Kindling Neighborly Connections between People and Nature.

Friday, April 24, 2020

Ancient fern relatives near Darling Run Access Area of the Pine Creek Gorge (April 24, 2020)

Many visitors to the Pine Creek Gorge may not think to pay heed to small pools of stagnant or slow-moving water along the path, especially not while the pools and riffles of beautiful Pine Creek run swiftly by on the opposite side of the trail. However, the unique characteristics as well as overall diversity of all that can be found in these small pools of stagnant or slow-moving water is remarkable. I was sauntering along the Pine Creek Rail Trail a little south of Darling Run Access Area...again...and a number of green stalks protruding out of a small pool to the left side of the trail caught my eye. There I happened upon one of the oldest known representatives of fern relatives, a horsetail. The fossil record shows that horsetails have been around for a very long time; since about 300 million years ago! Furthermore, early on in their evolutionary history these interesting plants of the genus Equisetum once grew to the size of a large tree!

green energy producing stalks and tall fertile stalk on right.
There are a number of things to note about these particular horsetails that I happened upon along the Pine Creek Rail Trail. First, in looking at the photo to the right, you'll notice a number of stalks grouped close together. Many of these, like their relatives the clubmosses, are likely attached to the same root system. Note also that some of the stalks are green with a spiraling of thin branchlets arranged outward and upward from the central stalk. These are energy producing stalks because the entire surface area of the above-water portion of the plant is photosynthetic. In addition, you may notice another stalk that is more of a pale color and has a cone-like structure at the top. This is a fertile stem, the horsetail's reproductive structure. Since these stems are connected at the roots (which makes them extensions of the same plant), the fertile stems receive energy via its root structures that are also connected to the energy producing stalks. It would be easy to make the assumption that these two different types of stalks (fertile and energy producing) are different plants entirely, but now we all know better.

fertile stalk.
Species identification of horsetails can be quite challenging and at the same time simple and straight forward. By taking a look at the outward appearance of these horsetails along the Pine Creek Rail Trail, I was able to determine, utilizing my Peterson Field Guide to Ferns of Northeastern and Central North America (2nd edition), that these were one of three species. Water horsetail, marsh horsetail, and field horsetail all have asceding branchlets that spiral around the central stalk. I needed to take my identification a step further by taking a look inside of one of the stalks. I don't like killing plants for identification purposes. Fortunately I was able to locate a fertile as well as an energy-producing stalk that were broken off and floating on the surface of the water. I took these home to look at under a hand lens.

These pictures that you see below are cross-sections of the horsetail stem that were photographed with my cell phone using my hand lens for added magnification. The definitive fingerprint of each species of horsetail is the pattern represented by the cross section of the stem.

cross-section of stalk.
The cross-section of the fertile as well as the energy-producing stalks were the same, confirming that they are the same species. These turned out to be marsh horsetail. According to my field guide, this particular species is described as a rare and local horsetail of open, wet woods. The marsh horsetail is a wild neighbor to appreciate, and it is not the only horsetail species that can be found in the Pine Creek Gorge. I hope you've enjoyed learning a little about this living representative of a very ancient category of plants, and that the next time you happen upon horsetails in wild spaces, that you might experience some of the the joy that I have found in making the acquaintance with these and others.

cross-section of stalk.

No comments:

Post a Comment