This species, in many respects, resembles F. vesiculosus, with 

 some varieties of which it has been occasionally confounded ; 

 but it has many characters by which it may at all times be 

 known, independently of the absence of vesicles, — which cha- 

 racter is too variable to be depended on, for in many forms of 

 F. vesiculosus vesicles are wanting. F. ceranoides may be readily 

 known by its much thinner and more transparent substance, and 

 by containing a less quantity of saline matters ; so that it dries 

 much more rapidly when removed from the water, and requires 

 far less steeping in fresh water when specimens are prepared for 

 the Herbarium. 



The usual habitat of this species is in places where a good deal 

 of fresh water mixes with the sea ; but it is by no means confined 

 to such places. I have gathered specimens on exposed parts of 

 the shore, where no fresh water flowed in. In the Loch of 

 Stennis, Orkney, where the water is but faintly brackish, a very 

 narrow variety is abundant. The greater the amount of saltness 

 in the water the broader is the frond, but in no case is the 

 substance so thick and leathery as in F. vesiculosus. The lateral 

 fructification is very characteristic of this species, but is not 

 essential, for there is a variety of F. vesiculosus figured by 

 Dr. Greville having also lateral fruit. 



Fig. 1. Fucus ceranoides : — the natural size. 2. Section of one of the 

 conceptacles, from the receptacle, containing spores and paranemata: — 



