They fought their way across it with renewed hope, for they could see the very definite spot where the lilies ceased to grow, and the beginning of a channel through the delta, and they felt that no obstacle to navigation could be as infuriating and exhausting as those lilies. The delta of the Bora is a mangrove swamp, for the water of Lake Wittelsbach, although drinkable, is very slightly brackish, sufficiently so for some species of mangrove to grow, and where mangroves can grow there is no chance of survival for other trees. Where the mangroves began, too, the water lilies ended, abruptly, for they could not endure life in the deep shade which the mangroves cast. They reached the mouth of the channel and peered down it. It was like a deep tunnel; only very rare shafts of light from the blazing sky above penetrated its gloomy depths. The stench as of decaying marigolds filled their nostrils. The walls and roof of the tunnel were composed of mangrove roots and branches, tangled into a fantastic conglomeration of shapes as wild as any nightmare could conceive.
