Crepidomanes minutum is a filmy fern (Hymenophyllaceae) native to the Waimea Valley, O’ahu, Hawaii. The leaf blade of a filmy fern is usually only one cell thick.
Filmy ferns are restricted to rainforest habitats that are continuously moistened by spray from waterfalls or seeps. They have existed since the Upper Triassic 200 mya., when many of the first dinosaurs evolved.
Ever since reading Oliver Sacks’ Oaxaca Journal, I’ve been mulling over the intrinsic beauty and mystery of ferns. And, I know, “mystery of ferns” sounds like an optimistic textbook chapter in a freshman biology course. But plants this ancient can’t help but have a fascinating air about them.
And a leaf blade one cell thick? Imagine if humans had that problem. Full-contact sports would be horrible. —MN