Saturday, December 7, 2019

Grapefern



Hiking along the Mail Trace Road, Barb spotted a solitary green fern poking out of the drab floor of dried leaves.  It had what appeared to be green leaves spread out around the base and a 12" bright green stalk with light green bumps lining the underside of stems like little grapes.

When she touched the stalk there was a tiny cloud that drifted away.  The cloud of spores was released with each touch, as shown in this video.  We went back home to identify it.  What in the past would have been a nearly impossible task of thumbing through books became a one minute exercise with the photo above sent in to Inaturalist.

Wikipedia
This is a cutleaf grapefern, Sceptridium dissectum, a common fern, although easy to overlook when hiking as it is frequently found in overgrown disturbed areas.  It is a perennial but is easier to find this time of year because of its strange growing season. To grow it depends on a mycorrhizal fungus association in the soil.  Ferns are different from our common flowering plants and don't get as much respect, the Rodney Dangerfields of the plant world.  Stick with me as we muddle through this difference.

This grapefern produces a single frond (large, divided leaf) which spreads out at ground level, usually with lacy edges.  This often turns from green to a bronze color during the winter.  In fall, mature plants grow a single fertile section, which stands on a long stalk above the sterile part.  They are named for the round, clustered sporangium (spore cases) extending from the top of the stalk which have some resemblance to a bunch of grapes.  When we touched the stalk, the cloud you saw was the spores drifting away to the ground.

From here the fern life cycle gets very technical and hard to describe in simple terms.  Rather than confuse you further, I would suggest reading the best description I have found, here from UPenn.edu.

Resurrection fern during dry period
 Add water, no stirring required.
Another common fern species that can be overlooked is this resurrection fern, Pleopeltis polypodioides.   Gala Solari shared these photographs before and after a rain.  This is an epiphyte or air plant, meaning that it gets its nutrition and water from the air and the bark surface of a tree.  It is able to survive long dry periods and lose up to 97% of its water.  It does this by curling up its fronds, turning gray-brown and appearing dead.  Add rain and viola! it greens up.  It can survive drought for many years this way.  You can watch one revive in this time-lapse video.


From now on I will give a lot more respect to the ferns I encounter, even if I am still struggling to understand their strange life cycle.

You can read about the Christmas Fern in this month's Missouri Conservationist 
at this link.