Google “osmunda” and the online dictionaries will tell you that the word refers to a genus of ferns. Cobb’s A Field Guide to the Ferns mentions that the name came from Osmunder, the Saxon god of war (os=god, mund=protector).  In other sources, I found that Osmund, the Waterman, once hid his family in a stand of Royal Ferns (Osmuda regalis) during an invasion by Danes.  After ferrying the enemy across the waters, he was able to rescue his wife and daughter from their hiding place.

Another source claims a Latin origin where os=bone and mundare=to cleanse, referring to the herbal use of the Royal Fern (Osmunda regalis) for treating injuries.

Whatever the etymology, the family Osmundaceae – The Flowering Ferns – contains one genus (Osmunda) with three gorgeous species in our region, all of which can be spotted in the Red Pine Forest at Audubon.

Most plentiful are the Cinnamon Ferns (Osmunda cinnamomea).

Cinnamon Fern

At this time of year (mid-late spring), it is easy to spot a Cinnamon Fern by the fertile fronds – which grow separately from the vegetative fronds – in the middle of the clumps and are, when mature, the color of the spice that is their namesake.  These fertile fronds were green when they first appeared before the leaves, and they will whither first, too.  If you come after the fertile fronds have gone, look for clumps where the sterile leaves are mostly erect and where the stems have a slight groove.  (In comparison, the leaves of the Interrupted Fern curve outward and the stem is round.)  Also check the back of the frond.  Cinnamon Ferns will often display little fuzzy tufts at the base of each leaflet.

The fertile fronds of the Interrupted Fern (Osmunda claytoniana) are, well, interrupted.  At the bottom and top of the frond are sterile, green leaflets.  In the middle are the spore-producing fertile leaflets which start out green in early spring and turn brown as they ripen.

Interrupted Fern

Not all of the fronds are interrupted in this way.  So check the stem to see if it is round, rather than grooved.

Last, but certainly not least, is the Royal Fern (Osumunda regalis) – the one that looks (to me) least like a fern.

Royal Fern

With Royal Fern, the fertile leaflets appear at the top of the frond and, as with the others, they start out green, but turn brown as they ripen.

In all three of these species of the Osmundaceae family, the spores themselves are green and capable of photosynthesis.  They are short-lived and must germinate within a few days to be viable.

Fascinating to me is the life cycle of ferns…  Spores do not produce ferns…  well, not directly.  A spore grows into a gametophyte which contains both egg and sperm producing parts.  According to Associate Professor Raymond Milewski of East Stroudsberg University in Pennsylvania, the sperm will “swim across a surface film of water” to reach the egg.  SWIM?  Whoa…  (Click –> here for a You-Tube video!)  A proper fern will develop from a fertilized egg.


If I have ever seen a gametophyte, I didn’t know it at the time.  Now I want to see one…  Hmm…  I wonder how big they are…  Could I find one in the woods?

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