92 



The Ohio Naturalist. 



[Vol. VII, No. 5, 



pellicle is sloughed off. As in other kelps the sporangia do not 

 develop simultaneously but one finds on sectioning a fruiting 

 lamina (fig. 1 a), by the side of those which are nearly mature, 

 many others much shorter and younger. The paraphyses, in 

 the material studied, do not conform to the usual type in the 

 Laminariaceae and instead of being clavate with heavy gelatin- 

 ous tips are linear and without any thickening of the wall at the 

 tip. Their chloroplasts are localized at a point a little back from 

 the colorless tip forming a definite brown stratum above the tops 

 of the sporangia. The discovery of such a character in Cy ma- 

 there is somewhat of a surprise for it was expected that the genus 

 was like Laminaria in this respect, a fact which lead Kjellman 

 '93 to ascribe to it in his key, the usual clavate paraphyses. 



Fig. 1. a. Camera drawing of a portion of a fruiting lamina, show- 

 ing sporangia and paraphyses. X 110. b. Camera drawing of a portion 

 of a cross secticn of a stipe showing pith web and sclerenchyma. X 110. 

 e-i. Diagramatic cross sections of the lamina to show the development 

 of the plicae. 



In respect to the development of the pithweb Cymathere 

 shows a great resemblance to Renjreivia parvula, contrasting 

 strongly with the Laminarias as exemplified by L. bongardiana. 

 The hyphal elements are very short, composed of short cells. 

 Trumpet hyphae are very scarce and poorly developed (fig. 1 h). 

 In this respect this genus is very much less highly developed 

 than most of the Laminariaceae. 



The smallest specimen (fig. 2) of Cymathere found measures 

 about 2 mm. in length. The identification of s])ecimens of this 

 size is, however, somewhat uncertain for I know no character to 

 differentiate them from other kelps when so young. In this 

 specimen the lamina is plane, only one cell in thickness, and oval 

 in .shape. The stipe is about half as long as the lamina and sev- 

 eral cells thick; in its centre can be seen with a hand lens a faint 

 narrow longitudinal streak composed of longer cells which prob- 

 ably become the pith web. The holdfast of course is the primi- 

 tive disc. 



