June is the month when I’ve tended to find the first primary evidence of Hymenoscyphus fraxineus, the ascomycetes fungus responsible for the dreaded Ash Dieback. By this I mean that the while the presence of the disease is manifest all year round in terms of the sight of dead or dying ash trees, this is the time when one can first see the tiny ascocarp fruiting bodies responsible for spreading the spores. Hunt around in the debris at the base of an afflicted tree, and one can find these miniscule cream-coloured goblet-shaped ascocarps on the blackened fallen petioles and rachises of the previous year’s growth; the stems and stalks that make up the recognisable ‘pinnate’ leaf form of this species, with the blackening itself symptomatic of the presence of this destructive pathogen. The timing is interesting in that, with ash one of the last trees in our wooded environments to come into leaf, these ascocarps first begin to appear at a time when all good healthy trees should be in full leaf, shooting their spores (more specifically ‘ascospores’) into the air where they infect their host, unimpeded by the early plants of the woodland understory such as anemones, arums and bluebells that have by now died back for another year. The infection becomes evident on the tree itself with the blackening and wilting of leaves and shoots from July to September (Chalara fraxinea was the name for this separate asexual stage, and hence, before the link to the H. fraxineus was discovered, the name Chalara Ash Dieback took hold). [caption id="attachment_38272" align="aligncenter" width="675"] The unwelcome site of Hymenoscyphus fraxineus ascocarps growing from blackened twigs beneath ash trees.[/caption] I covered Ash Dieback in some detail a few ago, but for this months Fungi Focus, I want to discuss a few small lookalike species – the term discomycetes is used to describe the cup-shaped ascomycetes – that shouldn’t be such cause for alarm. The ascomycetes can be a horrible group when it comes to identification, with at least double the amount of species worldwide than the other major phylum of fungi, the basidiomycetes, and a scant few of them baring common names. Going by visible features alone, it is difficult enough to pinpoint down to genus level, yet alone species, with close microscopic scrutiny necessary to go any further. A case in point is Hymenoscyphus albidus, whose ascocarps look identical to H. fraxineus to the naked eye: Both grow exclusively on ash and both have the same blackening effect on the fallen petioles on which they grow. It is for this reason that H. fraxineus has also gone under the synonym H. pseudoalbinus. The only difference between this native fungus and the invasive interloper believed to have arrived from Asia, aside from the fact that it doesn’t kill its host, is that H. albidus does not possess hook-like “Croziers” at the base of its asci (where the spores are produced) – something that can only be ascertained microscopically.  [caption id="attachment_38273" align="aligncenter" width="675"] The related and near identical looking Hymenoscyphus scutula, fruiting on a dead bramble stem.[/caption] I don’t wish to blind the reader with science here, but one take home point is that if you do find tiny nail-shaped ascocarps on blackened fraxineus (ash) debris, it doesn’t necessarily spell doom for your local ash population – it might well be this harmless indigenous species. Another thing to consider is that the Ash Dieback fungus might not only be laying waste to our native ash population, but also outcompeting H. albidus in the process, thus another species falls under threat, albeit a miniscule fungi that is not quite so cherished as our ash trees and indeed is barely noticed by most of us. How many people are scouring the UK to estimate the ratio of H. albidus to H. fraxineus at the moment? Probably less than a handful, if any, I’d say. There are 155 species in the Hymenoscyphus genus according to Wikipedia, but there are probably many many more. Even the dozen or so listed in Peter Thompson’s Ascomycetes in Colour (2013) and Læssøe and Petersen’s Fungi of Temperate Europe (2019) look so similar as to make the eyes water. Some can be identified by their host – they might grow on leaves of specific plants, dead stems of herbaceous plants, or nuts and acorns – although never with total certainty. For example, I found similar tiny cream ascocarps growing on a dead blackberry stem. They seemed to fit the description of Hymenoscyphus scutula. The spores matched too, but even then, I couldn’t be 100% sure.  [caption id="attachment_38274" align="aligncenter" width="675"] These yellow discomycetes growing on a chestnut husk are probable Hymenoscyphus serotinus, although one can never be certain without checking under the microscope[/caption] Some are slightly more notable in the colour department. The small yellow cups I found growing on a chestnut husk could have been H. seritonus, or maybe H. monticola, or maybe something different entirely. I wasn’t going to bash my brains out trying to get any further in such cases, and nor should you. This is very very advanced specialist stuff. (For the record, as well as looking at spore shapes and sizes, the serious “ascomycetologist” would look at features such as the lengths of the asci and the ‘paraphyses’, the sterile hair-like filaments also contained as support structures within the fruit bodies). Anyway, lets move on to simpler things, namely two species of discomycetes that look superficially rather similar to the Ash Dieback fungi but are much easier to distinguish. These are Spring Pins (Cudoniella clavus) and Oak Pins (Cudoniella acicularis). One difference that can be noted with these and the Hymenoscyphus species is that the hymenium, the upward facing fertile surface in which the asci are embedded and release their spores from, is convex than concave – more dome-shaped than cup-shaped, although sometimes flatter. The appearance of both of these are of little nails or pins, as spelled out in the ‘clavus’ (for ‘nail’) part of the Latin name for Spring Pins. [caption id="attachment_38275" align="aligncenter" width="675"] Spring Pins (Cudoniella clavus), can be found growing twigs and other deciduous litter in freshwater environments..