Trochila ilicicola A fungus on holly leaves

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

For those of an inquisitive disposition, one of the wonderful things about natural history is its ability to generate an inexhaustible supply of questions one doesn't need to be a professional to either ask or investigate: Noticed something alive!? O.k., so what is it?...and what does it eat?... what eats it?...when does it mates, how does it mates?...You get the idea.

To supply a germane example: In a previous posting on my garden's holly tree, I reported being struck by the small number of creatures reported to derive nourishment from holly's tough and spiny leaves. This started me wondering about what creature might surmount the seemingly even tougher problem of eating dead holly leaves...

...photo 1 (click on photos to enlarge) shows a holly leaf I found in the leaf litter beneath my tree. Photo 2 shows a 100x magnified version of some of the small black dots decorating the surface upper-centre, and photo 3 some of the larger ones covering the remainder of the leaf.

It's perhaps no surprise to learn that the agent of decay of dead holly leaves is a fungus. Fungi are separated into two great divisions ('phyla'), the basidiomycota (=most of the familiar 'mushrooms') and the ascomycota which are typically small, cup shaped fungi (see a previous posting for more details). Clearly photo 2 shows my fungus to be one of the latter. The cup's inner surface (hymenium) is the site of spore production.

In the case of my holly-leaf, a little web searching (specifically of the encyclopaedic bioimages site) suggests the species of fungus at work is Trochila ilicicola. (A smaller question I do have however, is whether the two types of black spots - the smaller dimples of photo 2 , and larger pustules of photo 3 - might conceivably be two different species. Can anyone comment?)

I'm led to understand my cup fungus has a rather neat trick up it's sleeve, namely a hinged lid which it can open when conditions are damp (and hence good for liberating spores), and close when conditions are dry. I didn't get the opportunity to try observing this under the microscope, but you can find some photos on the fine mycolog site.

So there you have it. The next time you take a walk on an late autumn day when interesting natural history might seem in short supply, try picking up a dead leaf!

Indian peacock and peahen Pavo cristatus

I am an amateur naturalist trying to discover something about all the lifeforms in my garden.

No, despite appearances to the contrary I have not abandoned my blog. I hope one or two of you may still be visiting.

Some time ago you'll recall I was pleased and surprised to be visited by a white budgerigar. It seems that the larger exotic birds are not to be outdone however, as around six-thirty one morning in recent July, I was delighted to encounter a couple of Peafowl pecking around on my lawn. I hastily grabbed my camera and achieved the not-very-good photo (left) before they fled over the wall. I assume my birds came from a local farm or some country estate, but I do not know from which.

A few minutes internet searching informed me that my birds are Indian Peafowl (Pavo cristatus), as opposed to the endangered Green Peafowl (Pavo muticas) from Java and Burma. Males of the latter species can be identified by a tall, spiky crest on their heads.

Much the most famous feature of peafowl is of course the peacock's fantastic fan tail (sadly mine didn't display). Ever since Darwin, naturalists have been fascinated to understand what possible evolutionary purpose it can serve to sport such an unwieldy appendage; The benefit of carrying around a large iridesceant sign, seemingly pefect for announcing to predators "Here I am! Eat me!", isn't obvious!

My quest to understand a little more led me to an excellent review paper by one R. Gadakar (here). In brief, my understanding is as follows: As a Peahen, one approach to selecting a mate is to choose those males who most strongly advertise their health and vitality with a large fan. So far so good, but the question this poses is whether the extravagant fan we see today has arisen because at some point in history females selected to breed with males with a slightly longer tail, which led to male-offspring with slightly longer tails, from which later females again selected the longest...i.e. whether today's fan is a result of 'run-away selection' (in which case the fan is beautiful but it is not, per se, an honest indicator of the male's health). Or whether an alternative hypothesis holds i.e. the so-called Zahavi's handicap idea, which states that any male able to carry around such a huge encumbrance and yet still survive (evade predators etc.) must somehow be truly fit and strong i.e. the tail is not only beautiful but also honest indicator of the fitness of the male.

