BRIAN and Wilma Rittershausen have won a unique accolade from the Royal Horticultural Society.

At the society's 2009 awards ceremony in London, the brother and sister orchid specialists from Burnham Nurseries Ltd at Forches Cross, near Newton Abbot, were jointly awarded the Westonbirt Orchid Medal for outstanding literary achievement on the subject of orchids.

The family's well known books on orchid culture, some of which have been printed in many different languages, have been in continuous print for more than 50 years.

This is the only occasion this medal has been given separately to two individuals.

With the rising popularity of orchids, the range of literature on these splendid plants is fast expanding, making the recognition for Brian and Wilma's achievements all the more special.

Brian said: "We are very, very pleased, this is a real honour. It is something quite unique as it is only awarded for literature."

The award traces its history back to the famous orchid collection held at Westonbirt in Gloucestershire.

In 1926, the collection passed to Mr H G Alexander, probably the greatest orchid hybridist during the first part of the 20th century.

When he retired in 1960, Mr Alexander donated a fund to the Royal Horticultural Society to provide for an award to be known as the Westonbirt Orchid Medal to commemorate the collection.

Struck in gold, it was to be presented annually in several categories for personal achievement at the discretion of the orchid committee.