In northern Canada, the forest floor is carpeted with reindeer lichens. They look like a moss made of tiny gray branches, but they're stranger than that: they're composite organisms, a fungus and algae living together as one. They're a major part of reindeer diets, hence the name, and the forest depends on them to move nutrients through the ecosystem. They also, at least in parts of Quebec, are having a lot more sex than scientists expected. In a new study in the American Journal of Botany, researchers found that the reindeer lichens they examined have unexpected levels of genetic diversity, indicating that the lichens have been doing more gene-mixing with each other than the scientists would have guessed.