Some aspects of the life history and cytology of Stictyosiphon tortilis (Rupar.) Reinke

Abstract

1. The life history of Stictyosiphon tortilis was investigated by means of observations on the shore throughout the year, supplemented by observations on spores grown in culture.
2. The germlings obtained in culture lived for several months and reproduced asexually by plurilocular sporangia, but no new macroscopic generations was produced.
3. Nuclear divisions were followed in the vegetative cells and developing sporangia of the macroscopic plants and in the vegetative cells of the germlings.
4. Chromosome counts of 44+ were obtained in the vegetative cells of the macroscopic plant, and counts of up 26 in the developing sporangia and the cells of the germlings. These figures, together with the prolonged prophase and appearance of pairing during the first division of the sporangial initial, indicate that this division is meiotic.