A "Three New Sedge" Day!

It's not everyday that I get to see a sedge (Carex) species that I haven't seen before.  Imagine my surprise and excitement, then, at having the opportunity to see three sedge species I'd never seen in a single day... just one state away in Michigan!  Well, I guess the Upper Peninsula technically counts as Michigan, even though it feels a bit more like Alaska.

 

Carex media

On 11 July 2014, I was in the Upper Peninsula to prepare for a field trip I was leading at the annual Michigan Botanical Club Foray.  Prior to our trip, Brad Slaughter contacted Janet Marr about getting access to an island just off of the mainland, and Janet made contact with the landowner and was able to get permission for us to borrow canoes to access the island.  During our free time, Erin Victory, Brad, Janet, and I paddled out to the island with hopes of seeing Intermediate Sedge (Carex media) and Ross' Sedge (Carex rossii).  Janet had recently been to the island and was able to take us directly to a clump of Intermediate Sedge. 

Carex media; note the fresh spikelet.

Intermediate Sedge has a circumboreal distribution, and although it is widespread in Canada, it is only known from eight states (and that includes Alaska).  In Michigan, it is only known from Keweenaw County, where it is found on Isle Royale and on the north shore of the peninsula. As such, it is considered threatened in Michigan. This handsome sedge grows in thin soils of forest openings and on rocky shores.

Carex media along the shore of the island.

As we continued our hike across the small island, our next target was Ross' Sedge, and it wasn't long before we started locating populations of this rarity as well. Ross' Sedge is in section Acrocystis, meaning that it shares characteristics with Pennsylvania Sedge (Carex pensylvanica), Whitetinge Sedge (Carex albicans), and Parasol Sedge (Carex umbellata).

Carex rossii

Similar to Intermediate Sedge, Ross' Sedge is state threatened and known in Michigan only from Keweenaw County. This is one of several western disjunct species that occurs in the Upper Peninsula; it is much more widespread in the western United States and most of Canada.

Spike of Carex rossii.  Note the leaf-like lowest pistillate bract of the non-basal spike.

Ross' Sedge occurs in sandy and rocky soils in a range of habitats such as coniferous woodlands and prairies; in Michigan, it grows on rocky bluffs and slopes.

Carex rossii

The third new sedge of my trip, Back's Sedge (Carex backii), was found at Brockway Mountain after receiving a tip from Tony Reznicek.  To find this unique sedge, I drove in persistent rain to the approximate location of the plant, located it from the car, and hopped out for some very quick photographs.

Carex backii

Back's Sedge is morphologically similar to James' Sedge (Carex jamesii), putting it in section Phyllostachyae.  If the somewhat hidden spikelets were overlooked, it may look like a vegetative sedge in section Laxiflorae.

Carex backii.  Note the wide bracts that conceal the spikes.

Back's Sedge has a mostly northern distribution in the United States and is also known from Canada. In Michigan, it is found throughout much of the western Upper Peninsula, as well as in a handful of mostly northern Lower Peninsula counties. It grows in dry rocky and sandy ground, either in the open or in shade