Galanthus have now been lost, and others not seen by the authors). They differ particularly in the size, shape, and markings of the flower, the period of flowering, and other characteristics, mainly of interest to the keen (even fanatical) snowdrop collectors, known as "galanthophiles", who hold meetings where the scarcer cultivars change hands. Double-flowered cultivars and forms, such as the extremely common "Galanthus nivalis" f. "pleniflorus" 'Flore Pleno', may be less attractive to some people, but they can have greater visual impact in a garden setting. Many hybrids have also occurred in cultivation. In the UK these species: and these cultivars:
Chlamydomonas nivalis such that it is covered by the carotenoid globules full of astaxanthin that will provide protection against UV radiation. The majority (91%) of astaxanthin derivatives are stored in its monoester form within dormant "C. nivalis" red cysts. Astaxanthin is the pigment that makes the cell appear deep red. Other pigments that can also be found in "C. nivalis" include violaxanthin and fadonirubin. Visible algal blooms could be a crucial determinant of surface albedo. It has been suggested that algal blooms partially composed of "C. nivalis" may contribute to lowering ice and snow albedo. The red coloured pigments produced by the