These, and hundreds of other equally suggestive facts, all pointing to geographical, climatic, and other influencing conditions, as the real objective points of inquiry, have been constantly before our botanical friends; and yet they have been content with Mr. Darwin's theory of climbing mountains to cross the geographical equator, under the impression that an enormous ice-cap, or rather prodigious "ice-ulster," would ultimately drift them into the southern hemisphere, or enable them to "coast" their way thither with the greatest imaginable ease. But why insist upon the migration of plants growing in the lowlands and about the bases and sides of mountains, and not suggest some means of transport for the equally beautiful flora, known as "alpine," on the mountain summits of the earth? These are distributed, as we have before shown, over all our mountain systems, in all latitudes and in all parts of the globe, as well as in the higher regions of vegetation as we approach the north pole. Surely, the delicate little harebells of these alpine regions should attract some interest, if not sympathy, from those who are constantly hunting up means of transport for the more hardy and robust plants that seem able to take care of themselves almost anywhere.
When the next great ice-cap shall sweep down from the north pole upon these beautiful alpine flowers they will have to travel somewhere. There is manifestly as much necessity for them to get out of the way as for the rest of the flora. How will they manage to get down the mountains into the lowlands, and traverse uncongenial plains and deserts, to find other and far-distant alpine homes? They can never, of course, get very far away from the regions skirted by eternal frost, for their cup of joy must be chaliced by the snow-flake, or their beautiful life is soon ended. But if all our alpine flora have traveled from one evolutional centre, or have been "created but once in time and place," how have they managed to cross the thermal equator and spread themselves out over all the alpine regions of the globe? We call upon Mr. Darwin and Professor Gray to rise and explain. Not that we want any explanation, but that their theory of plant-migration stands sadly in need of one.