RYTIPHL^A. 81 



out ; branches erecto-patent, with acute axils, the uppermost becoming 

 rather broader towards the apex, more or less regularly bipinnate ; the 

 lower pinnae very short, with minute, subulate, simple pinnules, the upper 

 much longer, with decompound or sometimes again pinnated pinnules ; all 

 the divisions very erect. Colour a dark brownish red. Frond reticulated 

 with veins, and marked with arched, transverse striae, or dark lines, at dis- 

 tances of about half the diameter apart ; these indicate the joints of the 

 internal axis, seen through the surface. Fruit has not been found in 

 Britain. 



3. R. thuyoides, Harv. ; stems erect, rising from creep- 

 ing fibres, terete ; below simple and set with short, spine- 

 like ramuli ; above much branched ; branches crowded, 

 very erect, bipinnate ; pinnae pinnato-multifid; axils rounded. 

 Harv. in Mack. Fl. Hib. iii. p. 205 ; Wyatt, Aly. Danm. 

 No. 305 ; Harv. Phyc. Brit. t. cxxii. 



On rocks in tide-pools, frequent. Perennial. Summer and autumn. 

 Stems 3 or 4 inches high, twice as thick as hog's bristles, cylindrical, erect, 

 below either naked, or furnished with short, spine-like ramuli, or with 

 broken remains of old branches ; much branched above ; branches long, 

 crowded or fasciculate, quadrifarious or distichous, very erect (with a deter- 

 minate oblong-lanceolate outline), bipinnate, middle and lower pinnae pin- 

 nato-multifid, ultimate ones simple, or wilh the tips cloven. Articulations 

 obscure, shorter than broad, scarcely obvious in the branches, more con- 

 spicuous in the ramuli, reticulated with veins. Capsules ovate, scattered 

 or clustered, borne by the ramuli, very rare ; tetraspores ternate, in distorted 

 ramuli, frequent. Antheridia bright yellow, gelatinous, constantly pro- 

 duced in summer. Colour a dull brown or brownish yellow, becoming 

 black in drying. 



4. R. fruticulosa, Wulf. ; stems diffuse, branched from 

 the base ; branches divaricating, pinnato-dichotomous, inar- 

 ticulate, set in the lower part with short, horizontal, multifid 

 ramuli ; in the upper, more or less pinnated with larger, si- 

 milarly divided branchlets ; axils rounded ; ramuli marked 

 at short distances with transverse striae, as if jointed ; veins 

 reticulated. Harv. Phyc. Brit. t. ccxx. Pol. fruticulosa, 

 Harv. in Mack. Fl. Hib. iii. p. 205 ; Hook. Br. Fl. ii. p. 327, 

 (in part}. Fucus fruticulosus, E. Bot. t. 1686. 



Between tide-marks, on sand-covered rocks. Perennial. Summer. 

 Common. Fronds 3 6 inches high, robust, cylindrical, much branched 

 from the base, branches divaricating, with very patent axils, repeatedly di- 

 vided in a pinnato-dichotomous manner, set in the lower part with short, 

 alternate, horizontal, squarrose, multifid ramuli, about a line in length, in 

 the upper distantly pinnated with similar but larger branchlets. Articula- 

 tions scarcely obvious in the larger branches, very apparent in the ramuli, 

 reticulated with veins ; the transverse striae or dissepiments opaque. Cap- 

 sules ovate, sessile, very rare ; granules ternate, in swollen ramuli, common. 

 Antheridia frequently occur, imparting a yellowish colour to the plant. 

 Substance cartilaginous. Colour dull reddish brown, or greenish yellow. 



G 



