CHONDftUS. 437 



tide, the stalk is very long and very strong (PL I., figs. 1, 2, 3). 

 In the forms found higher up on the seashore, and there- 

 fore more frequently and longer exposed, the whole plant 

 is smaller and the stalk proportionately shorter, the frond, 

 however, is often broader (fig. 4, 5). 



All forms agree in showing a repeated and fairly regular 

 bifurcation of the frond into flat lobes, which gradually 

 get broader at their further ends. A small indentation 

 between two projecting points at the tips of the lobes 

 indicates where the next bifurcation will take place. The 

 segments of the frond not only become broader, but also 

 thinner in texture. The broadening out of the lobes 

 causes an overlapping of the segments. 



The colour of the frond varies from dark red to light 

 pink, and a brownish colour with a dash of pink. 



The following are some of the measurements taken on 

 our plant. The largest specimens gathered at low-water 

 mark are as much as 15-17cm. (6-7 7/ ) high, with a frond 

 12'5cm. (5") across (fig. 1). The stem in such a case 

 would measure about T5mm (iV) in thickness. At higher 

 water marks the plants are found in pools only, and not on 

 the bare rock, as at the lower tide marks. In the former 

 case they are much smaller in height and grow in very 

 close, low tufts. They are, however, usually propor- 

 tionately very broad (fig. 4, 5). 



The functions of the shoot are best expressed by the two 

 words assimilation and reproduction. The shoot probably 

 is extremely active in absorbing food material from the 

 surrounding water. This, however, is a point about which 

 we know practically nothing of a definite nature. It is 

 very difficult to keep marine plants in culture, because we 

 do not know what the essential features of the conditions 

 are which obtain in their natural haunts. Algae may be 

 kept for a very long time in fairly dark and cool rooms 



