‘Mushroom season, Josh,’ he keeps explaining. ‘It’s a good, damp one this year, but a touch too cold I’d say.’ He ushers me down into a ditch to show me a line of what look like eggs, stood in a neat little row all along a rotting tree-stump. ‘Puffballs. When they get ripe, they’ll explode.’

I can’t pretend I’m that interested. When he starts talking about ‘mycology’, and how the ‘mycelium’ is actually a giant web of interconnected fibres that can span huge areas, I know I should be a little more enthusiastic. For some reason, probably the Thursday sessions, my interest in biology isn’t very high at the moment.

As we get towards the top of the hill, the scrubby woods give way to more sandy terrain, with low gorse bushes speckled with yellow flowers. Grandad picks one and pops it in his mouth.

‘Want one?’

I shake my head.

‘Now, look at this, Josh!’ He’s stooped at the side of a larger gorse bush, his fingers holding back a tuft of grass at the base of what is, actually, quite an impressive mushroom. It looks like the ones in kids’ books – a flat, red disc on the top of a long, straight stem, covered in little white flecks. The edge is starting to curl back on itself, and the white bits underneath are going slightly orange. Beneath it, there’s a slightly smaller version, it’s top not yet flat, but even redder, even shinier, like a snooker ball.

‘Can we eat those?’ I ask.

‘Only if you want a quick way to shuffle off this mortal coil,’ Grandad replies. ‘These are fly agarics, Josh. Very poisonous indeed. Best left alone, but very good for looking at.’

I nod, trying to look interested.

As we watch, a small black beetle crawls over the rim of the smaller one’s top. It twitches this way and that before it’s joined by another one. Under the gorse bush, there’s a small bird hopping around, probably trying to keep out of the wind. I wonder what it would be like to be a small creature; a creature small enough that this mushroom, or this gorse bush, could be my whole world.

‘Yep, kill you straight off, these buggers will.’ Grandad wakes me from my daydream. ‘Or they’ll make you very high. Now let’s catch up.’

The question I was going to ask rides the wave of my surprise and comes out as a splutter. ‘Grandad?’

Yes, Josh? Grandad doesn’t miss a beat, his eyes sparkling with humour.

I regather my composure. ‘If I wanted to plant something now that would come up early in the spring, what kind of thing should I plant?’

‘To flower early in the spring? Easy. Narcissi.’

‘What?’

‘Daffodils.’

‘Oh. The yellow ones?’

‘Or you can get white varieties. Orange trumpets. Gorgeous.’

‘So I’d plant the seeds now?’