It is impossible not to encounter dotted polypody or ‘ae along the Kīlauea Iki day hike in Hawai’i Volcanoes National Park.
Dotted polypody is one of the first vascular plants to colonize post-lava flow landscapes. In areas with such exceptional drainage, ferns need to establish in areas where small amounts of moisture can be retained from aeolian-deposited (wind) organic matter, such as crevices. This is also true for ferns in other broadly-disturbed ecosystems, such as alpine scree and boulder fields. Even though little rainwater persists at ground level, frequent rainfall helps the fern’s water-dependent life-cycle complete.
Kathy Valier, in her Ferns of Hawai’i, describes dotted polypody in part:
The fronds of plants growing in forests form a single flat plane, but the variety vulcanicum that grows in crevices of windswept lava flows feathers its pinnae horizontally.
The species is endemic to the Hawaiian islands, found on all sizable land masses except for Kaua’i and Ni’ihau. The variety in today’s photographs, however, is restricted to just three islands: Hawai’i, Maui, and Moloka’i.