April, 1919.1 THE GERMINATION AND DEVELOPMENT. §5 



Porphyra on the terraces seems to give evidence for this view. 

 The experiment block should have had coarser surface than 

 it had. 



Thus, one of the important aims of the present experiment 

 has been missed, as it appears to me. The other aim, i.e., to 

 ascertain the attaching season of the " rock-porphyra " spores 

 has been achieved. We are now sure that the spores of either 

 P. leucosticta var. suborbiculata or P. linearis come out from 

 an unknown source in the latter part of October and take their 

 anchorage on the substratum. In this respect, it is same as 

 P. leucosticta var. elongata { — P- tenera Kjellm). 



It may be here added, at the same time, that the spores 

 of Ulothrix suhBaccida and those of Urospora penicillilormis 

 make their appearance in autumn while their spores have been 

 discharged from the matured fronds early in spring. How they 

 pass the summer months we know nothing about. 



From the studies of Bornet and Thuret^\ Berthold^\ 

 ScHMiTZ^^ and others, we are convinced that the prepaga- 

 tion of Porphyra is carried on by two different ways ; by 

 sexual carpospores and by asexual tetraspores ; the carpo- 

 Spores being formed by fusion of immotile pollinoids and carpo- 

 gones, both transformed from vegetative cells. The carpospores 

 or the tetraspores are immotile. They come off from the frond . 

 as they are ripe during February-April in temperate regions and 

 later in colder seas. These spores or what appear to be, 

 come out from somewhere and get hold of rocks or twigs late 

 in October and develop into the well acquainted fronds of 

 Porphyra. Where and in what state they pass these several 

 months is a problem ncn yet thoroughly investigated. 



Berthold^^ states : — " Die nahere Untersuchung zeigt nun, 

 das es bei Bangia und Porphyra die ungeschlechtlich Sporen 

 sind, welch unraittelbar zu neuen Pflanzen heranwachsen." He 

 could not positively prove that the carpospores germinate 



1) BoENET et Thuret: Eludes Phycologiques. 



2) Bertholb : Bangiaceen. 



?)) ScHMiTZ: Bangiaceiie, in Engler n. Prantl: Pflanzenfamilien, Algae, p. 

 309. 



4) Berthold: Bangiaceen, p. 18. 



