Sun Spurge Euphorbia heliscopia

I am an amateur naturalist trying to discover everything living in my garden.

After a series of postings on some of the smaller and arguably more curious lifeforms present in my garden, today's posting features something I suspect most of you will find all too familiar: a garden weed.

Growing in my vegetable patch (at (0.1,1.7) - see here) is the weed seen in photo 1 (click photos to enlarge). It has quite happily survived the British winter frosts.

Working with my copy of The Wild Flower Key (F. Rose, Penguin), I had no difficulty in identifying my plant as a member of the (amusingly named) spurge family (supposedly a word derived from 'to purge' - a reference to the plant's laxitive effect). There are over a dozen British spurges however, so identifying the species involved slightly more work, but on the basis that my plant has a smooth (non-hairy) stem; leaves edged with tiny teeth, arranged in alternating fashion along the stem; and a "flower head" (umbel) with five-fold symmetry - together with a few other features relevent to the key in the book above - I'm identifying it as Sun Spurge (Euphorbia heliscopia).

Sun Spurge is normally a single-stemmed plant. Occasionally however, as in photo 2, it may banch from the base (since this plant is a common weed in my garden I felt no compunction in pulling it out to photograph it).

Photo 3 shows Sun Spurge's five-fold symmetric 'umbel'. The five leaves at the base of the umbel are known as bracts. The individual 'cups' containing the tiny central flowers are known as involucres.

An obvious feature of Sun Spurge is that the flower-head is almost entirely green. Since much of any plant's effort goes towards harvesting sunlight, it clearly makes sense to pack every available surface with green chlorphyll. What puzzles me is that most plants don't do this however. Instead they use up precious resources producing brightly-coloured flowers, the said purpose being to advertise their presence to pollinating insects (or so I understand). The question I then have however, is why Sun Spurge doesn't need to do the same? Can anyone comment?

Reminding me of piece of surrealist sculpture from an Yves Tanguy painting, Photo 4 shows a closeup (40x magnification) of one of the tiny flowers of Sun Spurge, peppered with yellow pollen grains. My understanding is that the small, green, plate-like 'petals' nearest to you are nectar producing glands. The round object in the background is the plant's ovary-containing female fruit. The three forked prongs sticking up from it are stigmas. A pollen grain landing on one of these will fertilise the ovary, causing the fruit to swell up, eventually to the point of bursting when it explosively scatters seed over the surrounding soil.

Sun spurge is part of the large Euphorbiaceae family of plants comprising some 7,50o species. The leaves are a favoured food of the caterpillars of the Spurge Hawk moth (a migrant visitor to Southern Britain). When broken, the stem bleeds a milky-white sap and from my copy of Medicinal Plants In Folk Tradition (Allen and Hatfield, Timber Press) I learn that our ancestors used the sap to cure warts. I certainly don't advise anyone try this however since the sap is a serious irritant and worse, a carcinogen. If that isn't enough to deter casual experimentation, as the book describes, one man given a dose 'as a joke' (!) in the ninteenth century:

'ran up and down the street like a madman, and swelled so big that his friends had to bind him round with hay-ropes lest he shall burst'

With friends like that who needs enemies!

A lichen Physcia tenella

I am an amateur trying to learn something about everything living in my garden

I promise to return to more sizable and familiar lifeforms soon, dear readers! For today's posting however: another lichen.

The lichen seen in photo 1 (click to enlarge) decorates many of the branches of my garden apple tree (at (1.2,1.5) - see here) and I'm almost certain (see shortly) in identifying it as Physcia tenella ('it' being either of the two greyish patches below the coin, as opposed to the yellow lichen left of the coin which - though I've not examined it is detail - is probably our old friend X. parietina)

The meaning of the Greek physcia (pronounced 'Fisk-ee-a') seems to be a matter of debate on the internet. I have come across it variously translated as "bellows", "breath-like", "sausage-shaped" and "blister"! Can anyone clarify the true meaning?

P.tenella is my blog's third example of a foliose lichen. According to my copy of the scholarly Lichens (F.S. Dobson, The Richmond Publishing Co.), Physcia lichens can be distinguished from other foliose lichens, in part, by their narrow (<~2mm) lobes, and septate spores (septa being thin, internal dividing walls - see here for some examples) - though I confess I've not looked for the latter.

