Plate XXVIII. 

 Fig. 123. POLYSIPHONIA FIBRILLOSA. 



Colour. Brownish-red in deep water; pale straw in shallow pools; becoming purplish 

 in drying-. 



Sulstance. Tender and e^elatinous; soon decomposing. 



Character of Frond. Thread-hke {filamentous)', solitary or tufted; jointed; very much 

 branched. Stem robust below; becoming finer u})wards; simple, or once or 

 twice divided; naked near the base; then set throughout with short, slender, 

 finely-divided side-brauchlets, whose tips are clothed with fibres. Branches 

 rather robust, wide-spread; of various lengths; the lowermost generally longest; 

 sometimes simple, but usually many times re-branched, each set more slender 

 than the last (these also, in luxurious specimens, set with short, slender 

 branchlets); the last branchlets hair-like; their tips splitting into numerous 

 cobweb-fine fibres {jihrilliferous). Joints not visible in the stem nor lower 

 part of the branches; obvious above; marked by two or three upright lines 

 (internal tubes). 



Internal Tules. Four. 



Measurement. From 6 to 10 inches long. 



Fructification. Of two kinds. 1. Clustered spores in broadly ovate, scarcely stalked 

 capsules; external. 2. Tetraspores immersed in swollen, distorted branchlets; 

 large. 



ILdbitat. Our coasts generally. On rocks, stones, and algse between tide-marks. 

 Often in pools left by the falling tides. Frequent. 



Fig. 124. POLYSIPHONIA VARIEGATA. 



Colour. A dark purple-brown; brighter when dry. 

 Substance. Rigid below; very soft above. 



Character ofi Frond. Dense tufts of jointed threads {filaments) much branched; as 

 thick as hogs' bristles below; hair-like above. Branching forked (<:?/c72ofc»moz^s) ; 

 the lower angles of branching {axils) very wide-spread. Branches somewhat 

 zigzag, long, much divided; set with tufts of very fine, delicate, closely-forked 

 branchlets. Joints clearly visible throughout; marked by three, broad, upright 

 lines (internal tubes). 



Internal Tuhes. Six; sometimes, but rarely, seven. 



Measurement. From 4 to 10 inches long. 



Fructification. Of two kinds. 1. Clustered spores in broadly ovate, wide-mouthed, 

 shortly-stalked capsules; external. 2. Tetraspores immersed in swollen branchlets. 



Habitat. Plymouth, and various places near it. On mud-covered rocks in bays and 

 estuaries. Also on Zostera, Chorda filum, floating timber, &c. Very local, 

 and therefore rare in Britain. Common at Venice and in North America. 



Fig. 125. POLYSIPHONIA SIMULANS. 



Colour. Reddish. Substance. Stiff and brittle. 



Character ofi Frond. Tufts of jointed threads {filaments) branched from the base; 

 bushy. Stems irregularly set with spines which hold the plant together, so 

 that it is difficult to disentangle. Branches alternate, wide-spread, repeatedly 

 but irregularly branched like a feather {pinnate); the last set but one, long 

 and simple; set with short, distant, spine-like branchlets. Joints visible 

 throughout; marked with many upright lines (internal tubes). 



Internal Tubes. About twelve. 



Measurement. From 2 to 3 inches long. 



Fructification. Of two kinds. 1. Clustered spores in nearly globose or ovate capsules, 

 with a wide mouth; external. 2. Tetraspores immersed in swollen branchlets. 



Habitat. Jersey. Torquay. Orkney. On rocks and in tide-pools near low-water 

 mark. Rare. 

 55 



