NEW ZEALAND FERNS 55 



As for its distribution Hymenophyllum Malingii is altogether 

 absent from the rain-forest in general. It is present only in those 

 associations which contain as an important or dominant tree 

 Libocedrus Bidwillii (Pinaceae) upon the trunks of which it grows, 

 forming wide patches by means of its extremely slender branching 

 rhizome. It appears to much prefer dead to living trees, but it 

 is occasionally found on the latter, as also, I believe, upon living 

 and dead Podocarpus Hallii. 14 The Libocedrus association occurs 

 in both the North and South Islands. It is usually subalpine, 

 but where it descends to a low altitude the fern is still always to 

 be expected. The distribution of the association is widely dis- 

 continuous, as in the case of Banks Peninsula where H. Malingii 

 in conjunction with Libocedrus at one time occurred while the near- 

 est other example would be more than fifty miles away to the west. 

 The species is also recorded from Tasmania, where it is stated by 

 Rodway 15 to occur only on the trunks of Arthrotaxis selaginoides. 



Gleichenia dicarpa is an extremely wide-spread fern in New 

 Zealand growing fully exposed in the open and denoting wet, 

 sour soil. The pinnae are plagiotropous in position, and fre- 

 quently arranged in two or more tiers, one above the other. The 

 ultimate segments of the pinnae are pouch-like beneath through 

 the extreme recurving of the margin. This pouch-like form is 

 virtually the sole specific character separating G. dicarpa R. Br. 16 

 from G. circinata Sw., the segments of which are flat. Gleichenia 

 dicarpa var. hecistophylla (A. Cunn.) Hook. f. is the common heath 

 or moor fern of Auckland. According to Cheeseman's specific 

 description the " segments are strongly incurved beneath, some- 

 times as much as in the typical form, but variable in this respect." 

 This character, however, I recently saw to be environmental 



14 Also recorded by E. P. Turner on Dacrydium intermedium (Report on a botani- 

 cal examination of the higher Waimarino District, p. 3, Wellington, 1910). 



15 Rodway, L., The Tasmanian flora, p. 290. Hobart, 1903. (Pinaceae.) 



16 According to the Index Filicum, pp. 321-322, Gleichenia dicarpa does not occur 

 in New Zealand but G. linearis (Burm.) Clarke, while G. hecistophylla A. Cunn. 

 = G. alpina R. Br. These conclusions I have no means of verifying as I write, 

 and so am following Cheeseman's nomenclature (op. cit., pp. 1117-1119), which does 

 not affect at all the statement as to plasticity or the conclusion derived therefrom 

 as to specific identity in two species held to be distinct. 



