Slither, Slither....

Whenever gardeners gather together in spring, sooner or later the conversation comes around to slugs, those destroyers of horticultural dreams. So, bearing in mind the words of the 6th. century BC Chinese military strategist Sun Tzu - "If you know both yourself and your enemy, you can win a hundred battles without a single loss" - here are pictures of two of the worst offenders. Double-click for larger images. First up, the netted slug Deroceros reticulatum, which so often crawls into lettuces. The colour can be quite variable but this pale grey and buff form is common in my garden, but...

... the ID character that gives this slug its common name is the dark network pattern on the tail end of its body, which you can just see in this view, at the back of the animal.

And here's another slug that will be slithering out in search of tender young seedlings as soon as mild, moist spring days arrive. This is the Budapest slug Milax budapestensis. In this view you can see the open breathing pore (the pneumostome) that leads to the slug's lung. Those little parasitic nematodes that you can buy to kill slugs, as an environmentally-friendly alternative to slug pellets, crawl in through there, breed and kill their host.

The Budapest slug has a distinctive yellow keel that runs along the top of the rear half of its body.....

... and the pneumostome is located towards the back of that 'saddle' at the front of the body, while.....

... the dark stripe that runs along the underside of the foot is also a distinctive feature.

One of my project students, Jack Brooks, is currently investigating whether there are any natural extracts from plants that might be used to deter slugs (they are supposed not to like garlic, coffee and extracts of ivy leaves) that could be used to protect vulnerable seedlings in spring. He's also looking at which garden slugs are damaging and which are harmless to plants - the leopard slug (sometimes called the great grey slug) is supposed to be blameless as far as damage to garden plants is concerned. We'll report back on how the research goes....

Mossy Invader

The invasive alien plant species that tend to hit the headlines are the large ones - like giant hogweed and Japanese knotweed - but there are smaller species that have snuck in largely unnoticed and have become an almost ubiquitous element in our flora. This is the Cape Thread Moss Orthodontium lineare which was unknown in Britain until 1922, when a bryologist called E.V. Watson found it on some rocks in Cheshire. Since then it has spread the length and breadth of the British Isles. It comes from the southern hemisphere, from Africa, South America, Australia and New Zealand, but until Watson found it the moss was unknown in Britain. Those drooping spore capsules are a distinctive characteristic and the fact that they are produced in such profusion in spring and release so many spores goes a long way to explaining how it has spread itself around so effectively.

Yew

These strange objects are the pollen-producing structures of a yew tree. There are separate male and female trees and at this time of year these little pollen-producing cones, known botanically as strobili, are very conspicuous on the male trees, releasing pollen that's carried on the wind to the females. Yew belongs in the division of the plant kingdom known as the gymnosperms that includes the cone-bearing conifers, but unusually it doesn't produce its seeds within a woody cone. Instead each seed is carried in a succulent red cup, which you can see by clicking here.