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344 TROPICAL NATUREprotecting them under glass from our sudden changes oftemperature, so that they are themselves an additional proofthat tropical light and heat are not needed for the productionof intense and varied colour. Another important considerationis, that these cultivated varieties in many cases displace anumber of wild species which arc hardly, if at all, cultivated.Thus there are scores ofspecies of wild hollyhocks varying incolour almost as much as the cultivated varieties, and thesame may be said of the pentstemons, rhododendrons, andmany other flowers ;and if these were all brought togetherin well-grown specimens, they would produce a grand effect.But it is far easier, and more profitable for our nurserymen,to grow varieties of one or two species, which all require asimilar culture, rather than fifty distinct species,most ofwhich would require special treatment, the result being thatthe varied beauty of the temperate flora is even now hardlyknown, except to botanists and to a few amateurs.But we may go further, and say that the hardy plants ofour cold temperate zone equal, if they do not surpass, theproductions of the tropics. Let us only remember suchgorgeous tribes of flowers as the roses, pseonies, hollyhocks,and antirrhinums; the laburnum, wistaria, and lilac; thelilies, irises, and tulips; the hyacinths, anemones, gentians,and poppies, and even our humble gorse, broom, and heather ;and we may defy any tropical country to produce masses offloral colour in greater abundance and variety. It may betrue that individual tropical shrubs and flowers do surpasseverything in the rest of the world but that is to be;expected,because the tropical zone comprises a much greater land areathan the two temperate zones, while, owing to its morefavourable climate, it produces a still larger proportion ofspecies of plants and a greater number of peculiar naturalorders.Direct observation in tropical forests, plains, and mountainsfully supports this view. Occasionally we are startled bysome gorgeous mass of colour, but as a rule we gaze upon anendless expanse of green foliage, only here and there enlivenedby not very conspicuous flowers. Even the orchids, whosesuperb blossoms adorn our stoves, form no exception tothis rule. It is only in favoured spots that we find them in