dead nettle stems, one might spot the tiny tangerine-coloured fruiting bodies (ascocarps) of Calloria neglecta, an ascomycetes fungus specific to them. Two very similar looking species grow on ash keys: Diaporthe samaricola, grows on the seed part; the smaller Neosetophoma samarorum only grows on the winged part. An even more extreme example of host specificity is Diaporthe samaricola, which over the winter months appears as miniscule black dots, less than half a milimeter in diameter, on the dried winged seeds, or keys (‘samara’) of ash trees. However, they will only appear on the seed part of the ash keys. Another fungus, Neosetophoma samarorum, produces eruptions of even smaller dots on the winged parts of the keys. The two will often appear side by side. They have no adverse affect on the health of the tree in question, although there is another ascomycetes that does have a notoriously detrimental effect on its host - Hymenoscyphus fraxineus, responsible for Ash Dieback and detailed in a previous post. Its small, white nail-shaped fruitbodies can be found on the blackened twigs and petioles at the foot of the infected tree around June. Bracken Map (Rhopographus filicinus) is another commonplace and instantly recognisable species that is host specific. It can easily be spotted at this time of year in most places where you find dead bracken, just prior to a new season’s growth sprouting up to replace the last, but actually one can find it all year round. The reason for its name is self-evident, as it grows in elongated spreading black blotches that eventually merge to form irregular shapes like countries on a map. Dead bracken stems throughout the year can be seen hosting the tell-tale ascocarps of the Bracken Map. These blotches are the ascocarps, the fruitbodies from which the spores are released. The are described as pyrenomycetous, meaning that like the tarcusts or woodwarts or commonly-spotted Cramp Balls (Daldinia concentria, aka King Alfred’s Cakes), they are hard, brittle, and often carbonaceous, optimised to continue releasing spores over a relatively long period of time during the late-winter and spring months when the weather is relatively dry and temperatures start increasing, and yet there’s little greenery about to shelter them from the dry wind and lengthening hours of sunlight or get in the way of spore dispersal. Each of these fruit bodies contains numerous tiny ‘perithecia’; flask shaped pits in which the asci sacks and the spores that develop within them are housed and are kept from dessication. The spores are released from holes known as ‘ostioles’ in the top of the perithecia that cover the black surface of the Bracken Map. If one looks really closely, one can see that the ostioles in the case of the Bracken Map are elongated along the length of the bracken stems. The ostioles from which the spores are released can just about me made out when the ascocarp is looked at extremely closely. The shape of the ostioles are a key feature in identifying other pyrenomycetous fungi, as detailed in my 2020 post on Woodwarts, Blackheads and Tarcrusts. It’s just as well, because there are many other types of such fungi that are not quite as distinctive-looking as the Bracken Map, and often much much smaller. I’ve been scrutinising various hedgerows recently, and noting that despite their superficial similarities, the seemingly identical black dots that appear on, for example, elder or hawthorn, are often very different species from those that appear on the woody dead stems of clematis or hogweed or other plants. Fortunately, for those with a microscope, these kind of ascomycetes do have very distinctive spores that often serve as much better means of identification, in consultation with the literature cited above, than the actual ascocarp fruitbodies. As mentioned, basidiomycetes produce their spores externally on basidia, growing like apples from trees almost, and so they are typically asymmetrical and one can note the vestiges of a kind of stem by which they were attached to the basidia. The ascospores of ascomycetes tend to be much more symmetrical, often much larger and in some cases much more complex, consisting of multiple cells in different arrangements.  These tiny specks on a dried hogweed stem could be anything, but the complex multi-celled spores compare with a species called Pleospora phaeocomoides. The spores of the Bracken Map are a great example of this – they are 27-35x7-8 microns in size, making them about three to four times the size of a typical mushroom-shaped basidiomycetes type like a Brittlegill – and to put this in perspective, they are just a smidgen smaller than the 40-micron threshold considered visible to the naked eye, or about the size of a small grain of salt. They are crescent shaped with 4-8 segments, and look rather like croissants under the microscope. I’ve detailed a scant few of these types of fungi prevalent over the next few months that can at least be recognised without recourse to a microscope. There are, however, at least 10,000 ascomycetes species found in the British Isles alone, so this is clearly a subject few will want to engage with too thoroughly. There are a couple of other more readily identifiable species that might catch the attention of the woodland walker, however, but I’ll leave these for next month... Bracken Map
Fire and forests.

Fire and forests.

by The blog at woodlands.co.uk, 25 March, 2022, 0 comments

There is evidence that trees lost to fires and drought are not returning to fire damaged areas.  Fire has been ‘part and parcel’ of  the dynamics of some forest ecosystems.  The fires take out smaller trees, giving space and light to others.  Fire (or the smoke associated with it) can even help the seeds of some species to disperse and/or germinate (eg. serotiny in certain Pines). Different chemicals from smoke such as karrikinolide and glyceronitrile are known to play key roles in smoke-stimulated germination of certain species, such as heather. However, climate change is affecting forests (and woodlands) across the globe. Fires are becoming more frequent (associated with increasing drought) and trees are struggling to return / regenerate after intense or repeated fires.  An analysis of a number of sites in the Rocky Mountains suggests that in some areas fire, moisture stress and increasing temperatures result in a loss of resilience so that forested areas are being replaced with shrubs, grassland and flowers.  "Fire refugia" are areas that somehow avoid significant or frequent damage; they burn less often and/or less intensely than the surrounding landscape.  Such areas are important in the recovery of the ecosystem after a fire - allowing re-population of the area with a variety of species.  [caption id="attachment_35352" align="aligncenter" width="650"] Woodland recovering from a fire[/caption] Consequently, studies have been directed towards understanding the physical and biological nature of such refugia.  The work has focused on mature, conifer dominated forests in the States (The Klamath-Siskiyou region)  and the fires that have occurred over a period of some 30 years.  It was found that refugia were associated with physical features of the habitat such as rocky outcrops, depressions in the landscape.  It was also noted that the density of the smoke that the fires generated was a factor in tree survival (perhaps dense smoke offered a degree of shade?).   The area studied has a complex and diverse geology,  with varied habitats that support considerable biodiversity.   Fire has always been a key factor in the maintenance of the varied landscape but with the climate becoming hotter and drier, there is concern that an increasing frequency of fires will ‘eat away’ at the forest’s ability to regenerate - with the loss of refugia and incineration of seed banks in the soil. Severe fire can reset the path of succession - so that forest can be reduced to bare soil. Complex and established communities of fungi, microbes, plants and animals are lost, reduced down to bare soil. Intense heat will damage the structure of the soil, reducing its organic content and its complex community of microbes. In extreme cases, this can lead to the erosion of the soil.  

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