[/caption] Spring Pins, as the name suggests, appear from April to July, and usually in great abundance. They are not limited to ash trees anyway, but are found on any deciduous litter and dead wood in wet habitats; the ones depicted here were growing on fallen twigs in a ditch, a typical environment as they often appear in clean still or flowing freshwater habitats.  They are creamy white to yellowish and average around 4mm in diameter, getting up to 8mm according to Thompson, so do appear significantly larger than H. fraxineus. They are longer stemmed too, on average, and have a slightly gelatinous although not quite translucent appearance. This combination of size, shape and habitat should make this relatively widespread fungus not too challenging to identify. [caption id="attachment_38276" align="aligncenter" width="675"] Long-stemmed, gelatinous, with dome-shaped caps and slightly larger in size, Spring Pins are easy to distinguish from Hymenoscyphus species.[/caption] Oak Pins are also common. These are much smaller, with the markedly dome-shaped caps just 1-4mm in diameter, the margins slightly in-rolled so that from above they look like tiny gilled mushrooms such as the smallest mycena species – although a look underneath with a hand lens will clear up any doubt. These are much whiter than the other species discussed thus far, although develop black and brownish spots as they age.  One notable aspect to Oak Pins is that if one looks really closely, one can see that they are slightly hairy, particularly on the stems. But their substrate, not to mention their sheer proliferation across it, should be the real clincher for ID purposes. They almost exclusively appear on very old well-rotted oak stumps, and later in the year too – from August throughout the winter into March, although with the British climate as unpredictable as it is, quite possibly outside of these months. [caption id="attachment_38277" align="aligncenter" width="675"] Oak Pins (Cudoniella acicularis), another common find; smaller, whiter, with slightly hairy stems and discolouring with age.[/caption] June is hardly considered the best time to be out looking for fungi. These examples should show that there is still plenty about during the early Summer months, but many species are very small, very obscure and often very difficult to identify. This post, I hope should go some way to rectifying this final problem for some of them.  And if you do find what you suspect to be Hymenoscyphus fraxineus, don’t forget to report it. Happy hunting! [caption id="attachment_38278" align="aligncenter" width="675"] A proliferation of Oak Pins across a rotting stump.[/caption]

So, you’ve decided to plant trees, or maybe you want to buy land for tree planting, but you’re not entirely sure exactly how to plant trees correctly. There are several things that need to be considered when going about planting trees, including choosing the right tree, deciding where to plant it, and making sure it takes root and grows successfully. Once you’ve planted it, you need to keep an eye on how it establishes itself in its new location. When is tree planting season? It’s best to plant trees with before the spring and summer. The rainy spring and hot summer conditions can spark the tree to grow, so it’s important for you to establish the tree in its new location before this change in conditions. As a result, the best time to plant trees is from November to March, with planting in November giving the tree a bit more time to get settled (for its roots to establish) before the warmer seasons. Though you can technically plant a tree in the summer, this could increase the chance of it not establishing. It’s best to plant trees when the weather is cool.  Where is the best place to plant trees? You have several options for where to plant a tree, whether that’s in your garden, on someone else’s land or on tree planting land that you have recently bought. When deciding to plant you must consider what the space has to offer; for example, if you have less space, like a small garden, it might be best to choose a smaller tree that’s easy to prune and that won’t interfere with the infrastructure of your house or its surrounding area. If you have a larger garden or a plot of land you’ll have more options, and could consider things including the topography, soil type and aspect, when selecting species. Though many trees can survive in any conditions, some prefer specific conditions. If you don’t own the land you’re planning to plant on, you will need to get permission from the landowner before doing so. If you do own the land, you won’t need planning permissions unless your project is over 2 hectares in size, at which point some environmental assessments may be necessary.  There are also some places where you can’t plant trees, such as on archaeological sites, or sites with rare or protected species. Grasslands that have never been ploughed, wetlands and heathlands are not suitable for planting trees. Planting next to some rivers could also be regulated, but you’ll need to talk to the Environment Agency to make sure. If you’re unsure about whether you can plant on your land, you can check with the Forestry Commission.  