Green-winged Orchids

Field full of Green-winged Orchids, Anacamptis morio, and Meadow Buttercups, Ranunculus acris,
with a Wild Service Tree, Sorbus torminalis, in the distance.   Marden Meadow, 25 May 2013.

So, we had some good weather over the Bank Holiday Weekend, which surprised a lot of people.  On the Saturday I went with the Orpington Field Club to Marden Meadow, a group of three fields with a reputation for interesting plant life.

They are probably best known for their Green-winged Orchids.  Two of the fields are full of them; more orchids than I have seen in one place before.  Most of them are purple, but some are pink (or "salmon", as the official accounts have it) and a very few are white.

Green-winged Orchid, Anacamptis morio.  Purple, pink and white specimens.  Marden Meadow, 25 May 2013.

Their name comes from the green stripes in the upper petals, which are there whatever the main colour of the flowers.   There is an alternative name; Green-veined Orchid. 

The walk was led by Irene Palmer, who is something of an orchid specialist and also has a good eye for a photo.  It was she who lined up the image at the top of this entry, which I think is a very satisfactory composition, and combines the orchids, the meadow, and a scarce Wild Service Tree.

Irene also found a bumblebee with an exciting feature; pollinia from the orchids attached to its face.  Again, Irene found the creature and I took the photo.

Bumblebee, Bombus pascuorum, with Green-winged Orchid pollinia, Anacamptis morio.
Marden Meadow, 25 May 2013.

Orchids bundle their pollen into these packages, and there are various complex ways in which insects are enticed into positions where the pollinia become attached, and eventually transferred to another orchid.  This is made even more interesting in that some orchids do not produce any nectar, so if insects visit them, it is presumably because they resemble flowers which have produced nectar for the bees in the past.  The Green-winged Orchid is one such, and this is evidence that at least one bee has been fooled! 

Garden Solomon's Seal

Garden Solomon's Seal, Polygonatum x hybridum.  On the railway embankment, 18 May 2013.

This is a photo I took while working on the London Flora Project.  The local railway embankment has several garden escapes or throw-outs that have thrived in this mostly undisturbed environment.  This one just happens to be a rather nice photo, with the sun shining through the leaves.  It was taken through a hole in a mesh fence, and you can see the blurry wires at the corners.  There are garden bluebells in the background.

We know this is the garden variety of Solomon's Seal because there are two ridges on the stems.   There is a wild species with round stems and one with four ridges, and this is a cross between them. 

According to WIkipedia, the plant got its common name because depressions in the root look like royal seals; or alternatively, that the cut root resembles a Hebrew character.   I see no such depressions in photos of the roots on line.  I think imagination has been at work; perhaps in giving it its name, and certainly in thinking up explanations for it.

Mugshots

Common Carder Bee, Bombus pascuorum.  In my garden in Hayes on 8 May 2013.

I don't just get moths in my garden trap.  In fact I am seeing hardly any moths at the moment.  But this bumblebee did turn up, resting on the egg cartons.

The name "Carder Bee" has a tangled origin.  Carding is the process of pulling raw wool between two spiky paddles to straighten out the fibres ready for spinning.  It's called carding because originally dried teasel heads, which are naturally spiky,  were used for this purpose; and carduus in Latin meant a spiky plant, probably the one we now call a Cardoon.

Anyway, does this bee look cuddly at all?  It's certainly furry.

Wasps definitely do not look cuddly.  I caught this one in my doctor's waiting room.  It was pretty lethargic, but people don't like even lethargic wasps, and it was easy to catch in a specimen tube.  I brought it home and took its picture.

Common Wasp, Vespula vulgaris, caught in the doctor's waiting room in Hayes on 17 May 2013.

Different wasp species have different patterns of black and yellow on their faces and abdomens.  I don't have a selection yet, but they do come to the trap so maybe I will see some more this year.

Three Geraniums

Herb Robert, Geranium robertianum, on my street in Hayes, 12 May 2013.

I am taking part in the London Flora Project, which aims to update our knowledge of which plants can be found in the Greater London area.  I have a square kilometer to survey that includes my house and street, and I am finding that it sharpens my perceptions and improves my knowledge of what surrounds me.

Yesterday I found three species of Geranium on my own little street, growing in the verge or in cracks in the paving and asphalt.

