Sunday, February 27, 2011

Fragile Fern

Just what is it that makes us feel Spring is coming? I had a real feeling of it yesterday, so took K-dog for a walk and thought about this interesting question as we stumbled about in the ice-covered snow. There's not much snow right now, but what there is, is covered with a crust of ice so you stay on top of it for two steps, then you crash through the next. Add in the fact that much of my path is at a sharp angle (sideways, I mean) and you can see why we were stumbling about. Kip didn't have as much trouble as I did of course but even he took a few lurches. At one point he walked easily up a large boulder, and then slid back down! We went down to the rock wall where the Fragile Ferns are. I half-way thought there might be visible fiddleheads, but of course it is much too early yet.

The light is brighter, that's one sure sign Spring is coming. On the other hand, while I understand the maple sap has been running for several weeks, I see no sign of the buds on the trees swelling yet, nor do I see that red flush over the marshy areas that are always first signs of Spring around here.

Springtails, those weird tiny black bugs also called Snow Fleas, are another Sign and there were plenty of those. They hatch in their multitudes on warm days, covering the snow with black specks. I wonder what eats them. Apparently they spend most of their time underground and are one of the partners in a complicated three-way deal involving underground fungi, and Pine roots. I've heard that many Fleas means many mosquitoes, so we'll see. Not so many Fleas as usual this year.

When we got to what I call Fern Rock there were of course no fiddleheads yet. Here's a picture of the rock
showing them in early May. It's amazing how this small fern can grow in only a crack in a vertical rock face. If you look just right of middle, you can see a small plant all by itself in only a crevice. This rock is pretty well vertical, so how does rain get in? Maybe it trickles down and is slowed and diverted by the lichens. Come to think of it, the picture does show an area of rock above the little plant with less lichen cover, and a trail of moss below it.

Fragile Fern, Cystopteris fragilis, is one of the very first ferns come alive in Spring. It's called Fragile Fern because it goes dormant in dry times, but fragile it is not. It occurs all the way into the Arctic Circle, so it has to be tough. It's botanical name makes more sense. 'Cystopteris' refers to the sori, which start with indusia that look like tiny bladders. As the spores mature they push out the side and the indusia rupture and wither. Mature spores are black, and you can always tell a Fragile Fern by the black spore dots. In the picture below (bottom right) you can see the immature sori, and above it some mature ones. Note that some of the sporangia, which hold the developing spores, are already empty, and thus look brown. So the pinnule in the picture has some sporangia still holding spores, and some that are empty. The spores develop fast so it can be tricky to get some for propagating.

Mind you, this fern is not hard to propagate. Cuttings of the rhizome work quite well and are easy as get if you can find a Fragile Fern growing on a rock (instead of in it!) or even in the ground as it sometimes does. Spores germinate readily and the sporophytes develop rather quickly. That said, the plants I have in the fern propagator right now are a year old. They have matured enough to have fertile fronds! Don't know how they'll react to being planted out this summer. They will have skipped a whole winter..... sort of like some of us like to do.

Fragile Fern is great in the rock garden, usually staying under 18" high, and fine in dappled shade or even full sun, as long as you either keep it watered or stay philosophical when it goes dormant.

And it's a sure sign Spring is here.

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