Plate XXIX. 



Fig. 129. POLYSIPHONIA SUBULIFERA. 



Colour. Purplish; becoming darker in drying. 

 Suhstanee. Stems elastic; branchlets soft and tender. 



Character of Frond. Tufts of jointed threads (^filaments)., much branched. Stems 

 wavy; as thick as hogs' bristles below; becoming finer upwards; once or twice 

 divided. Branches wide-spread; wavy; of unequal lengths; irregularly re- 

 branched; lesser branches long, rod-like; furnished with very short, scattered, 

 simple, spine-like, almost horizontal branchlets. (See figure of a magnified 

 bit.) Joints visible throughout; marked with from four to six upright lines 

 (internal tubes). 



Internal Tubes. About thirteen. 



ItLeasurement. Four or 5 inches long. 



Fructification. Of two kinds. 1. Clustered spores in ovate capsules; external. 



2. Tetraspores immersed in swollen branchlets. 

 Habitat. Torquay and Weymouth. Abundant in Roundstone Bay, Ireland. Dredged 



in from five to ten fathoms' water. Very local, therefore rare. 



This species bears a greater resemblance to young specimens of RytlplhlcBa 

 frutlculosa than to any other plant, but is softor and more slender, and may 

 always be distinguished by its distinctly jointed stem and branches. Its pe- 

 culiarly thorny habit is so unlike any other PolysipJionia of the same size, that 

 it can hardly be confounded with any. It approaches nearest to the following 

 (P. atro-rnhescens), but the branches are much wider spread, and the branchlets 

 are simple, not clustered in tufts. 



FIG. 130. POLYSIPHONIA ATRO-RUBESCENS. 



Colour. Deep red or brownish when full grown; becoming black in drying; the lesser 

 branches of very young specimens bright red. 



Substance. Rigid when full grown; the branchlets soft when young. 



Character of Frond. Dense tufts of jointed threads (filaments) ; or covering the rocks 

 in wide patches ; more or less sparingly branched. Stems thicker than horse- 

 hair, simple or nearly so; more or less furnished with long, upright, simple 

 branches. Branches sometimes re-branched; furnished in greater or less abun- 

 dance with very short, awl or spindle-shaped, upright branchlets, scattered 

 singly or in tufts. Joints visible throughout; marked with several lines 

 (internal tubes); sometimes, but not always, spirally curved. Root fibrous 

 (not usual in Folysiphonias). 



Internal Tubes. About thirteen. 



Measurement. From 2 to 6 inches long. 



Fructification. Of two kinds. 1. Clustered spores in nearly globose, wide-mouthed 

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



The young state of this plant is wanting in the tufted branchlets, and the 

 tops of the branches are very soft and bright red, retaining the colour in drying. 

 Such specimens are, however, generally found with their roots, which, being 

 fibrous, instead of the more common disc, serve as a clue to the species. For 

 one other Poly sip] honia, see Plate XXX. Fig. 134. 



57 I 