Two further distinguishing features of P.tenella are i) the presence of eyelash-like cilia on the edges of the lobes. You can see these in the 40x-magnified photo 2. (Can anyone tell me what purpose it serves to lichen to 'sprout' these?) And ii) the presence of granular soredia (see here for my explanation of what these are) decorating the ends of the lobes. Were I to observe the soredia 'packaged' together inside little 'hoods' I understand I'd be looking at the closely similar lichen P.adscendens (since its not obvious they are, I'm sticking with my identification as P. tenella).

Finally, two nice facts about P.tenella I got from reading my copy of Lichens (O.Gilbert, The New Naturalist series). Firstly, P.tenella is one of three British lichen species favoured by long-tailed tits (Aegithalos caudatus) in building their nests (on average each nest contains nearly 3000 lichen flakes!). Secondly, being fairly acid- and nitrogen-tolerant (not all lichens are), in areas where people walk dogs, P.tenella is one of the commonest lichens to colonise the region marginal to that patch of tree-trunk known to professionals as "the canine zone" . It shouldn't be hard to imagine what this is!

A lichen Punctelia (Parmelia) subrudecta

I am an amateur naturalist trying to work out all the things living in my garden.

What better way than to start 2008 than with my second lichen (photo 1 - click to enlarge).

This one is growing on a bough of my garden apple tree (at (1.2,1.5) - see here) and is once again an example of a foliose (flakey, 'leaf like') lichen.

As explained in my previous posting, lichens are an organism that comprise a combination of a fungus and an algae. You might expect a curious life form such as this to have some unusual means of propagation and dispersal. In fact, lichens have at least three. The method(s) a given lichen favours can be a handy hint towards identification.

One method by which lichens disperse, as discussed last time, is via spores produced from fruit-like bodies called apothecia. The white bumps peppering my lichen's surface (thallus) in photo 1 are a second. As photo 2 (40x magnification) shows, these bumps consist of small white granules known as soredia. Soredia are little lumps of lichen (some fungal hyphae and a few algal cells) whose purpose is to flake away, hopefully to land somewhere new where they can set up home.

With regard to reaching a species identification, as I've said before I'm basically a novice when it comes to lichens. Based on the very handy A Key to Lichens on Twigs (Wolseley, James, Alexander) - a leaflet produced by the excellent Field Studies Council, together with a copy of the highly scholarly Lichens (F.S. Dobson, Richmond Publishing Co.) that Santa was generous to deliver me recently, I'm going with the identification Punctelia (Parmelia) subrudecta. I'm not 100% confident in this as the books above describe this species as having a grey thallus, whereas I'd definitely say that in my photo is greenish. That said however, the photo of P. subrudecta on the excellent site of the Botanical Museum of Oslo seems a good match. Furthermore, as I mentioned in my previous lichen posting, another handy tip for the identification of lichens is the use of chemical tests: according to the books, P. subrudecta turns red when exposed to a drop of sodium hypochlorite (=household bleach). The reaction was small and fleeting, but as shown in photo 3 (you'll want to click to enlarge), removing a small piece of my lichen and testing it resulted in just such a reaction. In short, I'll stick with identification for now and inmvite the experts out there to correct me!

A Nematode Worm

I am an amateur naturalist trying to learn a little about everything living in my garden.

When I started my blog a year ago, in order that I might avoid "species-count overload" (something that raised some comment and debate at the time) I made the rule that I'd confine my attentions to creatures of a 'sensible size' (a few mm upwards). This remains my broad intention. Since, however, a) rules are made to be broken, and b) Santa has recently been kind enough to deliver me a copy of Life In The Soil (James Nardi, The University of Chicago Press) which contains instructions for making a soil-sampling device known as the Baermann funnel, I can't resist devoting a posting to one of the smaller denizens of my garden.

So, what is a Baermann funnel? As the book says, it is a device whose extreme simplicity belies it's enormous effectiveness in extracting creatures from soil samples. My version is shown in photo 1. To make one, simply cut the end off a plastic fizzy-drinks bottle, fill with an inch of water, stuff a handful of soil inside a muslim bag or stocking (anything with holes small enough to retain the soil but allow small critters to wriggle through), place inside the section of bottle and then stand, cap down, inside a pot so as to position the the lower part of the soil in darkness. Finally stand the whole thing under a source of light (e.g. a desk lamp). Critters in the soil, eager to escape the bright light and heat from the lamp will wriggle down through the soil, through the holes in the stocking and out into the water. After a couple of hours you can unscrew the bottle cap, let the water out into a saucer and look to see who's now swimming around in it....

