Apparently the vegetable kingdom in Mars, instead of having green for a dominant colour, is of a vivid blood-red tint. At any rate, the seeds which the Martians (intentionally or accidentally) brought with them gave rise in all cases to red-coloured growths. Only that known popularly as the red weed, however, gained any footing in competition with terrestrial forms. The red creeper was quite a transitory growth, and few people have seen it growing. For a time, however, the red weed grew with astonishing vigour and luxuriance. It spread up the sides of the pit by the third or fourth day of our imprisonment, and its cactus-like branches formed a carmine fringe to the edges of our triangular window. It broadcast throughout the country, and especially wherever there was a stream of water.
In the end the red weed succumbed almost as quickly as it had spread. A cankering disease, due, it is believed, to the action of certain bacteria, presently seized upon it. Now by the action of natural selection, all terrestrial plants have acquired a resisting power against bacterial diseases--they never succumb without a severe struggle, but the red weed rotted like a thing already dead. The fronds became bleached, and then shrivelled and brittle. They broke off at the least touch, and the waters that had stimulated their early growth carried their last vestiges out to sea.