Blechnum filiforme or Icarus filiformis or pānako or thread fern is the most common, but unusual ground fern in the Tawa reserves. Its unusual features are that it is the only climbing species of Blechnum in New Zealand and it has three different types of fronds – juvenile, adult sterile and adult fertile. Blechnum species usually have separate fertile and sterile fronds while other ferns bear spores directly on one kind of frond.
Endemic to NZ, pānako or thread fern is the most common ground fern in Tawa bush reserves. The juvenile form creeps along the ground, and fronds grow out from a rhizome (horizontal underground stem).
The adult fronds grow out from the rhizomes as they climb up tree trunks.
Separate fertile fronds that bear spores also develop from rhizomes with thread-like brownish leaves, that give it its common name ‘thread fern’.
Recognition features of pānako:
Article Source: Gil Roper October 2021 Newsletter