44 
Geo. K. Sutherland. 
Cercospora plays very much the same part along the tidal zone 
that Cladosporium does above it. Like the latter it is widely 
distributed, and its conidia and mycelium may be found in almost 
any piece of decaying seaweed picked up from rock-pool or beach. 
Dried fronds of Laminaria showing Cladosporium usually also bear 
scattered conidia of this species. These are invariably of the short, 
stout, dark-coloured type and arise from a brown mycelium showing 
evidence of restricted growth. This would point to the adaptation 
of this saprophyte to thrive best in the zone either entirely 
covered with salt water or periodically submerged. Conidia and 
creeping superficial mycelium have been found on living plants. 
For example, they occur on blackened areas on actively growing 
specimens of Furcellaria fastigiata, but, owing to the presence of 
bacteria and also of a finer mycelium in the infected portions, it is 
uncertain which is the primary factor in attack. 
The mycelium is developed in the sub-stratum, but creeping 
surface branches also abound. The hyphae vary from 2-8/x. in 
diameter and may be sparsely septate or consist of short, stout 
nodulose cells. This variability is even more pronounced when 
grown in cultures. While immersed portions are usually hyaline or 
faintly coloured, exposed hyphae become light brown. The simple 
or branched conidiophores are erect or sub-erect, bearing conidia 
either singly at each tip or, by a later development of small 
swellings, aggregated in lax capitula of from three to five (Fig. 4, /). 
These arise as small buds and elongate rapidly, sometimes becoming 
uniseptate at an early stage (Fig. 4, 2) and developing the other 
septa as they grow, sometimes attaining almost their full length 
before the appearance of any division. In the latter case the conidia 
are usually of the long narrow type. When the fungus is growing 
under dry conditions, as on the thalli strewn along the upper beach, 
the conidia are short, dark-coloured and slightly constricted. The 
same type is produced in cultures where the conidiophores are at all 
aerial, but, when there is abundance of moisture, the long, narrow 
multiseptate type is predominant (Fig. 4, 3 and 4). The amount of 
moisture also affects the degree of colouration, both of the fertile 
branches and the conidia. 
Cercospora salina responds to culture conditions and grows 
luxuriantly on agar extract of almost any seaweed. Naturally the 
conidia also germinate readily in salt water, but there the 
development of mycelium is very slight. If it fails to find a 
suitable sub-stratum it proceeds to form conidia of an extremely 
