Fig. 259. CALLITHAMNION TETRICUM. 



Colour. A dull purplish-red or brown. 



Substance. Rigid and harsh, but very fragile when once dried. 



Character of Frond. Thread-shaped {filiform); jointed; tufted or single; much 

 branched. Stems short and shaggy; dividing into several principal branches. 

 Branches several times re-branched; ropy; closely furnished throughout with 

 straight, rigid, hair-like branchlets; some simple; some clothed with short, 

 regularly-set, alternate hv^inchlQieens. 



Joints. Obscure in the stems; visible in all the branches. 



]\Ieasurement. From 2 to 8 inches long. 



Fructification. Of two kinds. 1. Minute spores in large oval capsules, generally in 

 pairs, sessile near the tips of the branchlet6^?^s. 2. Minute oval tetraspores, 

 sessile on little stalks which spring from the branchlettf^;;^s. 



Habitat. South of England. South and west of Ireland. On perpendicular sides 

 of rocks, between tide-marks. Frequent. 



Fig. 260. CALLITHAMNION EOSEUM. 



Colour. A fine purple-red when young; when old, brownish; becoming brighter in 



fresh water. 

 Substance. Very soft. 



Character of Frond. Tufts of slender-jointed threads {filaments) ; excessively and 

 loosely branched; often entangled. Stems set throughout with long, wavy, 

 spreading branches, which are re-branched in a similar way. Secondary set 

 furnished with branchlets, beautifully and regularly plumed like a feather with 

 brancliletde«.5. 



Joints. Visible throughout in young plants; in older, the stems opaque and full of 

 veins. 



Measurement. From 3 to 4 inches long. 



Fructification. Of two kinds. 1. Minute spores in clustered capsules, sessile on the 

 branchlets. 2. Oval tetraspores, sessile on the inner side of the hvdiY\c\\\Q\jeens . 



Habitat. Our shores generally. On rocks and the larger Fitci, near low-water 

 mark. Also in estuaries and muddy places. JSTot uncommon. 



Fig. 26L CALLITHAMNION TRIPINNATUM. 



Colour. A fine crimson. 



Substance. Soft and delicate; closely adhering to paper. 



Character of Frond. Tufts of jointed threads {filaments); much branched; the 

 whole plant at one level. Stems furnished throughout with irregularly alter- 

 nate branches. Branches set throughout with regularly alternate branchlets, 

 beautifully plumed like feathers. Upper branchlet^^;^6', longish; lower, short, 

 or altogether wanting; one, however, always rising at the base of each branchlet. 



Joints. Visible throughout, even under a pocket lens. 



Measurement. From 1 to 2 inches long. 



Fructification. Only one kind observed. Oval tetraspores, sessile on the branchlet^^ws. 

 Habitat. West of Ireland. On rocks at extreme low- water mark. Very rare. 



The solitary branchletee^^ rising from the angles of branching {axils) distin- 

 guishes this plant from G. Boireri, wliich it otherwise much resembles. 



38 