So here they are, starting with  a well-known woodland plant, Herb Robert (above).  The leaves are finely divided, and in dry or sunny places are often tinged with red, as here.  It has pretty pink flowers, or sometimes white ones.  (There's a white one in this post: Spring at Keston).

Shining Crane's-bill, Geranium lucidum, on my street in Hayes, 12 May 2013.

This next plant is one of several specimens growing in the cracks.  Look how shiny it is compared to the Herb Robert!  The flowers are quite similar, but the leaves are very different.

I thought of this as a tall woodland plant and I was very surprised to see it here, hugging the ground, but looking around on iSpot I can see several observations in similar places.

Flower of Shining Crane's-bill, Geranium lucidum, on my street in Hayes, 12 May 2013.

The third geranium is a tiny, humble thing that hides in the short grass in a mown verge. The flowers of this one are noticeably different, in that the petals are deeply notched so that one looks like two.  It actually has only five petals, like the others.

Dove's-foot Crane's-bill, Geranium molle, on my street in Hayes, 12 May 2013.

That's true of several Geraniums. There are two possibilities when identifying a plant that looks like this; it could either be Dove's-foot Crane's-bill or Small-flowered Crane's-bill.  You can sort them out by counting the stamens, in theory, but in practice they tend to fall off easily, and if some are missing the count will come out oddly.

Closeup of Dove's-foot Crane's-bill, Geranium molle, on my street in Hayes, 12 May 2013.

So you need to look at the hairs on the flower stem.  If they are all short, it's a Small-flowered.  Here, there are some short and some longer, so it's a Dove's-foot.

So, three wild Geraniums just outside my door!  I am pleased.

Another Insectivorous Plant

Flower of Butterwort, Pinguicula grandiflora, on my balcony in Hayes.  12 May 2013.

I have had no luck with Butterworts in the past.  Twice I have bought one and watched it slowly die.  But nevertheless, I tried again.

In January 2012 I bought a few small hibernacula of Pinguicula grandiflora.  These are the form the plant takes when it hibernates in winter, like little green buds.  It makes a bunch of little offshoots during the year, and these are what I bought, in their winter form.

They grew, and then they disappeared, only halfway through the year.  Well, I had seen some Sundew species do something like that, so I thought they might still be viable.  I put them out on my balcony and kept them wet.  And waited.  Squirrels dug them up, and some of them disappeared completely.  I was not too hopeful, but when I looked under the surface this spring I found lots of little hibernacula.  This time I just left them outside, though I put a few into different pots, some of them indoors.

Butterwort, Pinguicula grandiflora, on my balcony in Hayes.  12 May 2013.

The squirrels dug them up again, and I pushed them under again.

Now they have all come up, and the ones that are outside are all flowering!  So the answer to cultivating these is: leave them outside, keep them wet, keep the squirrels off them, but otherwise ignore them. 

Butterwort, Pinguicula grandiflora, on my balcony in Hayes.  Detail of leaf with trapped insect.  12 May 2013.

This is how they eat insects.  They are not spectacular like Venus Flytraps or Sundews.  At most, the leaf edges can curl up a little.  But a close look  at the leaves shows that they are covered with sticky-tipped hairs, smaller than a Sundew's but the same kind of thing.  When an insect gets stuck, glands in the leaves exude digestive juices, and the result is absorbed into the plant.

Wikipedia says the flower stems are long so that pollinators are kept well away from the leaves and don't get eaten, but I notice that the flower stems of mine are also covered with sticky hairs, so I am not convinced.

Tiny Beauty

Drosera pulchella on my windowsill in Hayes.  7 May 2013.

This exotic bloom is a miniature, only 12 mm across.  It's a Sundew from south-western Australia.  The whole plant that it belongs to is only  2 cm across.  I posted a photo of it here:
Drosera pulchella.

Here's another shot showing the slender flower stalk and the rosettes of the parent plant.  As you can see, it's an insect-eater, though because of its size it can only catch very small insects.  It gets the occasional fruit fly from the kitchen.

Drosera pulchella on my windowsill in Hayes. 7 May 2013.

Heterostyly

Pin-eyed and thrum-eyed primroses on "Primrose Bank" off Cudham Road.   29 March 2011.

