Snarky Septuagenarian--Plant Diversity in Daily Life

I'm over 70. One of the priviledges of age, I'm told, is to be irascible, telling you HOW IT IS! without worrying about your reaction. If I'm going to exert that power, I'd better get to it. So I'll allow my Snarky Septuagenarian to appear, today talking about: Plant Diversity!

You can't just say "oak" when recommending a plant. Which oak?

oak, Colorado

Common Names--Too Many Shared Names

Calthus palustris  Do you call it cowslip or (marsh) marigold?

Nobody regulates common names. That's one of the reasons for scientific names. The rule on scientific names is: each organism has one and only one name, not shared with any other organism. 

Common names don't obey either of those rules. I wrote previously about multiple common names for the same plant. (link) That is annoying, because sometimes you don't recognize that someone is talking about a plant you know only because they're using a different common name. 

I think the same common name for different plant is even more unfortunate. In this day of using words on the internet to learn about things, shared common names lead to at best, time wasted working out which plant you want, and at worst, possible poisoning because one plant with that name is toxic and one isn't. 

another cowslip Primula vulgaris

another marigold, Tagetes sp.