Smaller things

I was wondering how the queen bumblebee from October 28th was doing, and this morning we had a gap in the rain. Sure enough, at around 10 am, she was back at the Lavatera in the garden. (Well, I'm assuming it was the same one. Either we have two queens, each making a winter nest, or one queen working hard at getting her winter nest established. Either way, it's a notable observation.) I had hoped to follow her flight, but she went quite high and flew south so, sadly, her nest isn't all that close to me. It will be very interesting to see if we start to get B. terrestris workers in the next few weeks. Having said that, we had the first frost of the year last night. It was only a couple of degrees below, but a frost all the same. Here's a shot of the roof of my car:

Frost patterns

When the weather is on a bad run it's time to gather some samples and do some microscopy and deeper research.

There's a little mushroom that appears on my lawn several times a year. I know it's a Galerina, but today I decided to get it to species:

Galerina clavata

I put a specimen on a glass slide and waited overnight for a spore print. Here's the print on the slide waiting to be examined under the microscope:

Galerina spore print on the microscope

You can clearly see the brown spore print in that shot. (The blue column is the light shining up on the underside of the slide.)

We need to examine spores at a magnification of at least x400:

Galerina spores at x400

These spores are described as 'almond-shaped'.

I noted that the base of the stipe on the specimen was woolly white, so that makes it Galerina clavata, a common mushroom in association with mosses in lawns.

Liverworts are amongst our most overlooked plants. They are mostly tiny, and many could easily be assumed to be mosses. An in-situ shot would show nothing recognisable, so I took this shot (sample size about 3 cm. across) on paper in the study.

Liverwort sample about 3 cm. across

There doesn't seem much to work with there, but once you get a sample under the microscope, everything becomes clear. This sample is mounted on a slide ready for the microscope:

Liverwort sample on slide ready for microscopy

Note that the individual leaves have no central vein - a clear indication for a liverwort. There are no underleaves, and the leaves look to be entire, without lobes or teeth. Microscopy, however, reveals that the leaves are very slightly toothed - more so in the lower leaves - and that the teeth contain very few cells:

Cells in leaf tooth

All of this leads us to Plagiochila porelloides, which in this case is the predominant plant on the rear wall of the ditch where I found it.

I'm currently working on lichen microscopy. This is a specimen of Xanthoria parietina, an extremely common lichen that can be found on wood or stone and even on glass:

Xanthoria parietina

Lichens are an association between a fungus and a photobiont (either an alga or a cyanobacterium). Since the fungus is the only part of the organism that reproduces freely, I refuse to see this as symbiosis: I consider that the fungus (which needs the photobiont in order to survive) is virtually parasitic on the alga (which can and regularly does live happily on its own, without help from the fungus). This shot at x30 shows the circular cups which are the spore-producing, reproductive part of the fungus:

Fruit bodies of Xanthoria parietina

More moss

A rare bit of sun and I was out like a shot.

Wall-tops are the place to find a number of mosses including the very handsome Tortula muralis (guess where it got its specific name from).

Last year's capsules are still in place (those are the taller, brown ones), but if you look closely you can see the new ones emerging just above the leaves.

Tortula muralis capsules - old and new

Emerging capsules of Tortula muralis

To give some sense of scale, the new capsules are about 5mm long.

The rear walls of ditches are also rich in moisture-loving plants. The following shot shows at least two species of liverwort and one moss.

1) The thallose liverwort Conocephalum conicum
2) The moss Plagiomnium undulatum
3) The liverwort Plagiochila porelloides

Liverworts are either 'thallose' (flat and ribbon-like) or 'leafy', and we have one of each in the shot above. The area in the shot is about 20mm across.

Humidity-loving ditch-dwellers

Liverworts are fascinating little plants that can be found on the back wall of ditches, on damp walls and hidden in rock crevices, woodland paths and tree-trunks : anywhere that it's fairly dark and damp.

Thallose liverworts are easy to identify: they are ribbon-like with a flat main structure (thallus). This is Conocephalum conicum, showing the lizard-skin-like thallus which readily identifies it.
(Width of thallus about 10mm):
And here's a habit shot, specimen about 10cm. long:



Leafy liverworts are more difficult to separate from mosses without magnification. This wonderful specimen is Plagiochila porelloides, with the main 'stem' in the foreground being about 12mm long.
You really do need to get a magnifying glass on these to identify them as liverworts, and you need higher magnification to identify them to species. The leaves are often very complex, with folds and pockets, presumably to retain water if their source dries out.

Having said all that, what about this one?



Well, just to complicate things, this is a moss: Hookeria lucens. The leaf cells are so large you can see them with the naked eye. Specimen shown about 15mm long.

So what differentiates a liverwort from a moss? The defining difference is in the rhizoids (root-like structures used to grip the substrate). In mosses these are multi-cellular, but in liverworts they are single-celled structures. That's all very well under the microscope, but in the field we have to use a combination of features, such as leaf arrangement, leaf lobing (no mosses have leaf lobes), presence of thallus and shape of reproductive organs, if visible.