60 



Dansk Botanisk Arkiv, Bd. 2. Nr. 2. 



Dictyopteris Lamx. 



1. D. delicatula Lamx. 



Lamouroux in Journ. Phi- 

 lom., 1809, no.20, tab.6, fig.B. 

 A. Vickers, Phycologia Bar- 

 badensis, part II, pi. III. 



Haliseris delicatula C. Ag., 

 Species, p. 144. J. Agardh, 

 Spec. Alg., vol. I, p. 116. KüT- 

 zing, Tabulæ Phycologicæ, 

 vol. IX, pi. 56, flg. II. 



The thailus consists of 

 two layers of cells (Fig. 

 41 a) with the exception 

 of the ribs in the edges 

 and in middle of the frond 

 where it is composed of 

 several layers of cells. In 

 transverse sections these 

 ribs are seen to contain a 

 string composed of cells 

 with very thick walls in 

 which pores are present (Fig. 41 b). Of these M 1Ie Vickers re- 

 produces figures drawn by Bornet. The wall consists of cellu- 

 lose; it is coloured blue by chlor-zinc-iodine. In a longitudinal 

 section the cells of the 

 strings are found to be 

 long , cylindrical with 

 oblique end-walls. 



The hairs are only 

 present upon the one side 

 of the thallus ; they are 

 placed many together in 

 roundish or oval groups 

 and occur regularly upon 

 both sides of the mid-rib. 

 In the basal part the 

 plant is fastened to the 

 substratum by means of 

 rhizoids. These grow out 



Fig. 40. Dictyopteris delicatula Lamx. 

 A part of the thallus. (About 3 : 1). 



Fig. 41. Dictyopteris delicatula Lamx. 



partly from the cells along a > transverse section of the thallus with a 

 r J . ,i, group of hair, b, transverse section of the 



the margin of the thallus edge of the thallus. 



