The Loddon Lily is also known as the Summer Snowflake, it is like a giant Snowdrop.There are two subspecies.
L. aestivum subsp. aestivum is native in some areas and subsp. pulchellum is an alien (which was in cultivation by 1596) but they have long been confused and the true subspecific identity of some records is in doubt. However, the presumed native distribution of subsp. aestivum in Britain and Ireland is stable. As aliens, both subspecies readily become naturalised in suitable situations and appear to be increasing.
The differences between the two are minimal and that no doubt accounts for the two being muddled up until quite recently. The native subspecies has the main flower stalk with little serrated edge. This can be seen (just) in the some of the photographs below.
I have seen this plant in various gardens and at Slimbridge, however I have also seen it in an isolated woodland near Hastings in Sussex. Here it may well have been a true native, in that where it was growing was a long way from any roads or any habitation and the wood was surrounded by private land, fields and other woods. Reference to the BSBI web site distribution maps shows that it has not be recorded from the tetrad where I saw it but has been recorded from two adjacent tetrads, one to the north and one to the west.
There are normally 3 or 4 flowers hanging down from the end of the main stalk (scape) and this is in effect an umbell but not like the typical umbels of Cow Parsley and Hogweed. They flower in April, so much later than Snowdrops, however despite their other common names which are Summer Snowflake and Summer Snowdrop, you would hardly say it is a summer flower. The reason for Loddon Lily is because it grows in the Loddon valley
After flowering the seed pod develops into a large round structure which is quite spongy and can float.It is thought that this may aid in the dispersal of the plant as they often grow by water courses and seed pods falling into the water potentially could get washed some distance from the parent plant. The ones I found near Hastings were next to a wet area that had a small stream running through it so could potentially have arrived in this way.