Compared with what has been already achieved, there remains, in certain departments of the Flora of New Zealand, much more yet to be accomplished—much that can probably only be properly executed by the resident or local botanist, who can leisurely study living forms on or near the locality of their growth. Of no groups of plants is this remark so true as of the Protophyta—the Desmidiaceæ, Diatomacea, and Palmellaceœ. The first and the last may be said to be almost or quite unknown ; while our knowledge of the Diatomaceæ of the New Zealand islands is nearly altogether confined to my own local and limited collection from the neighbourhood of Dunedin, in the province of Otago. * There is here, therefore, for the local botanist, not only a most extensive and varied, but almost untrodden, field of research; and it is with a view to incite him to cultivate this most promising field that I venture to offer the following remarks. While the work of collection is comparatively easy, that of examination is far from being so. All the groups in question require the laborious care of the skilled microscopist; and labourers of such a class are not numerous, either in a new colony or at home. But there is no reason why collectors should not be numerous—why they should not supply the materials for work to the systematist in his cabinet. The collector, and the examiner or describer, arc necessary complements to each other. While the latter seldom has opportunity to collect over wide areas, he can utilise the materials supplied by the less skilled travellers who have such opportunity : so that each has his appropriate and indispensable place in the advancement of science.