Last weekend I was out with the Kapiti-Mana branch of Forest and Bird, giving them an introduction to ferns. A few weeks back, I gave a similar walking-talk at Otari-Wilton’s Bush in Wellington. Many people find ferns an appealing group to learn. Aside from their iconic status in New Zealand, good learning resources are available, and there are enough different New Zealand ferns to be a challenge without being overwhelming. Most forested sites in New Zealand will be home to between 20 and 50 species of fern.
When teaching people how to identify a fern plant, I stress that there are four characteristics to initially look for:
1) does it have reproductive structures? Fern reproductive structures occur on the underside (or margins) of the frond. The shape (e.g., round versus elongate into lines) and position (i.e., on the margin or away from the margin) are important. Related ferns almost always have similar reproductive structures, even if their fronds look completely different.
The nature of the reproductive structures can be critical for identifying a fern. If I happen upon a fern I don’t know and it does not have reproductive structures, I do not bother attempting to identify it. If you’re learning ferns, I recommend you do the same.
2) does it have scales or hairs or is it naked (glabrous)?
Hairs are only one cell wide, but this can only be checked with a microscope. As a general rule, if you can’t decide whether something on a fern is a scale or a hair, call it a scale if it is obviously wider than your own hairs.
3) how divided is the frond? It might be undivided (= “simple”), or once divided, or twice divided… etc.
4) are the fronds tufted, or do they arise along a creeping rhizome (modified stem)?
Noting these features will help you identify a fern. These features are what I make sure I record when I am collecting and/or photographing ferns.
The Kapiti-Mana Forest and Bird trip was to Mangaone Walkway near Waikanae. Below are the ferns we discussed. Several of them already feature in: