I’ve found three new sites for the greatly under-recorded Brown Bent Agrostis vinealis this year, so thought I would post a first account of the four pasture species. The next few weeks are probably still good for finding vinealis.
Common Bent Agrostis capillaris has a strong claim to being the commonest and most widespread grass of all and should be expected in all managed un- and semi-improved grasslands, as well as many derelict and reverting improved ones. The open post-flowering panicles are available from August and persist in identifiable form right through the winter (pic 7).
Creeping bent Agrostis stolonifera does not attain the abundance of capillaris over such wide areas but is nevertheless ubiquitous in our county. To make a record, look for classic material in damp and poached places (though it will almost certainly be hiding in plain sight in many others). Field gateways (both arable and pasture) and urban and suburban brownfield are equally as likely to turn the plant up. Such classic material has obvious stolons (tillers), and can generally be told from other stoloniferous species by hairless, narrowly-triangular leaves which are rolled in the shoot. (The closest plant when not in flower is creeping foxtail Alopecurus geniculatus, and it may not be possible to make a distinction when there are no traces left of the very different inflorescence, though that plant has proportionately shorter leaf blades which expose more of the stolon and are often bluish and waxy in texture.)
Note that common and creeping bents are often impossible to distinguish with certainty in grassland. This may be because of under-recognised hybridisation, but is more likely to be due to their plasticity. Unless you’re doing a quadrat, this is not so very bad though – just move on until you find more typical material.
Velvet Bent Agrostis canina and Brown Bent Agrostis vinealis can be bracketed together on account of their much narrower leaves than the previous two, and have been regarded as conspecific in the past. Both are much more local, but are generally plants of better-quality habitat and are under-recorded, so do make an effort to get to know them. Velvet Bent is stoloniferous like Creeping Bent, but its narrower leaves and more profuse stolons yield up a low, dense, unidirectional sward like the combed pelt of an animal in the wet, acid places where it grows, which is extremely distinctive. This pelt typically forms an understory to the rushes and other plants with which it grows and is often a rather bluish-green. It has long ligules on its tillers like stolonifera; they often look even longer though, because they are emanating from proportionately narrower shoots.
Brown Bent vinealis has the same narrow leaves but lacks the distinctive stolons. It is thus a tufted, narrow-leaved plant like many others and will be extremely easy to miss, even when flowering, because it will often be growing in amongst capillaris. It may also be glossed over when not in flower as Festuca ovina. The best tips for finding it are to single out its habitat – dry, acid grassland, and visit these in late summer when its distinctive panicles, which close tightly after flowering, are apparent. It is possible that the dry summer of this year has made the tuftedness of this plant more apparent, as vegetation in-between has been burnt off. Certainly the plants I saw this year at Garway, Broadmoor and Cefn Hill had a more obviously tufted structure than capillaris, which usually exists in dense turf, making its growth form difficult to discern. At Ewyas Harold, where vinealis and canina confusingly grow very near one another, colour differences are useful, plus the fact that the tufted vinealis ‘sticks up’, whereas the creeping canina stays lower to the ground.