...and unless you happen to have taken a soil sample from Mars or somesuch, the answer will be: Nematode Worms.

Why? Because, quite simply, nematodes are the most numerous (multicelled) animal on the earth. A square metre of soil may contain a million of them. They are found everywhere (p176 onwards of this book) from the rainforests, to Antarctica, to the mud in the bottom of the ocean, to the soil in my vegetable patch. The much cited quote is from Nathan Cobb, "the father of nematology in the U.S.", who gave the following powerful description of their ubiquity:

"[...] if all the matter in the universe except the nematodes were swept away, our world would still be dimly recognizable, and if, as disembodied spirits, we could then investigate it, we should find its mountains, hills, vales, rivers, lakes, and oceans represented by a film of nematodes. The location of towns would be decipherable, since for every massing of human beings there would be a corresponding massing of certain nematodes. Trees would still stand in ghostly rows representing our streets and highways. The location of the various plants and animals would still be decipherable, and, had we sufficient knowledge, in many cases even their species could be determined by an examination of their erstwhile nematode parasites."

Togther with some nice animations pertaining to the body parts of nematodes, The Virtual Nematode site even has a computer-generated movie of the nematode-remains of an earth-blown-apart!

So, what did I find in my Baermann funnel. Answer, within an hour I'd collected more than twenty worms from a single handful of soil. Photo 2 shows one of them (40x magnification, click on photo to enlarge).

Now, those of you who follow my postings will know I generally make some effort to try to establish the specific species of creature I've come across. In the case of my nematode however, I feel I may have met my match. According to the book above some 15,000 species of nematode are known. If this weren't daunting enough however, it's estimated this may represent only about 3% (!) of the number of species awaiting discovering. It's probable that new species are appearing, and sadly that human activity is extinguishing others, all the time. If you want your name associated with the discovery of a new species of animal, you could do worse than to make a Baermann funnel!

I've not tried to work out the species of my nematode. It could be that I am making too much of the difficulty of identifying nematodes however (?). Certainly the UNL Nematology Lab has an online interactive key which looks a good way to get started. It seems you can make some headway by looking to see whether the mouthparts of your worm are those of a herbivore suited to piercing plant roots, those of a bacterivore suited to hoovering-up bacteria, or 'other' (fungivore, fellow nematode predator etc.). If you're an amateur brave enough to be cataloguing the nematode fauna of your back yard do please leave a comment.

European Holly Ilex aquifolium

I am an amateur naturalist trying to discover a little about everything living in my garden.

Today's posting is something of a milestone for me as it marks not only my 'species count' reaching fifty, but also one year (give or take a few weeks) since I started blogging the life in my garden. Looking through my window, I find my perception of my garden has been entirely transformed over the course of past year. Previously my garden was a place where 'some plants and stuff grew'. When I look at it now, it seems to be positively vibrating with life; I now know it's a place where snails stab each other with daggers in the name of love; native plants rub shoulders with exotic immigrants; spiderlings enagage in matricide; earwig mothers lovingly tend their eggs; female moles fight aggressive underground battles; ants ferry primrose seeds to and fro; fungal threads push their way through the soil and little lichens eek out quiet lives on exposed stone ledges. To name but a little of the activity going on all around me.

In the year since I started my blog I've had 2859 visits from 851 cities acround the world. At least a few of you have come back more than once, so I guess my postings must provide some small entertainment value. The purpose of my writing has always been to help fix in my own mind a little of the natural history of my garden. If in the process, I'm able to provide a few minutes diversion for some of you out there, I'm very happy.

Enough of the self-referential ramblings! On to the star of today's show, and what could be more appropriate to this festive season than photo 1 (click to enlarge), European Holly (Ilex aquifolium).

According to my copy of The Collins Tree Guide (Johnson and More), the holly (Ilex) genus contains some 400 species (together with numerous garden-centre cultivars). Only one is native to Europe, though as the book says, European Holly (Ilex aquifolium) 'has some claim to be the most ornamental of all' - a sentiment with which I'm in full agreement.

