Saturday, 28 August 2010

Agrostis capillaris - Common Bent

Common Bent  Agrostis capillaris

Grass of the Month - August

I chose to put Common Bent in August because it does not start to flower until well into July, so it fully out by August. Patches of ground that just have Common Bent can stand out in early summer - May, June and early July - because they are green and flowerless then, compared to surrounding areas with other grass flowers.

And where do you find Common Bent?

Common Bent ( Agrostis capillaris ) – small, delicate and inconspicuous - is one of the commonest grasses. Remember running barefoot on the garden lawn as a child? You were probably running on Common Bent, along with needle-leaved Red Fescue. It grows in nutrient poor lawns, acid grassland pastures, sandy soils and in heather moorland.

Heath Bedstraw, Tormentil,  Betony, and Bitter Vetchling are some of the prettier wildflowers that can be found on more interesting Common Bent grassland

Up at Winskill which is on limestone rock, Common Bent is only a very minor component of the limestone grassland, but it is the major plant in the hollows that are filled with loess (soil made from dust blown up from surrounding areas at the end of the last ice age)  - see below

The light green area with no purple Knapweed is an area with little else except Common Bent - this is where loess is deposited
Its inflorescence is like a spreading Christmas tree with many hundreds of tiny spikelets – tiny because each spikelet contains only one flower. Bents ( Agrostis ) have only one flower per spikelet, Meadow grasses ( Poas ) have several flowers per spikelet
The plants are small and so nondescript – no hairs, no big leaves, no stolons. The emerging leaf is rolled and hairless, and the short narrow 2mm-wide blades come away from the sheath at a wide angle. The ligule is very short. It grows in little tufts and these are linked by rhizomes, but you can't see these as they are underground.

Common Bent becomes much more exciting on metal ore spoil heaps such as at Pikedaw above Malham, where it is one of the very few higher plants that can tolerate the metal pollution. Since nothing much else will grow, a delightful pattern of small tufts arranged within bigger patches can be seen.

Bentham is a small  town ten miles from Settle.

Could Bentham mean land of Common Bent?

The word Bentham ( Benetain in the Doomsday book) comes from the word meaning rough grass or reeds.

So I like to think it could refer to Common Bent. However other grasses were once called bent – including. Purple Moor ( Molinia caerulea ) once known as White Bent which grows in abundance in white sheets on damp parts of Newby Moor and the moor south of Bentham.

I hope you found this useful - Why not come on a Grass Identification course? And have fun learning about grasses with other people. J.A.

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