THALLOPHYTA 



FLORIDE.E 



POLYSIPHONIA FASTIGIATA, Grev. 



I. This seaweed is found on all our coasts, growing 

 in dense reddish-brown tufts, which are fixed firmly on 

 to the thallus of AscopTiyllum (Ozothallia) nodosum, 

 Le Jolis. It grows to a length of about two inches, and 

 the thin cylindrical thallus is frequently branched in an 

 apparently dichotomous manner : on some of the plants 

 taken in autumn there may be recognised with the 

 naked eye, or with a simple lens, roundish bodies borne 

 laterally (cystocarps) ; on others irregular yellowish 

 tassels at the ends of the branches, these are the 

 antheridia, and they are best seen on specimens taken 

 in early summer ; on others again dark irregularly dis- 

 posed swellings may be recognised in the substance of 

 the thallus, these are the organs of vegetative repro- 

 duction (tetraspores). 



II. The material to be used for microscopic investi 

 gation should be either quite fresh, and be kept, and 

 mounted in salt water, or better in weak glycerine, 

 or it should be treated while quite fresh with a solution 

 of picric acid in salt water (see p. 6), and after washing 



