NEW OR CRITICAL BRITISH ALGJ2. 
51 
Lyngbya gracilis, Rabenh . Flor. eur. Algar ., n., p. 145. 
Mr. Holmes informs us that he found this plant in shallow pools 
between Portland and Ferry Bridge. It was growing over plants 
of Rhizoclonium riparium and other algae, and as it is of a deep red 
or violet colour when fresh Mr. Holmes at first mistook it for the 
reflection of the setting sun in the water. The plant is of interest 
as being the only representative of the sub-genus Leibleinia , Gom., 
the members of which are attached by the middle instead of one 
end of the filament, found on the shores of Britain. The fila- 
ments, as has been already mentioned, are epiphytic. They are 
very slender, being from 5-8 p in diameter and seldom more than 
15 or 20 mm. in length. The sheath is very thin, and almost 
invisible. The trichomata are torulose, and are not attenuated 
above, the joints are square or rather shorter than the width of the 
filament. The apical cells are rounded and slightly thickened. 
Judging from the dry specimens the filaments appear to form 
prostrate layers of no very great size. 
Ittonostroma quaternarium, Desmaz.Pl. crypt. Fr. ( nouv . ser.), No. 603. 
Fronds of irregular shape, from 6 inches to a foot or more in 
diameter, of a bright, clear green colour, at first attached in the 
middle by a small disc-like root, but usually found unattached and 
floating on the surface of the water. In section the frond is from 
20-25 p in thickness. The cells when viewed from above are 
roundish and usually collected into twos, threes, or fours. In 
section they are oval or semi-circular, usually from 15-17 p high. 
In pools of brackish water near the old Castle, Portland. (E. 
M. Holmes.) 
Symploca atlantica, Gom. Monog. des Oscill., p. 129. 
Dr. O. Nordstedt has very kindly sent us a specimen of this 
plant gathered by him at Ferryside, near Carmarthen, in 1885, 
this, of course, being the locality where it was first found. Mr. 
E. M. Holmes has also sent us some fine specimens of this plant 
from Portland. The species is easily recognized by its clear blue- 
green colour, all the other British species of marine Symplocce 
being of a deep steel grey or black colour. 
IMCicrocoryne ocellata, Stromf. 
We are glad to be able to state that Mr. Holmes has also found 
this species at Portland, on the stems of Chorda filum , the host 
plant on which it was originally found by Stromfelt. As already 
stated in this Journal our specimens were found on Castagnea 
Griffithsiana ; we have also found it on Rhodymenia palmata and a 
variety of other host plants. 
Lyngbya confervoides , Ag. Syst. Alg., p. 73. 
Tufts large, soft, and slippery, from one to two inches in length, 
yellowish-brown or blackish-green, often turning to a violet colour 
when dry, prostrate, or erect. Filaments intricately interwoven, 
straight, rather stiff. Sheath hyaline, never turning to the 
yellowish tint ’so apparent in old specimens of L. cestuarii. 
Trichomata olive or bright green, not constricted at the joints, not 
