Tuesday, July 28, 2015

Sedge Heads

To know the sedges, you have to be serious. A fanatic? Perhaps not. But certainly you have to enjoy detail.

The sedges make up, by far, the region's most diverse genus. Swink and Wilhelm list 149 species of these grass-like plants (genus Carex) in the Chicago region. This contrasts with 16 species of buttercups (genus Ranunculus) and 6 blazing stars (genus Liatris).


Many of us have great affection for Somme forest preserve. Yet, our team doesn’t know the ecosystem until we can identify the plants. Facing this challenge squarely, six of us last Sunday braved heat and bugs to find and learn sedges. In the end, we found and identified 24 species. Pretty good for one morning.

The photo above wouldn't be complete without our teacher, fine citizen-scientist, John Balaban. 
Having a great teacher is an honor. John Balaban is a true "citizen scientist" - a volunteer expert. With his wife Jane, he has taught classes on dragonflies and sedges - and has the noble distinction of discovering the endangered "awnless graceful sedge" in Illinois. 

At least that's what its called in The Plants of the Chicago Region by Swink and Wilhelm. Most sources, if they give it any "common" name at all, call it "handsome sedge". Is there really a "common name" for such an obscure plant. Let's face it, no there is not. Its only real name is the scientific name, Carex formosa. "Formosa" does mean "handsome" or "beautiful." But someone who wants to learn sedges might as well learn the scientific name. At least then you can talk with botanists. If you just learn the "common" name, which nobody knows, you won't be able to talk with anybody. 

To figure out the name of a sedge, you need a scientific "key" (a written series of choices), and the key requires you to study fine detail. Is the stem hairy? Are the seeds three sided?

One of the first sedges we found was Carex rosea. (In this case, the "common name" 
is actually helpful. It's called "curly-styled wood sedge." To tell most sedges apart you have to
look at their sexual organs. The "style" is the feathery sticking-out part of the female flower, 
the part that receives the pollen. In the case of Carex rosea, if you look close 
(through a ten-power lens), you can see that those styles make graceful curls. 


There's only one other sedge that you're likely to mistake for "curly-styled wood sedge." That's "straight-styled wood sedge" (Carex radiata). But in the field you can pretty much tell them apart by the fact that rosea stems stand up straight while radiata stems lay out flat to the sides. Perhaps they should have been called "stand-y up sedge" and "fall-y down sedge." But perhaps it's easier in the case of sedges to stick with the scientific names, that don't change from book to book. 


Some sedges are easy to recognize at a glance, like the one shown above, 
bur sedge (Carex grayi). There's nothing else that looks like it, 
at least once you get to know it a bit. 

Another one that's pretty easy is shown below. Somewhat similar, 
but the seedhead is cylindric rather than spherical.
It's called hop sedge (Carex lupulina). 

Hop sedge is named for its similarity to the hops (Humulus lupulus),
often shown on beer cans, because they're the main flavoring for beer. 
Many sedges have little clusters of little seed heads, like the one shown below, Carex tenera.
They often take a lot of study, but this one is distinctive 
because its stem takes a right-angled turn just below the seed head. 

Once we'd "learned about twenty of these, some people's heads started to clog.
Others, those with orderly minds, seemed to thrive on the challenge.
Luckily, John Balaban, in common with God as shown on the ceiling of the Sistine Chapel, was capable of transmitting inspiration and knowledge through a single finger. 

The find of the day was the big endangered sedge shown below.
Carex tuckermanii
"Bent-seeded hop sedge" if you want the "common name" of this rare beauty.
The seed packets on this one are so fat that only a few can only fit around the stem.

What difference does it make if we know which sedge is which?
One answer (among many) is that, if we know where the rarities are, we can restore health 
to those habitats first. Many species are being lost in many preserves because of neglect. 
In the absence of fire, invasive species choke them out.

You could say that biodiversity is important because it of all these little reasons. 
For example there are some species of butterflies that utterly depend on a few species of sedges. 
Of course, then some people will ask, who cares about butterflies?

This sort of question was raised at a contentious public hearing 
about whether some construction project would have to be moved 
because wrecking the ecosystem on the site chosen would have wiped out a rare plant.

One angry citizen asked, "What good is this plant?!?"
Botany professor Hugh Iltis responded, "What good are you?"
His answer probably didn't convert many of the pro-developers. 
But he did imply a thoughtful question: What makes us think we're so important 
that we have the right to eliminate other species?
Fortunately at Somme, there's no conflict with "progress."
The site was bought by the public decades ago 
"to protect and preserve, restore and restock the natural flora and fauna." 

The question now is, do we take good care for it?
Fortunately, learning to know, and appreciate, and take good care of the ecosystem 
is a great pleasure to many of us. It makes us happy to be generous to sedges.

A Note At The End
Below are the names of the species that we identified. 
(We still have more that we haven't keyed down yet.) 

SCIENTIFIC NAME                      CC  W   COMMON NAME
Carex annectens xanthocarpa   7   0    small yellow fox sedge
Carex cephalophora                    3   3    short-headed bracted sedge
Carex crinita                               10  -5    fringed sedge
Carex crus-corvi                         10  -5    crowfoot fox sedge
Carex festucacea                         8    0    fescue oval sedge
Carex grayi                                   7   -4    common bur sedge
Carex grisea                                 2    1    wood gray sedge
Carex hirsutella                           4    5    hairy green sedge
Carex hirtifolia                            5     5    hairy wood sedge
Carex lupuliformis                    10   -5    knobbed hop sedge
Carex lupulina                             7   -5    common hop sedge
Carex muskingumensis              8   -5    swamp oval sedge
Carex pellita                                 4   -5    broad-leaved woolly sedge
Carex pensylvanica                     5    5     common oak sedge
Carex radiata                               6    1     straight-styled wood sedge
Carex rosea                                  4    5     curly-styled wood sedge
Carex shortiana                        10     0     Short’s sedge
Carex sparganioides                   3    0     loose-headed bracted sedge
Carex sprengelii                          9    3     long-beaked sedge
Carex squarrosa                       10   -5     narrow-leaved cattail sedge
Carex stipata                               3   -5     common fox sedge
Carex tenera                                8    1     narrow-leaved oval sedge
Carex tuckermanii                    10   -5     bent-seeded hop sedge
Carex vulpinoidea                   2   -5    brown fox sedge 








In the list above, the "CC" is the Coefficient of Conservatism, a measure of how indicative the species is of quality habitats. A "0" might be found in any weed patch. But a "10" would nearly always be found in a highly diverse, healthy ecosystem. 

The number under "W" indicates wetness, that is, how dependent the species is on dry habitats. A "5" species is most likely found in well-drained uplands. A "-5" species often grows in standing water.