This groundbreaking AIDGAP guide uses vegetative characters to identify the 90 most common grass species found in the UK. Grasses form the matrix of a wide range of habitats. They also provide important cover in urban landscapes, including road verges, parklands and playing fields. As a result, grasses are an essential component of most habitat survey protocols. These include Phase I Habitat surveys, National Vegetation Classification (NVC), farm stewardship surveys and Habitat Condition Assessments. Unfortunately most grass identification keys need flower heads to be present. This is fine in mid summer, but is not always practical in spring, autumn and winter. Potentially this limits habitat surveys to the summer months. But field surveys are needed all year round. Moreover, even in summer, cutting and grazing will remove flower heads, and competition can inhibit flowering. This new vegetative key will help surveyors carry out fieldwork throughout the year. Users do not need expensive or specialist equipment.