Good question @marblely. Normally I can find the answer by searching for 'looks like.... + images' and then look for good quality websites (eg RHS even wikipedia :)

In this particular case I first looked up 'white campion' and as the photo didn't match at all I just adjusted my search : 'looks like campion, etc' and then switched to the 'images'.
I dream of having a tricorder though 😍 ...