Many collectors’ references are cited throughout Trees and Shrubs Online, often in the form of an initial or acronym associated with a serial number. To help decipher these the following list is provided, but further references are also available in the annual editions of The RHS Plant Finder (for example, Lord 2008). We are very grateful to Susyn Andrews for her help in compiling this list. There is occasional variation in the form in which such references are cited, as different institutions use different forms (for example, W&H and WAHO both relate to collections made by Roger Warner and Lord Howick).
Collection numbers are an important part of the data associated with wild-origin material, and should never be discarded from labels or records.