382 
C. danicum has been met with in May to July, in 4—13 meters’ depth. It reaches 
a length of 15 cm and has been found with antheridia in May, with cystocarps and 
tetraspores in July. 
Localities. Sa: GC, north of Fyn. — Lb: DF, E. of Bogø; DC, Aakrog Bugt; DB, Lillegrund; 
DX, Vodrups Flak. — Sf: UX, Skjoldnæs; CV, Billes Grunde. — Sb: UE, Vresens Puller; UU, Snode 
Rev. — Bw: DU, off Dimes Odde. — Bm: KT, Gedser Rev; at Stevns Klint (Joh. Lange). 
8. Ceramium rubriforme Kylin. 
Kylin 1907 p. 183, pl. 7 fig. 7. 
After having examined recently original speeimens of C. rubriforme Kylin Dr. 
PETERSEN refers to this species two specimens from one locality in the northern 
Kattegat and with doubt one from the South Fyn Waters, formerly referred to C. 
Rosenvingü f. intermedia. The former are 15 cm long and bear ripe tetrasporangia (May). 
Localities. Kn: Krageskovs Rev, 4—5 m. — Sf: (?) CU, at the N. end of Flæskholms Flak, 5,5 m. 
9. Ceramium arborescens J. Agardh. 
J. Agardh 1894 p. 33; Henn. Petersen 1908 p. 67 and 91, pl. III figs. 1—2; 1911 pl. II fig. 6. 
The species is rather extensively spread in the Danish waters from the North Sea 
to the Baltic Sea around Møen. It seems to be only little influenced by the salinity of 
the water, for the maximal length, 17—18 cm, is reached in the North Sea and the 
Baltic Sea as well. It occurs mostly near low-water mark, but has been met with 
in depths down to 12 meters. It is most frequent in spring (May) but has been 
observed in the months of April to September, with cystocarps and tetrasporangia in 
May to July. 
Localities Ns: Thyboron, pier. — Sk: Hirshals, E. side of mole and stony reef near land. — 
Lf: Glyngore. — Kn: Frederikshavn, harbour; boulder at Jegens Odde. — Ke: GI, Ostindiefarer Grund. 
— Ks: OP, Lysegrund. — Sa: KL, Bjarkes Grund; Kalo reef; Korshavn, reef; Hofmansgave (Hofm. 
Bang); Odense Fjord (C. Rosenberg). — Lb: Knudshoved, S. of Anslet Hage. — Sf: Svendborg. — Sb: 
Korsor (Hornemann); DN, Vengeance Grund, 12 m; UF, near Hov Sand; DQ, off Nakskov Fjord; UR, 
S. of Albuen. — Su: Dragør. — Bw: UQ, off Tillitse; UP, off Kramnisse Gab. — Bm: Stevns Klint, 
washed ashore (Joh. Lange); Rødvig, reef E. of the harbour; Klintholm harbour. 
10. Ceramium Rosenvingii Henn. Petersen emend. auct. 
C. Rosenvingii Henn. Petersen f. fransgrediens Henn. Petersen 1908, pp. 66, 91, figs. VI,2, VII,1, pl. II fig. 7. 
Frons dichotoma, apicibus rectis vel curvatis. Corticatio confluens, exceptis 
apicibus ramisque superioribus. Zone corticales discrete ab utroque margine crescentes. 
Tetrasporangia verticillata non erumpentia. Color subruber. HENN. PETERSEN. 
With regard to the present circumscription of the species comp. above p. 381. It 
has been collected in April to July, most frequently in May, in 1 to 9,5 meters’ depth. 
