The Day of the Triffid was a Friday. On August 9 1850 the Royal Botanical Gardens at Kew recorded the arrival of 40 plants sent by Philipp von Siebold, a doctor and botanist, from Leiden in the Netherlands.

The gift was unsolicited. Siebold, who had brought 12,000 plants to Europe from Japan in 1829, asked only for some samples in return. But Kew did not reciprocate. “On account of the bad selection he is written to, telling only six of them are probably new to us,” says the ledger.