In common with nettles, Holly is mostly dioecious (Greek 'two houses') meaning that individual plants are either male or female and cross-pollination is required to produce a 'berry'. Male flowers can be identified by the presence of four, yellow anthers. Females have a single style.

Holly berries are toxic. According to this site as few as three berries are sufficient to bring on unpleasant side effects.

Strictly, as pointed out in my copy of The Field Guide to Trees (Mitchell, Collins) holly berries are not in fact berries at all. Instead, they are what botanists term drupes. As this site explains, berries have seeds directly surrounded by soft fleshy fruit (grape pips being an example), whilst drupes have their seeds surrounded by a woody 'shell' ('endocarp') (as peaches do).

Holly is a popular food with the caterpillars of the Holly Blue butterfly (Celastrina argiolus), the Double-Striped Pug moth (Gymnoscelis rufifasciata) and the Holly leaf miner (the larvae of a fly, Phytomyza Ilicis). According to a paper by T.R.E. Southwood from 1961 however, of all the common species of British tree, holly has the lowest number of predatory insects - a mere seven species. I find this amazing. There are simply so many (tens of thousands at least) of insect species in Britain, and they are so good at finding ways to eat things, that for one of our commonest woodland trees to be 'immune' to the advances of all but seven really surprises me. Unfortunately reading the full paper above would require me to pay a subscription (see here for my grumble about this) so I've not been able to learn more about the details (if anyone can give me a simple explanation of why so few insects predate holly, do please leave a comment).

Photo 2 shows a close up of the trunk of my holly tree (which is growing at (1.6,1.7) - see here). Holly wood is pale and has been traditionally used to make the white pieces in chess sets. On the odd occasion when I've found the need to prune my tree I've found the branches to be tough and flexible. Pure speculation on my part, but I can imagine hunter-gatherers in Britain a couple of thousand years ago finding a use for the strong bendable branches of holly as lashings.

A more certain past use of holly wood has been for the manufacture of bird lime (a sticky glue used to coat twigs for the purpose of catching song birds alive). I haven't come across a definitive recipe (not that I'd want to make said glue in any case!) but I understand it involves boiling and fermenting the wood and bark in water.

As most people know, holly has a strong symbolism in Christianity, the spiky leaves being associated with Christ's crown of thorns, and the red berries with drops of His blood, hence the line from the famous Christmas carol The Holly and The Ivy

Of all the trees that are in the wood
the holly bears the crown

I read that the religious symbolism of holly stretches much further back into the past, to pre-Christian times. I find so many supposed 'factual' accounts of pagan rituals, Druids etc. on the web to be such a mix of fable and wishful thinking however, that I struggle to know which to believe. I'll defer further comment therefore (if anyone can point me to an historical account from some reputable source do please leave a comment). Instead, I'll leave a final, upbeat word to who else but Willie Shakespeare:

Then heigh ho! the holly!
This life in most jolly!

Happy Christmas all!

Intermediate screw moss Syntrichia (syn. Tortula) intermedia

I am an amateur naturalist trying to learn something about everything living in my garden.

Photo 1 (click to enlarge) shows a patch of moss growing on top of a large stone in my garden, closeby my kitchen door (at (0.9,1.5) - see here).

In fact there are a number of mosses present in photo 1. Though I've not taken the time to examine it in detail, from its appearance I believe the flat feathery one below the coin in the centre of photo 1 to be our old friend Silky Wall Feather moss (Bracythecium rutablum).

The moss that's the focus of today's posting however is that directly left of the coin with leaves arranged in little 'rosettes'.

Photo 2 shows a close up (100x magnification, 1 small graticule division = 10um) of one of the leaves. Things to notice include the tiny spines on the translucent hair emerging from the end of the leaf; the rounded leaf end; the fact that towards the mid-point along its length, the leaf narrows a little and simultaneously 'recurves' (folds over at the edge). Another microscopic feature, most easily seen in the 400x image of photo 3, are the circular cells in the mid leaf, becoming oblong at the edges. Finally, a feature of my moss shown in photo 4 (I've 'tweaked' the colour and contrast on this photo to show things up a little better) are its brown, cylindrical setae (spore capsules). Taken all together, and referring to my battered copy of British Mosses and Liverworts (E.V.Watson, Cambridge Univ. Press 1955), everything points to my moss being Tortula intermedia (Intermediate Wall Screw moss). The site of the British Bryological society has a lovely close-up photo under the alternative name Syntrichia intermedia.

