New Species - Burnet Saxifrage

Every year there seems to be a new meadow plant species but I was wondering whether this year was going to be an exception - until today. In the middle of the uncut part of the East Field is a single umbellifer which turned out to be Burnet Saxifrage (Pimpinella saxifraga). As usual I have no idea why it should turn up after we have been managing the meadows for eight years. Was the seed waiting all this time for the right conditions? Could a bird or animal have brought it in? Is there some Burnet Saxifrage in a nearby field or garden? Anyway it's a brilliant new flower to have - as a late flowering umbellifer it must be great for invertebrates. When I went to photograph it this morning there was a Silver Y moth resting on the stem. I just hope it manages to seed before it is eaten by a careless deer or rabbit