Wednesday 3 June 2020

Hairy-fruited Sedge—Keep an eye out!

Hairy-fruited Sedge (Carex trichocarpa) is an uncommon sedge in Ontario, ranked S3, meaning there are between 21 and 80 locations for it in the province. All photos here are from a population in London (not sure if it was known previously, but I stumbled across it last June).

This is a species of wet meadows, sedge marshes, and floodplains in the Northeast, seldom found far from a river or stream. It is rare throughout most of its range.

Carex trichocarpa distribuition (map from FNA)

In Ontario, most records of the species are from along larger rivers, such as the Thames, Sydenham, Grand, and the Don. Smaller watercourses, such as Big Otter Creek and Talbot Creek, also have records. It is apparently widespread along the Thames River especially, and is listed as 'uncommon' in Middlesex county.

While sedges (Carex spp) are often considered pretty difficult to identify (and that's not necessarily wrong!), Hairy-fruited Sedge is somewhat easily recognizable. To start, look for a sedge where the clumps of leaves look 'messy'. 

Scattered clumps of Carex trichocarpa

One of the clinching identification features is the burgundy leaf sheath apex. This is where the leaves meet the stem (also called the culm). This feature is sometimes described as a 'burgundy snake's tongue'. There are several species that may look similar, but this feature is pretty diagnostic.

This sedge often forms colonies of mostly vegetative plants (ie not reproductive), with a few flowering plants. When present, the fruits, which are called perigynia, are pubescent, or hairy, which is where this plants common name comes from. The perigynia are quite large. The female (with the perigynia) spikes are called 'pistillate spikes', and are widely separated from the male spikes, called 'staminate spikes'. Pistillate spikes are typically found below the staminate spikes in sedges.

This is a species that is likely quite easily overlooked, and is bound to show up in many new places. From the 2017 Oldham list to the Vascular Plants of Ontario's Carolinian Zone, Hairy-fruited Sedge is listed as uncommon in Middlesex, and rare in Chatham-Kent, Elgin, Oxford, Haldimand-Norfolk, Brant, and the Ecodistrict 7E-4 (parts of Toronto, York, Peel, and Halton). 

This species is currently not listed from Essex, Lambton, Hamilton, or Niagara, but could very well be found there. In particular, Lambton county has lots of potential for this species, since the Sydenham River runs through part of it. Perhaps the Ausable River may have potential for this species as well. EDIT: I just became aware of a recent 2019 Lambton record

Keep an eye out while on your travels through floodplains and meadows near rivers!, streams, and creeks! Perhaps more populations of this species will turn up!

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