London’s vegetation is a dynamically rich palette of the native plants that have survived the onslaught of urbanisation. Those that we have bought in from elsewhere to feed and clothe ourselves, those that prettify the city and serve industry, and those that have arrived accidentally.
The city holds plants that have been here since before London was built, and those that have arrived in the past few years. Nevertheless, given the conditions of the city, it is with considerable surprise that a couple of spikes of lizard orchid (Himantoglosssum hircinum) were spotted in 2006 by a bus-stop near Syon, west London. They have blossomed each year since.
The lizard orchid is one of our most magnificent plants, and one of Britain’s rarest, found in less than 20 populations. Since its discovery in England by Thomas Johnson (‘The Father of British Field Botany’) in c1630, its distribution before 1910 was largely restricted to the south-east, with most populations found around Dartford.
Emerging in late June it can be impressively tall, growing up to a metre in height in robust purplish-green brush-like spikes. The flowers give the orchid its name – the labellum looks like the legs and long, twisting tail of a lizard. Pale and greenish, with delicate pink spots and stripes, as many as 80 flowers will adorn each ‘spike’.
But beauty is skin-deep; these flowers give off an odour reminiscent of goats (hence its Latin name hircinum). In common with many orchids, it has evolved sophisticated techniques to ensure pollination. In this case flies, and some bees, are attracted by its distinctive smell.
The lizard orchid is still restricted to the south and east of England. It prefers soils with a high alkalinity; open calcareous grassland, scrub edge and sand dunes. Populations occur in Kent and Sussex (at about sea-level), Somerset, Devon, Gloucestershire and the North and South Downs. Given its rarity and vulnerability, lizard orchid is listed as a protected species on Schedule 8 of the Wildlife & Countryside Act 1981, and listed on internationally designated Special Areas of Conservation for certain habitat types.
Population numbers are known to have dramatically changed with time. There was a marked peak towards the end of the 1920s and early ‘30s, followed by a rapid decline and a remarkably constant number from 1950-90, since when there has been a rise. The most impressive are probably the glorious stands on the Royal St George’s Golf Course at Sandwich in Kent (and spreading undoubtedly to other coastal courses across southern England, with seeds hitching a ride on golfers’ shoes).
Quite how a lizard orchid managed to take root in an otherwise unremarkable suburb of London is still unknown. It is at its northern-most global limit in southern England, although it has been suggested that it could begin to move further across the country as the climate changes. Less severe frosts and increased rainfall in autumn and winter, without a severe drought in the spring, will favour flowering, seed production and, therefore, a growing range. The Syon plant is either a bizarre one-off interloper or at the vanguard of an orchid expansion.
© Mathew Frith | with thanks to Mark Spencer