78 Mr G. W. Traill on Sphacelaria radicans. [sess. lf. 



Britannica, occurs at low water in continuous loose tufts, 

 seldom exceeding half an inch in height on this coast ; of a 

 dark olive-green colour when mature — lighter when young. 



It generally frequents exposed places where there is some 

 surf, and is often found lining the sides of small channels 

 among rocks into which the sea rushes with violence. More 

 rarely the tufts occur in a matted state in a tenacious deposi- 

 tion of sand. 



Sporangia, which are well known, occur in winter. They 

 are produced along the sides of the upper branches ; are 

 sessile, very numerous, and clustered together, as shown in 

 the accompanying plate. 



The other plant — Sphacelaria olivacca, J. Ag. 2^artim, Con- 

 ferva olivacea, Dillwyn — occurs, on the contrary, a little below 

 the high-water mark of neap-tides, and generally in the 

 shade. It grows in dense velvety patches of an olive-brown 

 colour, which, however, become olive-green when dry. It 

 adheres closely to the rock, and has the liabit of Callitham- 

 nion Rothii, which it often accompanies. 



It is a very much smaller plant than the former, the 

 fronds being generally only about the l-16th of an inch in 

 length. 



Seeing that Harvey made no mention of the fruit applic- 

 able to this form, and also that there did not appear to be 

 any record of its ever having been observed, I watched the 

 plant at Joppa at frequent and regular intervals during the 

 last eighteen months, and succeeded in finding simple oval 

 zoosporangia in a young state on the 19th of December. 

 These are almost invariably on short-jointed pedicels or 

 branchlets ; and not sessile or clustered, as in Harvey's 

 Sphacelaria ra dicans. 



The fruit had reached maturity by the 15th of January, 

 at wliich date many of the zoosporangia had l)urst at the 

 apex, and had allowed their contents to escape. The 

 accompanying plate shows the fructification in its mature 

 state. 



