2 Transactions. 



for patience in dissecting to hinder its being collected in comparative 

 abundance.* 



There is no doubt that the wet temperate climate of that part of 

 New Zealand subject to the excessive western rainfall is especially favour- 

 able to pteridophytic growth and to the sexual reproduction of the plants. 

 In the present paper I propose to give an account of my search for 

 and discovery of the prothalli and young plants of Tmesipteris in the 

 neighbourhood of Hokitika, in the Province of Westland, New Zealand, 

 and to describe the form, structure, and development of the prothallus 

 and sexual organs and of the young plant, and also to trace some of the 

 early stages in the development of the embryo. Two writers have pub- 

 lished certain results obtained by them in their search for the gametophyte 

 of the Psilotaceae. Lang (1904) has given a description of a single pro- 

 thallus which he has provisionally referred to Psilotum. This prothallus 

 is certainly a puzzle, for on the one hand the finding-place strongly 

 suggests that it belongs to Psilotum, but on the other its form and 

 structure differ very widely from what I propose to describe for Tmesi- 

 pteris, and from what Professor A. A. Lawson, of Sydney University, 

 has already described. Lawson (1917a) gives a preliminary account of 

 the prothallus of Tmesipteris based upon several specimens obtained by 

 him from different localities in eastern Australia. This account was pub- 

 lished early in 1917, but came into my hands only at the end of the 

 year, when my own paper was almost completed. No reference to it. 

 therefore, will be found in the body of the present paper, but in the 

 concluding section I have compared in detail my own results with his, 

 and noted our points of agreement or otherwise. There is a considerable 

 literature dealing with the anatomy and morphology of the adult plant 

 in the Psilotaceae. The more recent of those writings, such as those of 

 Scott (1909), Bower (1908), Seward (1910), Thomas (1902), Boodle (1904), 

 Ford (1904), and Sykes (1908), have brought together a weighty body of 

 evidence for relating the Psilotaceae with the fossil Sphenophyllales. In 

 my comparative remarks I have endeavoured to consider the results 

 obtained from the study of the prothallus and young plant of Tmesipteris 

 with regard to the systematic position to be assigned to Tmesipteris and 

 Psilotum. 



As on other occasions, I desire to acknowledge the special debt of 

 gratitude I am under to Dr. L. Cockayne, F.R.S., for his constant 

 encouragement and advice, and also to Professor C. Chilton, M.A., D.Sc, 

 for his kindness in giving me free access to the Botanical Laboratory at 

 Canterbury College. 



*The following may be cited in this connection: H. Bruchmann, Uber die Pro- 

 thallien und die Keimpflanzen mehrerer europiiischer Lycopodien, pp. 4 and 5, 1898 ; D. H. 

 Campbell, The Euspomngiatae (the adult gametophyte of Ophioglossum molucca num and 

 O. pendulum), pp. 11 and 13, 1911 ; M. Treub, "Some Words on the Life-history of 

 Lycopods" (tropical species), Ann. o/ Bot., vol. 1, pp. 119-23, 1887; J. E. Holloway, 

 ••Studies in the New Zealand Species of the Genus Lycopodium, Part I," Trans. N.Z. 

 Inst., vol. 48, pp. 259-63, 1916. In the last- mentioned paper I described the discovery 

 of three species of Lycopodium prothalli of the L. c< rn u u m type, one epiphytic species 

 of the L. Phlegmaria type, and three subterranean species of the L. complanatum and 

 L. clavatum types, the three latter being found in abundance. Since writing this paper 

 I have found the prothalli oi the three epiphytic varieties of Lycopodium which occur 

 in New Zealand, in the case of two of them in great abundance, and have also continued 

 to come across sporeling plants and prothalli of the three subterranean species in many 

 different localities, and in large numbers. 



