#true fern

12/14/16: Selaginella willdenowii or “Peacock fern”; plant species that is a type of “spikemoss fern” and is considered a fern ally, not a true fern, meaning it has characteristics like that of a true fern, but it is not technically classified as such. This species is unique in that it has iridescent blue leaves! The iridescence is apparently caused by something called “thin-film interference” produced by a thin layer of cells part of the cuticle layer, above the epidermis (the outer “skin” of the plant). The theory behind this adaptation is that is helped reduce light intensity from the sun!