I always remember this one by a) recalling what it looked like last time I saw one and b) remembering that the lesser one is pointless (i.e. the leaflets don’t have a point, just a notch) which I now see works as a description when you are on a walk pointing plants out to people but is perhaps less useful when written down. It’s quite a small annual and the one most likely to be growing in your lawn as a weed except we don’t call them weedy lawns anymore we say they are biodiverse and we celebrate the fact they are there etc. but frankly it’s just a really good excuse to not weed them because everyone has more interesting things to do than weeding the lawn, don’t they?
