Sunday, February 24, 2008

New Species Discovered

Even in a populous, well-explored state like Ohio, new species lurk. While unearthing anything new to science is always exciting, these new discoveries usually aren't shockingly abrupt finds, like, say, a red, yellow and orange macaw found hiding in the depths of an Ohio forest. No, they are typically evolutionary rather than revolutionary.

One of the most recently described new sedges fits the mold for recent finds. And it's one we have in Ohio, although apparently quite rare here. Usually, some authority who has made a study of a group of poorly known and often difficult to identify group of organisms makes the find. As they become more familiar with the group that they are studying, the researcher begins to see differences among species that aren't well explained. Further work sometimes reveals that these different entities are in fact very different, and consistently so. After much work to document this, sometimes we end up with newly described species that were hiding under our noses.

In the plant world, this has been happening routinely with sedges of the genus Carex. A huge (Ohio has over 160 species) and at least superficially intimidating group, sedges are often shunned even by botanists. Too bad, they are very interesting, often aesthetically striking plants that are extremely important ecologically.

We're lucky to have North America's - and perhaps the world's - foremost sedge authority a stone's throw to the north. Dr. Anton (Tony) Reznicek resides at the University of Michigan when he isn't searching the Americas for Carex. Tony's efforts along with those who he works with and advises has led to many of these newly described sedges, as he and others continue to expand our knowledge of these plants.

So it was only fitting that one of the newest described species is named Reznicek's Sedge, Carex reznicekii. Described by David Werier in 2006 and published in the botanical journal Sida, this obscure plant is actually fairly broad ranging, occurring from eastern Pennsylvania south to Georgia and east to Missouri and Arkansas. Ohio is at the extreme northern limits of its range, with only three records thus far known, from Adams, Jackson, and Meigs counties.

Carex reznicekii is cryptic in the extreme, and is part of a section of Carex that is tough to recognize, and that might be stating things mildly. The massive, sprawling genus Carex is divided into sections to make things more manageable, and this plant is in section Acrocystis. They are very interesting little woodland sedges, but quite easy to walk right over and never know you just passed by a perfect specimen. In fact, noted Ohio botanist Lucy Braun, in describing the sedges of Ohio in her 1967 book the Monocotyledoneae of Ohio, missed the most common Ohio member of this section altogether!

Long before Carex reznicekii was described, I collected it in Jackson County, in 1990. The specimen is housed at the Ohio State University herbarium, and some photos of it follow.

Here's my sheet, from nearly 18 years ago. Plant specimens that are properly prepared and stored can last nearly indefinitely, and provide a valuable record of our plants. As we learn more about our flora, these specimens are invaluable to researchers. Many if not most of the now many records of Reznicek's Sedge come from herbarium specimens like this one, as researchers checked back through similar appearing species.

Here is one reason this group of sedges has been so overlooked. When in full fruit, as this specimen is, the reproductive parts are hidden near the bases of the leafy tussocks. Thus, when one looks down on some of the species in this group, they appear to be little more than sterile tufts of grass. And get passed by. As we've learned more about Acrocystis sedges, we've found them to be surprisingly common, much more so than was thought even a few decades ago.

Here is a tighter view of the reproductive parts of Carex reznicekii. Sedge fruit are known as perigynia, and are the little clumps of fruit amongst the leaves. Most visible of the three inflorescences in this photo is the one at top dead center. Even though an an effort was made to arrange this specimen so that the perigynia would be visible, they still don't exactly jump out. You can imagine that in the field, they are essentially invisible thus making the plant very easy to ignore. It may be that sparrows play a role in dispersal of Carex reznicekii. The fruit are right at eye level for ground-feeders like Eastern Towhee, which are common in the habitats this plant occurs in.

Here's my label for the above depicted specimen. There's a saying that the least important bit of info on an herbarium label is the name. Because they change. Most critical is the information like locale, date, and collector. With a bit of searching this population could probably be relocated by an independent searcher. I still remember it, and the reason I collected this material is because it looked strange to me at the time. It is labeled Carex umbellata because at the time, that's the closest entity I knew to put it in. When news of Carex reznicekii emerged, ODNR botanist Rick Gardner began checking Ohio herbaria for it and found this specimen. Right above my label is Rick's annotation from this year. Above his label is that of the master himself, Tony Reznicek, confirming the identity.

So, perhaps not the most exciting way to discover new species, but this is how it often happens.


Phil Rury said...

I've been searching for good photos of herbarium specimens or live plants of this Bartonia to prepare for a rare plant search in NY and yours were the BEST photos I could find online! No Images of Type Specimens at US or NCU, no images at USDA Plants Database, and a few poor quality field photos posted by NYNHP, which also appear in the NYNHP fact sheet.

Phil Rury said...

I was too hasty and had meant to say "of this Carex and of Bartonia paniculata" - if you or any reader has good photos of Bartonia paniculata, please email me at THANKS!