Plate XXVIII. 
Fig. 123. POLYSIPHONIA FIBRILLOSA. 
Colour. Brownish-red in deep water ; pale straw in shallow pools ; becoming purplish in drying. 
Substance. Tender and gelatinous ; soon decomposing. 
Character of Frond. Thread-like {filamentous^ ; solitary or tufted ; jointed ; very much 
branched. Stem robust below ; becoming finer upwards ; simple, or once or twice 
divided ; naked near the base ; then set throughout with short, slender, finely- 
divided side-branchlets, 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 {fihrilliferous). Joints 
not visible in the stem nor lower part of the branches ; obvious above ; marked by 
two or three upright lines (internal tubes). 
Internal Tubes. Four. 
Measurement. From 6 to 10 inches long. 
Fructification. Of two kinds. 1. Clustered in broadly ovate, scarcely stalked cajisw/ds ; 
external. 2. Tetraspores immersed in swollen, distorted branchlets ; large. 
Habitat. Our coasts generally. On rocks, stones, and algge 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 of Frond. Dense tufts of jointed threads {filaments') much branched ; as thick as 
hogs’ bristles below ; hair-like above. Branching forked {dichotomous) ; 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 Tubes. 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 of 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 up- 
right 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. 
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