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Posts Tagged ‘Dryopteris intermedia

Evergreen Woodfern (Dryopteris intermedia Muhl.)

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On Sunday, I looked for and found my first November fern!  Since we had about 25 cm of snow yesterday, I may have found my only fern of the winter!

The fern I found is an evergreen fern, pressed close to the earth this time of year. 


For me, identifying ferns is always a challenge.  I use the Peterson Field Guide,  ‘A Field Guide to the Ferns and their Related Families’  by Boughton Cobb, 1963. Then I turn to a very helpful website .

With patience and careful attention to some key features, I can usually figure them out.

checklist issued by the Nova Scotia Museum for a fern project several years ago; a checklist like this is helpful to double-check your identification

The key features for the fern I found are:

  • the roughly triangular shape
  • the ‘thrice-cut’ nature of the leaves (cut once into leaflets or pinnae, a second time into subleaflets or pinnules, and a third time into lobes)
  • the stalk is greenish and scaly, not hairy
  • the lowest pair of inside subleaflets (next to the stem) of the lowest leaflet are slightly shorter than the second subleaflets next to the stem (if you look closely at the photo above, this feature is hard to see due to the camera’s perspective – the best example is the fern at the upper right).  

This fern is the Evergreen Woodfern (Dryopteris intermedia), closely related to and difficult to distinguish from the Spinulose Woodfern.

a leaf of the Evergreen Woodfern... the lowest pair of inside sub-leaflets at 'A' are shorter than the next pair at 'B'... this is the feature distinguishing the Evergreen Woodfern from other Woodferns

Written by jane tims

November 25, 2011 at 6:46 am

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