Saturday, January 27, 2007

Wall Screw Moss and Grimmia pulvinata

I am attempting to identify all the life in my garden. In recent postings I have investigated a few of my garden's common birds and a common weed. It is time to take on a more ambitious identification challenge: moss.

I have not hitherto taken much notice of moss! I have to say however, that having begun to look for it, it does have a certain appeal for the amateur naturalist. Firstly, a lot of it is really rather beautiful once you begin to examine it closely, and secondly you can be pretty much guaranteed to find some to study any time you go outdoors at any time of year (c.f. say, wildflowers, butterflies etc.).

Common on my garden wall (around (1.8,1.0 see The Lie of the Land) see are the small moss 'cushions' seen in the photo 1. Following some head scratching (see below) I think I'm confident in stating that there are two distinct species of moss at work here.

Photo 2 shows things more clearly. The left hand moss clearly has elongated thin spore capsules on upright stalks ('setae'). Clicking on photo 2 to enlarge it and looking carefully you'll see the right hand moss is also 'fruiting', but its setae curl back on themselves to 'bury' the spore capsules amongst the leaves. After many hours work I'm reasonably confident in identifying the left as Wall Screw Moss (Tortula muralis) and the right as Grimmia pulvinata (for which I can't find a common name - comments anyone?).

The obvious challenge in identifying a moss is the small size of any distinguishing features. Recently however I purchased a 'Westbury SP30' student microscope from Brunel Microscopes (for anyone looking to do similar, I'd recommend the company - extremely helpful on the phone and they delivered the 'scope in 48hrs).

It turns out that moss leaves make inherently 'good viewing' under the microscope since in most cases the leaf consists of simply a monolayer of cells. Putting a moss leaf under the microscope, you immediately get a view of living cells without any of the 'messing about' with microtomes and stains I believe is often required with other 'higher' plants. Photo 3 shows the fairly regular cells of G. pulvinata (100x; 1 small graticule division = 10um) and photo 4 of T. muralis (450x; 1 small div. =2.5microns) - which remind me of miniature four leaf clovers.

The most striking thing about both the leaves of G. pulvinata (photo 5) and T. muralis (photo 6) under low magnification (100x, 1small div.=10um) are the inordinately long white hairs at the end of the leaf. These hairs give the 'cushions' their silvery look in photo 1 above. With regard to telling the leaves apart, photo 6 shows that the more rounded ('ovate') leaf ending of T. muralis. A second differentiating feature of G. pulvinata are the tiny spines protruding from the leaf hairs (photo 7, 400x) (the leaf hairs of T. muralis are smooth).

To identify my mosses I used the key in British Mosses and Liverworts, E.V. Watson (Cambridge Univ. Press). Helpfully, Andrew Spink has reproduced this key on his website. The images of T. muralis in the British Bryological Society Field Guide were also useful. (I couldn't find G. pulvinata there - does it have another name?). I took the microscopic photos by simply holding the lens of my camera up to the eye piece of my microscope (hence the reason they're not very good!).

Finally - as an illustration of how small the world is (or how big the internet depending on your point of view) - I discovered in the course of my searching that Patrick Roper has also been busy this month blogging about T. muralis. Great minds think alike..?

Sunday, January 21, 2007

Shepherd's Purse

I have set myself the challenge of trying to catalogue all the life in my garden (see Rules of Engagement posting). I've made a start in my two previous postings by describing two common bird vistors to my garden.

This posting marks my first foray into botany. This is a challenge. I know a little about Britain's birds and the larger fungi. My knowledge of wild flowers is very scant however. In light of this, I decided I might be best to start by finding a plant in my garden that was in flower, so as to maximise the chance of me correctly identifying it in my copy of The Wild Flower Key, Francis Rose (pub. Warne 1981). This being the middle of the British winter however (albeit an exceptionally mild one) I wasn't certain I would find one. On one edge (at 1.2, 0.8 - see Bird's Eye View ) of my lawn however I found this :

After some work I'm confident that there is Shepherd's Purse (Capsella bursa-pastoris) in my garden. The above book describes the arrangement of its tiny (~2mm) white flowers as comprising an 'erect raceme'.

A search of the internet informs me that Shepherd's Purse is an edible annual or biannual herb, with a taste reminiscent of mustard (I haven't tried it myself so can't confirm or deny this) and apparently a delicacy in parts of China.

In the course of my searching I came across the wonderful Harvard University Arnold Arboretum website, a search of which turned up an article by one Helen Roca-Garcia on the history of my humble weed. From this I learn that Shepherd's Purse was described by William Coles in 1657 in his book Adam in Eden as

'...Shepherd's Purse or Scrip after the likeness the Seed hath with that kind of letherene bag, wherein Shepherds carry ther Victuals into the field'.

The article also quotes the 16th century physician Dodoneous

"Sheepeherds Pouche groweth in rough, stonie, and untilled places"

He was obviously familiar with my lawn!

Perhaps the most remarkable comment I came across was that contained in Wikipedia's article, namely that the seeds of Shepherd's Purse when moistened become viscous and can trap insects (including mosquitos) rendering it a "bordeline carniverous plant".

