The Ruizia mauritiana is a large green shrub with cascading leaves shaped like lovehearts. There’s one just off the main walkway through the magnificent Temperate House in London’s Kew Gardens, a Victorian marvel nearly 200 metres long. Among all the surrounding greenery, the plant looks unassuming – but examples of this specimen are extremely rare. In fact, by the mid-1990s, it was thought to be extinct in the wild. But then came some thrilling news: a 10-metre tall example had been spotted in the Mauritian highlands. And soon Kew’s scientists were wading through a guava thicket in the east African island nation to take some cuttings.