Saturday, April 17, 2010

Adder's Tongue Fern

This tiny plant is called Ophioglossum or Adder’s Tongue Fern. At barely two inches tall, it produces a single, fleshy leaf. Mature plants will also produce a stem bearing the spore producing structures. I think this is a lovely little plant and enjoy finding it scattered widely across Blue Jay Barrens.

Adders Tongue Ferns often grow in bunches or colonies of many plants. I find them primarily in historically undisturbed areas such as old fence rows and field corners. In some locations they appear to be migrating into the adjoining fields.

My personal name for this fern is the Aggravation Plant, because of the aggravation is causes when I try to identify it to species. There are several species of Ophioglossum and they are all similar in appearance. There are two that are known to occur in this area and a third that is found a couple of counties to the east and could possibly show up here. The problem may be that I have too many plant ID references. If I look in just one book, it’s not hard to come to a definite conclusion. It’s when I try to verify that ID in another book that things fall apart. The plant shown here neatly fits the description of the species that has leaf blade fully open and leaf tip rounded.

However, the next plant down the line fits exactly, the definition of a different species that displays a folded leaf blade and a pointy leaf tip. Two species side by side? Not likely. When you scan the surrounding population, you see leaves of every shape and all gradations in between. Of course, there are some other characteristics that the books describe as being more definitive.

Most books point to the venation as being the defining character. Well, these are some thick leaves and no amount of sunlight shining through the back of the leaf is going to allow you to get a good look at the veins. The easiest way I’ve found to view the veins is to drop a fresh leaf into alcohol to remove the chlorophyll and then put the leaf under a dissecting scope. What I see is a pattern of leaf venation that doesn’t match any of the illustrations in the books. Fortunately, the plants don’t have a long season, so when they soon whither, I will assure myself that next year will be my time to crack the Adder’s Tongue Fern mystery.

No comments:

Post a Comment