Plate XXVI. 
Fig. 113. POLYSIPHONIA FIBRATA. 
. Colour. Dark red-brown below ; rosy above. 
Substance. Tender and gelatinous ; decomposing rapidly in fresh water. 
Character of Frond. Very dense tufts of jointed threads {filaments) ; much branched. Stems 
as thick as hogs’ bristles below, becoming very fine upwards ; simple or alternately 
branched. Set at greater or less distances with very slender, forked {dichotomous) 
branchlets, more or less tufted ; whose abrupt {truncate) tips are clothed with colour- 
less, forked {dichotomous) fibres, bearing at certain seasons tiny yellow pods {antheridia]^ 
whose office is not thoroughly ascertained. Angles of branching {axils) all spreading. 
Marked throughout with two upright lines (internal tubes). 
Internal Tubes. Four. 
Measurement. From 2 to 10 inches long. 
Fructification. Of two kinds. 1. Clustered spores in ovate or globose capsules; external; 
plentifully scattered. 2. Tetraspores immersed in the swollen upper branchlets. 
Habitat. Our coasts generally. On rocks, stones, and algas, between tide-marks. Not uncommon. 
Fig. 114. POLYSIPHONIA SPINULOSA. 
Colour. Dark red. 
Substance. Rigid, though fine. 
Character of Frond. Short, delicate tufts of jointed threads {filaments) very much branched. 
Branching alternate. Branches spreading; irregularly set; clothed with short, straight, 
spreading branchlets ; several times re-branched ; the last set, thorn-like, and horizon- 
tally spread ; their tips sometimes minutely divided ; each division bearing a long, 
colourless, jointed thread. Joints marked by two or three upright lines (internal 
tubes). 
Internal Tubes. Four large and several lesser ones ; more of these in the branches than 
branchlets. 
Measurement. One or 2 inches long. 
Fructification. Only one sort observed. Clustered spores in globose, unstalked {sessile) capsules ; 
external. 
Habitat. Appin. Very rare. 
A plant which, like the next, has only been found once; the solitary specimens being 
preserved in Sir William Hooker’s Herbarium. 
Fig. 115. POLYSIPHONIA RICHAEDSONI. 
Colour. Dull red ; becoming darker in drying. 
Substance. Rigid ; elastic. 
Character of Frond. Small tufts of jointed threads {filaments) much, branched. Stem, hogs’- 
bristle thickness at base ; finer above ; alternately branched throughout ; the branches 
long, spreading, often issuing horizontally ; set in the upper part with widely-spread- 
ing, straight, partly forked {sub-dichotomous) ^ partly alternate branchlets. Main 
joints marked with several irregular lines (internal tubes), twisted. 
Internal Tubes. Five. 
Measurement. Three or 4 inches long. 
Fructification. Only one kind observed. Clustered spores in globose, unstalked {sessile) capsules ; 
external. 
Habitat. Colvend, Dumfries. 
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