‘Today I have grown taller from walking with the trees’
~ from the poem ‘Good Company’ by Karle Wilson Baker (1878-1960)
I wanted a relatively short walk between rain showers so headed to a small local green belt where Oak saplings were planted a few years ago, and my wander turned into a challenge to see how many different types of gall I could find in just this one small copse of young Oaks. The answer? Six!
First up, Knopper galls, caused by the wasp Andriscus quercuscalicis. For more on that gall, see my August 2017 post Oak galls: knoppers and artichokes.
Next, Marbles, which I covered in Oak galls: marbles and apples, August 2017.
Then, I found some Common spangles (below left), caused by the wasp Neuroterus quercusbaccarum. More on that mouthful in Oak galls: currants and spangles, August 2017.
You may have noticed my photo of Marble galls also had something else on the leaves. These were Smooth spangles (above right), a product of the wasp Neuroterus albipes.
I covered both Smooth spangles and this next gall, the Oyster, in the same blog: Oak galls: spangles and oysters, September 2017. The photo on the left above shows Oysters just beginning to form on the spine of the leaf; the one on the right shows two more developed examples, both on the same tree.
And, last but most certainly not least, as there were thousands of these on all the Oak trees I looked at, Silk button galls, caused by the wasp Neuroterus numismalis. I wrote about those in Oak galls: ram’s-horns and silk buttons, September 2017.
Not a bad haul for an hour turning over leaves and peering amongst branches. I didn’t find examples of all the Oak galls I’ve found before but I was very happy with this sampling.
When I got home from today’s walk, I discovered I had a hitchhiker, tucked up snugly in the hood of my jacket. I presume this Hawthorn shieldbug got brushed off its bush and on to me as I pushed through the snagging branches of some young Hawthorns earlier in the day. After a couple of quick photos, I placed it on the window ledge and off it flew in search of the nearest Hawthorn.
The key to where to locate this gorgeous butterfly, the Purple hairstreak, is in its scientific name Favonius quercus – quercus is the genus of the Oak tree – and I suspect that there are many more colonies of Purple hairstreaks living in our old Oak trees than we currently know about, as these butterflies spend much of their time unseen, high in the leafy boughs, feasting on honey dew.
There is a colony at Lavernock, and I’ve seen these butterflies at a couple of locations along the road that leads to Lavernock Point, but they were the only local sites I knew about. So, you can perhaps imagine my delight when, during Thursday’s walk at Cosmeston Lakes Country Park, I came face to snout with a female Purple hairstreak, which had ventured down to head height, and was happily running her yellow proboscis over the honey-dew-covered leaves.
This was the closest I’d been to one of these lovely creatures and had previously seen neither the purple sheen on their open wings nor the yellow proboscis. I was in butterfly heaven!
I’m not good at tree identification but I think this is most likely a Hybrid Black-poplar (Populus x Canadensis agg). It’s growing in a local park alongside the river – they like wet landscapes, and are frequently planted in parks and gardens but have also become naturalised in much of Britain.
What caught my attention with this tree was not the leaves or the bark or the shape but its seed fluff, which is so abundant at the moment that it’s covering the nearby path like snow in summer.
Poplar trees are dioecious, meaning there are separate male and female trees, and you can tell this one is a female because it’s producing the seeds, with all that fabulous white fluff attached.
When walking along a narrow path between fields last week, I turned to face into the neighbouring hedgerow so that two other walkers could safely pass behind me. In so doing, I noticed these galls, which I think are Aceria campestricola (also known as Aceria ulmicola).
These growths betray the presence of the hundreds, perhaps thousands of the tiny mites that have caused these galls to form.
These particular galls can only be found on specific elm species, which in Britain include English elm and Small-leaved elm.
These stopped me in my tracks!
I’d enjoyed a nice amble around a local park and was on my way home when I spotted these incredible galls and just had to stop for some photos. The galls are caused by tiny mites that spend the cool winter months huddling in cracks on the tree’s bark, then head out on to the leaves when they sprout in the springtime.
The mites are leaf-sap suckers, and their sap sucking causes a chemical reaction in the leaf, which in turn prompts the leaf to produce these small, conical, hollow growths. The mites are incredibly tiny – less than 0.2mm long apparently – so they’re almost never seen, whereas their cosy gall homes can grow to 8mm long and, when they’re as bright as these ones were, are very obvious on the leaves.
I’m not sure which mites these are as I’m not sure which tree species this is. One mite species, Eriophyes tiliae, is the gall causer on Large-leaved lime trees (Tilia platyphyllos), Common limes (Tilia x europaea) and some hybrid Lime species, and another mite, Eriophyes lateannulatus, causes very similar galls on Small-leaved Limes (Tilia cordata) and hybrid Limes.
This must be the largest Oak apple gall I’ve ever seen – it was at least 1½ inches across, and it had attracted the interest of several small wasps, though these are not the wasps that created the gall in the first place.
I assumed that they were parasitic wasps about to use their long ovipositors to inject their own eggs into the gall, and it turns out my assumption was correct. Thanks to the British Plant Galls account on Twitter (@BritGalls), and to another Twitter user’s tweet, I’ve learnt that the tiny wasp in the photo below is a member of the Chalcis genus of wasps, probably one of the family of Torymidae. They are ectoparasites: their larvae feed on the larvae of the Oak apple gall wasp that created the gall in the first place.
It’s that time of year again, when the Hawthorn blossom scents the air with its distinctive perfume and carpets the ground with its snow-like blossom.
My Flora Britannica reminds me that Hawthorn, also known as the May tree, was ‘the ancestor of the Maypole, the source of May Day garlands … and one of the models for the foliage which wreathes the faces of Green Men carved in churches and inns.’
For lots more fascinating information on the Hawthorn, check out my previous post here.