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.

Resolving the Green Mass

by Carl Strang

How do you perceive the wild landscape around you? There’s no correct answer to this question. Even professional ecologists wear blinders or, at least, view the world through the filters of their experience and biases. Speaking for myself, as a terrestrial vertebrate ecologist I am ignorant of much of what is going on beneath the surface of the water. I can sympathize with those who view vegetation as an undifferentiated green mass.

However, I have spent some time studying insect-plant interactions. I have seen how plant-eating insects are dietary specialists to various degrees, and the literature has enlightened me on how plant chemical defenses force this specialization. Insects that eat forbs typically are limited to a single species or group of closely related species. Because woody plants commonly defend themselves with tannins, insects that go after woody plants often have broader diets. Such patterns enrich my understanding of ecosystems, and inform my understanding of vertebrate ecology. Animals which eat plants or insects are influenced by what is going on between plants and insects. Plant diversity leads to insect diversity leads to terrestrial vertebrate diversity. A consequence of all of this is that I have learned to identify woody plants and forbs, and so no longer view those many kinds of plants as a green mass.

Now I am trying to go farther, by studying the non-forb herbs. I want to improve my understanding of grasses, sedges and other plants of that ilk. It begins with learning to identify them and grasping their local biodiversity. The process particularizes the remaining green mass. Lately I’ve been focusing on sedges at Mayslake Forest Preserve. I found a species with an amazing ecological range, from partly shaded woodlands to open prairies and marsh edges.

This I have identified as the common wood sedge, Carex blanda. If I am correct in assigning all these plants to this same species, the ones growing in more open environments are a little larger, and the clusters of male flowers at the ends of the stalks are on slightly longer stems. Note that the female flowers are segregated onto separate clusters below the male flowers.

Another sedge is somewhat more restricted ecologically, and so is less common.

This one keys to Carex pellita, the broad-leaved woolly sedge. Again the male and female flowers are segregated, but the scale is larger, so that the plant is taller, the flower clusters longer. The plant also is more erect in its stance. This species is limited to edges of marshes and wet prairies at Mayslake.

Another marsh edge species remains unidentified.

Here each flower cluster contains both male and female flowers, the females at the tips and the males below them.

This one would key strongly to Carex sartwellii, the running marsh sedge, except that it appears to grow in tufts rather than from runners. I hope to get some resolution as the seeds mature. The point is that I am gaining enlightenment about the diversity and habitat specificity of this group of plants. Bit by bit, the green mass is resolving to a mosaic of separate species, allowing me to build an increasingly sophisticated understanding of the Mayslake landscape.

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