A few flowers have a very interesting method of ensuring that they do not pollinate themselves, but are always fertilised by pollen from a different plant.  It is called heterostyly, and works like this.

Some individuals have their anthers at the ends of long filaments, and stigmas on short styles.  Others are the opposite; long styles and short filaments.  The best known examples are primroses, like those shown here.  If you can see the round stigma, the pollen-bearing anthers are down out of sight.  A flower that looks like this is called "pin-eyed."

If, instead, you can see a cluster of anthers covered with pollen, then the stigma is out of sight below.  These flowers are called "thrum-eyed."

So, if an insect goes to collect nectar from the nectaries at the base of the petals, pollen will rub off on it in one of two positions.  This position will match the position of a stigma on a different plant, but not on the same plant, not even another flower of the same plant.

Of course this is not perfect, because pin-eyed pollen could rub off onto a pin-eyed stigma as the insect works its way inwards.  But there is more.

Another common heterostylous plant is Forsythia, the bright-yellow-flowered shrub that's popular in gardens and hedges.  It's in full flower now, but when I looked round, I could only find thrum-eyed examples.

Forsythia x intermedia on Saville Row, Hayes.  Thrum-eyed.

This is a cultivated hybrid, propagated by cuttings, so it is quite possible that there aren't any pin-eyed plants of this variety in this locality.  That would explain why they don't seem to set fruit.  Of course the natural species, which I haven't seen, would have both types. They aren't native to Britain.

As well as the heterostylous positioning of pollen and stigma, these Forsythias have another trick.  Their pollen starts off with a chemical that inhibits germination; and pin-eyed and thrum-eyed plants produce different chemical inhibitors.

The stigma of one type of flower has an enzyme that puts the inhibitor from the other type out of action, and allows the pollen to go ahead and germinate.  So if pin-eyed pollen does get onto a pin-eyed stigma, it stays inhibited, and it just can't germinate.  Only thrum-eyed pollen will find a welcome here.  (I don't know whether primroses do this.)

There are even plants that have three different lengths of filament and style, so that the flowers come in three varieties.  One of these is the Purple Loosestrife. I know a few places where this grows.  It flowers later in the year, and when it does, I will see what I can find!

You might wonder why it is important that plants should not be self-fertilised.  Some plants seem to do very well without needing to be cross-pollinated.  The theory is that for heterostylous plants, the genetic diversity provided by regular cross-pollination gives these plants an evolutionary advantage.

[The information about chemical inhibitors in Forsythias comes from an abstract I found on line: "Zur Physiologic und Biochemie der Selbststerilitat bei Forsythia" by F. Moweus, published in the Biologisches Zenralblatt, 1950, vol. 69, pp. 181-197.]

Bees and Flowers

Marsh Marigold, Caltha palustris, in the pond in Spring Park, 24 April 2013.

I was in Spring Park recently and I was pleased to see a good display of Marsh Marigolds in the pond.  It's an artificial pond, lined with rubberised plastic to retain water, fed by one of the springs from the hillside it sits next to.

You can just about see, if you enlarge the photo, a dot on one of the flowers a little right of centre.

Bee on a Marsh Marigold, Caltha palustris, in the pond in Spring Park, 24 April 2013.

It's a bee.  A solitary bee, not a hive-dwelling honey-bee. 

Yellow-legged Mining Bee, Andrena flavipes, on a Marsh Marigold, Caltha palustris. Spring Park, 24 April 2013.

In fact it's a female mining bee, so-called because they dig holes in tightly packed earth in which to lay their eggs.  I have shown these bees before, here: Andrena flavipes in Jubilee Country Park and here: Andrena flavipes on Keston Common. The second link shows one of the holes.

This one is a female.  There were males around as well:

Yellow-legged Mining Bee, Andrena flavipes, on a Marsh Marigold, Caltha palustris. Spring Park, 24 April 2013.

This one was feeding on a dandelion near the pond.  Their home is a footpath that runs along the base of the wood.  I would have liked to get a photo of one of the bees entering or leaving a hole, but they are extremely wary when they are on the footpath, which is a reasonable response given the number of people and dogs who go along it quite unaware of their presence.  (The people are unaware; I can't vouch for the dogs, but they ignore them.)

Spring flowers and spring insects!  At last.