One of the paintings at the Ancient Landscapes exhibition was Paul Nash's November Moon, according to the catalogue Nash had been interested in how the moon appears in daylight in November. Autumn is a time of decay and death, and of course the painting has the cypress trees, evergreens associated with immortality, this tree also is part of death as well, connected with the Greek underworld.
Here Nash is playing the cycle between dying and living, the large mushroom at the forefront and the convolvous or Morning Glory one representing autumn and death, the summer flower twisting its way following the sun. This painting is very similar in expression to the Sun Eclipsing the Sunflower shown earlier on, and its soft pastel tones hide a more dramatic expression.
This picture by Nash is not in the exhibition, but again the moon figures strongly, the rounded hill is probably the Wittenham Clumps in Oxfordshire, which he painted several times, a more formalised version can be seen in Under the Hill.
Partial Eclipse of the Sun. .http://thelmawilcox.blogspot.com/2008/08/blog-post.html