What species to plant? When it comes to selecting species, there is no right or wrong answer, and different species can flourish equally in the same location.  People often prioritise planting native broadleaved species, which is widely encouraged, but not essential.  Planting a range of species can improve resilience and resistance to disease, while also having excellent carbon storing capabilities! A diverse mix of deciduous trees will also be beneficial to wildlife.  In the UK there are lots of options for native trees. Examining what’s already growing in the surrounding areas will give you an idea of what will grow successfully. You might have a specific goal in mind when planting trees, such as attracting more wildlife to an area - a tree with nuts and berries (such as rowan, elder, blackthorn, or hawthorn) will be best for this - or maybe you’re looking to reduce flooding, in which case alders and willows are good options; particularly next to watercourses. The size of the space you have available is important to consider, as larger trees may eventually  encroach upon your home once they reach maturity, so may not be suitable in a back garden. For smaller gardens, consider trees such as crab apple, alder, bird cherry, dogwood, elder, or goat willows, which are naturally small, or trees that can easily be pruned back to the desired size like holly or hazel.  What do I need to plant a tree? Not a lot of equipment it required to plant a tree: you’ll need a spade, a tree (which could be bare root, cell grown on root ball), a tree guard for protection and a cane/stake for support.  If there are browsers or grazers in the local area (such as deer) then stock proof fencing around the perimeter of the young woodland could be useful to keep them out.  A mulch (or equivalent material) is also important, to keep down the grasses and weeds which can provide unwanted competition for young trees.  Mother nature will almost always take care of the watering required, but some irrigation (from a spring, river or mains connection) can be handy in particularly dry spells. Rain water collection systems could also be utilised.   Steps to plant a tree Preparing the land & choosing a spot Before you dig a hole to plant your tree in, prepare the soil for planting. This involves cutting any grass short and weeding the area, which prevents the tree from competing with other plants for water and gives it the best chances possible! After working out the density at which you would like to plant, it’s sensible to mark where each tree will go with a stake.  This should be a safe distance away from any buildings, other trees or infrastructure (don’t forget about power lines and pipes!). Planting density can vary on species, as well as desired outcomes, but it’s worth bearing in mind that the denser you plant, the sooner you will get a closed canopy, which is a nice milestone in the development of a woodland.  Either 2m or 3m gaps are fairly standard.  For hedge planting smaller gaps are advised, with 30cm or so between each tree; for thicker hedges make a double row of trees in a zig zag pattern with 50cm between the rows. Digging a hole Once you’ve done your preparation, it’s time to dig the hole! There are several tree planting methods, including pit planting, spiral planting, and t-notch planting. Pit planting works on all soil types; spiral planting works on bare soil and grass and is good for stony soil; and t-notch planting is a quick method for grass-covered ground.  Pit Planting Dig a hole deep enough to take the length of the roots of the tree. Pick up the tree by the roots and place it in the hole, pushing it to one side to see how deep it is in the hole and to ensure all the roots are covered. Using the heel of your boot or your hands, firm the soil around the roots, making sure there are no air gaps.  (Another way to prevent air gaps is to spray water on the soil after backfilling halfway, and again once you have completed filling the hole.) Place the tree guard around the tree and hook it around the stake, and push it around 1cm into the ground. Spiral Planting Press the depth of your spade into the ground, pushing forward to create a slit that’s deep enough for the roots of your tree. Using the spade to keep the slit open, place the tree inside the hole with the top of the roots 2cm below the ground. Remove your spade and push the soil back around the roots of the tree, again checking that there are no air gaps. T-Notch Planting Create the first ‘notch’ by pushing the depth of your spade into the ground. Then, to create the second ‘notch’ do the same thing at a right angle to the first notch, creating a ‘T’ shape. Return the spade to the first notch and lever it upwards, parting the section of soil. Hold your spade there, placing your tree in the space created before removing the spade to allow the soil to fall into place. Ensure that all roots are in the hole and adjust the tree so that it’s at ground level, before firming the soil around it. How To Plant A Root Ball Tree If you’re planting a ball root tree, or a tree from a pot, dig a hole 2-3 times the width of the roots, but no deeper than the length of the roots. Break up the clumps of the roots so that the roots don’t grow circularly. You might choose to leave 25% of the root ball higher than the surrounding soil level, and taper the soil so that it covers the roots before adding a layer of mulch. After Planting Mulch Mulch is a good way to retain the moisture of the soil surrounding your tree.  It can keep the roots cool, and protect the roots of your tree from extreme weather conditions. Mulch will also keep competitive weeds and grasses at bay, which can be problematic for a young tree.  