Cattleya Orchid and Three Hummingbirds 1870s. The NGA describes the work: "Lichen covers dead branches; moss drips from trees; and, a blue-gray mist veils the distant jungle. An opulent pink orchid with light-green stems and pods dominates the left foreground." On the right, two green-and-pink Brazilian Amethysts hover about a nest while a red-tailed Sappho Comet perches nearby. Cattleya Orchid and Three Hummingbirds Cattleya Orchid and Three Hummingbirds (1871) is an oil on mahogany panel picture by Martin Johnson Heade acquired by the National Gallery of Art in 1982. Inspired perhaps by the works of Charles Darwin and Frederic Edwin Church, Heade planned to produce
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