Noticing Things about Sedges

by Carl Strang

One of the awareness skills we need to develop to enjoy nature fully is to attend the little things. This is crystal clear in tracking, but I’m also finding the subtle differences in the Carex sedges often have significance. I gave an example a few days ago with Carex grisea, which at first glance was very similar to the common Carex blanda, and even keyed to it, but that conclusion just didn’t fit what my eye was telling me, and when the flowers matured I was able to gain a satisfactory result. Carex is a big genus, and when you focus on the little things in these superficially similar, grass-like plants, you notice some patterns.

For instance, some produce flowers in tight spiraling clusters. Some of these have been given English names that include the word “fox.” There’s the common fox sedge, Carex stipata, which I featured in an earlier post.

This one has thick, triangular, but soft stems.

Last week I found another species, which grows in somewhat drier soils at Mayslake Forest Preserve. Carex annectens var. xanthocarpa also is known as the small yellow fox sedge.

In addition to the habitat difference, annectens has much less squishy stems.

The concentrated flower clusters make these easy to spot.

Here we back off to take in an entire tuft of annectens. Those distinctive flower clusters make this plant stand out against the wall of green.

This week I added yet another “fox sedge” to the Mayslake list, though I gather that this is not a close relative of the others.

The brown fox sedge is Carex vulpinoidea, the “vulpinoid” part of the species name perhaps a reference to this not being a “true” fox sedge.

Not every sedge with this kind of tight arrangement of flower clusters is that easy to spot. Such is the case with a species I found in Mayslake’s north savanna.

The plant’s tufted form makes it stand out a little, but the flower clusters are small.

Closing in on the flowers, in some ways they are reminiscent of the fox sedges on a smaller scale.

This one I identify as Carex cephalophora, the short-headed bracted sedge.

If you have been following my sedge posts, you can guess what I think of that English name.

Sometimes a sedge has a distinctive quirk. One example I found in the north savanna last week is Carex tenera, the narrow-leaved oval sedge (which I also include on the list of species with uninspiring English names; I find tenera much easier to remember).

This little plant has one well separated lowest flower cluster, then an elongated delicate stem that tends to flex, and is tipped with more tightly packed flower clusters.

In the next photo you may find it difficult to distinguish the entire Carex tenera plant, but do you find that the odd flowering stalks stand out?

You may be able to pick out several flower stalks against the darker background in the upper part of the photo.

Finally, the shapes of flower clusters may stand out. I’m probably bugging some botanists with my use of the non-technical “flower clusters” term. For those who may be interested, the entire floral display of a sedge is divided into units called spikelets. Sometimes the spikelets are distinctive enough to distinguish in my photos, sometimes not, hence my preference for the vaguer non-technical term. Last week I ran into a large patch of a fairly tall sedge with distinctively pointy spikelets, growing near the stream corridor marsh.

These keyed to Carex scoparia, the lance-fruited oval sedge.

While I’m iffy about the “oval” in this one’s English name, I like the reference to the pointiness implied by “lance-fruited.”

In contrast, some sedge flower clusters are very round looking. Here is an example.

This one is Carex molesta, the field oval sedge.

“Oval” again. What’s with this “oval?” It looks so different from scoparia. I have found molesta in a wide range of habitats at Mayslake, both open and partly shaded, but usually with fairly wet soil.

Again, the distinctive flower clusters make the molesta tuft stand out.

Incidentally, this proves to be the species that confused me earlier in the season, seeming to key to Carex sartwellii. Waiting for the flowers to mature did indeed clear up the identification. My Carex species count at Mayslake already is up to a dozen, and I’m sure there will be more as the season goes on.

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5 Comments

  1. June 2, 2011 at 9:52 pm

    Hi Carl. You really seem to be picking up the sedges pretty quickly! They get a bad reputation because there are so many species, but as you are finding out they aren’t that bad if ou spend time keying them out and if you convince yourself that you can in fact learn them.

    I’m sure you measured them, but make sure the perigynia of your Carex normalis are less than 2mm wide. The plant in your photo looks a bit like Carex molesta, but the latter species would have perigynia greater than 2mm wide.

    I think the name “Oval” comes from the Latin name for the section to which these sedges belong, Ovales, which may be a reference to the shape of the bodies of the scale-like perigynia.

    • natureinquiries said,

      June 3, 2011 at 3:23 pm

      Thanks, Scott,
      I just ran out for a fresh sample, and the little suckers have grown. The keys don’t indicate when measurements should be taken. Now they have reached the size you suggest, and so I will correct that identification.
      Regards,
      Carl

      • June 3, 2011 at 6:35 pm

        Hi Carl. The keys are based on mature perigynia. I think Flora of North America states this, but most keys do not. It is frustrating early in the season when you can’t always put a definite name on a sedge because it simply isn’t mature enough…

  2. Penelope said,

    November 26, 2012 at 4:36 pm

    Dear Carl,
    I am a university student in Australia. Although I work on insects, I’m interested in Carex because the group has unusual chromosome variation. I would like to get permission to use your photographs of Carex in my conference presentations when I talk about chromosome variation in groups other than the insects I work on. It will only be one photograph per talk, and I will make sure any photographs I use of yours are acknowledged to you. Thank you for your help and time.

    • natureinquiries said,

      November 27, 2012 at 6:48 am

      Hi, Penelope,
      You may use the photos. If you e-mail me at wildlifer@aol.com with the ones you want to use, I can send the full size files. I compress them in the blog to minimize loading time. Thank you for your interest.
      Regards,
      Carl


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