Saturday, July 16, 2016

Man there are a lot of Carex

I've been making a concerted effort this summer to learn my true sedges i.e. the genus Carex. Carex is by far our largest genus of plants locally, with 169 species listed for Southern Ontario.  For perspective, that is about the same as the number of butterfly species recorded in the province. Still, it wasn't until I actually started identifying them that I realised how amazing the diversity really is in this group.

The genus can (simplistically) be separated from other members of the sedge family, and from other grass-like plants, by a few characters:
  • Growing in wet and/or shady areas, rarely in dry open habitats
  • A more or less triangular stem
  • Separate male and female flowers, in adjacent clumps or completely separated
  • Seeds enclosed in a case (the perigynium), each with a single accompanying scale
And now for a random selection of species I've photographed recently! I'm only using Latin names here. Although there are common names for most species, they are very inconsistent between sources and don't seem to see much use.

This is one of the most attractive species I've encountered: C. buxbaumii. This species and the next four were all growing in wet areas between dunes at Rondeau Provincial Park.

C. aurea is easy to identify once it develops this nice golden colour to its peryginia.

C. pellita has very hairy peryginia, although that may not be clearly visible in this photo. A hand lens is an absolute necessity when identifying sedges!

C. crawei is mostly restricted to shores of the Great Lakes in our area.

C. viridula has distinctive dense little spikes. The thin white spikes at the top are the remains of the male flowers.

Moving away from Rondeau (although this species is likely found there too), C. flava is closely related to C. viridula, but with long beaks on the peryginia. 

Most sedges have pretty thin leaves, but a few forest species have much wider ones. This is C. plantaginea with its creased leaves and red-banded stems.


C. albursina has smoother leaves as well as wide bracts covering the spikes of peryginia.

Some species have big inflated peryginia, like C. lupulina seen here.

C. utriculata is more subtly inflated.


C. atherodes can be confused with the more common C. lacustris, but among other things can be distinguished by very hairy leaf sheaths (where the leaf meets the stem).


C. vulpinoidea is easily recognised by the thin bracts projecting from the inflorescence, and seems to be most common along trails through wet areas.

And to finish off, a couple of bog species. This pretty one is C. magellanica.

And finally, C. oligosperma, a true bog specialist.

If you've made it this far, congratulations! Believe it or not, the photos above represent only about 8% of the local sedge diversity. Certainly a group that will take many years to master!


  1. Nice shots Reuven. A keen eye for details and putting in the effort to ID specimens can yield some nice rarities. I especially like the Carex crawei.

    1. Thanks Patrick. I am certainly enjoying myself with these sedges.

  2. Congrats, Reuven, on diving into the world of Carex! You will have to expand your 'Winged Things' label :-).

    1. Not necessary - the Ovales group of sedges are distinguished by their "winged" peryginia!