52 



CARL SKOTTSBERG, MARINE ALGjE 2. RHODOPHYCEJE. 



Polycoryne Skottsb. in Kylin & Skottsb. p. 36, f. 17 e, 18; t. 1 f. 4. 



P. radiata (Skottsb. 1. c. — Fig. 24 — 25. 



The male plant of this curious parasit e was discovered on a piece of Nithophyllum 

 (probably N. Smithii, see above) from South Georgia, St. 18, 1902. The fronds are terete 

 or elliptical in section, and resemble the sporophyte, fig. 24 a. The formation of sper- 

 matanges and spermatia are illustrated fig. 24 b — c; there is considerable likeness with 

 the figures of Delesseria sanguinea in Svedelius' paper pl. 5, f. 6 — 12. 



Fig. 25. Polycoryne radiata: a tip of small sterile shoot, showing formation of cortex, x 360: b section of höst and 

 parasite (dotted); C — d another section, seen from both sides; all x 180. 



Of the sporophyte, new microtome sections were prepared, fig. 24 d — g. The sporo- 

 phylls are terete or flattened. The tetrasporangia are borne laterally on sterile cells, 

 at least in most cascs (fig. 24 d — f ), but I cannot see anything very remarkable in this 

 feature. 



As an intimate knowledge of the mode of growth would help us to understand the 

 affinities of this strongly reduced parasite, I have examined a great number of young 

 shoots, but their microscopic size and the rapid formation of cortex makes it difficult 

 to obtain good results. To judge from fig. 25 a the central cells do not diYide by inter- 



