Armsteong. — On a natural Arrangement of New Zealand Ferns. 361 



Asplenium, sp. Probably another species of this genus, found in the 

 lower Canterbury Alps, will yet be added to our list of New Zealand ferns, 

 and admitted to specific distinction. It is intermediate in appearance be- 

 tween A. faccidum and A. hooherianum, and frequently produces dense 

 masses of sori covering the whole under-surface of the frond. It has been 

 erroneously referred to A. richardi by collectors of living ferns. 



HymenojyJujllinn. The great increase in the number of species of this 

 genus is noteworthy. In the " Handbook " only fifteen species are given, 

 whilst I here acknowledge twenty-six, and I am by no means sure but that 

 I ought properly to have admitted several more. This is undoubtedly the 

 most difficult New Zealand genus of ferns, and requires to be carefully 

 studied in the living state. I think that most of the species here given will 

 be generally admitted in the future, seeing that most of the New Zealand 

 species suppressed in the first edition of the " Synopsis" have been re-ad- 

 mitted in the second. Probably also several new ones remain to be 

 discovered. It will be seen that I have restored Mr. Colenso's old species 

 H. revoliitum, which I consider quite as worthy of specific standing as H. 

 imilaterale, H. montanum, and others. H. cheesemanii is closely allied to H. 

 minimum, but differs in the ciliated margins and costa. It is the least 

 satisfactory of aU the species adopted here. 



H. armstrongii is also allied to H. minimum, but differs essentially in the 

 remarkable border, and in the columnar receptacle being frequently exerted, 

 which led Mr. Baker to place it in the genus Trichomanes (see Synopsis 

 Filicum, first edition in appendix). It is, however, more naturally allied in 

 habit to Hymenophyllum, and was first referred to this genus by Sir. J. D. 

 Hooker on its discovery in 1867. 



Of Mr. Colenso's H, erecto-elatum 1 have not yet seen specimens, but he 

 is such a careful observer, and is so well up in New Zealand plants, that I 

 have little reason to doubt its distinctness. The same author's H. imsillum 

 is certainly very near to H. tunhridgense, but I accept it for the present. I 

 have placed H. lyallii in this genus, although it was referred to Trichomanes 

 in the " Synopsis," because it appears to me to have more of the 

 habit of Hymenophylluvi than of Trichomanes ; but it cannot be denied that 

 the New Zealand species of the two genera present a graduated series of 

 forms, and the hmits of these two genera are anything bixt clearly defined. 

 Still, it is convenient to keep up both generic names, and I think it will be 

 found best to refer those species with long, distinctly-exerted, columnar 

 receptacles and densert issue to Trichomanes, and the remainder to Hymen- 

 ophyllum. H. malingii is a difficult plant to place, but apparently it comes 

 nearest H. (sruginosmn. 



46 



