Galanthology?

Some time ago now I discovered that there are more types of Snowdrop than"Single" & "Double".
How many, in fact, I shudder to think after visiting a few specialist sites.
What really snarles me up though is the fact that to the inexperienced eye, (Mine) some of them SEEM to be indistinguishable one from t'other.
Some appearing even more alike than these two. The only difference I could see in these two adjacent flowers was petal (Tepal) size/shape.