The global orchard of wisdom woolsthorpe, york, cambridge

A rather hobbled apple tree stands in the grounds of Woolsthorpe Manor in Lincolnshire. It is said that a well-timed act of fruit-shedding on its part inspired Sir Isaac Newton to his theory of universal gravitation in 1665-66, thus earning the tree a special place in the hearts of scientists everywhere.

A host of grafts have subsequently been nurtured by way of homage.

There is one at York University, in a courtyard within the physics building, from which apples are picked to make a pie for the first meeting of the department's board of studies each autumn term.

Three are in Cambridge - one in the Isaac Newton Institute, Clarkson Road; one close to Trinity College's great gate; and one in the northwest corner of the Botanic Garden.

Another is at the National Physical Laboratory in Teddington, London.

Others went to New Zealand, South Africa and Australia.

Grafts were shipped to the US in the Second World War, and one wound up by the Behlen Laboratory at the University of Nebraska.

All except one have been verified through genetic fingerprinting. Tests suggest that the tree in the President's Garden of the Massachusetts Institute of Technology, presented by a senior US politician, is an imposter.