I have failed to think up a simple way to restate this (indeed, as the paper above says, the trend in biology these days is to get away from the vagary of mere words and express things in terms of mathematical models where possible), but a (very incomplete) analogy might be following: some female humans prefer their men well muscled, as a sign of their vitality. For the humble male there are then two routes to getting-the-girl: One, a regime of healthy food and physical exercise. Two, steroids and plastic surgery! The latter may achieve the visible appearance of the 'body beautiful', but it could hardly be called an honest statement of the chap's health and fitness. By contrast, in seeking to achieve the rippling musculature beloved of the ladies, the former approach requires males to accept the 'handicap' of limited diet and punishing gym sessions, but in the long run this 'handcap' is actually likely to positively benefit both their own and their offspring's health.

The existence of this, the (Zahavi's) handicap hypothesis out there in nature however was controversial amongst evolutionary biologists when it was first suggested, and therefore it has been important to find ways to test it. Which brings us back to peacocks: Glass-jawed weaklings beneath steroid-inflated shells, or supermen in both looks and deeds?

Some of the definitive studies of peafowl have been performed on a feral population at Whipsnade Zoo here in the UK Firstly it is known that peahens select those peacocks with the most symmetric tail fans. High symmetry is strongly correlated with a large number of eye spots. And what have the studies at Whipsnade concluded about those males with the highest eye spot count? That they i) have better reserves of body fat ii) have higher survival rates (against loss to foxes etc.) and iii) father healthier, fatter chicks.

In short, no preening primadonna he, the male peacock really is both both beautiful and honest!

A Flesh-Fly, family Sarcophidae

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

Photo 1 shows a fly I found sunning itself on my bird-table late last summer.

I have no expertise when it come to fly-identification. With the help of the very nice colour plates in my copy of Insects (Michael Chinnery, Collins) however, I'm fairly certain my fly is a member of the Sarcophidae family of so-called Flesh-flies.

In general, identifying flies down to species level is a job for the experts. Page 27 of this book (The Sarcophagidae of Fennoscandia and Denmark, Thomas Pape), partly available online, gives you a flavour of what's involved. Dipterists spend a lot of their time looking at genitalia (!) -that of flies being an important aid to species recognition. I didn't subject my fly to the indignity of this, so can't be confident about its species, though from the book above a guess might be Sarcophaga carnaria (can anyone confirm or correct this?)

There are some 120,000 species of fly (Diptera), with 15,000 occurring in Europe. Chris Thompson's Diptera site contains a wealth of information, including specifics on the Sarcophagidae.Flies are distinguished from other insects in part by having only two wings, their hind pair having shrunk down to vestigial 'stumps' called halters.

There are some 2600 Sarcophagidae flies, about 300 occurring in Europe (this site lists them) and about 60 in Britain. As the name Flesh-fly implies both adults and larvae (maggots) are often associated with carrion, though in fact there is considerable variation in feeding habits across species: some concentrate on small corpses (this site has some closeups of an adult feasting on a dead caterpillar); some larvae are parasites of other insects; some predate snails, others earthworms; some species are able to live on a purely vegetarian diet. Sometimes of course, Flesh-flies become associated with human corpses. As a consequence the Sarcophagidae have been well studied by the science of forensic entomology which aims to get information about the time of a person's death by the rather grisly process of analysing any insects infesting the corpse.

The Sarcophagidae are viviparous (=females give birth to live young, the larvae). This book (Natural Enemies of Terrestrial Molluscs, G.M. Barker) explains this as an adaption to give the flies a speed advantage when it comes to getting their their young established on an ephemeral food item such as a corpse as rapidly as possible.

A final question I am left with is what purpose it serves my fly to sport the "zebra-like" black and white stripes on its back. Can anyone enlighten me?

Glistening Inkcap Mushroom Coprinellus micaceus

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

After a goodly absence (apologies dear readers) it's time to return to the task of cataloguing my garden's life.

