Michael McCarthy: The fog lifts on the beauty of grass

Know what Yorkshire fog is? No, it's not the mist that swirls up off the Humber on a winter's evening. It's a plant. To be more precise, it's a grass. And when you have a close look at it, it's a lovely grass.

Not many people do, I should think. As far as most of us are concerned, grasses are the great forgotten members of the plant kingdom, and it isn't hard to see why. They have no use for colour.

There are greens and yellows and browns in grasses, of course, but essentially they are monochrome, so much so that when, in 1965, the 88-year-old clergyman and flower-painter William Keble Martin published what some regard as the most inspiring plant book of the last century, The Concise British Flora In Colour, with 1,500 illustrations and even the rushes and the sedges coloured in, he drew the 150-plus grass species in black and white.

The reason for their lack of colour is a simple one – grasses are pollinated by the wind. This means that they do not need the brilliant shades of red and yellow and blue and white with which insect-pollinated plants decorate their reproductive organs – their flowers – so that bees and such will be attracted in to do the pollinating; and therefore we pass them by as unattractive, uninteresting. We ignore them even though the grasses, the Gramineae, form the world's most important plant family – as far as humans are concerned – because they are the home of all our crops, from wheat to rice to maize.

I confess to having ignored grasses myself until recently. What has changed for me has been spending the summer chasing butterflies for The Independent's "Great British Butterfly Hunt". Two major butterfly families – the "skippers" and the "browns" – lay their eggs on different grasses and so, in looking closely at all our 58 butterfly species, I have become aware of the world of grass for the first time. I am abashed at the scale of my ignorance. But ignorance is something it's never to late to address – once it is admitted.

A regal weed

Yorkshire fog, Holcus lanatus, is not the only British grass with a charming name. You can find cocksfoot and crested dog's-tail, floating sweet-grass and bulbous meadow-grass, holy grass and marram grass, bristle-leaved bent and squirrel-tail fescue, creeping twitch and barren brome. And then there is darnel, Lolium temulentum, which Shakespeare knew so well and which he includes in the garland of weeds with which the mad King Lear decorates his head – "darnel, and all the idle weeds that grow/In our sustaining corn".