Ten morphotypes attributed to different species of Porphyra have been found in the central coast from Chile. In this paper we report the chromosome number and microfluorometric studies in P. columbina from Montemar, Chile (32 degrees 57'S - 71 degrees 33'W). Reproductive gametophytes from two morphotypes were separated by morphology, sexuality and characteristic pattern distribution of reproductive cells: P. columbina (monoecious interspersed male and female patches distribution) and P columbina f. l (dioecious and monoecious sectorised male and female patches distribution). The results of P columbina (n=20 gametophytes) showed a basic haploid chromosome number of n=3, except one frond with 2 and 3 chromosomes in their cells. The results of P columbina f. l (n= 26 gametophytes) showed a haploid chromosome number of n=4, but the haploid condition was found inconsistently in some fronds, having a chromosome range from 3 to 5. Mean of nuclear DNA fluorescence of spermatangia and zygotosporangia of both morphotypes had coherent haploid and diploid values. Inter morphotypes comparison of nuclear DNA fluorescence values in spermatangia had significant differences (P<0.05).