Finally, it’s September and the number of plants in flower is starting to dwindle. I still found around 80 species in flower, though in many cases these were just a few stragglers hanging on after most had set seed. I had no choice but to walk my route on a very windy day near the end of the month just before Storm Ali so, although there were still plenty of Speckled wood butterflies and dragonflies around, none would sit still long enough for me to take their photo!
The most obvious decreases in plants flowering this month were for two contrasting reasons – rampant nettles along parts of the path have shaded out or obscured some smaller plants whilst, conversely, the trimming of other verges has led to the premature demise of some, such as wild carrot, which I’ve seen flowering elsewhere. One positive sign was that, where long vegetation on some of the meadow areas had been cut, the cuttings were left in situ to seed next year’s growth.
Yellow rattle seed heads (Rhinanthus minor)
The only ‘new’ plants I found in flower this month were Tormentil (Potentilla erecta), from the rose family and Hop trefoil (Trifolium campestre) from the Fabaceae or legumes. In both cases, I suspect they have been there all along but I’ve somehow just noticed them for the first time! Florally, the main difference between Tormentil and the Creeping cinquefoil I’d noticed previously is the fact that, unusually for the rose family, Tormentil only has four petals.
Tormentil, Potential erecta (left) and Creeping cinquefoil, P. reptans (right)
In the case of Hop trefoil, it is the hop-like seed head which distinguishes it most clearly from the ubiquitous Black medick.
Hop trefoil seed head, Trifolium campestre (left) and immature Black medick seeds, Medicago lupulina (right)
A couple of plants which I haven’t seen in flower since much earlier in the year are also flowering again now – Red dead-nettle from the Lamiaceae and Common field speedwell, from the figwort family.
Red dead-nettle – the aptly-named Lamium purpureum
Apart from that, seed heads are stealing all the glory at this time of year – after all, there is no point in a plant having attractive flowers to ensure pollination if it doesn’t carry through and disperse the resultant seeds effectively.
The brightly-coloured fruits of the rose family, which encourage animals and birds to eat them and spread the seeds within, are obvious everywhere. Hawthorn seems to have done particularly well after our warm summer.
Indian or Himalayan balsam is an equally successful plant with quite a different strategy – when the ripe fruits are touched they spring open explosively at the base, firing seeds in all directions. The plants are a metre or more tall, so seeds can travel some distance.
Indian balsam, Impatiens glandulifera, fruit
Wild angelica, Angelica sylvestris
The daisy family, of course, are the real experts at wind dispersal, producing small, light achenes (fruits) with parachutes of tiny hairs (the pappus) to catch any breeze. Whether the pappus hairs are branched are not is one diagnostic feature for distinguishing some of the trickier species. In fact, this is how I realised last month that what I’d taken to be a Marsh thistle (Cirsium palustris) in early summer was actually a welted thistle (Carduus crispus)! In many species, for example Hawkweeds, the achenes are held on a central swollen stem from which they break away when ripe.
Hawkweed seed head, Hieracium agg.
In others, such as Knapweed, they are released when the involucre dries up and opens out.
Achene dispersal in Greater knapweed, Centaurea scabiosa
Last but not least we come to the monocot seeds – The bur-reeds which were still flowering in August are now shedding their fruits, which break away from the swollen stem tissue. These tiny fruits have the advantage of water to aid their dispersal – the pond surface was covered in them.
Fruits of Branched bur-reed, Sparganium erectum, breaking away
The other, really obvious, change as I walked my route was the autumn leaf colours appearing in the hedgerows – who knows how many leaves will be left by October!
Anyway, here is September’s list of plants in flower.
|Lesser spearwort||Ranunculus flammula|
|Creeping buttercup||Ranunculus repens|
|Common nettle||Urtica dioica|
|Common mouse-ear||Cerastium fontanum|
|Red campion||Silene dioica|
|Perforate St John’s-wort||Hypericum perforatum|
|Creeping cinquefoil||Potentilla reptans|
|Bramble||Rubus fruticosus agg.|
|Meadow vetchling||Lathyrus pratensis|
|Black medick||Medicago lupulina|
|Ribbed melilot||Melilotus officinalis|
|Hop trefoil||Trifolium campestre|
|Zigzag clover||Trifolium medium|
|Red clover||Trifolium pratense|
|White clover||Trifolium repens|
|Tufted vetch||Vicia cracca|
|Bush vetch||Vicia sepium|
|Rosebay willowherb||Chamerion angustifolium|
|American willowherb||Epilobium ciliatum|
|Broad-leaved willowherb||Epilobium montanum|
|Petty spurge||Euphorbia peplus|
|Fairy flax||Linum catharticum|
|Herb Robert||Geranium robertianum|
|Indian balsam||Impatiens glandulifera|
|Rough chervil||Chaerophyllum temulum|
|Autumn gentian||Gentianella amarella ssp amarella|
|Large bindweed||Calystegia sylvatica|
|White dead-nettle||Lamium album|
|Red dead-nettle||Lamium purpurea|
|Water mint||Mentha aquatica|
|Ribwort plantain||Plantago lanceolata|
|Hoary plantain||Plantago media|
|Red bartsia||Odontites vernus|
|Common field speedwell||Veronica persica|
|Hedge bedstraw||Galium mollugo|
|Lady’s bedstraw||Galium verum|
|Field scabious||Knautia arvensis|
|Devil’s-bit scabious||Succisa pratensis|
|Common knapweed||Centaurea nigra|
|Creeping thistle||Cirsium arvense|
|Spear thistle||Cirsium vulgare|
|Hawkweed sp.||Hieracium agg|
|Autumn hawkbit||Leontodon autumnalis|
|Rough hawkbit||Leontodon hispidus|
|Common ragwort||Senecio jacobaea|
|Perennial sow-thistle||Sonchus arvensis|
|Prickly sow-thistle||Sonchus asper|
|Smooth sow-thistle||Sonchus oleraceus|
|Scentless mayweed||Tripleurospermum inodorum|