1903.] HEDOPIIYLLUM SPIEALE, ST. NOV. 167 



cavities in the stipe and holdfast remain unaltered, but more or less becoming 

 insignificant when compared with the younger stage. 



The medulla is ellipsoid in a transverse section of the young stems 

 but soon becomes compressed accompanying the development of the stem. 

 In the armed specimens we find the primary medulla much compressed 

 into linear form and another ring around it ; the arms have simple in- 

 complete ring, a part of which has travelled into the torn off portion of 

 the lamina (figg. 2.4). 



/. Kamtschathensis^^ differs from the type by having very long stipe. 

 It measures 1.5-2.0 cm in diameter and 20-30 cm in length. The upper 

 portion of the stipe becomes complanated and much broader, and the margins 

 turning inward at this region. In other respects similar to the type. 



There is no doubt that the present species has close similarity with 

 Hedophyllwn suhsessih. The former is easily separable by the spiral 

 rolling of the both margins at the transition region. This character had 

 not been found in the latter though minute investigations have been done 

 upon the plant by the American algologists. But in Hedophyllum subsessile 

 the basal margins have a tendency of folding inside while in Hedopliyllura 

 sessile no such indication could be found. The wearing of the primary 

 lamina is also limitted to Hedophyllum sitbsessile and none of the circum- 

 stance had been noticed in the allied species. 



Among the multitudinous forms of Laminar eaceous plants, Eiseniaj 

 Arihrothamnus, ThalassiopliylUim, aud Hedopliyllum have their primary 

 lamina to be worn away in the adult stage. Only one species among the 

 members, Hedophyllum sessile, is the exception. If all the members of 

 Echlonia have been transferred to Eisenia, which is highly probable, we 

 shall have more of the case. The first of the above mentioned four genera 

 has uo visible rolling in the lamina, as the corresponding position is assumed 

 by a number of the ligules. But it is clear that the both arms tend to 

 turn inside, especially when they are not in a great length : cf. Illustr. 

 d'Alg. d. Japon. PI. XIX-XX.-^ Besides, we have a species of Agarum 

 with its lamina scrolled at the base. 



1. Eupreclit mentions several forms of Laminaria digitata to occur in the Ochotsk sea. 

 One of the form had the basal region rolled inside at tlie margin (Tange. p. 352) : and he 

 mentions Laminaria dermatodea in the list of algae collected by Wosnessenski at Yavina, wliere 

 the present writer lias collected this plant. These remarks shall be discussed in future in 

 connection with the present form. 



2. Suringar ; Musee Botan, d. Leide. T. II. 



