Botrychium is a genus of ferns, seedless vascular plants. Botrychium species are known as moonworts. They are small, with fleshy roots, and reproduce by spores shed into the air. One part of the leaf, the trophophore, is sterile and fernlike; the other, the sporophore, is fertile and carries the clusters of sporangia or spore cases. Some species only occasionally emerge above ground and gain most of their nourishment from an association with mycorrhizal fungi. They are unusual among tracheophytes ("higher plants") in that at least some species produce the sugar trehalose.