Thursday, 23 June 2016

Grey bulrush and a few other sedges and rushes from Pennington Flash

Really quiet for birds at the Flash at the moment, so I've moved my attention to other things.  Yesterday I had a look at some of the sedges and rushes that are growing around the small pond near the point at the bottom of Ramsdales Ruck. I was particularly interested in what initially looked like bulrush but on (much) closer inspection (i.e. under the microscope) turned out to be grey bulrush, a largely coastal species which apparently can be found at ex-colliery sites in the North West due a saline element to the seam. I don't know if this is due to something that they used to get the coal out of the ground or if it is naturally in the ground and has been brought to the surface and dumped with the slag but it's certainly resulted in enough salinity in the water to allow grey bulrush to grow.


Grey bulrush Schoenoplectus tabernaemontani.



This is a grey bulrush inflorescence or flower head made up of many spikelets.


This is a single grey bulrush spikelet under the microscope on 20x magnification. The spiklet is made up of several flowers or florets. In reality this is about 6mm long.

This is a single glume taken from the spikelet. Each floret has a pair of glumes at its base which protect the floret. Apart from being a generally greyer plant which is a bit subjective, grey bulrush differs from bulrush Schoenoplectus lacustris in that it's glumes are densely covered in small red spots. This is grey bulrush. Interestingly it is a sedge NOT a rush!

There were several other interesting rushes and sedges around the pond, including false fox-sedge Carex otrubae.


False fox sedge


False fox sedge




Not the cleanest of cuts, but this is a section of the stem of false fox sedge showing the classic triangular stem of a sedge. If it was true fox sedge Carex vulpina, the three "wings" of the stem would be a lot more pronounced.

A glume (the small scale at the bottom) under the microscope. The glume of false fox sedge has a green mid rib as you can see in the photo. True fox sedge does not show this feature.

Here are a few rushes from the pond.


Hard rush Juncus inflexus


Soft rush Juncus effusus


Jointed rush Juncus articulatus

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