Alternative options to mulch include bits of old carpet, sheep’s wool or anything that will keep the light off the soil and prevent growth around the base of the tree.  If you choose to use mulch, leave around 1-2 inches of space around the base of the tree, and place mulch about 1 sq/m around the tree. Watering Watering your tree correctly is extremely important for it to grow successfully. You will need to ensure that you water your tree correctly until its roots are properly established in its new location. This can take anywhere from a few weeks to a few months, up to a year. Here in the UK, in autumn and winter, our rainy climate is usually sufficient to enable the trees to establish and flourish on their own.  Some additional irrigation from a stream or water run off can be helpful if it is particularly dry. Pruning Before you plant your tree, you might choose to prune branches, but you shouldn’t do so immediately after planting. Wait until after a full season of growth to do ‘corrective’ pruning. Plant Around Your Tree The area surrounding your tree provides the perfect environment to plant other shrubs and plants. Planting wildflowers can help attract diverse wildlife and creates a variety of food and shelter for different species. If you’re planting several trees, the space between your trees will encourage different habitats to form and improve the biodiversity of the area. It could be nice to form a footpath between your trees so that you can easily access them and enjoy the advantages that come with being surrounded by nature. Go, go, go! Now that you know how to properly plant trees, get planting! Don’t be discouraged if the tree you’ve planted doesn’t grow successfully- there are endless variables that can affect why this might happen, but if you follow the above tree planting tips you should be on the right track. There will always be a certain percentage of trees which fail to establish.  There are so many benefits to tree planting on your physical and mental health, and is one way to do our bit to help the protect the environment from the effects of climate change, so there are plenty of reasons to keep trying!  

Beech and climate change. Beech trees are important (ecologically and financially) in the woodlands and forests across Europe.  Beech has a wide distribution from Southern Europe up into Scandinavia.  However, the beech has a relatively shallow root system and this makes it susceptible to drought.  In recent times, as a result of climate change, extreme weather events such as drought have become more common.  Analysis of beech tree rings (from 5000+ trees) across Europe suggest that whilst those Sweden and Norway are growing quite well those in Southern Europe are not, in fact growth may have declined by as much as 20%.   Current climate projections suggest that beech growth / productivity in southern areas may decline further, with increasing mortality. Warning signals. Many animals are able to send signals to other members of their species warning them of imminent danger, such signals can be warning sounds or ‘scents’.  The scents may be in the form of pheromones, essentially ‘airborne hormones’. Now there is growing evidence that plants may be able to act in a similar way.  For example, if mint leaves are damaged by a insect herbivore attack, then field mustard and soybean plants growing in the vicinity respond to the volatile chemicals released by the mint and activate their leaf defence systems (this often involves creating an unpalatable taste).  The volatile compounds released (during damage) are ‘oils’ or terpenes, like  β-Ocimene.  β-Ocimene has a sweet, woody fragrance but it is not clear how it stimulates other plants into activating the genes for their defence mechanisms.   Research is underway at the Tokyo University of Science. Lead and Birds of Prey.  Birds and Prey feed upon flesh they scavenge (like the entrails of deer, or dead pheasants) or from animals they capture.  The trouble is that often this flesh is riddled with bits of lead shot.  Lead is a poison, and is not easily eliminated from the body.  Animals injured by lead shot may suffer a slow and agonising death. Those that feed upon them also accumulate lead in their bodies, which affects their physiology and behaviour. Now Cambridge based scientists have studied the lead levels in a variety of birds of prey.  They looked at lead levels in the livers of some 3000 raptors. Birds, like eagles, are worst affected as they are long lived, breed later in life and rear relatively few young per year.  For a number of species, they have been able to estimate the % reduction in population size that the lead is responsible for. Species Estimated % loss of population White tailed eagle 14 Golden Eagle  13 Griffon Vulture 12 Red Kite & Western Marsh Harrier 3 Buzzard populations are estimated to be 1.5% smaller, which may not seem much but it equates to the loss of some 22,000 birds. Lead is still used in shotgun cartridges, many pheasants are still  killed with lead based ammunition, despite requests to hunting groups to switch to non-toxic gunshot (by 2020).  Full details of this work can be found here. Warmer autumns and butterflies. Green veined white butterflies are common in the U.K. and Europe.  Researchers in Sweden have been looking at how they might respond to warmer and longer autumn weather.  Under laboratory conditions, they exposed the chrysalises (over-wintering stages) of the butterfly to warmer autumnal conditions.  They found that the chrysalises used more energy and lost more weight under these conditions, and were less likely to survive to the adult / imago stage in the following Spring.  With global warming affecting our climate, it could be that populations of this butterfly could struggle as time passes.

