So I was telling a friend about this blog, and I mentioned that I had keyed out one of the plants that I didn’t know – and she asked me what it means to “key”. So if you’re a veteran botanist, forgive me. But if you are a newbie, here it is: a plant key is a book of all the plants in an area, and it consists of a very long set of either-or questions. If you patiently (and correctly) follow the trail of questions along, eventually it will lead you to the only plant that has all of the characteristics that your plant has. A key is full of all sorts of obscure terminology like awn, bract, fusiform, and stolon. You also will stumble across common words that, in the context of the key, have specific meanings – like scale, or ray – which don’t mean at all what they do in the rest of the world. Back when I was in college, my botany-student friends and I would get together at parties, and as the beers went by we would have increasingly passionate conversations about some class or another. My roomate always loved hanging out with us, because he could make jokes later about how we were speaking an incomprehensible language. But that’s botany – you have to learn the language, and then it’s loads of fun.
Here in Marin, the two keys that are most important are the Jepson Manual – which is the definitive key for the state – and the Marin Flora, which narrows down the number of choices by a lot, since you are only having to consider plants that are actually found in this county. Also handy is the Peterson Field Guide to Pacific States Wildflowers, which is a guidebook, not a key, but has a lot of the more common plants which you can look them up according to color and flower type.
To key a flower, you’ll need a good hand lens (high powered magnifying glass) and maybe a pair of tweezers.