Saturday, April 14, 2018

Flies, ferns and trees

Now spring is advancing rapidly there is a large variety of bees and flies sunning themselves on the trunk of the birch tree.  For example, the hoverfly below.

Over the last few days there have been several male sallow catkins (Salix caprea) on the ground in or near M3.  They must have come from the large example some twenty metres to the south which has flowered well this year and I suppose they must have been blown across, though I do not recall seeing this before.  They may be just fallen flowers but there is enough left in them to support and protect the sallow fly larvae (Egle spp.) that live inside them: a good example of a symbiosis where both species benefit and no harm is done.

In Planet Terracotta a leaf of the wood anemone (Anemone nemorosa) has appeared as it usually does.  It has now survived in this rather hostile environment for ten years, but shows no sign of flowering or spreading.

In contrast to the wood anemone, the broad buckler-fern (Dryopteris dilatata) continues to enlarge and now has seven fronds. They grow very rapidly once they start, but I wonder why they don't all develop at the same rate.  It has an Award of Garden Merit from the Royal Horticultural Society and is a very common wild plant in our area.

Another fast developer is the sycamore (Acer pseudoplatanus).  This year at least six seedlings have appeared, more than at any time before.  As seedlings the species is very attractive but, if left, I fear they would come to dominate the whole of M3.  Considered by most to be an introduction, there are relatively few insects that eat the leaves and, with its fast growth, it can quickly become a dominant or the only species where it flourishes.  As I said when I found a sycamore seed in M3 last autumn, I do not know the source of this species as there are no trees nearby that I know of that are large enough to bear fruit.