The woodlands blog has previously reported on the worrying decline in insect numbers, but there has been yet another report detailing significant falls in the populations of (flying) insects.  This survey was run by Buglife and the Kent Wildlife Trust  (KWT) using a smart phone app - “Bugs Matter”. The survey suggest that between 2004 and 2021 the number of flying insects (in Kent) has fallen by some 70%.  This finding is not dissimilar to that carried out in rural Denmark which found an 80% decline in insect numbers between 1997 and 2017. Insects are vital to the functioning of ecosystems.  They help maintain: A healthy environment Contribute to the recycling of organic matter Act as pollinating agents Help control pests Without insects the ‘web of life’ begins to fall apart.  The loss of insects and other forms of wildlife can be helped by: Creating larger areas of natural habitats (many have been lost to roads, agriculture, urban expansion) Creating wildlife corridors to link up similiar habitats / ecosystems throughout the landscape Creating wild flower ‘meadows’ by road sides, verges etc Reducing the use of pesticides and other chemicals which have significant effects on wildlife The Buglife survey makes use of a simple technique to estimate insect abundance - the ‘splatometer’.  This involves counting the number of ‘squashed’ insects on car registration plates.  The Danish survey used a similar method but looked at insects found on car windscreens.   This summer Buglife is hoping that people will again contribute to another survey using the splatometer technique.  The survey will run from June 1st to August 31st.   To contribute to the survey you will need :- The “Bugs matter” app (free) and a smart phone. To create an account to send in your results Clean the car number plate before the start of any journey in your vehicle At the end of your journey, count the number of squashed insects on the number plate (using the splatometer grid - which will be sent to you) and take a photo. This enables Buglife to calculate the ‘splat rate’, that is the number of insects recorded per mile.  NB.  Journeys on wet days are not recorded as rain might wash off any insects from the number plate.   The more journeys and counts that you can carry out the better, and zero counts of squashed insects are just as important as those with an actual number of squashed insects. Note : The app includes a tutorial and some safety advice. It is available for android or apple phones.