The first piece of news is that sadly I've had to remove (to my compost bin) a good proportion of the ivy I blogged here. This proved necessary as the sheer weight of ivy caused the collapse of my garden fence! A sad aspect to this is that, as I commented previously, my ivy has proved a popular nesting site with my garden birds (in clearing the foliage this time I uncovered a bird box I had previously stuffed into the ivy, containing an old robin's nest). The good news is firstly that ivy grows so aggressively in my garden that it's certain to recolonise swiftly as soon as I re-erect my fence, and secondly that in clearing it away I came across the subject-matter for today's posting, growing on some old logs: the mushrooms seen in photo 1 (click to enlarge).

I have a little knowledge of British fungi, so I was quickly able to identify my fungus as a Coprinus mushroom. The little "mica-like" flecks on the young caps helped me to identify my mushroom as Coprinus micaceus.

As the great majority of mushroom guides will tell you, there are more than a dozen British Coprinus species, all readily recognised by the characteristic that the whole cap of mature mushrooms "autodigests" and turns into a thick, black, inky, spore-laden liquid, as opposed to the more typical mushroom habit of liberating spores as "dry, airborne powder". You can see "ink" starting to ooze from the mushroom in the centre of photo 1 (the one with its stipe ("stem") touching the coin)...

...Except it turns out the books are wrong! More specifically, although it is true that several hundred mushroom species world-wide share this 'inky' habit, the approach that mycologists have traditionally taken of classifying them all as members of the genus Coprinus seems to be wrong: following DNA sequencing, Hopple and Vilgalys published a scientific paper in 1999, showing that many of the traditional "Coprinus" mushrooms are in fact unrelated to each other (at genus level at least). Worse still, the Coprinus "type species" (i.e. the species most neatly embodying the features of the Coprinus mushrooms = Coprinus comatus) turned out to be genetically rather atypical!

All of this means that mycologists are having to do some serious thinking about how to re-write the textbooks. The current approach is to divide the previous Coprinus genus, into four genera: a small collection of true Coprinus mushrooms and additionally the Coprinopsis, Coprinellus and the Parasola mushrooms. There's a very readable account of all this at Tom Volk's site.

I've known amateur naturalists who get rather heated about splitting and re-naming species, genera etc. on the basis of genetic analyses. 'Species', they say, 'should be defined according to what things look like in the field!'. I don't personally agree with this. To replace one genus with four, superfically identical genera may be inconvenient for the amateur, but at the end of the day if that's the scientific truth of things, I say 'so be it'. Mother Nature isn't obliged to set things up in a way that's convenient for the amatuer and the fact that she sometimes doesn't surely increases the fascination of the studying things?

One final thing that intrigues me is the phrase "mica-like flecks" that all the books seem to use when describing my mushroom, and lends itself to the species name "micaceous". Had I been the first to discover and name my mushroom, I imagine I might come up with "cottony" or "bobbley" to describe the young caps. I doubt the mineral mica, would have entered my head! Just about the one thing I know about mica comes from school physics lessons: namely that that it exhibits a curious optical phenomena known as double refraction (birefringence). You can see a nice photo here. I regret I didn't get a chance to experiment with my mushrooms to find out, but I just wonder whether the flecks on the caps perform any similar "optical magic". Does anyone know?

White tipped bristle moss Orthotrichum diaphanum

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

Photo 1 shows another of my garden-wall-top's community of mosses. For this photo I was fortunate to be able to borrow a fancy digital camera. I'm most impressed with the close-up ability, as compared with the results from my own humble little 'point and click' camera, normally responsible for the snaps on this site. The Walloon bank balance may need to take a hit at some point!

Photo 2 (click to enlarge) shows a 40x magnified view of a single leaf. Distinguishing features are the circular leaf cells, the central vein that fades out just before the end of the leaf and the 'recurving' (folding over) of the leaf edge. Another obvious feature is the long, white 'hyaline' (=clear) hair at the end of the leaf. Quite a number of mosses sport such hairs (see my previous postings on S.intermedia, G.pulvinata and T.muralis for example). A pure guess on my part is that these hairs act as condensation sites for droplets of dew, thereby helping the moss to collect water. I've no evidence for this however. Can anyone comment? Anyway, regardless of their purpose, these features taken all together identify my moss as Orthotrichum diaphanum in my trusty copy of British Mosses and Liverworts (Watson, Cambridge).

