Orchidaceae tubers after detecting the plants underground by scent. Orchids have been used in traditional medicine in an effort to treat many diseases and ailments. They have been used as a source of herbal remedies in China since 2800 BC. "Gastrodia elata" is one of the three orchids listed in the earliest known Chinese Materia Medica ("Shennon bencaojing") (c. 100 AD). Theophrastus mentions orchids in his "Enquiry into Plants" (372–286 BC). Orchids have many associations with symbolic values. For example, the orchid is the City Flower of Shaoxing, China. "Cattleya mossiae" is the national Venezuelan flower, while "Cattleya trianae" is the
Basics of blue flower colouration This phenomenon we can observe in the morning glory (Ipomoea tricolor) and Japanese blue morning glory (Ipomoea nil) petals. During the flower development we can observe change of the flower colour form purple to blue. Morning glory has just one delphinidin type anthocyanin and the composition of it does not change during the flower development, but change of the colour is caused by increase of pH in vacuole of coloured cells from 6.6 in buds to 7.7 in fully matured flowers. During the early stage of development acidic pH is maintained by proton pumps, on the latter stage K+/H+ exchanger