Cattleya rex Cattleya rex Cattleya rex is a species of epiphytic orchid of showy white flowers, native to montane forests in Peru and Bolivia. Epiphytic herb with cylindric or spindle-shaped pseudobulbs, up to 35 cm. high, with one leaf at the top. Leaf oblong or elliptic-oblong, obtuse, light green, up to 35 cm. long and up to 6 cm. wide, coriaceous. Inflorescence up to 20.3 cm. high, with 3 to 6 (or 10) flowers. Flowers large and showy, up to 17 cm wide, with sepals and petals being cream-colored or ivory white, except the lip or labellum, which is colored with yellow,
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