For those of you unfamiliar with the art of moss identification (which included me when I began this blog a year ago ) clicking on 'moss' under the 'labels' menu on the left this screen and scrolling down, you'll easily be able to compare the leaf shapes of the different species I've blogged so far. You'll see that far from being all the same, different species of moss really do have their own individual and characteristic leaf features (some short and fat; others long and thin; some with hairs; some without etc.) - a strong aid to their identification.

O. diaphanum is a fairly common moss. According to my copy of The Moss Flora of Britain and Ireland (Smith, Cambridge) "[it] has been found on such unlikely materials as old linoleum, corrugated iron and tarmac". It is most common on trees and wooden fences.

Another feature obvious in photo 1 are my moss's brown setea (fruit stalks and capsules). The site of the Bryophytes and Buildings project - cataloging mosses in Edinburgh, Scotland - has some superb closeup photo's of the capsules and the 'peristome teeth' that are revealed when a capsule loses its lid. Experts use the shape and number of peristome teeth as another aid to species identification. I've read (though I can't remember where) that a moss's peristome teeth act as little mechanical devices, bending and flexing in response to passing air currents and changes in humidity and actually 'reaching inside' the capsule, 'scooping up' the spores therein, and flicking them out, away from the moss. Another of nature's tiny miracles!

Myrobalan Plum, Prunus cerassifera nigra

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

In my previous posting I talked about the appearance of daffodils here in Oxford heralding the arrival of Spring (though I might add that when I wrote the posting, the weather was warm and sunny, whilst today we're experiencing strong Arctic winds and snow - there is nothing so changeable as the British weather!).

Another pretty indication of Spring's arrival is the masses of blossom breaking out on the trees and hedgerows. One common example, found everywhere in parks and gardens here in the UK, is the blossoming of ornamental 'Myrobalan' Cherry-plum trees. I have one in my garden (at (0,1.1) - see here) - photo 1 (click on photo's to enlarge)

The botanical name for my tree is Prunus cerasifera, and on the basis that the blossom is pink (photo 2) and the leaves purple-red (see photo 3 taken late last summer), it is an example of the subspecies P. cerasifera nigra. (Were the blossom to be white, it would more likely be an example of the second common cultivar: P. cerasifera Pissardii).

Together with showing the toothed leaf margin (another feature aiding identification) photo 4 shows a closeup of one of my tree's 'fruits' (or, to give them their correct botanical name, drupes - see my previous explanation here). I've no idea what, if any, culinary use it's possible to make of these. Can anyone comment?

Though I intend to make an effort to observe more carefully this year, I also don't know what animals, if any, like to eat the drupes. I guess blackbirds, squirrels and pigeons, at least, might give them a try.

For completeness, photo to 5 shows a closeup my tree's bark, and photo 6 a view of the buds in late January, a few weeks before they blossomed.
And that would appear to be that! Those who follow my postings will know that I normally make some effort to link to websites providing interesting snippets of information on the 'lifeform' under discussion. When it comes to Myrobalan cherry-plums however I've drawn something of a blank! There is a fair amount of scientific literature out there devoted to trying to sort out the genetic relationships between all the various plums, cherries, peaches, apricots and almonds that constitute the Prunus genus. Specifically on the Myrobalan's however, I've found next to nothing of say which the amateur naturalist like myself might find interesting (any suggestions anyone?)

