One of our rarest plants. 

Some of our most colourful wild flowers are the annual weeds that used to be found in cornfields - cornflower, corncockle, corn marigold and the delightfully named Venus's looking-glass.

Corn cleavers.
Photo: I. Denholm

These arable weeds - which have been in the UK for hundreds of years, but are not actually native species - are seen less frequently now, since changes in farming practice. 

One such plant, corn cleavers, is now reduced to only one long-standing site in Britain, at the world-famous Broadbalk experiment site at Rothamsted Research in Herts., where BSBI's incoming President Ian Denholm worked for several decades as an agricultural scientist. 

Cornflower.
Photo: G. Calow

Corn cleavers is maybe not as obviously attractive as cornflower - it is unlikely to appear at the Chelsea Flower Show - but its rarity makes it of interest to botanists and it has its own modest charm. Ian brought some young plants of corn cleavers to the 2012 BSBI Annual Exhibition Meeting in Cambridge. 
He explained that seed collected from the Broadbalk population had been deposited in national collections and used (with varying degrees of success) for re-introduction programmes elsewhere in southeast England.