Rain and sunny spells have meant a warm moist spring, with many spring fungi. Some,
such as the delicious St George's Mushroom, have done very well and made very good
meal additions. A group of Horse Mushrooms grew in our garden, and provided us with
two good meals. In the autumn, Horse Mushrooms in our garden have been eaten to a
sponge by numerous small insect larvae before the mushrooms were big enough for us
to eat, but in the spring the parent insects are clearly not around and the mushrooms are
free of larval inhabitants. Anew one to me was the Shield Pinkgill Entoloma clypeatum,
which was growing in a group under a hedge of mixed Hawthorn and Blackthorn, precisely
as it describes in the books. We did not tuck into this one! If the weather continues like
this all through the summer and autumn we should get a good fungus year, after two
disastrous ones.
Reading in a monthly journal called Chemistry World, we found an article on fungi and
their interaction with rocks and minerals. It has been known for some time that a number
of bacteria can produce acidic or other juices that corrode some rocks and minerals,
weathering them and allowing invasion of lichens and then mosses, along with some
fungi. It now seems that some fungi can also be the pioneers on rocks, doing several
different chemical reactions. Some release acids that corrode minerals, particularly
limestones, making soluble calcium salts. Some do this using oxalic acid, which corrodes
the mineral but then precipitates the calcium ions again as calcium oxalate, making new
mineral crystals. Limestone is not the only mineral to be attacked. Metal salts of various
kinds can be eaten out of rocks, by chelating agents or ligands, dissolving metals from
minerals to make complex ions using a wide range of metal-bearing rocks. New minerals
can be deposited, some of which might be useful metal concentrates. Thus emerges a
whole new range of ways of weathering rocks, enlarging the area of biogeochemistry.
In the middle of May I went to look at our local colony of the scarce Yellow Vetchling.
Last summer over three quarters of the patch had been burnt out in August, and I feared
for the worst (see Newsletter 43, Jan 2004). Last year's plant count was about 350
plants, but the year before it was about 10,000. I found, to my surprise and delight,
about 3,000 plants, especially growing in the area that had been burnt. As this is only an
annual, its seeds were on the ground, and the fire must have gone so quickly just above
that many seeds had survived. Nearby had been a smallish patch of Burnet-saxifrage; it
too had been burnt, and I thought none would survive. So I was just as delighted to see
a number of basal leaves of it coming up between the other plants, and it too has clearly
survived the fire.
Out walking on a sunny afternoon we stopped in our tracks as a snake wriggled gracefully
across the path barely 2 metres in front of us. It paused a moment to sip some water from
a puddle, then disappeared into the greenery. We assumed it had been quite still,
sunbathing in the warm sunshine on the dry path, until it suddenly realised we were very
close. We got a good view of it. It was about 45cm long, background colour silvery grey
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Essex Field Club Newsletter No. 45, September 2004