Previously part of the Galanthus genus, but back in the 18th century Linnaeus split them into different genera as leucojum's 6 tepals are of equal length, whereas with galanthus, the 3 inner tepals are shorter. Recently other species have been moved into the genus Acis. Leaving only two species L. aestivum and L. vernum. Both with bell-shaped, pendent white flowers, often with each tepal tipped with a green or yellow spot. Both are called snowflakes, but quirkily, in the UK the summer snowflake (L. aestivum) flowers in spring and the spring snowflake (L. vernum) flowers in winter!
Both of the species are widely established outside of cultivation, having been grown here for hundreds of years; L. aestivum used to be considered native especially around tributaries of the Thames, though current thinking is that this is not correct. The flowers of both are visited by pollinators, especially bees.