No. 505] KELPS AND RECAPITULATION THEORY 17 



least at Port Renfrew, it seems probable that their pro- 

 duction is a seasonal phenomenon taking place only for a 

 limited period before the fruiting season. However they 

 are formed, they do not reach their full size at first. The 

 youngest are always shorter and narrower than the older 

 and entirely lack the characteristic base. Some of the 

 smallest remind one of the young sporophylls of Pterygo- 

 phora and have the appearance of being outgrowths from 

 the meristem as in that species, but the writer does not 

 feel sure that they are normal. Further information on 

 the origin of the sporophylls will be very welcome because 

 of its importance in determining the relationships of this 

 plant to the other genera of kelps. 



At length, by branching and production of sporophylls 

 a plant is formed with several hundred laminae, in extreme 

 cases reaching lengths of a meter, while the whole plant is 

 often two meters long. The stipe at the base becomes 

 10-20 cm. in thickness and is marked with many annual 

 rings of growth. The holdfast clings so tenaciously to 

 the rocks that it will support a man's weight. On a flat 

 bottom the plants stand upright, but they hang down when 

 growing on an overhanging cliff, as in the photograph 

 (Fig. 27). As in all water plants, their only way of main- 

 taining themselves in the strong currents in which they 

 live is by bending before them. Accordingly, rigidity is 

 developed only in very large basal portions of the stipe, 

 while the terminal branches have not sufficient stiffness to 

 support the plant when out of the water. Lessoniopsis 

 thrives only in places where the surf is very heavy and 

 is there found along with Postelsia, the sea palm, the 

 most typical of all the cumaphytes, but it does not with- 

 stand drying so well as that plant and consequently grows 

 at a considerably lower level. 



C. Egregia 



To one acquainted with the kelps only through the more 

 widely distributed genera such as Laminaria and Alaria, 

 Egregia must always be the most interesting of the fam- 

 ily. Algologists agree in assigning to this plant the high- 



