389 
Localities. Kn: Various localities at Frederikshavn and Hirsholmene (C. M. Poulsen. H. E. På 
K. R.); VT, VU, ZL, North of Læsø; FE, FF, Læsø Trindel, 10—15 m. — Ke: EU, Lille Middelgrund. — 
Km: FA and XC south of Læsø. — Ks: D, off the entrance to Isefjord. — Sa: FT, north of Samsø: 
bay of Nexelo (Th. Mortensen); BD, north of Tunø; AH’, Lillegrund at Fyns Hoved. — Lb: W. side of 
Æbelø; cV, off Røgle church; Snoghøj; Fænø Sund; Linderum; Aarøsund; Augustenborg Fjord. — Sf: 
UV, north of Ærø, 13 m; Nakke Odde, Avernak Ø. — Bw: Several places south of Als (bV, bY, bZ, 
cE, cG, near land at Kegnæs light-house, dK, Pøls Rev); LE, Vejsnæs Flak; LC, south of Gulstav. 
16. Ceramium fruticulosum (Kützing) J. Agardh. 
J. Agardh 1894 p. 31; Henning Petersen 1908 p. 70, 1911 p. 101. 
Hormoceras fruticulosum Kützing, Linnæa 1841 p. 734, Spec. Algar. 1849, p. 676, Tab. phyc. 12 1862, 
pl. 73. 
Dr. PETERSEN distinguishes the following forms: 
a, dichotoma H. Ptrsn. 1911 p. 71, H. Ptrsn. 1908, Tab. IV Fig. 2). 
Branches dichotomous or main stems may be developed. 
8, penicillata (Aresch.) H. Ptrsn. 1908 Tab. IV Fig. 3; 1911 Plate I Fig. 4. 
(Hormoceras fruticulosum Kitz. sensu stricto et Ceramium penicillatum Aresch.; C. 
penicillatum f. fasciculata Kylin 1907 p. 177). 
Very distinct main axes with lateral distichous shorter bushels. 
The third form described in 1908, f. rubroides H. Ptrsn., has been withdrawn 
by Dr. PETERSEN as, on closer examination, it turned out to comprise two distinct 
species, most of the specimens belonging to C. Boergesenü, one to C. atlanticum. 
C. fruticulosum occurs in the Northern Danish waters with comparatively high 
salinity. It has been met with in all seasons but most frequently in summer. It 
reaches a length of 9 to 13 cm. It was found sterile in winter (December), and 
spring (April), with tetrasporangia in May to October, with cystocarps in June to 
August; antheridia were met with in July. Antheridia may occur in the same in- 
dividuals as the cystocarps; they cover completely the joints of the upper part of 
the branches. In female plants spermatia may be found adhering in great number 
to sterile hairs in their whole extent (fig. 309). Sexual specimens are at least just as 
common as tetrasporiferous ones. The species occurs always near the low-water mark 
where it may be rather abundant, in particular in exposed localities, in the Skagerak 
often in company with Polysiphonia Brodiei. 
The two varieties have much the same distribution (Skagerak, northern 
Kattegat) and occur often in the same locality connected with intermediate 
forms. 
Localities. Ns: Thyboron harbour, outside of W. mole (3). — Sk: Hanstholm, 2 m (3); Bra- 
gerne, 2m (8); Lønstrup (8); Hirshals, mole and stones («, 8): Højen («). — Kn: Harbour of Skagen 
(&, B); harbour of Hirsholm («); Deget («) (Boye Petersen); Rønnerne N. of Frederikshavn; Busserey, in 
Ascophyllum nodosum (8); harbour of Frederikshavn («, 8, outside of S. mole); off Frederikshavn (©) 
(A. Otterstrom); Østerby harbour, Læsø («); harbour of Sæby («). 
