Ma cM Ulan: OBSERVATIONS ON PTERYGOPHORA. 731 



japonica,* Agarth f suggested that the type specimen was 

 nothing other than a mid-lamina of Ptcrygophora. While this 

 notion of Agardh's was incorrect, a comparison of specimens or 

 reference to Suringar'sJ plate of Laminaria japonica will make 

 it clear how natural might have been such a supposition on his 

 part. One also finds in the genus Laminaria forms suggesting 

 the pinnate disposition of laminae in Ptcrygophora. Such a 

 plant is figured and described by Kjellman under the name of 

 Laminaria radicosa. In this plant lateral outgrowths occur 

 upon the stipe below the lamina in quite the same position in 

 which they are developed in Ptcrygophora. They are not, 

 however, functional as additional laminae, nor do they particu- 

 larly increase the photosynthetic vigor of the plant. Laminaria 

 radicosa may, nevertheless, be regarded perhaps as showing a 

 transition to the type of Ptcrygophora. 



There are some objections to the classification of Plcrygo- 

 phora with Alaria. Among these, the character of the young 

 plant should be given weight. In Alaria the midrib is dif- 

 ferentiated at an early stage and is exceedingly distinct in plants 

 only two centimeters in length, while in Pterygophora plants 

 35 centimeters in length show the midrib but indistinctly in 

 the basal portion of the lamina. Anatomically Pterygophora 

 conforms to the type of the Laminarieae in the general character 

 of its tissues, differing in some marked particulars from Alaria, 

 although resembling the latter in absence of mucilage canals 

 structures which are present in most species of Laminaria. 

 The distinction of outer and inner cortex which is not always to 

 be made out in Alaria is very clear in Pterygophora. Upon 

 the whole there would seem to be little objection to the classifi- 

 cation of Plcrygophora in the tribe Laminarieae. Taking every- 

 thing into account, however, it will perhaps be best to consider 

 the genus as transitional between the Laminarieae and the 

 Alariideae. 



An examination of the anatomy of Pterygophora seems 

 further to strengthen the view of its close relation to Laminaria, 

 while the differentiation of its organs no doubt makes it readily 



* Areschoug, J. E. Phyceae Capenses, 29. 



t Agardh, J. G. Proc. Soc. Phys. Lund. Bot. Notiser, 1883 : 108. 1883. 

 JSuringar, W. F. R. Algae Japonicae, pi. //. 1870. 



g Kjellman, F. R., and Peterson, J. V. Om Japans Laminariaceer. Ur Vcga- 

 Expeditionens Vetensk. lakttagelser. , 4: 259, pi. 10. 1885. 