Can anyone comment on this? Is it true I have a carniverous plant on my lawn ? (I would love to see a photo of it trapping insects). And what does 'borderline' mean in this context?

Saturday, January 20, 2007


I have been reading 'The Life of the Robin' (4th edition) by David Lack (publ. Fontana New Naturalist) in an attempt to learn something about the robins (Erithacus rubecula) that live in my garden.

I see robins in my garden all year round and had always assumed they don't migrate. From reading Mr Lack's book however, I've discovered that although male (cock) robins very rarely migrate, remaining permanently with their terroitories, about three quarters of hen robins do. The book gives records of robins having travelled from southern Spain to northern Germany and, closer to home for me, a robin ringed in Berkshire (UK) being later recovered in Voorn, Holland.

One thing it surprised me to learn is that robin song is apparantly learnt and not instinctive; A robin chick raised by a nightingale will sing like a nightingale. Knowing this, I find it surprising that robins as a whole share a common song. Having every robin only learn its song from two others (its parents) would seem to me a guaranteed recipe for 'chinese whispers' i.e. for robin song to break-up into numerous very different local dialects. Or maybe it has? Can anyone comment on this?

I wrote here that life as a blackbird seemed pretty tough. I've discovered it is luxury compared to life as a robin! The annual mortality rate for robins is a massive 62% for adults and 72% for juveniles. The book lists causes of death including death by cats, drowning, starvation, hitting telegraph wires, other robins, stoats, weasels, rats, dogs, sparrowhawks, little owls, great grey shrikes and "hitting netting in fog". Remind me not to come back as a robin!

The famous feature of British robins is their relative tameness and status as 'the gardener's friend'. Certainly whenever I dig my garden I can be fairly guaranteed to have one accompany me, darting in to grab insects as I'm turning over the soil. I've heard the suggestion that this behaviour might have evolved through robins associating with wild boars as they rooted through leaf-litter in ancient forests. Apparantly however, robins on the European mainland do not share this characteristic, and instead are shy birds which avoid people. Why are things different here?

Other things I discovered from reading the book include:

That none other that Charles Darwin studied and wrote about robin song in his book The Descent of Man and Selection in relation to Sex (1871)

That there is a record of a robin making its nest on a wagon which later needed to be moved from Walton Heath to Worthing with the young still in it. The parent robin travelled with the nest for about a hunded miles each way, feeding the young en route.

I was particularly amused by the comment in the book :

"The robin uses his [life] for singing and fighting. The great crested grebe, on the other hand, was found by Julian Huxley to spend much of summer in courtship, and the cirl bunting, watched by L.S.V.Venables, seems to spend most of its spare time doing nothing in particular, a dull bird to watch"

Hooray for robins, boo for buntings!

Wednesday, January 17, 2007


It is time to make a real start on the task of cataloguing the things living in my garden. Here goes:

There are Blackbirds (Turdus merula) in my garden.

Perhaps not a fact likely to make my garden a place of pilgimage for the world’s birdwatchers! I have deliberately chosen to start with with this down-to-earth example however since:

a) I’m fairly confident I know enough to have not made a mistake in my identification (something that’s likely to become much more of a problem when I get on to cataloguing e.g. my garden’s lichens - a subject about which I know absolutely nothing as yet!)
b) I don't expect my claim to have seen blackbirds will evoke very great scepticism. Readers may forgive me for not including photographic evidence in this posting therefore. I’m not averse to the idea of including occasional photographs in postings. There are a great number of truly excellent bird and wildlife photographers and bloggers out there however. I’m not one of them! I don’t see there’s much merit in me cluttering up these pages with large number of (woefully amateurish) ‘snaps’.

In an attempt to learn something more about blackbirds I have been reading The Blackbird by David W. Snow (pub. Shire Natural History, 1987) – a scholarly but very readable account of their habits (for a review and photo of which see here). By interesting coincidence, the book’s cover notes tell me that Dr. Snow began his career as a field ornithologist in Oxford (in the 1950’s). In his booklet he makes a number of references to studies undertaken in ‘Oxford gardens’. I just wonder whether he ever looked at mine?

Two elements of the book particularly stood out for me:

Firstly, although a proportion of Britain’s blackbird population are migratory (migrating to Ireland and the European mainland apparently), despite this

“from an intensive 4 year study of an Oxford garden…[of]…some five hundred birds… there was no evidence any bird moved more than 2 miles from where it was ringed.”

Unless Blackbird have markedly changed their habits since the 1950’s therefore (can anyone comment on this?) it would seem very probable that the blackbirds I see in my garden stay with me all year round. I find this thought curiously comforting.

A second thing that stands out are the statistics on blackbird life expectancy: annual mortality rates are a whopping 33%; only 50% of garden nests are successful; and of nests that are successful, although an average of 4.1 young birds fledge, only on average 1.7 survive into the next breeding season.

Life as a garden blackbird is pretty tough is seems!

