Carex aureolensis

It was just about a year ago when I first heard of Carex aureolensis. While walking with a fellow botanist he asked if I had noticed it in the Cyperaceae volume of the Flora of North America (vol. 23). I had not. He then informed me that it had been split out of Carex frankii, a species I had seen throughout eastern North America and in which I had never noticed much morphological variation. I believe my reaction was typical of most biologists upon hearing of taxonomic change in a group thought to be stable. My lips tightened, my heart rate increased and my vision became unfocused as my brain slammed into a low, deeply contemplative, gear. After a few minutes of test driving the idea in my head, I said with a slow and worried countenance “I don’t know if I buy that”. Trail talk is cheap.

When I got home, I hit the index of FNA vol.23 and thumbed my way to page 519. Sure enough, there it was. I read the description, habitat and comments then flipped to the key characters. It all sounded legit; little overlap in easily seen morphological characters including habit and scale shape coupled with a definable geographical range. I quickly put the characters of C. aureolensis to memory; rhizomatous instead of cespitose growth; scarious tissue on the body of the pistilate scales; lanceolate to ovate staminate scales. I’ve been looking for it ever since.

For the past year, every time I would see C. frankii (below), or at least what I had always thought was C. frankii, I would run through the characters in hope of finding the elusive C. aureolensis.

I would start with the growth habit (rhizomatous vs. cespitose). This was never satisfying and what turned out to be C. frankii was always loosely cespitose at best and bordering on what I would call rhizomatous. Unsatisfied by ambiguity, I would snap a pistillate spike in half like a green bean from the garden and look at the scales subtending each perigynium.

Needle thin from base to tip every time and thus C. frankii. The pistillate scales of C. aureolensis should have membranaceous/scarious tissue on the body that often forms a tooth on both sides of the midvein similar to the stipules of native roses. The search continued.

Today started like most of my summer days. Up early, out the door, field work, home, sleep, repeat. Who knew that the series of events about to unfold would so profoundly change my life, dramatically reorganize my world perspective, reroute billions of synapses in my brain and leave me standing, shivering, in the mental frigidity of a shattered and hollow psyche. Well….not really….but it was kinda neat…..Basically, I stumbled onto C. aureolensis, collected some and went home. Boring to most, but to me, a great day.

Like many “new” names, C. aureolensis is not really new. It is resurrected. Described in 1855 by Ernst Gottlieb von Steudel (a distant cousin to Heinz the Baron Krauss von Espy, no doubt), it appears in none of the florae on my bookshelf before 2002 when Ford and Reznicek reinstated it as a distinct species (Flora of North America, vol. 23). Knowing when it was lumped or if it was ever even acknowledged would require more research than I have time for right now. Regardless, a big “hats off” to Ford and Reznicek. This thing is clearly distinct. So much so that when I first saw it I didn’t have a clue what it could be. After inspecting it for several minutes I decided it was similar to C. frankii but with a bit of C. squarrosa thrown in the mix. A second later, my brain, like an overexcited schoolboy squirming in his seat, raised his waving hand with an “ooh, ooh, ooh”. “Yes brain”, I replied. “It’s Carex aureolensis!!!”. Indeed, it was.

Here is the breakdown:

The population I found is clearly rhizomatous and easily evenly covering twenty square meters of wetland.

The plants are darker green (C. frankii is often a bit on the yellow-green end of the spectrum) and the pistillate spikes are more evenly distributed along the stem than C. frankii.

The pistillate scales have membranaceous tissue at the base (click on photo below to see it best). The bodies of the perigynia seem more squat than those of C. frankii.

So, there it is. The process of discovery as illustrated by my encounter with C. aureolensis. To me, one of the best things about being a botanist is the serendipity, surprise and elation of discovering a new plant. And while new plants to a region or even to science are certainly exciting, the innocent pleasure of finding a new plant to yourself, one you have been keeping an eye out for years, CAN be a higher reward; a private exchange between a hunter and his quarry. It is what keeps many botanists going when the days get long, the hills get steep, the Smilax gets thick and the myriad sacrifices of a nomadic life take their toll. It is in these moments that such discovery is needed most.


  1. So it does exist! Nice photos of the diagnostic parts of the plant. I've spent the past couple of days sampling quadrats in NE Indiana, seeing lots of Carex frankii and checking the growth form and pistillate scales on almost every one. After seeing your photos and reading your synopsis of real C. aureolensis, I think I will recognize it as something different when I finally do happen upon it myself.

  2. Yeah, like most good species it is quite obviously different to sharp eyes. I can see how pressed specimens might be misconstrued by gross morphology.

  3. Justin, as always an entertaining, satisfying, and enlightening read. I have yet to see C. frankii in Michigan, a species that was until recently actually state-listed, and is apparently showing up in all sorts of unsavory, degraded wetlands per a musician-cum-botanist-cum-musician in the environs of Kalamazoo.

  4. Ever since I read about it in FNA I have been looking for it in southern Ohio. I have not found it...yet.

  5. Brad- Thanks. Sounds like a story in there somewhere. My impression of C. frankii is that it prefers unsavory, degraded wetlands and road ditches throughout its range (I still like the single c-value per species regardless of state or region idea).

    Rick- If it is there, you would be the man to find it. The population I found was growing in a degraded, forested swale below an artificial pond. Cheers!

  6. I was looking through a folder of unknown Carex collected in S. Arkansas in the 70's at the Missouri State herbarium and could not figure out why a couple of the plants I easily identified as C. frankii were in an unknown folder. During my investigation I stumbled upon this posting. I pulled FNA V.23 off the shelf. Then I peered through the scope. Sure enough. They appear to be C. aureolensis. It's nice to know that someone was paying attention to recognize that it was different enough to not be C. frankii.


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