21 



cannot pretend to an intimate knowledge of this intricate and perplexing 

 genus. The chemical reactions of K and C on the upper surface and 

 medulla are (K — C — ). 



Thelotrema ohovatum (Sp. Nova). — The spores of this lichen differ in 

 shape from those of Th. lepadinum, and have altogether an appearance so 

 peculiar, that I have been tempted to elevate it into the rank of a species 

 under the name given above. Thallus yellow, rimulose, uneven, slightly- 

 nodulated; apothecia hemispherical, crowded in some parts; ostiolum 

 rounded, open, margin even; disk urceolate, scutelliform, dark brown, 

 proper margin inflexed ; spores eight, colourless, obovate, sharp pointed 

 at one end, rounded at the other, divided internally by numerous 

 -cross bars which do not reach the margin; epispore beautifully crenu- 

 lated. 



These characteristics are constant, at least in every specimen examined. 

 I have not seen T. subtile, but, judging from the description of it by 

 Leighton, in his Lichen Flora, I cannot reconcile myself to identifying 

 the present plant even with it. 



Psoroma athroophylhjbm (^Sp. Nova). — Thallus greyish brown, thick, 

 continuous, brownish black, and rough on the under surface, multifido- 

 laciniate above; laciniae closely imbricated, ascending, broad, margins 

 roundly crenate, their under surface somewhat paler; apothecia large, 

 rufous, rugose, margin elevated, granuloso-concrete ; spores eight, colour- 

 less, sphaerical, crenulate, in nearly single file in asci; paraphyses in- 

 distinct. 



This may be Psoroma euphylluTn (Nyl.), of which no description is 

 given in the " Flora of New Zealand," nor in any of the later papers to 

 which I have had access. 



Lecidea contigua (Fr.). — A curious form growing on earth. The apo- 

 thecia are sessile, and arranged in beautiful concentric rings ; the border 

 sharply defined and flat, being set at an angle to the surface, a disposition 

 seen in a certain proportion of New Zealand crustaceous lichens. The 

 internal organization resembles exactly that so characteristic of this 

 lichen. 



Lecidea enteroleuca (Ach.). — On earth. In this instance, also, there 

 are no elements of distinction of sufiicient importance to warrant a 

 separation. 



Platysma dermatoides (Sp. Nova). — Thallus firm, large, from six to 

 eight inches in diameter, roundish, thick ('3 mm,), brownish yellow or 

 buff colour, under side concolorous, closely and roundly lobate ; laciniae 

 sinuato-piiauatifid, apiceS rounded and recurved, often subimbricate, and 



