Equisetum

Tuesday, 26 March 2013.   I went for a walk today hunting for equisetum, or horsetail. In the Naturalists’ Training Course meeting tomorrow I’m to present on a species of it, Equisetum pratense, or Meadow horsetail, one of the seven species found here at KSR—that’s half the number of species known worldwide! I didn’t know, till I read in our text, there was more than a single extant species of horsetail, though it’s long been a plant I like. But the species I know is, I think, Equisetum hyemnale, Rough horsetail or Scouring rush—the one with stiff green stems, some with cone-like tips, that you spy alongside wooded paths or at the edges of ponds.

Here’s a photograph I took last August of a horsetail I saw here.

I’ve liked the plant, without knowing much about it, except that it’s been around for a long time. I used to take my daughters to the Royal Ontario Museum 30 years or so ago, to the old dinosaur gallery. Several dinosaurs were shown roaming through landscapes that included horsetails, some as large as trees, and I was startled and awed to discover that a form of those huge plants still existed.

The horsetails are vascular plants (that means they have a circulation system, similar to veins, that delivers nutrients between leaves and roots) allied to ferns, and like ferns they reproduce by spores. The stems we see are only a small part of the plant, for they grow up from perennial rhizomes. The rhizomes allow them to spread underground and, as I understand it, some large stands of equisetum are (like stands of trembling aspen) really a single plant. These stems are the primary organ for photosynthesis, since the plant has only relic leaves. I know that from the text – to look at a horsetail you’d think it has no leaves at all. The stems are interesting in another way, too – they can be either sterile or fertile. The production of spores is complex and I don’t grasp it yet, but I’m working on it.  

Meadow horsetail, the one I’m to present on, is described as “a delicate and airy plumed horsetail of the cool north” (and how lovely is that?) at:

http://www.rook.org/earl/bwca/nature/ferns/equisetumpra.html

Its other common names are Shade horsetail and Shady horsetail. Its Latin name, Equisetum pratense is derived from the Latin equus, for ‘horse,’ seta, meaning ‘bristle’ or ‘animal hair’; and partum, meaning ‘meadow’. It can be found in moist woods, thickets and meadows, and flourishes in partial shade to full sun. It produces fertile stems first, without chlorophyll; once the spores are shed (between April and early July) it turns green and grows branches. Its stems are deciduous, dying back in the winter.

Given that last fact, the horsetails I found on my walk today are definitely not meadow horsetail. I went back to the path where I’d photographed that horsetail with its spider web, sliding a bit over the snow—it’s gotten slippery as it’s melting--here are the photos I took:

It spread out quite a way up the slope, and its stems have definitely not died back though some of them are broken or bent from the weight of the snow.

I’ve learned meadow horsetail grows with whorled branches that are often horizontal or drooping, and usually with single stalks rising from the rhizome. It doesn’t produce a large number of fertile stems, but reproduces primarily through its rhizomes. I don’t think I’ve ever seen it—or if I have I didn’t recognize it as a horsetail. Come spring I’ll have to see if I can fine it here at KSR.

There are some good images of it at: http://www.florafinder.com/Species/Equisetum_pratense.php

But spring is actually making itself felt here at Jokers Hill, though the snow is still in the woods. Walking today I heard and saw water running everywhere. Red-winged blackbirds are calling—yesterday I heard a robin and mourning doves. And most of the fields are bare of snow.  

Just look at those blues!