CRYPTOGAMIA ALG.E. 233 



had been poured over it. Fl. Lap. 501. That some of the 

 red Ceramia undergo these changes with considerable ra- 

 pidity is true, but I have not observed this Plocamium to 

 do so. Immersed in fresh water the native dark red be- 

 comes perhaps brighter, but not the slightest taint is com- 

 municated to the water, and the plant suffers no further 

 change when it has been kept for several days constant- 

 ly steeped. When, however, it is left to bleach on the 

 shore, it suffers the changes mentioned by WAHLEN- 



BERG. 



136. LOMENTARIA. 



1. L. clavellosa, frond gelatinous, pink, much and irregularly 

 branched ; branches distichous, repeatedly pinnate, the ultimate 

 ramuli more or less lanceolate, attenuated at their base ; capsules 

 conical Bot. Gall. ii. 950. Fucus clavellosus, Eng. Bot. t. 1203. 

 Chondria clavellosa, HOOK. Scot. ii. 105. Gastridium clavellosum, 

 GREV. Alff. Brit. 115. 



Hab. Berwick Bay, amongst sea refuse, rare. Q 



2. L. articulata, frond reddish-pink, tubular, contracted and 

 chain-like ; branches fastigiate, dichotomous, and whorled ; cap- 

 sules obtusely conical Bot. Gall. ii. 950. Fucus articulatus, 

 LIGHTF. Scot. 959. Chondria articulata, HOOK. Scot. ii. 106. 

 Gastridium articulatum, GREV. Alg. Brit. 120. 



Hab. On rocks near low-water mark, abundant, but con- 

 cealed in general by the larger kinds. 



137. POLYIDES. 



1. P. rotundus, frond 3 to 6 inches high, dark purplish-brown, 

 dichotomous; branches fastigiate. GREV. Alg. Brit. 70. Fucus 

 rotundus, WITH. iv. 123. Chordaria rotunda, HOOK. Scot. ii. 97- 

 Spongiocarpus rotundus, GREV. Fl. Edin. 286. 



Hab. Coast of Berwickshire, rare. 7/ 



When not in fruit this Alga is with difficulty to be distin- 

 guished from Furcellaria fastigiata, but the root of the 

 former is a small solid disk, while that of the latter is 

 fibrous. 



