It’s nothing personal, but this fern is giving you the finger.
The best way to tell leathery polypody (Polypodium scouleri) from its polypody cousins is by its thick, leathery leaves. But the second-best way is by this fern’s long central frond–shaped rather like an expressive finger. The leaf is highly variable in size, usually growing from 6 to 18 cm but sometimes as much as 50 cm long, according to Jepson. As with all Polypodium, the underside of the leaves are decorated with the velvety brown spots of fertile, spore-producing sori. The fern blades sprout from underground rhizomes are white, and not licorice flavored
I haven’t seen this fern often–this one was spotted on the Steep Ravine trail on Mt. Tamalpais. Leathery polypody (also known as leather fern or leather leaf fern) can grow in a variety of habitats, including coastal strand, coastal meadows, and redwood forest. According to Plants of the Pacific Northwest Coast, it’s rarely found far from salt spray.
Flowers Of Marin 