I.—Extent of Diffusion.
With the view of indicating, as precisely as practicable, the present diffusion of each species, that Province of Auckland, as far south as Ngarua-wahia, has been divided (somewhat arbitrarily) into districts, as under:—
North Cape:—from Cape Maria Van Dieman and the North Cape, to Hokianga and the Bay of Islands.
Whangarei:—from Hokianga and the Bay of Islands, to Cape Rodney and the north head of the Kaipara harbour.
Waitemata:—from the south head of the Kaipara, and Cape Rodney, to the head of the Manukau harbour at Penrose, and the Tamaki at Panmure.
The Islands:—including the Cavalhos and Taranga groups, the Great and Little Barriers, etc., the Kawau, and those in the Firth of Thames.
Cape Colville:—the Cape Colville peninsula as far south as Kawæ-ranga and Wangamata Bay.
Waikato:—from Penrose and Panmure to Whaingaroa and Nga-ruawahia.
The district in which each species is known to occur will be indicated by the use of the numbers prefixed above; thus practically affording a separate list of the naturalized plants of each district; but it must not be supposed that these lists are complete, even for any one district. The naturalized plants of the western side of the North Cape district are quite unknown to the writer, and to a great extent those of the western side of the Whangarei district. The districts for which the lists are most complete, are Auckland, the Islands, and Cape Colville. Very little is known of the naturalized plants of the western and extreme southern divisions of the Waikato district, or of the East Coast, south of Wangamata Bay.