A Monoragpb of the Genus Alnria. 87 



<'erLerally occupying the entire surface except a narrow border 

 along the margin. 



Remarks on the limit of variation. Although tlie shape of the 

 base of the bhide of most members of the Laminariacese varies 

 according to tlie stage of development of the plant, the gradual 

 attenuation, e.g., narrow cuneate shape in the present species is 

 quite constant and remarkable. The substance of tlie blade is 

 coriaceous, resembling a thick parchment paper on drying. A 

 remarkable character of the present species is that the blade is 

 entirely wanting in cryptostomata as far as I could determine. 



Some specimens may have numerous small holes in the upper 

 and older part of the blade, often so numerous that the part gains 

 the appearance of a cribrous lamina. These perforations become 

 smaller in size and less in number as we trace them downwards 

 and finally they may bo reduced into mere brownish spots, very 

 sparingly distributed on the blade. Under the microscope, these 

 brownish spots show^ shallow depressions of the cortical part on 

 either surface with a much distorted arrangement of the cortical 

 cells. I was not able to find any reason for calling the depression 

 a cryptostoma or hair-pit. The specimens from Hidaka Province, 

 however, have had sparing cryptostomata showing with other 

 specific characters an intermediate form between the typical forms 

 of both A. prcelonga and A. crassifolia. 



A typical form of the present species has the sporophylls 

 arranged at regular intervals as in A. csculeuta and A. crassifolia. 

 The shape of the sporophyll is linear, with a round or obtuse 

 apex and an obtuse, very frequently asymmetrical, base. As al- 

 ready mentioned before, we sometime meet with an intermediate 

 form in the characters of sporophylls between the present and A. 

 crassifolia. In such case, the presence or absence of cryptostomata 



