Plate LVII. 



Fiff. 262. CALLITHAMNION ARBUSCULA. 



Colour. Dark clarety-red, or brown. 

 Substance. Stems gristly; branchlets very soft. 



Character of Frond. Thread-like {filamentous)] jointed; single or tufted; excessively 

 branched; bushy. Stem thick at base; often shaggy with fibres; bare at first; 

 then set with irregular, alternate branches. Branches twice or thrice re-branched 

 with shorter ones, which spring from all sides of the stem {quadrifarious') ; 

 and are all densely clothed with minute, overlappuig branchlets, also 

 quadrifarious. Branchlets plumed with pointed, spreading or back-curved, 

 simple or forked branchletee/i^, springing from each joint. 



Joints. Only visible in the branchlets and branchletm^^. 



Measurement. From 3 to 8 inches long. 



Fructification. Of two kinds. 1. Minute spores in large roundish capsules; sessile, 

 two or three together on the branchlets. 2. Globose tetraspores, sessile on the 

 inner side of the last branchlets. 



Habitat. Western shores of Scotland and Ireland, abundant. East coast of Scotland, 

 rare. Filey, plentiful on the north side of the bridge. On rocks and mussel- 

 shells, &c., from half-tide level to low-water mark. 



ISTot found on the same stations as C. spongiosum. 



Fig. 263. CALLITHAMNION FLOCCOSUM. 



Colour. A bright purplish-lake. 

 Substance. Very soft and flabby. 



Character of Frond. Dense tufts of hair-like, jointed threads {filavients) much 

 branched at intervals. Stems very slender; irregularly divided into several 

 principal branches, which are again once or twice forked {dichotomous). 

 Branches naked, or furnished at rather remote intervals with short, many- 

 times-divided (almost tufted), alternate, lesser branches. Every joint of the 

 whole plant bearing a pair of exactly opposite, very short, very slender, 

 pointed branchletm^5. 



Joints. Visible throughout. 



Measurement. From 1 to 5 inches long. 



Fructification. Only one kind observed. Oval tetraspores borne on the branchlet^e^is 

 near their base. 



Habitat. North of Scotland (Orkney, Aberdeen, &c.). On rocks near low-water 

 mark. Very rare. 



The fringing branchleteews of this plant form so distinct a character that it 

 is impossible to mistake it for any other species, 

 39 



