Encore - Black Spleenwort Fern and Fractals

April 06, 2019


Today and every Saturday Earth Science Picture of the Day invites you to rediscover favorites from the past. Saturday posts feature an EPOD that was chosen by viewers like you in our monthly Viewers' Choice polls. Join us as we look back at these intriguing and captivating images.

: Greg Parker
Summary Author: Greg Parker

August 2013 Viewer's Choice Upon returning from walking our dog, my wife told me that there was an excellent opportunity, over in the forest, to observe one of those mathematical modeling structures I’m so fond of. When she saw these unopened ferns, she knew that they were the sort of thing that would interest me.

The Black Spleenwort fern (Asplenium adiantum-nigrum) was first modeled using fractals by the British mathematician Michael Barnsley. The fractal code developed by Barnsley to model the fern is called an iterated function system (IFS). I used the Fractal type 0, IFS code, provided by the fractal rendering program Incendia EX V, to generate a structure resembling an unfurled fern; I also took a macro image of a real unfurled fern to show the marked similarity between the real and the modeled structures. Just as in the case of Barnsley's fully opened fern, the IFS code also models the unfurled fern rather well.

Photo Details: The camera used to take the macro was a Canon 5D MkII full-frame DSLR; Canon 100mm macro lens (non-IS) and; Canon MR-14EX ring flash. Manual settings of 1/500th sec. exposure; f/22; and ISO 100.