There’s a seemingly endless stream of bad news in the world: the coronavirus pandemic has forced us stay inside more than we’ve ever had to in our lifetimes, and there’s the ever-impeding threat of the climate crisis. Our collective mental health is suffering, and more than ever we’re looking for anything that can provide some alleviation from this.  The government recently found that almost half of the UK’s population say they are spending more time outside than they did before the pandemic, so it’s clear that green spaces are more important than they have ever been for both our own wellbeing and the wellbeing of our planet, which really begs the question ‘why not plant more trees?’  Why is tree planting good for the environment? Forest ecosystems are one of the world’s greatest carbon sinks in existence. They hold up to 45% of all the carbon stored on land, as well as being home to 80% of the animal and plant life on land. Maintaining our forest ecosystems could be one very large step towards solving the climate crisis; and though this won’t be enough on its own, it’s definitely a good place to start. On a smaller scale, one hectare of young woodland  has the ability to lock up over 400 tonnes of carbon.   Imperial College estimates that a tree planting initiative on a worldwide scale could capture the equivalent to one decade’s worth of carbon emissions (at current rates) by the time these forests reach maturity, or up to 1/3 of all emissions from human activities that remain in the atmosphere since the Industrial Revolution. How can tree planting can benefit you? Local tree planting initiatives are an excellent means of drawing a community together. Forest For Peterborough, a tree planting organisation in the UK, started in 2010 with the aim to plant 230,000 trees by 2030, and at the same time provides a space where the community can come together and learn how to make responsible and sustainable choices. In 1980 Edward O Wilson, American biologist, popularised the term biophilia to describe the innate connection people have to the natural world, and it’s true that we as humans seek and crave the comfort of the natural world, particularly in times of stress. The UK government estimates that visits to UK woodlands have saved an estimated £185 million in mental health treatment and costs. At the same time, street trees in rural areas are thought to have avoided £16 million in antidepressant costs, so why are there not more trees being planted in rural and urban areas? More local tree initiatives like Forest For Peterborough could both help save people’s mental health and help the UK government reach their target of becoming carbon neutral by 2050. Planting trees can also help with our physical health. It goes without saying that having poor mental health can begin to have an impact on our physical health, and vice versa (in fact, loneliness has the same affect as smoking 15 cigarettes per day), and having green spaces near our living areas helps to improve our attention and creativity. Walking amongst trees even boosts our immune system and reduces our cortisol levels. It’s also been shown that in areas affected by tree loss, women have a higher risk of cardiovascular disease (222,000 hectares of green space have been lost to urban sprawl between 2006 and 2012 in the UK) and senior citizen’s survival rate is 17% higher if their residence is within walking distance of a green space.  Planting trees can even help your wallet, too (maybe money does grow on trees!). Aside from saving the UK government millions of pounds in mental health costs and the projected costs that could come with the climate crisis in future, planting trees next to buildings can reduce the buildings’ energy consumption by up to 26%. This lowers the buildings’ internal temperature by 4 degrees in the summer and increases it by 6 degrees in the winter, so there’s less of a need for central heating and cooling systems (and of course prevents further emissions into our atmosphere). House prices rise by 9 to 15% if they’re near trees: they add to the aesthetic value of a neighbourhood, make people feel safer, and have been proven to lower crime rates. Why not plant trees? So, why plant trees? If planting trees for the sake of the planet isn’t enough of a reason, then there are plenty of ways tree planting can help you and your community. If you’re looking for tree planting opportunities there are plenty of events coming up, such as National Tree Day, which this year will be celebrated on July 31st. For the Queen’s Platinum Jubilee a tree planting initiative - The Queen’s Green Canopy- will encourages people across the UK to 'Plant a Tree for the Jubilee.’  Tree planting land for sale is available through the Woodlands website- let’s get planting!

May Fungi Focus - Campion Anther Smut  Spring is busting out all over, a time of fresh growth and new life. The past few months have seen a succession of our native woodland flora coming into their own; first woodland anemones then bluebells and primroses and now Ramsons  (wild garlic) and arums like the majestic Lords-and-Ladies or Cuckoo Pint. Amongst all this vibrant colour, it almost seems perverse to let ones thoughts wander to fungi, in most minds associated with death and decay.  