Interrupted brome (Bromus interruptus)

GenusBromus (1)
SizeHeight: 5-50 cm

The interrupted brome is classified as Extinct in the Wild (EW) on the IUCN Red List (1).

This member of the grass family was discovered in 1849 and identified as an endemic English species. It gets its unusual name from the fact that the individual flower spikelets are not continuous along the flowering stem, but are 'interrupted' with gaps between them.

Believed to be extinct in the wild, interrupted brome was formerly found in south and west England, from Lincolnshire down to Kent and Somerset.

This species used to be closely associated with arable farming and the animal fodder crop sainfoin, Onobrychis viciifolia, rye-grass and clover.

In the years following its discovery the plant spread rapidly, which suggested to some that the plant might be an introduced species. However, it is now believed to have been the result of a spontaneous genetic change that occurred to one of its related bromes, as they are a family much given to mutation events and hybridisation.

This species was last seen in the wild in Cambridgeshire, in 1972. One reason for its disappearance is thought to have been improved methods of agricultural seed cleaning. With the collapse of the market in fodder, following the decline of horse-drawn transport, interrupted brome had fewer and fewer opportunities to recover its dwindling populations. It is a poor competitor, and the development of highly competitive crops, which rely on nitrogen fertiliser, did not help the plant's fortunes, either.

The interrupted brome is listed under the UK Biodiversity Action Plans and included in English Nature's Species Recovery Programme. As it is now known to be extinct in the wild, it is vital that the seed bank is maintained and several botanic gardens hold stocks. These include the Royal Botanic Gardens, Kew, RBG, Edinburgh, Cambridge and Ness.

The plant is propagated from seed at the various botanical gardens. Land at its last known site in Cambridgeshire was cultivated in the hope that new plants might germinate from a buried natural 'seed bank'. However, this proved unsuccessful.

Interrupted brome is one of a large number of plants associated with farmland, which have disappeared or declined severely in number. It is highly likely that any project that benefits the brome will help conserve many other species as well.

See also Royal Botanic Gardens, Kew:

Information supplied by English Nature

  1. IUCN Red List (June, 2011)