Oct. i9i.-..] e OKAMXTRA.— UNDARIA, AND ITS SPECIES. 269 



euneate and the median portion of the lamina is more or less 

 thickened into broader or narrower fascia. In some specimens 

 the fascia is very marked and a little prominent, but not so 

 clearly marked out as the midrib of Hirome and Undaria. When 

 dried, it becomes indistinct. The margin of lamina is entire and 

 deeply undulato-plicated. The form of frond varies from lanceo- 

 late to ovate, oblong or roundish and the base from cuneato- 

 ovate to deeply cordate or auriculate. The length of frond in 

 such a roundish form is mostly short measuring 12-25 cm. in 

 length and 12-22 cm. in breadth. 



In the typical form the sorus is formed in broadh r linear or 

 linear-lanceolate area over both surfaces of the median fascia 

 (fig. 4), but in the roundish forms it is ovate or oblong as 

 shown in the fig. 5. In more than one case I have obtained 

 fructified specimens in which basal fructified portion of the 

 lamina becomes very much undulato-plicated and passes to the 

 wing stretching on both sides of the stem (fig. 6). Sori are form- 

 ed on both surfaces of thus undulato-plicated wing and con- 

 tinue to the fertile area of the lamina. In the normal frond, 

 sori are never formed in the wing of stem. 



Now I shall enter into discussions. Let us firstly consider 

 Hirome undarioides. It has a broadly ovate lamina whose 

 margins become undulated and sometimes cpiite entire but usual- 

 ly pinnated with short blunt segments with broad sinuses. 

 It differs from Undaria pinnatifida in its not being deeply pin- 

 nate, but even in the plant just mentioned the pinnate ramifica- 

 tion is often suppressed and, in such fronds, as I have stated 

 above, the dentate ligules at the transition part are entirely 

 wanting. The presence of a distinct midrib, of rugose-bulla- 

 tions, of c^ptostomata and of glandular dots is common to 

 the two plants. 



"The essential character of the plant to establish a new 

 genus " says the author of Hirome " lies on the sori at the 

 costal area." 1} Besides, he seems to have laid some importance 

 on the discontinuation of laminal sori with sporophyllic ones, 



1) Yendo: Three New Mar. Alg. from Japan, 1903, p. 102. 



