Mycology

The twelfth entry is la chiave dicotomica, and the adjective is worth taking apart, because English already owns every piece of it. It is Greek dikha, in two, plus temnein, to cut. That verb is one of the busiest Greek roots in English and it is almost never seen. « Anatomy » is ana- and temnein, cutting a body up, which is what the discipline first was. « Atom » is a- and tomos, the thing that cannot be cut, named a very long time before anybody cut one. « Epitome » is epi- and temnein, cut short, which is why it meant a summary before it meant a perfect example. And every « -ectomy » on a surgical list is the same verb doing the same work. So the name is a promise about method rather than about mushrooms: at each step the species still in play are halved, and the reader is asked for nothing except which half. The noun beside it pulls the other way, since la chiave is a key and a key opens — so the term holds two pictures at once, and only the adjective says what happens on the page.