It鈥檚 Britain鈥檚 dodo. Called interrupted brome because of its gappy seedhead, this unprepossessing grass was found nowhere else in the world. Sharp-eyed Victorian botanists were the first to notice it, and by the 1920s the odd-looking grass had been found across much of southern England. Yet its decline was just as dramatic. By 1972 it had vanished from its last toehold-two hay fields at Pampisford, near Cambridge. Even the seeds stored at the Cambridge University Botanic Garden as an insurance policy were dead, having been mistakenly kept at room temperature. Botanists mourned: a unique living entity was gone forever.
Yet reports of its demise proved premature. Interrupted brome has come back from the dead, and not through any fancy genetic engineering. Thanks to one green-fingered botanist, interrupted brome is alive and well and living as a pot plant. Britain鈥檚 dodo is about to become a phoenix, as conservationists set about relaunching its career in the wild.
AT FIRST, Philip Smith was unaware that the scrawny pots of grass on his bench were all that remained of a uniquely British species. But when news of the 鈥渆xtinction鈥� of Bromus interruptus finally reached him, he decided to astonish his colleagues. He seized his opportunity at a meeting of the Botanical Society of the British Isles in Manchester in 1979, where he was booked to talk about his research on the evolution of the brome grasses. It was sad, he said, that interrupted brome had become extinct, as there were so many interesting questions botanists could have investigated. Then he whipped out two enormous pots of it. The extinct grass was very much alive.
Advertisement
It turned out that Smith, who runs the school of plant sciences at the University of Edinburgh, had collected seeds from the brome鈥檚 last refuge at Pampisford in 1963, shortly before the species disappeared from the wild altogether. Ever since then, Smith had grown the grass on, year after year. So in the end the hapless grass survived not through some high-powered conservation scheme or fancy genetic manipulation, but simply because one man was interested in it. As Smith points out, interrupted brome isn鈥檛 particularly attractive and has no commercial value. But to a plant taxonomist, that鈥檚 not what makes a plant interesting.
Bromus interruptus could yet reveal how new species arise, and how they adapt to different types of farming. Crop breeders as well as conservationists should celebrate the plant鈥檚 survival, as genetic studies could show how a sudden simple mutation might generate an entirely new species. Such a 鈥渕istake鈥� of nature might point the way to key genes that control reproduction in grasses, perhaps.
The brome鈥檚 future, at least in cultivation, now seems assured. Seeds from Smith鈥檚 plants have been securely stored in the state-of-the-art Millennium Seed Bank at Wakehurst Place in Sussex. And living plants thrive at the botanic gardens at Kew, Edinburgh and Cambridge. This year, 鈥渂ulking up鈥� is under way to make sure there are plenty of plants in all the gardens, and sackfuls of seeds are being stockpiled at strategic sites throughout the country.
The brome鈥檚 relaunch into the British countryside is next on the agenda. English Nature has included interrupted brome in its Species Recovery Programme, and it is on track to be reintroduced into the agricultural landscape, if friendly farmers can be found. Alas, the grass is neither pretty nor useful-in fact, it is undeniably a weed, and a weed of a crop that nobody grows these days, at that. The brome was probably never common enough to irritate farmers, but no one would value it today for its productivity or its nutritious qualities. As a grass, it leaves agriculturalists cold.
So where did it come from? Smith鈥檚 research into the taxonomy of the brome grasses suggests that B. interruptus almost certainly mutated from another weedy grass, soft brome, B. hordeaceus. So close is the relationship that interrupted brome was originally deemed to be a mere variety of soft brome by the great Victorian taxonomist Professor Hackel. But in 1895, George Claridge Druce, a 45-year-old Oxford pharmacist with a shop on the High Street, decided that it deserved species status, and convinced the botanical world. Druce was by then well on his way to fame as an Oxford don, mayor of the city, and a fellow of the Royal Society. A poor boy from Northamptonshire and a self-educated man, Druce became the leading field botanist of his generation. When Druce described a species, botanists took note.
The brome鈥檚 parentage may be clear, but the timing of its birth is more obscure. A clue lies in its penchant for growing as a weed in fields sown with a fodder crop-particularly nitrogen-fixing legumes such as sainfoin, lucerne or clover. According to agricultural historian Joan Thirsk, sainfoin and its friends made their first modest appearance in Britain in the early 1600s. Seeds brought in from the Continent were sown in pastures to feed horses and other livestock. But in those early days, only a few enthusiasts-mostly gentlemen keen to pamper their best horses-took to the new crops.
Soon, however, the urgent need to feed the Parliamentary army in three theatres of war-Scotland, England and Ireland-forced farmers to produce more bread, cheese and beer. And by 1650 the legumes were increasingly introduced into arable rotations, to serve as 鈥済reen manure鈥� to boost grain yields. A bestseller of its day, Nathaniel Fiennes鈥檚 Sainfoin Improved, published in 1671, helped to spread the word. The arrival of sainfoin, clover and lucerne marked a revolution in farming technology and set the scene for the spontaneous emergence of Britain鈥檚 very own rogue grass.
Although the credit for the 鈥渄iscovery鈥� of interrupted brome goes to a Miss A. M. Barnard, who collected the first specimens at Odsey, Bedfordshire, in 1849, the grass had probably lurked undetected in the English countryside for at least a hundred years. Smith thinks the botanical dodo probably evolved in the late 17th or early 18th century, once sainfoin became established. The brome鈥檚 fortunes then declined dramatically over the 20th century, not least because the advent of the motor car destroyed the market for fodder crops for horses. Today, sainfoin has all but disappeared from the countryside, though you can sometimes spot its pretty pink flowers in downland nature reserves. These days, artificial fertilisers have made legume rotations redundant.
This intimate relationship with out-of-fashion crops spells trouble for anyone keen to re-establish interrupted brome in today鈥檚 countryside. Like many once-common arable weeds, such as the corncockle, its seeds cannot survive long in the soil. Each spring, the brome relied on farmers to resow its seeds; in the days before weedkillers and sophisticated seed sieves, an ample supply would have contaminated stocks of crop seed. But fragile seeds are not the brome鈥檚 only problem: this species is also reluctant to release its seeds as they ripen. Show it a ploughed field today and this grass will struggle to survive, says Smith. It will be difficult to establish in today鈥檚 鈥渋mproved鈥� agricultural landscape, inhabited by notoriously vigorous competitors.
Interrupted brome鈥檚 reluctance to spread under its own steam could have advantages, however. Any farmer willing to foster this unique contribution to the world鈥檚 flora can rest assured that the grass will never become an invasive pest. Restoring interrupted brome to its rightful home could bring positive benefits too, once this quirky grass wins recognition as a unique national monument. British farmers made it possible for interrupted brome to evolve in the first place. Let the grass grow once again in its 鈥渘atural鈥� habitat, say the conservationists, and it could become a badge of honour for a new breed of eco-friendly farmer.