V. RHODOMELACEtE. 45 



stem cartilaginous, but tender ; of the branches and ramuli very flaccid, soft and 

 lubricous. It adheres most closely to paper in drying. 



Var. /3, which I dredged in great profusion at Halifax harbour, where, in July 

 and August, it is one of the most characteristic plants, is often two feet long or 

 more, and excessively and almost intricately branched. The main stem and 

 branches are remarkably flexuous, bent from side to side in a zigzag manner, and 

 their lesser divisions are very frequently secund. Except in these characters, 

 wlkich I do not think of specific importance, this variety does not differ from the 

 ordinary form. 



Sub-genus 2. Polysiphonia. Primary tubes more than four. (Sp. 18 — 28.) 



18. Polysiphonia variegata, Ag. ; tufts dense, b^o^vnish purple or greenish ; fila- 

 ments setaceous and rigid below, capillary above, dichotomo-multifid, the lower 

 axils very patent ; branches somewhat zigzag, elongated, furnished with lateral, 

 capillary, very flaccid, multifid, purple ramuli ; internodes near the base shorter 

 than their breadth, once and half to twice as long as broad in the branches and 

 ramuli, three banded ; tubes six ; conceptacles ovate, short-stalked, xig. Sp. Alg. 

 2. p. 81. ./. Ag. Alg. Medit. p. 129- Harv. Fhyc. Brit. t. 155. 



Hab. On Zostera, &c. Annual. Massachussetts Bay, Dr. Durkee, Mr. Pike. 

 Peconic Bay, Prof. Bailey and W. H. H. Several places in Long Island Sound. 

 New York, Mr. Hooper., Calverleg, &c. Sullivan's Island, Charleston, Prof. Gibbes, 

 W. H. H. &c. (v. V.) 



In fine tufts. Filaments as thick as hog's bristle below, capillary and byssoid 

 above, two to ten inches long, dichotomous below, repeatedly forked, alternately or 

 irregularly decompound above ; the lower divisions spreading with very wide 

 angles and subdistant, the upper gradually more erect. In some specimens the 

 whole frond has a flabelliform outline and is pretty equally dichotomo-multifid, 

 none of the pencils of ramuli crowding on each other ; in others the principal 

 stems are a few times divided, nearly flexuous or zigzag, and alternately set 

 with pencils of closely dichotomous, crowded, subfastigiate ramuli. Internodes 

 visible to the base of the frond, and, except near the base where they are very 

 short, pretty I'cgularly once and half or tvs'ice as long as broad, showing three tubes 

 on the lateral view, and a circle of six (rarely seven) round a small central cell, 

 when cut across. No secondary tubes except toward the base of old stems. Apices 

 attenuate, with very short joints. Colour a dark, purple brown or blackish purple, 

 becominn- a brighter purple after having been dried. The sulistance is soft and 

 lubricous, but not very gelatinous, and tlic plant adheres closely to paper in drying. 

 Conceptacles broadly ovate or subglobose, widemouthed, pedicellate, scattered over 

 the branches. 



This plant, though in some respects variable, has a peculiarity of aspect which 



