Art. 43.—Studies in the New Zealand Hymenophyllaceae: Part I—The Distribution of the Species in Westland, and their Growth-forms. By the Rev. J. E. Holloway, D.Sc., F.N.Z.Inst., Hutton Memorial Medallist. [Read before the Philosophical Institute of Canterbury, 1st December, 1920; received by Editor, 5th December, 1921; issued separately, 8th June, 1923.] Plates 56–76. Analysis of Paper. Page Introductory 577 I. List of the Species 579 II. The Climate and Forest-covering of Westland 581 III. The Distribution of the Species in Westland 585 A. The Groups of Species and their Occurrence 586 B. Description of Two Selected Localities 599 C. The Growth-forms and their Relation more especially to the Vertical Distribution 604 D. The Bearing of the Distribution of the Species upon the Subject of the Phylogeny of the Family 609 IV. General Conclusions 616 V. Literature cited 618 Introductory. The Hymenophyllaceae constitute one of the most interesting of modern fern families, by reason of the fact that the family as a whole shows adaptation to hygrophytic conditions combined with a remarkable ability on the part of many of the species to flourish in more or less xerophytic situations. In the present and following papers I propose to set out the results of my studies in the New Zealand members of the family, basing my account of the distribution and of the growth-forms of the species upon what I learned as to their occurrence in the wet district of Westland, and in Part II comparing with these facts the ecology of the family as I have learned it in the drier parts of New Zealand. In the second paper I shall also bring together those facts concerning the general distribution of the species throughout New Zealand generally, and in the outlying islands belonging to the New Zealand Biological Region, which are contained in various botanical papers in the volumes of the Transactions of the New Zealand Institute and in other publications. Two noteworthy publications dealing with the filmy fern as a living plant are those of Giesenhagen (12) and Forrest Shreve (26). The former of these authors gives a general biological survey of the gametophyte, and more especially of the sporophyte generation, basing his account upon herbarium material. Amongst other species, he discusses seven which occur in New Zealand. Forrest Shreve's paper is the outcome of his studies on the Hymenophyllaceae of Jamaica in their natural habitat. He deals with the vertical and the regional distribution of the greater number of these species, and he describes a number of illuminating physiological experiments conducted by him with the purpose of ascertaining the exact relation of the species to the water-supply and their ability to withstand drying. New Zealand is well known to be a special centre of distribution of the Hymenophyllaceae. In actual number of species this family constitutes one-fifth of the entire fern flora of this country, embracing twenty-seven species, of which twenty belong to the genus Hymenophyllum and seven to Trichomanes. In the heavy taxad forests of the western districts, and more especially of Westland in the South Island, where the proximity of the high mountain-ranges to the coast-line causes the rainfall to be exceptionally heavy, the Hymenophyllaceae attain a notable luxuriance, and abound