Wednesday, June 15, 2011

Dryopteris goldiana at Abraham's Woods

I did a post about most of the ferns at Abe's Woods a few days ago, but I wanted to save Goldie's Woodfern, Dryopteris goldiana, for its own post. This species is close to my heart, since it's one of the (relatively) rarer members of the genus I study, and the population at Abe's Woods is really beautiful, and extensive. We saw it when we visited a couple of weeks ago, and the ferns were still unfurling, with many still in fiddlehead stage. I just went back to put out dataloggers, since I will be using this site for my research, and what a difference a few weeks makes! We've had a very strange, late spring here, and the temperature has gone from mostly in the 40s to mostly in the 90s over the last four weeks, and the ferns have responded in force.D. goldiana is one of the largest ferns we have in the woods around eastern North America (it could go toe-to-toe with Ostrich fern for that title), and it's remarkable to see how much they've grown and how quickly. Above and below are some 'before' shots...

And here are the 'after' shots. Quite a difference, huh?

These ferns are also showing off some helpful diagnostic characters. If you happen to come across an absolutely gigantic fern in the woods, and for some reason you're not totally convinced that it's Dryopteris goldiana just based on its massive-ness, here are a few things to look for. First, this species tends to have dense brown or golden-brown scales along the stipe (typical of the genus), but D. goldiana has a definite dark stripe down the middle of the scales, while many of the other Dryopteris I've come across in our area don't have this stripe. The arrangement of the sori is also pretty striking. They're very orderly, arranged in rows down either side of the costule of each pinnule, and have the typical Dryopteris form: a kidney-shaped, reniform indusium covering each sorus. Again, the only other really large fern you could confuse this with might be Ostrich fern, Matteuccia struthiopteris, but that one has totally dimorphic, separate sterile and fertile leaves, so should be easy to separate from this Dryopteris.

I included this last photo just to further impress you with the size of this critter, and I actually took a similar photo with Dryopteris celsa, the log fern, which is a polyploid between D. goldiana and D. ludoviciana. You can certainly see where D. celsa gets its size from!

1 comment:

Anonymous said...

Emily, great to read about this fern! I, too, am a botanist although "retired," whatever that means. Anyway, I am relandscaping my cottage in Michigan along the big lake and trying to use only native species. I think this fern will work for me due to its size, and, it is available from a local nursery. Amazing! Thanks, BLR