“ Herder was probably misled by the fact that the Danish word elle signifies not only elf, but also alder tree (Ger. Erle) . His mistake at any rate has been perpetuated by both English and French translators, who speak of a “king of the alders,” “un roi des aunes,” and find an explanation of the myth in the tree-worship of early times, or in the vapoury emanations that hang like weird phantoms round the alder trees at night. ”