Galanthus earlier authors had mainly relied on was shown to be highly homoplasious. A number of species, such as "G. nivalis" and "G. elwesii" demonstrated intraspecific biogeographical clades, indicating problems with speciation and there may be a need for recircumscription. These clades were assigned names, partly according to Davis' previous groupings. In this model clade Platyphyllus is sister to the rest of the genus. By contrast another study performed at the same time, using both nuclear and chloroplast DNA but limited to the 14 species found in Turkey, largely confirmed Davis' series and subseries, and with biogeographical correlation. Series "Galanthus" in
Chlamydomonas nivalis optimal position in the snow for moisture content, light, and temperature. When in the immotile cyst stage, the "C. nivalis" cells must depend on the flow of meltwater to move it by chance to a favourable area. The temperatures in which this species can survive in ranges from below 0 °C to just above 20 °C. Growth is slow when temperatures are below 5 °C. At 5-15 °C the growth of "C. nivalis" cells can outperform the growth of C. reinhardtii cells. Both species grow at the same rate at 20-25 °C. The growth of "C. nivalis" is suppressed when