80 Mr E. M. Holmes on Sphacelaria radicans, [sess. ll 



extending for many feet, alternating or mixed with Calli- 

 thamnion Rotliii. With a knife it can he cut off like turf. 

 This I have never seen to he the case with Harvey's S. 

 radicans, of which it would be impossible to obtain a felted 

 piece an inch square. This difference appears to arise from 

 the fact that in the former plant the radicles and ramuli are 

 densely felted together, which is not the case in the latter. 

 I have never met with this plant in the south of England. 



With respect to the fructification, the specimens of the 

 felted plant (*S'. oUvacca, Dillwyn) sent me by Mr Traill have 

 the sporangia distinctly stalked ; while those received from 

 him of the low-water plant exactly correspond with Harvey's 

 figure of ^S*. radicans, Harv., in having sessile bodies resembling 

 unilocular sporangia. I have, however, found specimens of 

 the latter plant at Falmouth with the fructification sessile 

 above, and stalked lower down on the filaments ; and in 

 English Botany the fruits of S. radicans are described as 

 " sessile or stalked." Moreover, Agardh describes them as 

 oval, long-stalked, situated on the upper ramuli singly, or a 

 few together C' subsingulis "). 



So far as I have observed in Mr Traill's S. olivacea, 

 Dillw., the unilocular sporangia are invariably stalked, and 

 more distinctly so, i.e., on longer pedicels, than in my Fal- 

 mouth specimens of S. radicans, Harv. 



Unfortunately, the length of the joints in S. olivacea 

 and S. cirrhosa, and Mr Traill's felted plant, are so nearly 

 alike, that the habit of growth and the angle at which the 

 branches arise, and the distinct localities at which they grow, 

 are almost the only characters by which to distinguish these 

 plants. (The same is the case with *S'. racemosa, which Mr 

 Batters was so fortunate as to find last month at Berwick- 

 on-Tweed in good fructification. This species has, I believe, 

 been only once or twice previously found — first, by Sir 

 John Uichardson, near Granton, in 1821 ; and next, by the 

 late Mr Hennedy, in the Clyde, according to Harvey, many 

 years subsequently.* In this species the joints are about 

 as long as Ijroad, resembling in this respect the above- 

 mentioned sjiecies. The plant is, however, taller, and grows 



* I have seen Ilcnnedy's simcimens, but couM finil no fruit on tlioni, and 

 doubt if they belong to Sphacelaria raceviosa. I sliould refer them to 

 SijIiMcelaria radicans, Harv. 



