Fig. 126. POLYSIPHONIA FURCELLATA. 



Colour. When recent, a bright brick-red; turning* umber-brown when dry. 

 Substance. At first firm, but becoming soft immediately. 



Character of Frond. Very slender tufts of jointed threads { filaments) much entanglefl, 

 wavy, excessively branched. All the branching regularly and repeatedly, and, 

 in the upper part, very closely forked {dicliotomous); angles of branchins^ 

 (axils) broad and rounded; branchlets upright, their points somewhat hooked 

 in. joints visible throughout; marked with several slender, upright lines 

 (internal tubes) which sometimes cross each other. 



Internal Tubes. About eight. 



Measurement. Five or G inches long. 



Fructification. Not found in Britain. 



Habitat. South shore of England and Ireland. Jersey. Found floating or by 

 dredging. Very rare. 



Fig. 127. POLYSIPHONIA FASTIGIATA. 



Colour. Dark -brown; reddish in deep water; becoming yellowish on exposed rocks 



left by the tide; drying quite black. 

 Substance. Rigid. 



Character of Frond. Dense, globular tufts of jointed threads { filaments) excessively 

 branched from the bnse. Filaments as thick as hogs' bristles, and of equal 

 diameter throughout the plant. All the main branches forked {dichotomous) ; 

 their angles of branching [axils) wide. Branchlets rather less regular; being 

 occasionally alternate. All the tips of the same len^jth as if they had been 

 cut to one level (forming a circle when laid out). Joints visible throughout; 

 marked with numerous upright lines (internal tubes) ; a dark central spot in 

 each. 



Internal Tubes. Sixteen or eighteen. 

 Measurement. From 2 to 4 inches long. 



Fructification. Of two kinds. 1. Clustered spores in ovate-stalked capsules, with a 

 narrow, protruding mouth; external. 2. Tetraspores, immersed in swollen, 

 distorted branchlets. 



Habitat. Our coasts generally. Parasitic on Fucus nodosus, and Fucus vesicidosus ; 

 but especially the former. Very common. 



Fig. 128. POLYSIPHONIA PARASITICA. 



Colour. A clear lake-red; becoming brownish in drying. 

 Substance. Ri^id, but not harsh. 



Character of Frond. Delicate, feather-like tufts of jointed threads {filaments), very 

 much branched. Stems rather compressed; simple. Branches alternate, generally 

 short below, longer above; once or twice re-branched like a feather {pinnated); 

 last branchlets simple, awl-shaped, acute, uprii^s^ht, alternate, closely set. Joints 

 visible throughout; marked with three or four lines (internal tubes) with 

 transparent spaces between. 



Internal Tubes. About eight. 



Measurement. From J inch to long. 



Fructification. Of two kinds. 1. Clustered spores in large ovate, shortly-stalked 

 capsules; external (very rare). 2. Tetraspores, immersed in swollen, much 

 distorted branchlets. 



Habitat. Our coasts generally. Sometimes parasitic on the larger algse. Oftener in 

 pools near low-water mark; growing on the pink incrustations formed by 

 Corallinas and Melobesias ; where few other plants are to be seen. 



56 