Ubiquitous and persisting through the winter, mosses are inherently 'good value' for the amateur nature lover (a remark I've made previously and heard reiterated on a radio documentary I enjoyed listening to recently via the BBC website). My blog has been my introduction to the mosses and I've thoroughly enjoyed discovering that life forms I'd previously regarded as 'undifferentiated lumps of green stuff' possess, in fact, a minute individuality and beauty all of their own. This is my second Tortula moss but once you've accustomed yourself to notice the difference there's no mistaking the green rosettes of our moss above from the the frosty-white pincushions of Tortula muralis I photographed a year ago. Hooray for the beautiful bryophytes!

Two fungi on apples - Venturia inaequalis and a Mucoraceae species.

I am an amateur naturalist trying to discover everything living in my garden.

I have a cooking-apple tree growing in my garden (more on which in a future posting). It produces far more apples than I can cook and winter finds my lawn carpeted with a layer of rotting windfalls. At the time of writing, a flock of songbirds (blackbirds, thrushes, redwings, starlings, fieldfares and others) are visiting my garden daily to eat their fill. Birds are not the only things devouring my apples however...

Photo 1 (click to enlarge) shows an apple clearly afflicted with an outbreak of brown scabs. Recently I acquired a second hand copy of Garden Pests and Diseases (Brooks and Halstead, publ. Simon and Schuster) and from this, and some follow-up searches on the internet, I understand the cause to be a fungus called Venturia inaequalis.

V.inaequalis infects both the leaves and fruit of apple trees and is a member of the enormously numerous division of fungi, the ascomycota = those fungi that "ripen" their spores inside tiny, sausage-shaped tubes called asci (see here for my photo of some asci and here for some more description from me).

In the case of V. inaequalis the spore-containing acsi are, in-turn, packed inside a body known as a psuedoperithecium (a "spore salt-shaker"). I made a little effort myself to try to obtain a microscope photo of one of these, but the strength of my resolve was weakened when I found the matchless images on Tom Volk's website (in any case, I believe I'm unlikely to find a 'fruiting' scab as I've read the pseudoperithecia tend to occur in Spring and are more common on the leaves).

In terms of edibility, brown scabs on apples are entirely harmless (no doubt the same can't be said of the fungicides commerical growers spray on apples to prevent scabs appearing!). Indeed, I've even heard it suggested that amongst the reasons for an increased incidence of cancers in the Western population is our unwillingness to imbibe a healthy population of micro-fungi on our vegetables. I can't vouch for the scientific validity of this theory. I do know you'd need to be very hungry to eat the apple in photo 2!

Looking closely at photo 2 you might notice the small white patches of mould upper left and centre. Viewed under the microscope (approx 40x magnification) a strange and delicately beautiful structure is revealed (photo 3).
On the basis of looks alone (always dangerous when dealing with fungi) and the excellent photo's on this site, I'm identifying this as a member of order the mucoraceae, the 'pin-head' moulds. The 'pin-heads' are technically known as sporangia and are filled with spores. They turn black as the spores mature (as some have in the photo).

To attempt to pin down my mould to one of the three-hundred-or-so mucoraceae species is really the domain of experts. Increasingly DNA analysis is emerging as the only sure-fire method for the identification for micro- (and indeed some macro-) fungi. Taking a shot-in-the-dark however I'll go with Rhizopus stolonifer and invite the experts out there to correct me.

V.ineaqualis and and R.stolonifer are far from the only fungi to attack apples (see here), I'm quite sure more searching would turn up more (a project for a future posting perhaps). For now I'm happy to chalk-up two more species on my garden checklist.

Finally, I mentioned the birds above feeding on the apples on my lawn. Watching them it seems they actively seek out the more rotten apples. I wonder whether they get some health benefit from this (the consumption of pencillin moulds perhaps?), or is it simply that the mouldy ones are the softest and best-tasting. A case of Stilton cheese at Christmas!