91 



The middle layer, however, is composed in L. japonica of larger cells 

 than in the present. The position and form of lacunas in the stem 

 distinctly separates the one from the other. In L. japonica they are 

 larger than in L. lony/pedalis and are situated beneath cortical portion 

 (Fig. 4.), while in the latter they are within cortical range. 



From L. saccharina which has a longer stem and a frond of similar 

 shape, the present species differs in the indistinctness of fascia and in 

 the presence of muciferous lacunas in the stem. 



Laminaria longed alis — Perennial ; Root branched, conical, with a ring of muciferous 

 lacunae beneath the cortex ; Stipe long, subtereie, complanated toward the base of a simple 

 lamina, with a close ring of small lacunae very near the periphery, and with an annual 

 ring ; lamina broadly lanceolate, jh broadly ovate at base, undulated at margin, with indis- 

 tinct median faecia and provided with muciferous lacuna?. Sori spread over the frond on 

 both surfaces, forming cloud like patches. 



Laminaria gyrata Ejellm. 



Laminar ia gyrataP has been described from the materials collected 

 at the Hokkaido by Kjellman who mentions that the stem has no 

 muciferous lacunae. My recent researches however prove that the ab- 

 sence of lacunas in the stem of plants of this species is not a fixed 

 character. In many specimens in my collection I studied the structure 

 of stem and I found that in some examples lacunas are entirely want- 

 ing, while in the other they are sparingly present. Even in one and 

 the same plant, one cross-section may shew a few lacunas, while another 

 shews none. Those, when present, are roundish or longish, being smaller 

 in size and situated just beneath the cortical layer (Fig. 7). They do 

 not form a continuous ring in a cross-section, being separated by more 

 or less wider patches of non-lacunose portion. 



These researches have been conducted in order to settle doubts which 

 arose in classifying the related plants collected in abundance in Urupp,Etro- 

 fu and in other places. They have all the other characters safely referable 

 to Laminaria gyrata, except the presence of lacunas in stem, which form 

 a continuous ring beneath the cortex. At first, according to the diagnosis 

 of L. gyrata given by Kjellman I took those plants for a new species, 

 which differs from the former species only in the presence of lacunas in 



i) l>e Toni Sjllog. Alg. JIL p. 348. 



