When we speak of grass we generally mean one thing, the small slim green herb which carpets the familiar earth. But there are many grasses, from the smooth close-set herb of our lawns or the sheep-nibbled downy greenness of mountain-pastures, to the forest-like groves which sway in the torrid winds of the south. Of these alone much might be written. I prefer, however, that name I have placed at the head of this article--taken, if I remember rightly, from a poem by the Gaelic mountain-poet, Duncan Ban Macintyre--and used in the sense of the original. In this sense, the Clans of the Grass are not only the grasses of the pasture, the sand-dune, the windy down, not only the sorrel-red meadow-grass or the delicate quaking-grass, but all the humbler greengrowth which covers the face of the earth. In this company are the bee-loved clover, the trailing vetch, the yellow-sea clover and the sea-pink; the vast tribe of the charlock or wild mustard which on showery days sometimes lights up field or hillmeadow with yellow flame so translucent that one thinks a sudden radiant sunflood burns and abides there. In it too are all the slim peoples of the reed and rush, by streams and pools and lochans: of the yellow iris by the sea-loch and the tall flag by the mountain-tarn: the grey thistle, the sweet-gale, and all the tribe of the bog-cotton or canna (_ceann-bàn-a-mhonaidh_, the white head of the hillside, as we call it in Gaelic), those lovers of the wilderness and boggy places. With these is the bindweed that with the salt bent holds the loose shores. With these are all the shadow-loving clans of the fern, from the bracken, whose April-green lightens the glens and whose autumnal bronze and dull gold make the hillsides so resplendent, to the stonewort on the dykes, the lady-fern in the birch-woods, the maidenhair by springs and falls, the hart’s-tongue in caverns, the Royal fern whose broad fronds are the pride of heather-waste and morass. The mosses, too, are from this vast clan of the earth-set, from the velvet-soft edging of the oak-roots or the wandering greenness of the swamp to the ashy tresses which hang on spruce or hemlock or the grey fringes of the rocks by northern seas. And with them are the lichens, that beautiful secret company who love the shadow-side of trees, and make stones like flowers, and transmute the barrenness of rock and boulder with dyes of pale gold and blazing orange, and umber rich as the brown hearts of tarns, and pearl-grey delicate as a cushat’s breast, and saffron as yellow-green as the sunset-light after the clearing of rains. To all these, indeed, should be added the greater grasses which we know as wheat and oats, as rye and maize. Thus do we come to ‘the waving hair of the ever-wheeling earth,’ and behold the unresting Mother as in a vision, but with the winds of space for ever blowing her waving tresses in a green gladness, or in a shimmer of summer-gold, or in the bronze splendour of the autumnal passage.