Return of the goldilocks buttercup

 

Goldilocks buttercup (Ranunculus auricomus) used to be common in our High Weald woodlands when I was a boy, but it seems to have become scarcer and scarcer over the years.

There used to be a small colony in the wood at the top of our lane but I thought this had gone.  Today though I was very pleased to find about half a dozen plants in full bloom beside the path.  Although the abundant celandines (Ranunculus ficaria) with their rather similar yellow flowers can make the goldilocks buttercup easy to walk past, it has an attractive, airy quality with delicate stems with their narrow upper leaves holding up the shining yellow flowers.

Many of the flowers do not have full compliment of petals, or have one or two normal petals plus a few abortive ones and I wonder if this is related to their asexual reproduction

Goldilocks buttercup can reproduce asexually and several hundred microspecies (also called 'agamospecies') have been described from mainland Europe.  Apparently there may be a similar number of these microspecies yet to be described in Britain.

If the plants can reproduce without pollination there would seem to be no need to attract insects making petals redundant.  However, asexual reproduction implies little or no variation so, presumably, the number and type of petals would remain the same down the generations and not 'evolve' into plants with petal-free flowers.

Variegated honesty returns

One of my favourite garden plants is the variegated form of honesty, Lunaria annua, an introduced species whose origin is unknown, though the perennial subspecies is found in Italy and the Balkans.  It has been grown in Britain since at least 1570.

The plain green form is attractive, but this version with cream edging to the leaves is quite spectacular as it rises into flower in spring.  There is also a white flowered variegated form.

Despite its scientific name, this plant is a biennial here: seed sown later this year will flower next year.  The seedlings are markedly variegated when they appear but quickly turn wholly green.  The variegation reappears as the plant develops towards flowering at the end of winter.  Then, of course, there is the later benefit of the silvery, penny sized seed pods.  The fact that these seeds can be seen through the thin walls of the pods is the reason for the name 'honesty'.

The leaves and roots are said to be edible and the ground seeds have been used as an alternative to mustard.  The scented flowers are attractive to insects and orange-tip butterflies will sometimes lay their eggs on the plant and, so far as I know, the caterpillars flourish on it just as much as on cuckooflower, Cardamine pratensis, their usual pabulum.

We used to have quite a number of self-sown plants in the garden every year and I thought I had lost them way back in the last century, so I was very pleased when this one appeared.  It is in an area where there was much deep shade under a Lawson's cypress removed last summer.  Clearly the advent of light and warmth has triggered a long dormant seed.

Less usual spring flowers

Spring is still running late, though the day before yesterday I saw the first blue on some bluebell buds.

Two of the rather less common spring flowers are the marsh marigold (Caltha palustris) and the wood dog-violet (Viola reichenbachiana).

Marsh marigolds seemed much commoner when I was a child and I know only a few places locally where they still grow.  Their preferred habitat is very wet meadows and most have these have been drained.  Even when they are re-flooded, the Caltha does not seem to return.

The violet is holding its own rather better, especially in well-lit areas of clay woodland.  It flowers slightly earlier than common dog-violet (Viola riviniana) which grows in similar places and the violet shade of the narrow flowers has rather more red in it than riviniana.

The scientific name of the violet pays homage to Ludwig Reichenbach, a 19th century German botanist.

A new toy

I have acquired a new toy in the shape of a digital microscope wired up to the computer.

It takes a bit of getting used to, but hopefully it will enable me to share some of the smaller creatures I come across with you.

As well as scanning over things, it is easy to capture a still, or even a video, and this can then be tidied up and kept on the computer.

My first effort (and I am sure quality will improve) was of the coffin fly Megaselia ciliaris (Diptera: Phoridae).

Only about 2mm long, I found several in one of my traps over a stack of decaying logs in the garden.  Megaselia is a huge genus and identification is often difficult as the flies normally have to be mounted on a microscope slide like this one and often dissected to see some of the smaller features.

One of the distinctive features of this species is the partially yellow front legs.

Tortoiseshells return

After some years of very low numbers, the small tortoiseshell butterfly (Aglais urticae) seems to be back in numbers.  Today I saw several, including the one below, in a rough field at Netherfield in East Sussex wheeling about and buzzing one another in the warm afternoon sunshine.

This recent decline has been linked to the parasitoid tachinid fly Sturmia bella which was first recorded in Britain in 1998 at about the time the decline of the small tortoiseshell began.  The butterfly caterpillars swallow the eggs of the fly while they are feeding and the parasitoid larvae develop inside them, eventually killing them.

Some research has been done on this and large numbers of small tortoiseshells have undoubtedly been attacked by Sturmia, but results are not so far conclusive.

It may be that we will now see cycles of abundance and scarcity of this species (as with the holly blue and its parasitoid).  More butterflies means more tachinids, but this leads to less butterflies and less tachinids and so on round and round

In praise of ragwort (Senecio jacobaea)

Ragwort flowers with cinnabar moth caterpillars.

Since 2003 common ragwort has been a proscribed plant due to the Ragwort Control Bill, introduced largely to protect horses that can be poisoned by the plant.  On nature reserves and roadsides as well as on farms and commons the plant has been pulled up in vast quantities.  It is ironic that, although the horse population must be far lower than before the internal combustion engine, the dangers of the plant have only recently been a subject of legislation.

Many naturalists are concerned about this wholesale destruction of a plant that has been with us for many centuries, particularly as a very wide range of insects feed on the leaves and flowers.  Indeed, the cinnabar moth has recently been made a Biodiversity Action Plan (BAP) species, due, no doubt, to the threat to ragwort.

Today I read the following about ragwort in a essay called Summer published in the book The South Country in 1909 by Edward Thomas (famous for his poem Adlestrop).  He is talking of the top of the South Downs and I have little doubt that if such a quantity of the plant appeared there today the authorities of the new South Downs National Park would be quick to get rid of it:

"There a myriad oriflammes of ragwort are borne up on tall stems of equal height, straight and motionless, and near at hand quite clear, but farther away forming a green mist until, farther yet, all but the flowery surface is invisible, and that is but a glow.  The stillness of the green and golden multitudes under the grey mist, perfectly still though a wind flutters the high tops of the beech, has an immortal beauty, and that they should ever change does not enter the mind which is thus for the moment lured happily into a strange confidence and ease."