377 
most developed in the summer months. The most frequent fructifications are tetra- 
spores and paraspores, often occurring in one individual. Tetraspores have been 
met with in May to Sept., paraspores in July to Sept., anther- 
idia and cystocarps each once in September. 
Dr. PETERSEN has in 1908 distinguished 5 forms to which 
he has now added the f. umbellifera here described. 
1. F. typica. 
2. F. strictoides, 
subf. «, 
subf. 8, corticatula Kylin (Cer. corticatum Kylin 1907 
p- 176). 
F. modificata. 
F. radieulosa. 
F. zostericola. 
-c 
zZ 
a 
Fig. 315. 
3 Ceramium diaphanum. 
F. umbellifera H. Prtsn. n.f. — Much branched towards the young _ pseudodichoto- 
a oN 
apex, with short internodes and somewhat divaricate branches. my- In both branches 
the last segment is on 
Form from protected water, analogous to C. rubrum f. radians and C. the point of branching. 
strictum f. stricto-tenuissima. Related to f. strictoides. (Henn.Petersen). © apical cell; s, new 
branches, c, central cell. 
Localities. F. typica. Ks: Harbours of Anholt and Lynæs. — Sa: Har- 390 : 1. 
bours of Koldby Kaas and Horsens. — Lb: Harbour of Rosenvold. — Sf: 
Svendborg. — Sa: Hofmansgave (Hofm. Bg.). — Sf: Svendborg. — Su: Harbour of Sletten. — Bw: 
Harbour of Gedser. — Bm: Rodvig; Faxe Ladeplads. 
F. strictoides. Ks: 3 localities in Isefjord. — Sa: Hofmansgave (Hofm. Bg.). — Sf: UV, 13 m. — 
Sb: 3 loc.; Nakskov Fjord (Th. Mortensen). — Sm: Venegrund. — Su: 5 loc.; harb. of Helsingor; 
Kalvebod Strand (M. L. Mortensen). — Bm: 1 loc. : 
F. modificata. Ke: Gilleleje (Lyngbye). — Ks: Harbour of Grenaa; near Rorvig. — Sa: 4 local. 
— Lb: 3 loc. — Sf: Svendborg Sund (E. Rostrup). — Sb: 4 loc. — Sm: 6 loc. — Su: 6 loc. — Bw: 
Near Sonderborg. — Bm: Stevns, Rodvig, harbour of Hesnæs. — Bb: 6 loc. around Bornholm, Chri- 
stianso, That. 
F. radiculosa. Bb: Allinge, Gudhjem, Christiansø. 
F. zostericola. Lf: LR, E. of Livø. — Sb: GY, 5,5 m. — Sm: HI; Stubbekøbing; Guldborgsund. 
— Su: Knollen. ; 
F. umbellifera. Ke: Gilleleje, E. of the harbour. — Su; Bay of Hornbek. 
3. Ceramium strictum Greville et Harvey. 
Harvey, Phyc. Brit. III Plate 334. Henn. Petersen 1908 pp. 61, 89, Figs. IV,2, 3. Tab. I Figs. 6, 7, Tab. Il 
Fig. 1; idem 1911, p. 98, Fig. 12, 3. 
With regard to the relation of Ceramium strictum to C. diaphanum reference may be 
made to the quoted papers by Dr. PETERSEN. C. strictum in the Danish waters reaches 
a length of 10 cm. Paraspores are the most frequent organs of reproduction; they 
were met with in almost all the waters where the species occurs, in May to Sep- 
tember. The tetrasporangia are much less common (once in Sm and some places 
in Bb, July and September); they occur partly in paraspore-bearing specimens, 
