Flowers of the same genus, and even of the same kind, are found of all colours. Roses, and particularly mallows, for example, vary through a great portion of the colorific circle from white to yellow, then through red-yellow to bright red, and from thence to the darkest hue it can exhibit as it approaches blue.
Others already begin from a higher degree in the scale, as, for example, the poppy, which is yellow-red in the first instance, and which afterwards approaches a violet hue.
Yet the same colours in species, varieties, and even in families and classes, if not constant, are still predominant, especially the yellow colour: blue is throughout rarer.
A process somewhat similar takes place in the juicy capsule of the fruit, for it increases in colour from the green, through the yellowish and yellow, up to the highest red, the colour of the rind thus indicating the degree of ripeness. Some are coloured all round, some only on the sunny side, in which last case the augmentation of the yellow into red,—the gradations crowding in and upon each other,—may be very well observed.
Many fruits, too, are coloured internally; pure red juices, especially, are common.