The flowers of the celebrated 'blue' orchid, Vanda coerulea 'The Node' (above), vary from mauve-white to lavender blue. The orchid was heavily collected from the wild before the development of equally popular hybrids. The Royal Horticultural Society started its own collection of orchids in the 1830s and has commissioned watercolour paintings of many of the prize-winning blooms as judged by its Orchid Committee. A selection of these, together with other orchid illustrations in its possession, has now been published in Orchids by Mark Griffiths (Scriptum Editions, £45).