Friday, April 27, 2012

Perigynia

Anyone who owns a “Flora of …” field guide has surely noticed that the Genus Carex can easily chew-up 50 plus pages of dichotomous key without the help of pictures or line drawings. It is intimidating. Ohio is home to more than 160 different species of sedges easily making it the largest genera in the flora. One of the primary characteristics used to identify sedges to species are the perigynia, an inflated sac containing the achene (seed). Usually a 20X hand lens is needed to observe the characteristics of these structures as most of them are around 3-4mm long. I have only been interested in sedges for a few years, but from my first look through the hand lens I was struck by the beauty of sedges especially when magnified.
Here is a banner of 11 different perigynia all from sedges native to northeast Ohio – can you identify any of them?



Here is a close up look at the staminate (male) spike on top and a pistillate (female) spike below.  This is Carex plantaginea (plantain leaved sedge).  A little more about plantain leaved sedge right here 

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