Plate XXV. 
Fig. 107. DASYA VENUSTA. 
Colour. Rosy red ; stems brownish. 
Substance. Very soft ; tender. 
Character of Frond. Thread-like {filamentous) ; much branched. Stem long, simple, semi- 
transparent, nnjointed. Branches alternate ; the lowermost longest ; the rest gradually 
shorter upwards, giving the front a pyramidal outline ; once or twice re-branched 
like a feather {pinnate) ; unjointed ; but clothed throughout with very slender, hair- 
like branchlets, which are jointed and many times forked {dichotomous). 
Measurement. From 3 to 4 inches long. 
Fructification. Of two kinds ; external. 1 . Clustered spores in ovate capsules, with a protruding 
mouth {urceolate, see figure) ; unstalked. 2. Tetraspores in pointed oblong, stichidia; 
stalked. 
Habitat. Jersey. Cast ashore. Very rare. 
Fig. 108. RYTIPHL(EA COMPLANATA. 
Colour. Brown-red ; becoming almost black in drying. 
Substance. Firm, elastic. 
Character of Frond. Thread-like {filamentous), but compressed ; much branched. Filaments 
opaque ; closely marked with lines across {transversely striate). Stem erect ; neaidy 
simple below ; much branched above. Branches erect, but spreading ; twice or thrice 
re-branched, like a feather {pinnate) ; the lower branchlets always short or stunted ; 
the upper longer, straight, rod-like ; giving a stiff, formal character to the plant. 
Measurement. From 2 to 3 inches long. 
Fructification. Has not been found in Britain. 
Habitat. South of England and West of Ireland (Miltown Malbay, in one particular pool, 
abundant). On the rocky beds of shallow tide-pools, exposed at low-water mark to 
full sunshine. Very rare. 
The lines across {transverse strioe) characteristic of the genus, look in this species as if they 
were arched, but this is an optical delusion. They are best observed through a pocket lens. 
Fig. 109. POLYSIPHONIA URCEOLATA. 
Colour. Full red ; becoming dark in drying. 
Substance. Rigid ; wiry. 
Character of Frond. Long, dense, bushy tufts of jointed threads {filaments) ; much branched ; 
loosely entangled. Branches partly forked {sub-dichotomous) ; partly alternate ; erect, 
but spreading ; more or less furnished with very short, alternate, spreading or back- 
curved {re-curved) branchlets. Joints marked with two broad upright lines (internal 
tubes seen through) ; or, if the filament be twisted, part of a third becoming visible. 
Internal Tubes. Four. 
Measurement. From 3 to 9 inches long. 
Fructification. Of two kinds. 1. Clustered spo7^es in capsules; external. Capsules generally 
stalked, ovate, with a protruding mouth {urceolate). 2. Tetraspores immersed in the 
upper part of swollen branchlets. 
Habitat. Our coasts generally. On rocks between tide-marks, or on the stems of Laminaria 
digitata. Common. 
' Varying very much in delicacy. Often as thick as horsehair at the base of the filaments, 
but sometimes approaching the slenderness of P. formosa. It is always more rigid in substance, 
however, and its short back-curved branchlets are another mark of distinction, particularly in 
specimens growing on L. digitata. 
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