Country diary 1920: algae continue to run riot on the water

A thick green scum lies on the still water at the edge of the withered reed bed. It is late, for surely the “breaking of the meres” is a late summer occurrence; it is then, not November, that the algae, the phytoplankton, run riot, tinting the water with their profusion. As a rule in autumn the water is clear, for the abundance of diminutive animals which form the zooplankton are hyaline and almost colourless. Behind the reed bed is the brown bracken, deepening daily in colour, though the upper fronds are still yellow and even green; amongst them the campions persist in opening fresh flowers, replacing those which are bleaching to pale pink, and where the bramble tangle is covered with berries which have died without ripening there are a few white blossoms and flower-buds, fresh and green.

The trunks alike of birch, sycamore, oak, and fir are dotted with the speckled, wingless females of the mottled umber moth, often over a dozen on one hole. Clinging, too, like withered leaves, are the variable males, some with dark bands, some quite pale, others again bandless, their wings merely peppered with buff or brown. This is the third autumn running when this troublesome moth has been far above the normal; how long will the trees stand annual defoliation? So far, at any rate, they show no sign of weakness.