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THE AMERICAN NATURALIST [Vol. XLIII 



terest. There is no difference, as far as the writer is 

 aware, between the fruiting habits of this and other kelps. 

 In quiet water the fragments of any fruiting lamina torn 

 off by the waves might lie undisturbed on the bottom and 

 the spores might germinate close to the point of libera- 

 tion. But this kelp is a cumaphyte growing exclusively 

 in the strong surf, and it is in surf-scoured situations 

 that the young plants are found best developed. This 

 would lead one to look for some method of basal branch- 

 ing or possibly budding of new laminae from the holdfast, 

 as is known in a few kelps which have 1 1 rhizomes. ' ' But 

 though hapteres and stipes are occasionally so completely 

 grown together as to appear branches of one plant, no 

 evidence of such branching in the young plant has been 

 observed and the writer must conclude that the clusters 

 are due to starting of many spores at one point. 



The young plants forming these clumps are thickly 

 splashed with checks of dark brown on the lighter color 

 of the body of the lamina. This is most conspicuous in 

 plants about 10 cm. long and is clearly brought out in the 

 photographs (Figs. 15, 21). As they grow older the spot- 

 ting tends to disappear, but traces of it can usually be 

 found in specimens of any age. No other kelp of the 

 region is similarly marked except Pterygophora, in which 

 the spots when present are much less distinct. As this 

 appearance arises very early it is of the utmost service 

 in identifying the plants while yet too young to have de- 

 veloped any characters of the adult. 



The smallest specimen found (Fig. 3) measured about 

 1.1 mm. in length. It was attached to the hapteres of 

 another plant of the same species twenty or thirty times 

 as long. When loosened from its hold it came away with 

 a mass of filamentous material which completely en- 

 veloped its base. In this tangle there was a considerable 

 portion of foreign matter ; but the appearance of the finer 

 strands was that of a protonema-like felt organically con- 

 nected with the young kelp which seemed to spring from 

 it like the gametophore of a moss. On teasing this away 

 it was seen that the primitive disc had not yet developed. 



