For your Christmas list*: a hand lens

(*Other popular religious and secular present-buying opportunities are available. Or just treat yourself.)

I've just been to Dartmoor with the new first years. Likely you went on this trip yourself and will be able to recall the amazing Wistman's Wood, an eldritch botanical wonderland dripping with lichens and mosses. I think it's one of my favourite places.

CC image by Alex Jane

Students are obliged to spend some time collecting data about un-botanical things like wind speed. But whenever possible I tried to lure them towards close examination of the weird and diverse species covering the trees and boulders. A few people looked like they got seriously hooked, which was very gratifying. And I think the secret to an appreciation of lichens and bryophytes is a simple thing: a hand lens.

I wish I could present one to everybody but it seems university bean-counters are not keen. I can always lend you one (quality and smeariness varies). But ultimately I would urge you to consider getting one yourself. It doesn't have to cost much and it will last you a lifetime. Plus you will always have it to hand if it just lives in your bag. And you won't have any slight squeamishness about holding it right up to your eye after a dozen other people have had it in their clammy hands. Seriously, it will open up a entire microscopic world that you cannot really predict. I'd say it makes Everything more interesting - the unsuspected detail of plants and invertebrates and all sorts. But in the short term it'll certainly make your collecting a more interesting experience and make it easier to identify what you're looking at.

Like I say a million times, 'Hold it right up to your eye'. CC image from the National Park Service.

But what to get? Magnification of x10 is fine for most things. You can get twin versions which have (say) a x10 at one end and a x15 at the other if you're feeling fancy. Another thing to consider is the diameter. My lens is about 15mm across. Larger diameters are recommended.  I thought I was quite happy with mine but now I'm starting to wonder if a larger diameter wouldn't be better - it transmits more light and makes things easier to see.

You do want something that's of good enough quality that it's not going to annoy you with its blurry pointlessness. You don't necessarily have to spend huge amounts though.

This Quicktest page shows you how different lenses vary in quality (which is quite eye-opening) and therefore in price. They have a large range for sale and they make it very clear what you're getting. There are also many other reliable places, like the local company Brunel Microscopes, or UKGE, or entomological suppliers like Watkins and Doncaster,

 This is the one I have at the moment, from Quicktest, which is about £30 with delivery. It has a slightly larger size than most, so lets in a bit more light, and seems super clear - I'm really pleased with it. But you don't have to go that mad - something about £15 can be pretty decent, judging by the advice linked to above. Cheaper ones are a good way in but they're necessarily blurrier and more likely to fall apart. I bought a load of half-decent ones for work last year, but they're extremely pocketable and disappear constantly. This is disappointing and makes me loathe to spend as much again - but then spending less is a false economy if the lenses are rubbish. So if you're even half keen it's a good reason to get your own and look after it - it should last a lifetime if you don't lose it!

I'd also recommend getting a lovely bright lanyard to attach to it. Then it's much easier to find if you put it down somewhere or it falls into the vegetation. There's a huge selection on Ebay, for example. If you wear your lens round your neck you will recognise and be recognised by other natural history buffs, like some sort of weird masonic tie / handshake. This is not necessarily a bad thing: you might meet someone knowledgeable and interesting. Nerdy, probably. But nerdy about something interesting.

Public domain image by Bill Gillette - girl on a fieldtrip in the Rockies, 1972

A useful thought I read recently - when you're using it, think of it as a keyhole. That is, you must put your eye right up to it to see through. Either bring the object you're looking at towards your eye, or (often more undignified but unavoidable) bring yourself close to the object. The latter is why you might see lichen enthusiasts sprawled across the landscape, bums in air, apparently pressing their faces against the rocks.

And finally, it's possible to integrate this low-tech highly-useful bit of equipment with modern technology: with a bit of practice you can take photos through it with your mobile phone. And those would be perfect stuck in your notebook.

(P.s. - What's more, a lens will repay you handsomely on the field trip to Tenerife, where there are many fascinating plants with strange adaptations to examine microscopically. I much recommend getting one in readiness for that).