In the latter country alone, very many (probably several hundred) square miles are covered by one mass of these prickly plants, and are impenetrable by man or beast.

Over the undulating plains, where these great beds occur, nothing else can now live.

Before their introduction, however, the surface must have supported, as in other parts, a rank herbage.

I doubt whether any case is on record of an invasion on so grand a scale of one plant over the aborigines.

As I have already said, I nowhere saw the cardoon south of the Salado; but it is probable that in proportion as that country becomes inhabited, the cardoon will extend its limits.