The culture of bisporangial plants of Dermatolithon litorale (Suneson) hamel et lemoine (Rhodophyta, Corallinaceae)

The crustose coralline alga Dermatolithon litorale from the Swedish west coast was cultured from bispores, with small shells as substrate. After 20 months fertile crusts were obtained. Twenty-six-month-old crusts were fixed and thin sections studied. The conceptacles contained only bisporangia with uninucleate bispores, as in the initial material. No other reproductive organs are known in this species. A previous cytological study on material from the same population showed that the uninucleate bispores are formed apomeiotically. The results of the current culture study thus agree with the previous cytological data. D. litorale has an apogamous and apomeiotic life history. Previous cytological studies on a second species, D. corallinae demonstrated that this alga has two parallel life histories in northern waters: one is triphasic (Polysiphonia-type) with meiosis at the formation of tetraspores and binucleate bispores, and the other is apomeiotic with uninucleate bispores. The occurrence of apomeiotic lif...