gen; NC, east of Tangen. — Ks: Pakhusbugt, Anholt, 19 m; Grenaa harbour; NB, Havknudeflak; MZ, 
north of Hjelm; D, north of Gronne Revle; RL; EH and NL, off Lynæs, Isefjord. — Sa: BF, off Sletter- 
hage; Kalo Rev; Aarhus; PC, between Sejerø and Ordrups Næs; PK, Norsminde Flak; YV, east of 
Samsø, 15 m (+ and ¢ in June); MX, at Tunø Rev; BC, off Hov Ron; BB, Søby Rev; aV, east of 
Endelave; DK, Bolsaxen; MQ, Paludans Flak; entrance to Korshayn; north coast of Æbelo; Hofmans- 
gave (Lyngbye, Hofman Bang, J. Vahl, C. Rosenberg). — Lb: Horsens Fjord west of Aldero; AX, Bjorns- 
knude; FZ, Kasser Odde; Fæno Sund; cZ, Knudshoved Grund; Aarosund (Reinke, !); CD, Helnæshoved 
Flak; Sonderborg. — Sf: CC, south side of Hornenæs; banks off Nakkebolle Fjord; UX and UV, north 
of Æro; CV, Billes Grunde; BX, Svendborgsund; Svendborg. — Sb: South side of Refsnæs; MN, north 
of Asnæs; GU, S.W. of Asnæs; AG, Romso; Reerso; GQ, west side of Slettings Grund; Kerteminde; 
Korsor; GY, west of Gjellegrund; Z, off Skagbo Huse; NS, BS near Nyborg; GZ, north of Egholm; Lo- 
hals harbour, near low-water mark; Snøde Rev, west of Langeland, 4 m, st.; T, Staalgrund, 9,5 m, ©; 
LB, Langelandsbelt, 17 m, 2. — Sm: CK, 9,5 m; CQ, 4,5 m, st. — Su: Hellebæk (Børgesen, !); north 
of Helsingor; PZ, east of Hveen, 10—19 m, 2; TF”, Staffans Flak, 11—13 m, st.; RH, Knollen, 9,5 m, 
st. — Bw: Flensborg Fjord (Suhr, Hansen): Egernsund, Graasten; cX, off the South end of Kobbel 
Skov; bZ, south of Sønderborg; DV, south of Marstal 9,5—11 m, st; LC, south of Gulstav, 11,3 m, st; 
KZ, off Kramnisse, 4,5 m, st. 
5. Callithamnion roseum Harvey. 
Harvey in Hooker, The English Flora, Vol. V, part I. 1833, p. 341; Manual Brit. Alg. 1841, p. 106; 
Phycol. Brit. pl. 230, 1849; Wyatt, Alge Danmonienses No. 44. J. Agardh, 1851, p. 36; Bornet in 
Borgesen, Mar. Alg. Fær. 1902, p. 377; Le Jolis, Alg. mar. de Cherbourg, no. 162; Kolderup Rosen- 
vinge 1920, p. 44. 
Phlebothamnion roseum Kützing, Tab. phyc. Vol. XI, tab. 97, 1861. 
Callithamnion byssoides K. Rosenvinge, 1911, p. 209. 
This species grows in certain localities in the 
harbour of Frederikshavn where it has been met 
with repeatedly during the last 27 years. Otherwise 
it is seldom found in the Danish waters. The Da- 
nish specimens agree with the species as described 
by Harvey and as understood in the above citations. 
They are up to 10 cm high. 
The filaments are branched on all sides, some- 
times, however, the branches are alternate biseriate, 
in particular in the undermost part of the upper 
branches, and then usually placed in a transversal 
plane, as pointed out by Borner (1. c.). The main 
axes are distinct, scarcely bent in zigzag. When 
the branching is regular and the plant is in active 
growth the segments are cut off by inclined walls. 
The young segments are only a little longer than 
broad (fig. 249). The branches are never branched 
Fig. 249. 
from the base. The number of joints below the Callithamnion roseum. Upper ends of shoots. 
first branch varies from 2 to many, at least 25: as In that on the left and in the middlemost 
im A the branches are arranged in a spiral, in the 
a rule, it is greatest at the base of the older branches. shoot on the right they are biseriate. 290: 1. 
