It has so often been emphasized that the flora of large tropical islands like New Guinea is still very imperfect, that the impression has been established that the data available should be in a state unapt to produce a conspectus or to procure valuable conclusions. Though it is certainly true that there are still immense plots of land entirely unknown from a botanical (or any other) point of view, and that we know but a part (but most probably more than one half) of the Papuan species of Pteridophytes and Spermatophytes, I am inclined to think that it is more than anything else the scattered nature of those data, that prevented us from realizing their intrinsic value. The time has come, I think, to pauze and to realize what has been done in the past years; to arrange the many uncoördinated data in such an order that, on one hand a comprehensive view may be obtained of what has come to our knowledge and on the other hand the gaps may become apparent. In this way it may be expected beforehand, that our present knowledge, however scanty it may be, may enable us to form some provisional conclusions of not too slight an importance and of not too mean reliability. Especially as far as floristics are concerned it is obvious that, for instance, consideration of one half of a flora will lead to practically the same conclusions as the whole flora would. In this investigation that is meant to be amplified by more detailed studies later on, I have, first of all, compiled an enumeration of the more important collectors and also of books and papers (cf. Annexes at the end of the present publication) which, together with the literature cited in some of them, may be considered as a basis to any student of the New Guinea flora, who desires to undertake a special investigation in this matter. As far as the facts are concerned my aims have been of a double nature; to get an impression of the principal associations of the island, and to arrange some floristic data in such a way, that they may become comparable to those of the surrounding islands and continents.