You may notice a distinct aroma of hay when you travel through certain sections of the park. That’s Hay Scented Fern (Dennstaedtia punctilobula) you’re smelling.
This patch is where Upper Giorgetti and Trillium intersect (Jct. 6), but my favorite spot is where Strong Angel travels under the powerline. I love to cruise downhill through that stretch in the early morning—it feels like descending on a cloud of green fluff!
Here’s a link to a good guide to start you on identifying other ferns in the park if you’re interested.