4 i 
New Marine Fungi on Pelvetia. 
Immense numbers of small perithecia are produced shortly 
after infection. They become superficial and consequently have 
well developed thick leathery walls. The ascospores likewise are 
protected by a thin mucilaginous envelope. 
PLEOSPORA PELVETIJE NOV. SP. (Fig. 4, 1—4). 
Mycelium thick, brown with irregular cells. Perithecia at first 
sunk, becoming superficial, large, black, leathery with short conical 
opening, 150-200/a in diameter. Asci cylindrical or with free end 
slightly tapering, thin walled, 110-125 /a x 25-30/a, 8-spored. Spores 
biseriate, elliptic-oblong, yellowish brown, generally seven cross 
septa and numerous vertical ones, slight constriction, 30-35/x x 12/a. 
Conidial form believed to be Macrosporium pelvetice. Conidio- 
phores branched or unbranched, 3/a, brownish. Conidia clavate, 
with 5-6 transverse and 1-3 vertical septa, 35-45/a x 11-12/a. 
Hab. At first parasitic on Pelvetia, then saprophytic. 
2 
Fig. 4. Pleospora pelvetia (1, 2) and Macrosporium pelvetice (3, 4). 1, section 
of thallus showing mycelium and conidiophores of Macrosporium ; 2, conidia of 
same ; 3, perithecium of Pleospora ; 4, ascus (a) and ascospore ( b) of same. 
This fungus produces very much the same effect upon plants 
attacked as does Botrytis. The thalli become withered and tend 
to break down into a brownish slimy mass. The thick brownish 
yellow mycelium penetrates and destroys the tissue ; the whole 
medullary portion becomes a mass of parasitic hyphse as in Fig. 4, 7. 
The cortical layers are also riddled and outside arise erect unbranched 
or slightly branched conidiophores (a) on which are borne the clavate 
muriform conidia shown in Fig. 4, 2. These vary considerably in 
shape, but usually show 5-6 transverse and one, two, or three vertical 
