493 
compressa prefers the open sea-shores, where it often forms a dense 
covering on the rocks during high-tide, e. g., at Hojvig »Flesen«. It is 
also found in low-lying tide-pools of fresh water. Yar. prolifera is a 
form from sheltered localities and is found in the interior of fjords, 
where, the water is only a little salt, and where it usually forms large 
detached floating masses. Var. micrococca grows commonly on exposed 
coasts at a very high level, where it is wetted by the spray only in 
rough weather, and where it forms a pale-green belt, often associated 
with var. minima and forma cornucopia? of var. genuina. At Bosdalafos 
at the west coast of Vaago I have gathered var. micrococca at a height 
of about 80 feet above sea-level. 
Almost all these varieties have been observed in the months from 
April to December, and fruiting in the same. They are common every¬ 
where along the Fseroese coasts in localities suitable for their growth. 
165. E. clathrata (Roth) J. Ag. 
var. Rothiana Le Jobs, Ulva clathrata 0 Rothiana, Le Jobs, 
Liste p. 50. 
var. Agardhiana Le Jobs, Ulva clathrata a Agardhiana, Le Jobs, 
Liste p. 49. 
The specimens referred to var. Rothiana are filiform, and much 
branched examples. The specimens referred to var. Agardhiana 
have broader branches, and, the main branch being often distinctly 
broader, they then strongly resemble forms of what Ahlner calls 
E. procera. 
As pointed out by Le Jolis, E. clathrata is distinguished by 
its decidedly genuine ramification, while, on the other hand, E. inte- 
stinalis var. compressa is proliferous, rather than branching, hut 
Le Jobs’s expression »rather« (plutol) indicates that it is often very 
difficult if not impossible to arrive at any definite conclusion re¬ 
garding the specimens in hand. 
In a gathering from Kalbakfjord, distinct trabeculae similar to 
those already mentioned under E. intestinalis var. compressa and var. 
prolifera were found in branches of a moderate thickness. They 
were distinctly visible through the walls of an uninjured plant 
which had been preserved in spirit. In this case again they were 
not true diaphragms, as a transverse section distinctly showed, 
but only plates or trabeculae stretching across a part of the lumen. 
Some of the specimens referred to this species were more or less 
closely covered with short prolifications and somewhat resembled 
Kiitzing’s figure in Tab. phyc., vol. 6, tab. 33; but from these very 
proliferous examples there was an easy transition to specimens al¬ 
most entirely without prolifications. I am of opinion that Sim- 
