Friday, September 20, 2013

Rare Sedge Discovery at Lawrence Woods

My job this summer with the Ohio Division of Natural Areas and Preserves (DNAP) allowed your blogger the pleasure of visiting and working in nearly 50 of our fine state's nature preserves, state parks, state forests, and metroparks.  Each and every one was unique and special in its own way with some being unequaled in the rest of the state.  I could easily spend all fall and winter writing and sharing many of my adventures from the past few months (and plan to!).  It's a shame so many people fail to see the charm and splendor of Ohio's natural landscape and think of us as a flat, boring hunk of real estate.  Few things could be further from the truth!

Lawrence Woods state nature preserve in southern Hardin county

One of those unrivaled gems I spent a number of hot, muggy, and buggy days in was Lawrence Woods state nature preserve in southern Hardin county.  This nearly pristine, somewhat old-growth woodland has a mixture of different forest types ranging from drier oak-hickory to inundated buttonbush swamp and tops out at over 1,000 acres in size.  Huge, ancient bur, red, white, and chinkapin oaks tower into the emerald canopy with beech, ash, maple, and hickory mixed in with impressive specimens as well.  Perhaps the most precious denizen of this sprawling wet woods is the state's largest population of the endangered and very rare heart-leaved plantain (Platango cordata); which also happens to grow intermixed with the largest population of the uncommon northern tubercled orchid (Platanthera flava var. herbiola) I've ever seen.

Northern Leopard Frog

It's not just the flora that is worthy of attention but the diversity of fauna as well.  White-tailed deer, wild turkey, fox squirrels, dozens and dozens of species of nesting birds, and plenty of amphibians call this large tract of mixed forest types home.  This gorgeous northern leopard frog is just one example of the wildlife waiting for those willing to enter its dim, mosquito-filled depths.

Swamp Rose (Rosa palustris)

However, this particular time I was there with sedges on my mind.  In a select spot near the southern edge of the preserve sits a low-lying, swampy area full of a rather scarce and unusual member of the Cpyeraceae family.

Inundated swamp forest full of the rare raven's foot sedge (Carex crus-corvi)

This summer's fortune of rain had the ground inundated with about a foot of water and in prime condition for the rarity I had my eyes set on finding.  Pin oak, swamp white oak, green ash, and red maple of various sizes abounded with a scattering of swamp rose (Rosa palustris), buttonbush (Cephalanthus occidentalis), and swamp dogwood (Cornus obliqua) growing out of the saturated, mucky soil.

Raven's Foot Sedge (Carex crus-corvi)
Raven's Foot Sedge (Carex crus-corvi)

It didn't take too long to spot the long, spiky fruit clusters of the state-threatened raven's foot sedge (Carex crus-corvi) growing in large, dense clumps throughout the water-logged swamp forest.  Of the 160+ species of Carex in Ohio, I think this one could take the cake for being the most conspicuous and attention-grabbing.  It almost looks like a flail-like weapon from medieval times to me!

An intriguing, suspicious sedge among the wetland plants

As I continued to wade through the water, keeping a census count of each clump of Carex crus-corvi I came across, I noticed an intriguing and suspicious looking sedge that just didn't look quite right.  The other typical sedges were there: C. frankii, C. crinita, C. lupulina, and C. comosa respectively; but this one just seemed to stand out.

A closer look at the suspicious sedge

It certainly looked similar to the abundant hop sedge (C. lupulina) growing throughout the swamp but its narrower, more elongated perigynia clusters and lime-green color had me scratching my head if this could indeed be the rare and painfully similar false hop sedge (C. lupuliformis).  In a flurry of excitement and suspicion, I plucked a perigynium off the cluster and ripped open the inflated, papery bladder to unveil the achene (seed); the best and most consistent way to differentiate the two species.

Carex lupuliformis perigynia and achene (L) compared to the same of C. lupulina (R)

What I was hoping to see was the mature achenes of the mystery sedge have conspicuous and clearly-defined knobby, pointy protuberances (umbonate in nerdy Latin talk) on the sides of the seed.  As luck would have it, the achenes showed off the desired trait beautifully and confirmed its identity as Carex lupuliformis.  In the photograph above you can see side-by-side comparisons of both the fruiting structures and individual achenes of C. lupuliformis on the left and C. lupulina on the right.  Notice the knobby protrusions on the C. lupuliformis achenes (creating an almost diamond outline) while C. lupulina has more rounded and elongated achenes.

Even better was the realization that this rare sedge had never been recorded for Lawrence Woods or Hardin county.  Another rare sedge find is always a great way to spend a day out in the field!  I collected a few specimens for pressing and after finishing my survey of the now two rare sedges growing under the oaks and ash, made the long trek back to my car with a satisfied smile on my face.  Not even the hoard of mosquitoes above my head and the ounce or two of blood I lost to their tenacious nature could break the happy mood I was in.  Serendipitous finds like these are always the cherry on top to any field botanist's work!

From L to R: C. frankii, C. crus-corvi, C. lupulina, C. lupuliformis, C. grayi, C. comosa, and C. crinita

Lawrence Wood's size and wonderfully intact and diverse plant communities certainly hold more secrets and surprises to find, I have little doubt about that.  With more exploration and time who knows what other goodies could be lying in wait.  I know I'll be back for more in the coming months and years; it's just the kind of place that's hard to stay away from for all the right reasons.

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