758 Proceedings of the Royal Irish Academy. 



unicellular uncinate pedicels, carried above the disc on a single basal 

 cell. 



Halitat. — On leaves of Nesodaphne Towa, Hook, f., near Picton 

 (Marlborough County, South Island), and at Eotorua (North Island), 

 New Zealand. 



B. Phycopeltis niyra, sp. nov. 



Thallus forming a thin cell-plate, growing in band-like, radiate, 

 or irregularly-spreading lobes ; never forming circular discs. Margin 

 more or less irregular, sometimes breaking into short cell-filaments. 



Disc-sporangia present ; but no true sporangia on pedicels as yet 

 known. 



Colour black (by reflected light) ; by transmitted light a dark 

 olive-green. 



Several varieties are distinguishable, differing in the size of the 

 cells, and in the presence or absence of vertical, multicellular, barren 

 hairs, rising from the cells of the disc. 



Habitat. — (1) On pinnae of Asplenium falcatum, Greymouth, New 

 Zealand. (2) On leaves of Nesodaphne Towa, Hook, f., from Picton 

 (Marlborough, South Island), and Eotorua (North Island), New 

 Zealand. 



The first species is characterized by the compact and regular 

 structure of the disc, and its even undivided margin. In its young 

 stages it is very like the P. epiphyton of Millardet, and the P. arundi- 

 nacce of Montague ; but later it spreads out widely over the leaf 

 surface, forming what appears often to be a continuous sheet; a 

 peculiarity which suggests the specific name here given to it. 



Among the East Indian species described by Karsten, the nearest 

 is his Phycopeltis aurea ; but in that case the margin of the disc is 

 lobate, the disc-sporangia elongate and terminal, and the thallus- 

 cells of very diiferent size and relative proportions. Moreover, the 

 stalked sporangia (" Hakensporangia " Karsten) in that species are on 

 unicellular stalks longer than the sporangium, without the hooked 

 form characteristic of the one now under consideration, and without 

 the equally constant basal cell. 



It is interesting to note that though the growth on any particular 

 leaf starts from many different points, yet the appearance, under low 

 magnification, of a continuous layer is produced. This is due to the 

 fact that the separate discs never overlap ; when one growing cell- 

 plate comes into contact with another, the margins fit accurately 



