Watery solution of iodine imparts to it a deep mahogany-brown colour; iodine and sulphuric acid occasionally, but not always, an azure-blue, methylviolet, a brilliant rose-pink and methyl-green gives a reaction very much like that of methyl-violet, but not so vivid.
The flowers issue from between the mammillae, towards the upper part of the stem, often disposed in a zone just below the apex, and are either purple, rose-pink, white or yellow, and of moderate size.
While the price of the finest tints of rose pink may range from go to £1 20 per oz., ordinary red-coloured small pieces sell for about £2 per oz., and the small fragments called collette, used for children's necklaces, cost about 5s.
P. vacciniifolium, 6 to to in., is a pretty prostrate subshrubby species, with handsome rose-pink flowers, suitable for rockwork, and prefers boggy soil; P. affine (Brunonis), I ft., deep rose, is a showy border plant, flowering in the late summer; P. cuspidatum, 8 to To ft., is a grand object for planting where a screen is desired, as it suckers abundantly, and its tall spotted stems and handsome cordate leaves have quite a noble appearance.
It grows about 5 feet high, the leaves are nearly round, the flowers in large clusters, bright rose-pink, about an inch in diameter, and open in early June.