The flora of a small area of field-layer vegetation at Wytham, Berkshire, is described. The spider fauna of the field-layer vegetation is discussed and 4 categories distinguished. The plant form, both living and dead, has an important influence on the number and type of webs which can be constructed. Two closely related spiders, Theridion sisyphium and T. impressum, with similar webs and habitat, mature at slightly different times in the summer, resulting in the former occupying mostly dead plants, while the majority of the latter species were found on growing plants. A census in October 1951 of 100 square meters of field-layer plants showed that there were 1.2 spiders per m2 and 9.2 plants. In October 1951 and April 1952, Theridion sisyphium and T. impressum were the most numerous species, followed by Dictyna arundinacea D. arundinacea showed a preference for the dead flower heads of Hypericum hirsutum and H. perforatum as a web-site, while other species were more generally distributed; the more abundant the plant species, the greater the proportion of the total spider fauna found on it. From October 1951 to April 1952 the number of field-layer plants in a 11 X 11 m square decreased by 37.3% and the total of spiders by 57.6%. The fall in the numbers of spiders in the ground vegetation during the same period varied from 13.0% to 45.0%. In spite of the fall in numbers of field-layer spiders the distribution pattern remained broadly the same from October to April. The physical and biotic factors of the field-layer environment are discussed. There is evidence to suggest that field-layer species have a much greater tolerance of water scarcity than the ground vegetation species living beneath them. The color patterns of field-layer spiders are better developed than those of ground living or litter species. In a well-lighted environment of contrasting light and shade, this is of value as an aid to concealment. In the litter, where little light penetrates, most species seldom exhibit patterning.