Nevertheless, there are whole swathes of species that make their homes on the living tissue of plants. The rusts, for example, are particularly conspicuous at this time of year when such early bloomers begin to die back. Many are specific to one plant, or jump between different species at different stages in their own and their host’s lifecycle. Identify the plant, and most of the time you can identify the rust. Wherever you find Alexanders, for example, you are likely to find Alexanders Rust (Puccinia smyrnii). Wood anemones play host to Tranzschelia anemones, while the orange circular blotches you can see on the leaves of Lords-and-Ladies (Arum maculatum) and Ramsons (Allium ursinum) are most likely caused by Arum Rust (Puccinia sessilis). In a previous two-part post, I’ve covered Bluebell Rust (Uromyces muscari), that usually appear just before the leaves begin to die back (part one can be read here and part two here), while I’ve also written about Blackberry Leaf Rust (Phragmidium violaceum), and Dock Leaf Rust (Puccinia phragmitis), this latter an example of a species that overwinters in a different form on a different host, in this case Common Reeds. Rusts are described as parasitic and pathogenic. For certain cash crops, host-specific rusts can cause havoc in commercial monocultures. The examples I’ve outlined above, however, might be considered opportunists whose lifecycles have evolved to fit in with their specific ecosystems. Needless to say, there are many, many species of rusts, and precious few people paying attention to them. [caption id="attachment_38169" align="aligncenter" width="675"] Beauty is in the eye of the beholder: Arum Rust on the underside of an Arum leaf.[/caption] This is even more the case of smuts. While some might argue that, for example, the circular arrangements of blisters of Arum Rust have a certain organic beauty, in the Haeckelian sense, few would make such a case for smuts. Rusts target the leaves or other greens part of plants, often manifesting themselves as their hosts die back. Smuts head straight for the reproduction organs – fruits, seeds and stamens. They are not called smuts for nothing. The name derives from the German for dirt, and indeed, they manifest themselves in thick coatings of dark brown to black spores (teliospores, to be specific, but there’s no need to go into the particular details here), transforming the parts of the plant they grow on into a dark sooty mass. Much of the attention focussed on them is on species that have commercial ramifications (again, like the rusts). Ustilago tritici, for example, affects the seeds of the cereals wheat and rye, and can result in serious crop losses. Unsurprising then that it should be one of the very few species detailed in the pages of Læssøe and Petersen’s Fungi of Temperate Europe. It would be a tough argument to make that smuts present much in the way of benefit to mankind, although it is worth mentioning that in Mexico, there is one species whose presence is more welcome: the Corn Smut (Ustilago maydis) transforms the kernels of maize into a delicacy known as huitlacoche. However, there are around at least hundred different smut species in the British Isles, and most are as common as the host they grow upon. This month’s Fungi Focus is on the Campion Anther Smut (Microbotryum violaceum), one of the most commonly reported and easiest to find, as Red Campion itself is in itself a very widespread native plant that pops up alongside roadsides, pathways and hedgerows to brighten up the summer months with its pink-red flowers. As should be clear from its name, this smut targets the anthers*, so can be spotted from a distance as the centre of the flowers will be a sooty brown to purplish-black colour (hence the ‘violaceum’ part of its name’) instead of the usual light pink, the stamen and anthers coated with this spore mass. [caption id="attachment_38171" align="aligncenter" width="675"] As nature intended? An un-smutty Red Campion.[/caption] While this smut adds little cosmetic appeal to the flowers, the teliospores do present a certain fascination when viewed under the microscope; spherical and ranging from 6-10microns in diameter, and covered in an intriguing pentagonal reticular pattern. The smut transfers itself to other plants by pollinating insects who would otherwise be involved in aiding the reproductive process of the campion itself. Smuts might be viewed as a sort of horticultural STD.  Nevertheless, the ubiquity of campion flowers at this time of year would suggest that this smut does not have a particularly negligible effect on the fecundity of this particular species. Indeed, from my own observations over the years, it is rarely that present even in areas rife with campion and when it does appear, it is localised to handful of plants. [caption id="attachment_38172" align="aligncenter" width="675"] The teleospores of Microbotryum violaceum, or more specifically,  M. lychnidis-dioicae.[/caption] Microbotryum violaceum is one of the more regularly recorded of the smuts that grown on the native plants of the British Isles, and as such one should consider it a native species in its own right.   In fact, more recent investigation has shown just how specialist it is. While I’m still using the old catch-all term for the sake of simplicity, it has been split up to create several more host specific ones: M. lychnidis-dioicae is the new name to describe the smut occurring on the anthers of Red and White Campion; M. coronariae appears on Ragged-Robin; M. saponariae on Soapwort; M. silenes-inflatae on Sea Campion and M. stellariae on Lesser Stitchwort. But one does have to ask oneself just how many people out there would consider a smut even worth recording. As specialist plant pathogens, individual species of smuts can be considered as rare or as common as their host plants, and with many native plants themselves under threat from habitat loss, their associated smuts suffer accordingly. Interestingly, according to a recent publication compiled by Ray Woods, Arthur Chater, Paul Smith, Nigel Stringer, and Debbie Evans entitled Smut and Allied Fungi of Wales A Guide, Red Data List and Census Catalogue (2018), “No smut species are specially protected under the Wildlife and Countryside Act 1981 but a single smut species (Urocystis colchici) found on Autumn Crocus (Colchicum autumnale) is listed on Section 7 of the Environment (Wales) Act 2013 as being ‘a living organism of principal importance for the purpose of maintaining and enhancing biodiversity in relation to Wales’.” The same publication lists the example of Urocystis ulmariae, found only once in Wales on a single Meadowsweet plant, and placed it in the “Critically Endangered D2” category. The fascinating The Lost and Found Fungi Project, conducted by mycologists at Kew Gardens to investigate whether historically reported fungi species that have not been recorded in recent years are actually extinct or just not recorded, has also focussed on Rusts and Smuts. It is worth a look just as an example that there is some interest in smut distribution and conservation.  