480 
also occur in December and in the following months. Still in May numerous cysto- 
carps may be found. Ripe tetrasporangiferous leaflets were met with in January to 
May, but the dissemination of the spores apparently takes place mostly in winter. 
The sporophylls reach a length of 20 mm. 
The age reached by the individuals of this species is not easy to determine 
with certainty, not only because the basal disc is able to produce adventitious shoots, 
as emphasised by Korkwırz (1900, p. 45), but also owing to the fact that new 
vegetative shoots may be produced not only in the autumn or in winter, but also 
in spring or early in summer on the new leaves, and there may thus possibly be 
produced two generations of shoots in one year. 
When in single cases, in specimens from the Little 
Belt, I have ascertained the presence of 7 generations 
of shoots in one specimen, it is therefore not per- 
mitted to conclude that it was 7 years old, though 
it is not improbable that it was really so. KoLkwitz 
thinks that D. sanguinea becomes “kaum Alter als 
einige Jahre’. I estimate the maximal age to be 
4—5, perhaps 7 years. 
Delesseria sanguinea reaches its greatest frequency 
Fig. 444. and the best development in comparatively deep 
Delesseria sanguinea. Adventitious branch ater with fresh flow, as in the eastern channel of 
of plantlet producing downward growing 2 S 3 
Ahrons ef ana Eds Zee iL. the Kattegat and in particular in the Belts and the 
Sound, where it is often predominant. In such places 
it often attains a length of 30 cm or a little more. In the open waters as Ns and 
Sk and in Kn it does not thrive by far so well and only reaches a length of up 
to 20 cm. Still in the western Baltie (Bw), in the deep channel between Lolland 
and Fehmern it reaches the maximal length. But in Bm it reaches only 18 cm and 
at Bornholm only 9 cm in length. The maximal length of the leaves varies about 
10 cm in most of the Danish waters, in Kn and Ke between 7 and 18,5 cm, in Sb 
between 6 and 17 cm, in Su and Bw between 7 and 14 cm. In Bm it is only 5—8 cm 
and at Bornholm 2—5 cm. The greatest breadth of the leaves is reached in the 
Northern and Eastern Kattegat where it is 1,5—7,5 cm, most frequently 2,5 —4,5 cm. 
In Sb the breadth is 1,3—4 cm, in the Sound 1,4—3 cm, in Bw only 0,8—1,5 cm, 
in Bm 0,3—1,3 cm and in Bb only 0,3 cm (comp. Plate VII figs. 1—4). The breadth 
of the leaves seems therefore to be more influenced than the length when the salin- 
ity of the water is diminished. 
D. sanguinea occurs in all the Danish waters except the Limfjord and other 
fjords. It does not grow in depths smaller than 4—5 meters and descends to 30 meters’ 
depth at least; in Sb it has been met with in 40 meters’ depth. It prefers water with 
a salinity of 20 °/,, or higher and with rather low summer temperature. It is char- 
acteristic to stony bottom in the deep channels in our inner waters, where it occurs 
in great specimens with several generations of shoots. 
