Do yellow snowdrops really exist?

Snowdrops are white, right? 

Actually, if you look closely at them you'll see that snowdrops are green and white - inside the bell of the flower there are green patterns, and the bits which join the flower to the stem are green too. Sometimes, instead of green these markings are yellow. Snowdrop fans think this is very special. 

It's just possible that in amongst the millions of snowdrops at Walsingham there are one or two yellow ones, hiding. But don't trample on the others, trying to find them! 

Oh, and I thought Jim was being silly about the monks planting snowdrops, but I've found out that it might be true. They might have planted them so that they could fill their churches with white flowers in February, at Candlemas, in honour of the Virgin Mary.