One might question the worth of recording, studying or conserving fungi species that so evidently hamper the reproductive abilities of their hosts. As ever, I’d argue in these posts that until the funding and human effort is put into such endeavours, we will never know. * anthers - pollen producing part of the stamens. Wild garlic

We know that insects (especially, bumblebees, bees, hover flies) are the world’s top pollinators, and we also know from many reports that many insect species are in decline.  Crops such as tomatoes, blueberries, peppers, cocoa, coffee, almonds and cherries are dependent on these pollinators.  Climate change, increasing temperatures and extreme weather events are affecting plants and animals across the world, and it seems that social insects, like bumblebees, are particularly impacted. Research with bumblebee colonies (at Stockholm University) has indicated that if the colonies are exposed to higher temperatures (than normal) then the workers in the colonies were smaller.  This decrease in body size could affect their foraging behaviour and the collection of pollen,  which would mean less food brought back to the colony and reduced pollination of plants. Studies in the United States looked at some 20,000 bees  (bumblebees, leafcutter bees, mason bees etc) along the Rocky Mountains, a region which is vulnerable to climate change.  It was found that the larger bees (particularly bumblebees) and those that built nests with combs were affected most by increases in temperature.  On the plus side, smaller (soil nesting) bees fared better.  Bumblebees would seem to have a lower heat tolerance.  The loss of bigger bees, which generally can fly and forage further may again mean reduction in long distance pollination (which promotes outbreeding in plant populations). One reason why hot or hotter weather affects bumblebees is that it influences the nectar that the bumblebees collect.  The balance of the various micro-organisms (bacteria and yeasts) in the nectar changes.  Whilst bumblebees are attracted to nectar with some microbes in it, a small change in temperature can speed up the metabolism / growth of the microbes so that they use up more of the sugar - with the result that it is less palatable / less nutritious for the bees.  Experiments conducted at the University of California have shown that bees did not ‘like’ the nectar rich in microbes, nor a sterile one - with no microbes at all. There seems to be a 'happy medium' in terms of the composition of the nectar. There seems to be a growing consensus that climate change, increasing temperatures and extreme events are pushing bumblebees (in particular) beyond their physiological limits. [caption id="attachment_38081" align="aligncenter" width="650"] Bumblebee visiting foxglove[/caption]

Certain woodland plants are found in the understory.  Plants like wood anemones, woodruff and lungwort bloom early in the year. These plants make use of a ‘window of opportunity’ when the light levels are good as the tree canopy has not developed, the leaves have not yet expanded. They use this ‘window of light ‘ to flower.   However, climate change is affecting many ecosystems - including woodlands.  With warmer temperatures, leaf buds tend to open earlier and the leaves begin to expand.  If the window for growth is reduced, how can the wood anemones and others cope ? [caption id="attachment_38093" align="aligncenter" width="700"] wood anemone[/caption] To investigate this question, scientists based the Universities of Tübingen and Frankfurt examined thousands of preserved herbarium specimens of early flowering plants, dating back over a hundred years.  The sheets not only hold specimens collected when they were flowering but also have  information on ‘when and where collected’.  Each sheet is a a moment in time from over a century ago.  Collectively, the 6000+ sheets allowed the scientists to establish historic flowering times of woodland plants over large areas of Europe. [caption id="attachment_38094" align="aligncenter" width="700"] Woodruff[/caption] The information extracted from the herbarium records revealed that plants like wild garlic and wood sorrel now bloom some six days early than at the beginning of the twentieth century.  For each 1oc rise in (Spring) temperature, their lowering has advanced by more than 3 days.  This means that they have gained time in the light - in an open canopy.  Whilst they may have gained time,  these early flowering plants are at greater risk of frosts.  It may also be that their pollinating agents may not be around - unless they too have brought forward their development / life cycle. There is some evidence that such changes are taking place.  Recent work at Wytham Wood (outside Oxford) has shown that blue tits have moved forward their egg laying to 'match' the development of the oak canopy, and the appearance of caterpillars (on which the young are fed).  Essentially, the timing of the food chain has changed..  Hopefully, such changes will occur in different ecosystems across the country.