LICHENS AND FUNGI OF OTAGO, NEW ZEALAND. 437 



Lichens, especially the lower crustaceous groups. By Korber, Stizenberger,* 

 Mudd, and others, the genus is classed among the Verrucariacece {Lichens) ;f but 

 while Korber proposes enlarging his genus at the expense of the Sphcerice (Fungi), 

 Mudd J is apparently disposed to hand over the genus itself, with all its species, 

 to the Fungi. My own impression is, that in course of time the genus Micro- 

 thelia will be partitioned mainly, if not entirely, between the Verrucariacew and 

 Sphceriacei — between Lichens and Fungi. 



Sp. 1. M. perrugosaria, nov. sp. (figs. 23 to 28). 



Hab. Perithecia parasitic on the apothecia of Placopsis perrugosa, Nyl., which 

 I found somewhat plentifully on basaltic boulders on the top of Kaikorai Hill 

 (1092 feet). 



The parasite is best seen by moistening the apothecia of the Placopsis. The 

 disk or epithecium is naturally of a dark or dull port-wine red or crimson colour. 

 Under moisture this colour becomes lighter, the epithecium swells and becomes 

 waxy, and the black punctiform parasitic perithecia then become prominent 

 (figs. 23, 24). They occur in considerable numbers on a single apothecium; gene- 

 rally discrete or isolated; sometimes confluent. The perithecium is found, on 

 careful examination, to be, in its upper half, a papilla seated on the epithecium 

 of the Placopsis, while the lower half is immersed in its tissues (figs. 25, 26). 

 Its walls are formed of dark-brown, small, irregularly formed, and densely 

 aggregated cells (figs. 26). 



The paraphyses are delicate, filiform, indistinct; without clavate heads; 

 coloured yellow by iodine (fig. 27 a). The thecx are -0021" long, and -00045" 

 broad ; ribband-shaped or ventricose, according as the spores are arranged in one 

 or two rows ; 8-spored ; coloured yellow by iodine (fig. 27 c d), and thereby dis- 

 tinguished from the thecse of the Placopsis, which (with its hymenial gelatine), 

 under the same reagent, assume a beautiful Prussian blue, and which are -0045" 

 long, and -00045" broad (fig. 29). The spores are broadly ellipsoid or oval ; olive 

 or brown; 1-septate; seldom or never constricted at the septum ; polari-bilocular 

 in the young state, and otherwise resembling, on a small scale, the spores of 

 Physcia pulverulenta, Schreb, and other Lichens ; -00045" long, and 00025" broad 

 (fig. 28). They are readily distinguished from the spores of the Placopsis, which 

 are oblong-ellipsoid; with double contour ; simple; colourless; and -0006" long, 

 •00045" broad (fig. 30). 



* " Beitrag zur Flechten-systematik," 1862, p. 147. 



|- The most recent arrangement of the Verrucarice is by Prof. Garovaglio of Pavia (" Tentamen 

 Dispositionis Methodicse Lichenum in Longobardio nascentium," with Plates and Dried Specimens, 

 1865), who includes in the comprehensive genus Verrucaria, no less than 35 Massalongina genera, 

 and among these Microthelia, Korb., and its allies, Thelidium, Mass. ; Tichothecium, Flot. ; and 

 Thrombium, Wallr. 



J " Manual of British Lichens," 1861, p. 306. 



