4o 
Geo. K. Sutherland. 
and with projecting ostiole, at first sunk, finally superficial with 
brown leathery walls. Asci few, cylindrical with short thickened 
rounded apices, 30-35/z X' 10-14//, 8-spored. Paraphyses absent. 
Spores hyaline, two-celled becoming four-celled, surrounded by thin 
mucilaginous sheath, on the rupture of which the spore breaks at 
the weak middle into two portions, 12-15// x 3-4’5/z. 
Hab. Parasitic on Pelvetia in Britain. 
Fig. 3. Pharcidia pelvetia;. 1, thallus with perithecia on diseased patches 
(a) ; 2, section showing perithecia and dark-coloured parasitic mycelium ; 3, 
ascus (a) and ascospores ( b). 
This fungus is likewise parasitic, but is easily distinguishable 
to the naked eye from Stigmatea by the irregular outline of the 
blackened areas and the immense number of minute perithecia 
represented in Pig. 3, 1. Its stout, brown mycelium consists of 
thick-walled irregular cells with an average diameter of 3-4 /x, but 
frequently of 5// or even more. It forms close coils around the 
host cells into which haustoria are sent. 
Densely crowded hyphae riddle the cortical layers and send 
branches along the surface forming a loose network in the broken- 
down rind. The rapid extension of diseased patches makes this 
parasite a powerful factor in preparing the thallus for the subsequent 
action of saprophytic fungi and bacteria. 
