The desirability of publishing a compendious account of the plants of New Zealand having been represented to the Colonial Government by Dr. Knight, F.L.S., Auditor-General, and other gentlemen interested in the Natural History of the Islands, and in the development of their resources, that Government was pleased to entrust me with the preparation of such a work, and to place at my disposal the necessary funds for its publication, including a liberal remuneration for my services. I was at the same time instructed to make Mr. Bentham's ‘Hongkong Flora’ my guide as to the form of the work and method of describing the plants, and to adhere in these and in all other matters to the plan recommended by Sir W. J. Hooker for publishing in a uniform series Floras of all the British Colonies. The title ‘Handbook of the New Zealand Flora’ is adopted in accordance with the wishes of its promoters.

Though as complete as the materials at my disposal enable me to make this book, it is still imperfect as to the descriptions of several Orders of Flowering plants; whilst with regard to the Flowerless, it is tolerably complete in the Orders Ferns and Lycopods only; of the others, the islands no doubt possess twice as many Mosses and Jungermannias as have hitherto been discovered; and I have been able to offer but a meagre sketch of the Fungi, of the lower tribes of Algæ, and of the more minute and especially crustaceous Lichens that grow on rocks and on the bark of trees.