DESCRIPTION: Height up to 40cm.  An elegant and distinctive plant with upright stems and leaves of waxy grey-green. The upper triangular leaves borne in opposite pairs are fused around the stem.  The flowers are found in lax, branched clusters and are made up of 6 to 8 sunshine yellow petal lobes. DISTRIBUTION: Primarily found in central and southern England as well as in Wales and Scotland. HABITAT: A lover of chalk and limestone grasslands and dune systems. FLOWERING TIME: June to October. EXTRA NOTES: The plants waxy, blue-green leaves assist in water retention so survival can be had in the arid conditions in which the species grows.  The genus name 'Blackstonia' identifies the plant as 'Yellow-Wort' and honours the 18th century English botanist John Blackstone. The species name 'perfoliata' means 'through leaves'.