Classification is a natural human propensity—we organize our clothes, our kitchen cupboards, and our toys. This applies to the natural world, too, where animals and plants are grouped based on ...

Mr. Langellier is a writer and field botanist in Vermont. In 2009, the botanist Naomi Fraga was hunting a flower without a name near Carson City, Nev. Ms. Fraga saw that the plant was going extinct in ...