Monday, January 15, 2007

The Ones That Got Away

I want to record all the (tolerably sized - see Rules of Engagement posting 13th Jan 07) lifeforms in my garden.

I need to make a start.

I want to start off in an unorthodox fashion however, listing a species that doesn't visit my garden: I have a very passing knowledge of birds. I do know enough to identify a Lapwing, Vanellus vanellus (as part of my self-imposed project I am making an effort to 'Google' the Latin names of every species that comes along!).

My query is as follows:
I live in a county (Oxfordshire) where Lapwings are abundant: Having visited the RSPB bird reserve of Otmoor I know it harbours Lapwing "colonies" (does anyone out there know the collective-noun for Lapwings?) of several thousand. Despite this, I have never seen a Lapwing in my garden.

Why is this? Do Lapwings only land in large open fields, and never visit residential gardens? Or is it that my garden simply doesn't have the correct 'features' (for a list of which see The Lie of the Land posting 14th Jan 07) ?

Sunday, January 14, 2007

The Lie Of The Land

For those of you reading this blog for the first time, this posting is going to seem more than a trifle dull. Why should anyone wish to bore his legions of readers (hem,hem) with a list of the main geographic features of his garden? For an explanation (of sorts!) I can only refer you to prior postings ('The Rules of Engagement' and 'Birds Eye View' - posted 13,14th Jan 06 respectively).

O.k. - down to business:

In the main aeriel photo ('Where It All Lives' - right) the garden appears essentially as an equilateral the triangle with apexes located at coordinates (1,0), (0,2), (2,2).

One side of the garden - the side running from (1,0) to (2,2) - comprises an old natural-stone-and-morter wall, hidden at one end in the photo by trees and at the other by shadow. I've casually observed assorted mosses, weeds, snails, insects etc. making a home of this wall, but putting names to said organisms is a challenge that awaits me.

The green/grey line running from (1,0) to (0.5,0.8) is a concrete path edged by a low ~1m-high hedge (which I believe, but again have yet to confirm, is Box, Buxus sempervirens).

The region behind the house in the vicinity of (0,2) is a vegetable patch.

Running along the lower side of the garden from (0,2) to (1,2) is a larger ~2.5m-high hedge (which I again think may be Box). The hedge ends where it meets (at (1,2)) a line of various trees which continue along to the corner of the garden (2,2). I don't yet know the species of the large tree seen growing at (2,2).

The lawn (fairly clear in the photo I think) is 'tolerable' - by which I mean, that whilst it serves the primary function of a lawn of being green and (fairly!) kempt, it is no bowling green! I do not apply fertilizers, moss killers etc. As a consequence, along with the grass grows a quantity of moss, clover, dandelions and daisies. I am going to take a wild guess that, insects included, I will find myself having to identify somewhere between ten and twenty organisms from the lawn alone.

I have a some way to go before all my garden life is accurately catalogued!

Birds Eye View

After some small effort I have managed to acquire an aerial-photo ('Where It All Lives' - right) of the Walloon Estate from Google Earth and overlay it with a 2x2 grid that I hope will ease the task of describing where things are as I find them.

(I read on Google Earth's website that:

"You can personally use an image from the application (for example on your website, on a blog or in a word document) as long as you preserve the copyrights and attributions including the Google logo attribution. "

- so there seems no issue with me doing this.)

Henceforth, when describing where things are, I'll quote a grid-reference, quoting a horizontal coordinate, followed by vertical coordinate. So for example, at grid reference (1.1,1.5) you're looking straight down onto the Bramley Apple tree that sits in the middle of my lawn.

Saturday, January 13, 2007

The Rules of Engagement

Ideally I would like to discover the identity of all the organisms living in my garden. Since I read here however that "There are more organisms in one gram of soil than there are human beings on this Earth!" (does anyone out there have a comment on whether this is fact, speculation or exaggeration?) I guess I am going to have to set some constraints on my search:

I'm going to start with (a somewhat arbitary) Rule 1 therefore: I'll record any organism with a bodily dimension of more than 5mm.

Rule 2 is simpler: if it's alive in my garden I want to know about it. Birds, flowers, mosses, insects, lichens, spiders, trees, mushrooms....they're all 'fair game'

This immediately leads me to speculate over how many organisms I'm eventually going to find.

At this stage I really have no idea!

I am going to take a wild guess and say 250.

I'd be interested to invite comment on this number from readers of this blog. I'll describe some salient features of my garden in the next posting.

Where It All Starts

I read that the UK has some 270,000 hectares (27,000,000 square metres) of private residential garden. I want to know what's living in mine (seen in the photo, right).

As I imagine is the case for many people, I'm concerned by the wearying litany of gloomy ecological statistics I read in the press. This being a blog however, it's perhaps worth clarifying at the outset that I'm not setting out with any particular 'eco-manifesto'. My motivation here is simply one of good old-fashioned scientific curiosity: I want know what's living in my garden, because I want to know!

A second point to mention is that I have no training or professional connection with natural history (botany, biology, geology etc.). I suspect this is going to cause me problems. Oh well, here goes...