Galanthus leaves (vernation). In the era of molecular phylogenetics this characteristic has been shown to be unreliable and now seven moleculary defined clades are recognised corresponding to the biogeographical distribution of species. New species continue to be discovered. Most species flower in winter, before the vernal equinox (20 or 21 March in the Northern Hemisphere), but some flower in early spring and late autumn. Snowdrops are sometimes confused with the two related genera within the tribe Galantheae, snowflakes "Leucojum" and "Acis". All species of "Galanthus" are perennial petaloid herbaceous bulbous (growing from bulbs) monocot plants. The genus is characterised by the
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