48 BRITISH SEA-WEEDS. 



recorded British specimens were found by Mr. Lawers 

 in Molville Bay, county Donegal, in 1853, and more re- 

 cently it has been found at the Lizard, Cornwall, by Dr. 

 Hermann Becker. I have not seen any of the Irish spe- 

 cimens, but I have now before me two of the plants col- 

 lected by Dr. Becker. The latter appear to be smaller than 

 those from Donegal, being only of the minimum dimen- 

 sions above stated. They are entirely without branches, 

 and altogether differ so completely in appearance from 

 the forms of Desmarestia ligulata with which I am ac- 

 quainted, that I have hesitated to adopt the suggestion 

 that the plant is only an extravagantly wide form of that 

 species, and prefer to retain it under a distinct name, 

 pending the examination of a larger series of specimens 

 than has been hitherto available.* 



Desmarestia aculeata. Prickly Desmarestia. 



Frond cylindrical at the base, becoming flattish in the 

 upper part, much divided; branches and branchlets alter- 

 nate, tapering at the base, when young of a bright green 

 colour, tender substance, and fringed with slender threads ; 

 when old, brown, coarse, and covered with spines. 



Desmarestia viridis. Green Desmarestia. 



Frond cylindrical, filiform, much divided; branches and 

 branchlets hair-like, opposite. 



* Since writing the aboTe, I hare received from Dr. Becker a liberal 

 supply of specimens in a fresh state, and a careful examination of these 

 has fully convinced me that this plant is specifically distinct from D. 

 ligulata, and is identical with the Continental D. pinnatinervia. I 

 take this opportunity to thank Dr. Becker, both for the specimens 

 and for the information concerning them, and to record the fact that 

 he was the first, and, so far as I am aware, is the only discoverer of this 

 interesting Sea-weed in an English habitat. 



