Wednesday, 11 October 2017

Signs of autumn

We're well into October and there's no sign of frost. Nor am I expecting any for a while. Nevertheless signs of autumn are all around us: plants and animals seem to be influenced more by day-length than by temperatures. The study and measurement of seasonal changes is known as phenology but is frequently a very inexact science. People contributing to a phenological survey may, for instance, report honey bees in mid-winter when what they have observed is a Drone Fly, a bee-mimicking hoverfly. Nevertheless results are often intriguing.
The seed pods of Stinking Iris, Iris foetidissima, aka Roast Beef Plant, have now ripened and the orange coloured seeds now show through the gaping fissures. The birds seem to eschew these until later in the year when times are hard.
Iris foetidissima outside Byfield Co-op. 11 November, 2017
Trees are taking on autumn colours, none more so than the maples. We may lack the brilliant shows provided by their foliage in parts of north-east U.S.A. but our sycamores, Acer pseudoplatanus, do pretty well. The fact that sycamore is probably not native to Britain is of little consequence.
A scattering of Sycamore leaves beside the Tennis Club, Byfield.
11 November, 2017
Definitely non-native is the Narrow-leaved Ash, Fraxinus angustifolia. It is currently putting on a lovely display around Daventry and no doubt elsewhere. Its foliage has taken on a beautiful purple-maroon colour and this tree, native to Europe on flood plains from France to Turkey, is a welcome sight.(It is less welcome in parts of Australia where it is becoming a serious weed.) Unfortunately this lovely tree, together with the frequently-planted Manna Ash, Fraxinus ornus, is also susceptible to ash dieback.
Narrow-leaved Ash trees brighten up a car park in Daventry.
9 October, 2017
I must mention one feature definitely not expected in autumn. In our front garden clumps of Aubretia, Aubrieta deltoidea, are flowering quite splendidly and form a welcome source of nectar for late hoverflies and other insects. 

Aubretia, clearly confused, flowering in our front garden at Stefen Hill,
Daventry. 10 October, 2017
The study of natural history is constantly throwing up surprises!

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