What is it Wednesday: May 20, 2020

Can you identify what's in this photo?

Each Wednesday morning 

on Camp Lutherlyn's Facebook page

 the Lutherlyn Environmental Education Program posts a photo. 

Readers have all morning and afternoon 

to make their best guess about what the photo is. 

Around 6 pm LEEP provides the answer and a brief explanation.

Each week's What is it Wednesday post 

will also be posted on the Nature of Lutherlyn blog, 

 after it is posted on Facebook,

sometimes with additional bonus information. 

In addition to bringing you current editions of What is it Wednesday 

on the Nature of Lutherlyn blog, 

we will be reposting old editions,

creating a What is it Wednesday archive. 

This photo was posted as a What is it Wednesday on

May 20. 2020. 

And the answer is....

This is a frond of a type of fern called “interrupted fern.” 

The frond is the whole leaf of a fern; each division of that leaf is called a pinna (pinnae for more than one). In this picture we can see one pinna that is dark green and bumpy – that is the fertile part of the fern, the part that produces spores to create more ferns.

Many ferns have sterile frond and fertile fronds – some of the fronds have no spores at all (sterile), other fronds do have spores (fertile). In some ferns, the fertile fronds only have spores on some of the pinnae, usually near the top or near the bottom of the frond.

Christmas fern with smaller darker fertile pinnae near the top of the frond. 

Interrupted ferns are unique however – in their fertile fronds, the pinnae with spores on them are in the middle of the frond, with sterile pinnae above and below.

Interrupted fern with dark green fertile pinnae in the middle of the frond.

In these pictures, the fertile pinnae are dark green - that's what they look like when the spores are developing. They turn brown as the spores are mature, then become dark brown and shrivel up after the spores are released. Eventually they may dry up and fall off – leaving the fertile frond with a gap in the middle, looking like its growth was interrupted between the base and the tip of the frond

Fertile fronds of interrupted ferns usually have 3 or 4 pairs of pinnae in the middle of the frond have spores on them. In today's unusual fern however, there is just one fertile pinna on the frond.

Like and follow Camp Lutherlyn on Facebook, to see What is it Wednesday posts when they come out and have the opportunity to share your guesses in the comments!