The Queen heard author Leo Tolstoy’s famous quote about happy and unhappy families just days after senior royals were pictured together following the publication of a controversial book about the monarchy.

Christopher Woodward, director of the Garden Museum, quoted the Russian writer during a speech as he hosted Camilla’s visit to his institution’s Winter Flowers Week, an exhibition of five installations celebrating seasonal and sustainable festive decorations.

The royal family have made headlines in recent weeks following the release of Endgame by author Omid Scobie, who asserts that the future of the monarchy is “in a crisis”, with the Dutch edition of his book naming two royals at the centre of a race row.

The King and Queen were photographed with the Prince and Princess of Wales on Wednesday evening during the annual glittering Buckingham Palace diplomatic reception, widely interpreted by the media as a royal show of unity.

In his speech, Mr Woodward said about the exhibitions: “And the idea is that you often see work by floral designers at a wedding or at a party, this is the chance for the designers to pause and for five days have an audience to follow through the concepts and inspirations which make this beauty.

“And winter has been an enticement to foliage and to structure and – just look.

“Tolstoy began Anna Karenina ‘Happy families are all alike; every unhappy family is unhappy in its own way’.”

He went on to say: “And as you become older, I think you notice all the world’s little ‘rightnesses’ and study how many twists and troubles and turns lead to happiness, and how it has as many, more perhaps, colours and aspects as the more often studied tragedies.”

Speaking after the royal visit, Mr Woodward stressed the Tolstoy quotation was not a reference to the recent news stories about the royal family but about drawing attention to the museum’s ability to be an oasis to keen gardeners and members of the public.

He said contemporary art rightly draws attention to the “fissures and challenges” but there was also art that highlighted the “happiness and wholeness” of life.

He said about the Garden Museum, based in Lambeth, central London: “We want to make a space where people come here for a couple of hours and feel ready to go back into the city.”

There was a lighter moment during the visit when Mr Woodward’s young son Max shook hands with the Queen using his toy dinosaur.

The three-year-old had a few moments of playful tug-of-war with the Queen before she let go with a laugh.

Among the guests were TV gardener Alan Titchmarsh, president of the Garden Museum, and Shane Connolly, florist for the Queen’s wedding to Charles in 2005, who also created one of the designs for the new winter exhibition.

The Queen was also shown an exhibition showcasing the work of artist and gardener Frank Walter, a celebrated creative who was from Antigua – and when she saw a picture of her husband which the artist had in his home, she joked she recognised the face.