Along this avenue of death nothing can be more striking than the profusion of life.  It seems as if all the vitality of the many buried generations had there passed into the fuller life of nature.  You can trace the street of tombs into the far distance, not only by the ruins that line it on both sides, but also by its borders of grass of a darker green and greater luxuriance than the pale, short, sickly verdure of the Campagna; just as you can trace the course of a moorland stream along the heather by the brighter vegetation which its own waters have created.  Myriads of flowers gleam in their own atmosphere of living light, like jewels among the rich herbage, so that the feet can hardly be set down without crushing scores of them:  the Orchis rubra with its splendid spike of crimson blossoms, the bee and spider orchises in great variety, whose flowers mimic the insects after whom they are named, sweet-scented alyssum, golden buttercups and hawkweeds, Roman daisies, larger and taller than the English ones, with the bold wide-eyed gaze you see in the Roman peasant-girls, scarlet poppies glowing in a sunshine of their own, like flames in the heart of a furnace, vetches bright azure and pale yellow, dark blue hyacinths, pink geraniums, and “moonlit spires of asphodel,” suggestive of the flowery fields of the immortals.  My footsteps along the dusty road continually disturbed serpents that wriggled away in long ripples of motion among the tall spears of the grass; while green and golden lizards, sunning themselves on the hot stones, disappeared into their holes with a quick rustling sound at my approach.  The air was musical with a perfect chorus of larks, whose jubilant song soared above all sorrow and death to heaven’s own gate; and now and then a tawny hawk sailed swiftly across the horizon.  Huge plants of gray mullein towered here and there above the sward, whose flannel-like leaves afforded a snug shelter to great quantities of wasps just recovering from their winter torpor.  On the very tombs themselves there was a lavish adornment of vegetable life:  snow-white drifts of hawthorn and honeysuckle wreaths waved on the summits of those on which a sufficient depth of soil had lodged; the wild dog-rose spread its thorny bushes and passionate-coloured crimson blooms as a fence around others; and even on the barest of them nothing could exceed the wealth of orange lichens that redeemed their poverty and gilded their nakedness with frescoes of fadeless beauty.  On some of the rugged masses of masonry grew large hoary tufts of the strange roccella or orchil-weed, which yields the famous purple dye—­with which, in all likelihood, the robes of the Caesars were coloured—­and which gave wealth, rank, and name to one princely Italian family, the Rucellai.  Over the desolate tombs of those who wore the imperial purple, this humble lichen, that yielded the splendid hue, spread its gray hoar-frost of vegetation.