Plate XXIX. 
Fig. 129. POLYSIPHONIA SUBULIFERA. 
Colour. Purplish ; becoming darker in drying. 
Substance. 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-hranched ; lesser branches 
long, rod-like ; furnished with very short, scattered, simple, spine-like, almost hori- 
zontal branchlets. (See figure of a magnified bit.) Joints visible throughout ; 
marked with from four to six upright lines (internal tubes). 
Internal Tubes. About thirteen. 
Measurement. Four or 5 inches long. 
Fructification. Of two kinds. 1. Clustered in ovate external : 2. Tetraspores 
immersed in swollen branchlets. 
Habitat. Torquay and Weymouth. Abundant in Eoundstone Bay, Ireland. Dredged in from 
five to ten fathoms’ water. Very local, therefore rare. 
This species hears a greater resemblance to young specimens of Rytiphlceafridiadosa than 
to any other plant, hut is softer and more slender, and may always he distinguished by its 
distinctly jointed stem and branches. Its peculiarly thorny habit is so unlike any other 
Polysiphonia of the same size, that it can hardly be confounded with any. It approaches 
nearest to the following (P. atro-rubescens), 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. Eigid 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 abundance 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. Eoot fibrous (not usual in Polysiphonias). 
Internal Tubes About thirteen 
Measurement. From 2 to 6 inches long. 
Fructification. Of two kinds. 1. Clustered spores in nearly globose, wide-mouthed ; 
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 Polysiphonia, see Plate XXX. Fig. 134. 
I 
67 
