By Mirielle Lopez-Guzman

Jun 25 2019

While imaging herbarium specimens, I was struck by the unusual colors of the star cloak fern, Notholaena standleyi. This fern contains farina, a wax-like substance, of different colors on the underside of its leaves. The farina color differentiates the star cloak fern into 4 different chemotypes: Pallid, Yellow, Gold, and Yellow-Green. Pallid and Yellow chemotypes range from white to cream to light yellow. Gold and Yellow-Green type colors range from deep gold to greenish yellow to brown. The beautiful colors of the star cloak’s farina are sure to attract any passerby that happens upon it! The star cloak fern is found in north and central Mexico and the southwestern United States. An interesting characteristic of this fern is it has an adaptation to the periods of drought that are common in the environment it inhabits: the leaves curl up and remain that way until water becomes available again. It is not yet clear what the function of the farina is, but it has also been suggested to help protect the fern from its environment. See what their typical habitat looks like.

Interestingly the different colored chemotypes can be separated into ploidy levels. Ploidy level refers to the number of chromosome sets an organism has; Pallid and Yellow types are diploid (2 sets of chromosomes) and Gold and Yellow-Green types are tetraploids (4 sets of chromosomes). This difference in chromosome sets indicates that there may need to be taxonomic reclassification of the plant in the future. Though all of the chemotypes for Notholaena standleyi are currently considered the same species, they might be split into different species after more research is done.