LICHENS AND FUNGI OF OTAGO, NEW ZEALAND. 417 



19. Arthonia platygraphella, Nyl., Lich. N.Z., 258 (fig. 21). 



On " Totara" bark, Greenisland Bush ; associated with Opegrapha subeffigu- 

 rans, Nyl. 



The apothecia are frequently roundish and sub-convex, with a Lecideiform 

 aspect, exhibiting a thin, white, obscure, thalline margin. Sometimes they are 

 oblong and irregular, sometimes confluent. 



The thecce and paraphyses are unaffected by iodine ; the former {a) are 

 broadly saccate, as is the general character of thecse in the genus Arthonia; 

 8-spored ; 0009" long, and -0006" broad. The spores (b) are irregularly fusiform or 

 obovate, colourless, 3-septate ; -00045" long, and -00025" broad. They have fre- 

 quently much the appearance of half-spores — halves of fusiform, and 1- septate 

 spores — with minor nuclei, or granular contents. 



20. Platygraplia longifera, Nyl., Lich. N.Z., 258 (figs. 22-3). 



On the bark of dead trees ; Saddlehill Bush. 



The paraphyses (fig. 22 a) are subdiscrete, delicate, filiform, without clavate 

 heads. The theca? {b) are somewhat sac- shaped, 8-spored ; -0030" to -0036" long, 

 and -0006" broad ; generally tmtinged by iodine, but occasionally violet. The 

 spores (fig. 23) are acicular or narrowly fusiform, sometimes slightly curved ; 

 poly-septate (generally about 10-septa). They vary considerably in dimensions, 

 from -0009" to -0018" long, and -00015" to -00025" broad. 



21. Pertusaria perfida, Nyl., Lich. N.Z., 253 (figs. 24, 25). 



On tertiary grits and conglomerates, base of Saddlehill ; on trappean rocks, 

 Shaw's Bay, The Nuggets. 



The thallus varies in colour from dark slate or lead-colour to whitish. The 

 sterile portions are made up of a series of Isidia ; and the plant, in this state, 

 would have been described by the earlier Lichenologists under the genus Isidium.. 

 The fructiferous portions of thallus bear a great general resemblance to certain 

 forms of Lecanora cinerea, L. 



The paraphyses (fig. 24 a) constitute a network of very delicate, indistinct, 

 hyaline filaments, without clavate, coloured heads; and are thus typical, or 

 possess the ordinary characters of those of the genus Pertusaria. The thecce (be) 

 vary in length from -0069" to -0090", and in breadth from -0015" tp -00075", ac- 

 cording as the 8-spores are arranged in one (c), or a double (b) series, being in the 

 one case ribband-like, and in the other ventricose or obovate superiorly ; they 

 strike a beautiful blue with iodine (£), while the hymenial gelatine gives a violet. 

 The spoils (fig. 25) vary considerably in length, from -0006" to -0015", with a 

 general breadth of -0006" ; they are broadly ellipsoid ; simple, colourless, generally 

 exhibiting a double contour (b) ; granular, or full of oil globules in the young 



