428° 
plant might then be referred to P. divaricata Ag. which is otherwise not sufficiently 
different from f. aculeata to be distinguished from it as a different form. F. aculeata 
occurs in shallow water. It must be assumed that loose individuals of P. violacea 
drifted in shallow water may go on growing there and by the altered condition, in 
particular the stronger light, assume the appearance characteristic to this form. Spec- 
imens of f. fibrillsa growing in very 
sunny localities, e.g. the stony reef in Kalo 
Vig, may take an appearance reminding 
one of f. aculeata by squarrose branchlets. 
P. violacea may complete its develop- 
ment in a short period. Most of the in- 
dividuals probably only reach an age of 
a few months. This is at least the case 
with the specimens which grow on annual 
species of Algæ, e. g. Chorda Filum; they 
must have germinated in spring (May) 
or later, are fully developed in summer, 
and perish with the host plant in autumn. 
In favourable localities more than one 
generation may probably be produced in 
one summer. In the plant shown in fig. 
365, collected June 15th, which was cert- 
ainly only a few weeks old, a young 
procarp was already discernible in the 
trichoblast of the 20th joint of the plant, 
and another young plant of about the 
i J | Fig. 374. RL same size bore almost ripe antheridia. 
Polyphony ace f aut, Portion of shoo! With Most Of the specimens certainly perish 
in autumn after fructification, but other 
individuals endure the winter and recommence in spring the growth arrested during 
the winter. 
The growth ceases or is at least much diminished in August, and several in- 
dividuals then begin to lose the trichoblasts. In the following months the growth 
is likewise stopped or extremely feeble. In November all or most of the trichoblasts 
are thrown off, and that is also the case with the tips of many of the shoots. In 
December and January the species appears in the same stage (fig. 375). In the last 
part of December 1890, however, I found on the bottom of Holbek Fjord, which 
at that time had been covered with ice during a month, specimens with well 
preserved growing points and trichoblasts. The growth recommences in the last 
part of the winter. In the wintering specimens new shoots are found in spring 
growing out from the basal cells of the decayed trichoblasts, while the tips of the 
wintering shoots have fallen off. It seems, however, to be only a small number of 