I'll therefore end with my own observation: returning to the closeup of the blossom in photo 2 it's apparent the flowers have 5 petals (5 fold symmetry). Recently I watched a streaming lecture on the physics of crystals on the superb M.I.T., open course-ware, website (as you do!). The lecturer, one Prof. Wuensch, explained that star-fish have evolved five legs since objects with a 5-fold symmetry lack an 'easy' or 'weak' direction along which to tear or rip them (if startfish had, say, 4 legs they'd present a weak axis along which a fish could easily tear them into two, symmetric, 2 legged sections). I will end my posting therefore with The Walloon Myrobalan Blossom Conjecture:

Fruit-tree blossom commonly has 5-petals to make it more difficult for birds (such as Bullfinches) to dismember it.

discuss!

daffodil narcissus

I am an amateur naturalist trying to learn something about everything living in my garden.
Spring has sprung here in Oxford in the U.K. One of the cheeriest signs of its arrival is surely the great profusion (I'll spare you references to "hosts of golden-" etc.!) daffodils that pop up in our gardens, woodlands and on roadside verges. Photo 1 shows some of those appearing anually in my garden.

In fact, a number of different types of daffodil appear at this time of year in my garden. That I should find more than one is perhaps no surprise since, as I learn from the Warwick Daffodil Genetic Resource webpage, breeders have developed a staggering 25,000 daffodil cultivars! The Royal Horticultural Society site hosts a searchable database. The same site also gives details of the horticultural code system used by daffodil aficionados (narcissists?!) to label varieties. In brief, it works like this:

Firstly, decide which of the 13 divisions of daffodil yours belongs to. In the case of the daff in photo 2, though not obvious from the photo, I measured the central 'trumpet' (corona') as longer than the outer petals ('perianth segments'). This puts it in Divison 1. By contrast, the corona of the daffodil in photo 3 is more than 1/3, but less than the full length of the petals, putting it in Divison 2.

Next, write down a letter for the colour - White, Green, Yellow, Pink, Red or Orange - of the perianth segments. So, photo 2 becomes 1Y, and photo 3 2W. (There are rules on the RHS page above for what to do if your daffodils petals are multicoloured)

Finally, repeat for the corona (adding a hyphen '-'). So finally photo 2 = 1Y-Y and photo 3=2W-Y.

Simple! (Or at least that's my understanding - as always, my amateur identifications come with a health warning - I'm always happy to be corrected. )

Of course it's also possible to be more 'botanical' about things - working through phrases like 'dentate coronal rim'. The ultimate goal must surely be to pin down one's daff's to one of the >25000 listed varities. Breeders have come up with some great names - "Her Majesty Queen Alexandera"; "This Little Piggy" and "Singing Pub" being three that caught my eye. I'd be delighted if any expert out there can tell me the name of the daffodil's in Photos 2 and 3 .

For those interested in doing more than simply naming their daff., the definitive textbook would appear to be "Narcissus and Daffodil, The Genus Narcissus" (Edited by Gordon R. Hanks, publ. CRC Press). I don't own a copy, but rather helpfully, the publishers have put a substantial chunk of the book online. From this I learn that there are about 80 species (as opposed to sub-species cultivars) of Narcissus, forming part of the Amarillidacyeae family of plants that also includes the snowdrops and lillies. Something I'd not really considered was how bulbs grow and expand. The book gives a rather detailed account of this and explains that each year new flesh appears in the centre of the bulb, with progressively older flesh being found further out from the centre. The very oldest flesh ends up as the papery, thin skin one often finds on the outer surface of bulbs. Finally, it seems that daffodil bulbs contain some rather nasty, toxic, alkaloid compounds. This no doubt explains why, although bulbs in my garden commonly get dug up and eaten (by, I assume, squirrels or badgers), this never seems to happen to my daffodils. Britain's wild daffodil is Narcissus pseudonarcissus.

The 1st March is St. David's Day - the patron saint of Wales - and it's common for people to wear a daffodil buttonhole.

I'll leave two last words to William Shakespeare:

When daffodils begin to peer,
with heigh' the doxy, over the dale,
why, then comes in the sweet o' the year.
The Winter's Tale (Act 4, Scene 3)

and from the same play

Daffodils
That come before the swallow dares,
and take The winds of March with beauty
The Winter's Tale (Act 4, Scene 4)