V. RHODOMELACE^. 61 



purple-lake, clichotomous ramelli ; articulations of the ramelli many times longer 

 than broad ; conceptacles urnshaped, on long pedicels, rising from the branches ; 

 stichidia linear-lanceolate. Ag. Sp. Alg. 2, p. 117. Kutz. Sp. Alg. p. 796. Rhodo- 

 mma elegans, Mert. 



Hab. Growing on other Algai, on woodwork, rocks, &c. from low water mark to 

 the depth of several fathoms. Annual. Nantucket, Dr. Durkee. Greenport. Pro- 

 vidence, Prof. Bailey and Mr. Olney. Very common in New York Harbour from 

 Hellgate to Red Hook, Messrs. Bailey., Hooper., Walters, Pike., Cotrgdon, Calverley, ^'c. 

 Charleston, Prof. Gibbes, W. H. H. Key West, Prof. Tiiomey, Dr. Blodgett, W. H. H- 

 (v. V.) 



Root discoid. Stems from six inches to one, two, or three feet long, varj'ing in 

 diameter from the thickness of hog's juristic to that of a crowquill, or in the larger 

 specimens from one to two lines in diameter, softly cartilaginous when quite fresh, 

 but soon becoming very flaccid, either quite simple or divided below into a few 

 secondary stems, and set throughout the whole length with numerous lateral 

 branches, spreading on all sides. The branches are very irregularly placed, some- 

 times widely scattered, sometimes densely crowded ; alternate or subopposite, or 

 even fascicled ; they are simple, patent, virgate, either destitute of lesser bi'anches, 

 or furnished ■with very numerous, short lateral branches, so that the general frond 

 is sometimes but slightly divided and sometimes very bushy. All the larger and 

 smaller branches and the main stem when young are densely clothed with exceed- 

 ingly slender, bright purple, soft, confervoid ramelli. These ramelli are from two 

 to four lines long, dichotomous, a few times distantly forked, with the terminal 

 laciniae very long and filiform, but not tapering to the apex ; the apical cell being 

 very blunt. The articulations of these ramelli are of great length. Conceptacles 

 abundantly scattered along the branches, on long stalks. Stichidia attached to the 

 ramelli, one or more on each ramellus near its base, very slender, lanceolate, acumi- 

 nate, containing a double or triple row of tetraspores. Colour in all parts a brilliant 

 purple lake, well preserved in drying. Substance soon decomposing in fresh water. 

 In drying, the plant adheres most closely to paper. 



There are two principal forms ; one, which grows in deep water, has very long 

 simple branches, destitute of laterals ; the other, which grows within tide marks, 

 is short and bushy, with abundant secondary branches. The European forms of 

 this plant do not essentially differ. 



3. Dasya (Rhodonema) ramosissima ; stem cartilaginous, tough, inarticulate, 

 robust, attenuated and flaccid upwards, much branched ; branches several times 

 alternately decompound, denudate ; ultimate divisions setaceous, subarticulatc, more 

 or less completely clothed with dichotomous ramelli ; their apices incurved, atte- 

 nuate ; articulations three to five times as long as broad. Var. a ; frond naked, 

 except the tips of the ultimate branches, which are crowned with a dense tuft of 



