 The site is notable for (in the grassland areas) "Festuca ovina" (sheep's fescue), "Avenula pratensis" (meadow oat-grass), "Brachypodium pinnatum" (tor-grass), and "Polyommatus bellargus" (Adonis Blue) - a nationally scarce species of butterfly, and in the scrub areas, "Crataegus monogyna" (common hawthorn), and "Hedera helix" (ivy).Gallows Hill SSSI was first notified in 1965 under Section 28 of the Wildlife and Countryside Act 1981.The notification was revised in 1975.