in Dyeing. See Dyeing.

Colour of Plants, is an attribute found to be very variable. Different colours are observed, not only in different individuals of the same species, but likewise in different parts of the same individual. Thus, marvel of Peru, and sweet-william, have frequently petals of different colours on the same plant. Three or four different colours are frequently found upon the same leaf or flower, as on the leaves of the amaranthus tricolor, and the flowers of the tulip, auricula, three-coloured violet and others. To produce the most beautiful and striking variety of colours in such flowers, is the principal delight and business of the florist.

The primitive colours, and their intermediate shades or gradations enumerated by botanists, are as follow:

Water-colour, hyalinus.

WHITE.

Lead-colour, cinereus. Black, niger. Brown, fulvus. Pitch-black, ater.

YELLOW, luteus.

Straw-colour, flavus. Flame-colour, fulvus. Iron-colour, glaucus.

RED.

Flesh-colour, incarnatus. Scarlet, coccineus.

PURPLE.

Violet-colour, caeruleo-purpureus.

BLUE, caeruleus.

GREEN.

These colours seem to be appropriated to particular parts of the plant. Thus white is most common in roots, sweet berries, and the petals of spring flowers. Water-colour, in the filaments and styles. Black, in the roots and seeds; rarely in the seed-vessel, and scarce ever to be found in the petals. Yellow is frequently in the antherae or tops of the stamens; as likewise in the petals of autumnal flowers, and the compound ligulated flowers of Linnæus. Red is common in the petals of summer flowers, and in the acid fruits. Blue and violet-colour in the petals. Green in the leaves and calyx, but rarely in the petals. In the interchanging of colours, which in plants is found to depend upon differences in heat, climate, soil, and culture, a sort of elective attraction is observed to take place. Thus, red is more easily changed into white and blue; blue into white and yellow; yellow into white; and white into purple. A red colour is often changed into a white, in the flowers of heath, mother of thyme, betony, pink, viscous campion, cucubalus, trefoil, orchis, foxglove, thistle, cudweed, saw-wort, rofe, Colour. rose, poppy, fumitory, and geranium. Red passes into blue in pimpernel. Blue is changed into white in bell-flower, greek-valerian, bind-weed, columbine, violet vetch, milk-wort, goat’s rue, viper’s bugloss, comfrey, borrage, hyssop, dragon’s head, scabious, blue-bottle, and ipecac. Blue is changed into yellow in crocus. Yellow passes easily into white in melilot, agrimony, mullein, tulip, blattaria or moth-mullein, and corn marigold. White is changed into purple in wood-sorrel, thorn-apple, pease, and daisy.

Although plants are sometimes observed to change their colour upon being moistened with coloured juices, yet that quality in vegetables seems not so much owing to the nature of their nourishment, as to the action of the internal and external air, heat, light, and the primitive organization of the parts. In support of this opinion, we may observe with Dr Grew, that there is a far less variety in the colours of roots, than of the other parts of the plant; the pulp within the skin, being usually white, sometimes yellow, rarely red. That this effect is produced by their small intercourse with the external air, appears from this circumstance, that the upper parts of roots, when they happen to stand naked above the ground, are often dyed with several colours: thus the tops of forrel roots turn red; those of turnips, mullein, and radishes, purple; and many others green; whilst those parts of the same roots which lie more under ground, are commonly white. The green colour is proper to leaves, that many, as those of fage, the young sprouts of St John’s wort, and others which are reddish when in the bud, acquire a perfect green upon being fully expanded. In like manner, the leaves of the sea-side grape (Polygonum), which when young are entirely red, become, as they advance in growth, perfectly green, except the middle and transverse ribs, which retain their former colour.

As flowers gradually open and are exposed to the air, they throw off their old colour and acquire a new one. In fact, no flower has its proper colour till it is fully expanded. Thus the purple rock-julyflowers are white or pale in the bud. In like manner bachelor’s buttons, blue-bottle, poppy, red daisies, and many other flowers, though of divers colours when blown, are all white in the bud. Nay, many flowers change their colour thrice successively; thus, the very young buds of lady’s looking-glass, bugloss, and the like, are all white; the larger buds purple or murrey; and the open flowers blue.

With respect to the colours of the juices of plants, we may observe, that most resinous gums are tinctured; some, however, are limpid; that which drops from the domestic pine is clear as rock-water. The milk of some plants is pale, as in burdock; of others white, as in dandelion, euphorbium, and scorzonera; and of others yellow, as in lovage, and greater celandine. Most mucilages have little colour, taste, or smell. Of all the colours above enumerated, green is the most common to plants, black is the most rare.

Colour being a quality in plants so apt to change, ought never to be employed in distinguishing their species. These ought to be characterized from circumstances not liable to alteration by culture or other accidents. The same inconsistency of colour observed in the flowers, is likewise to be found in the other parts of plants. Berries frequently change from green to red, and from red to white. Even in ripe fruits, the colour, whether white, red, or blue, is apt to vary; particularly in apple, pear, plum, and cherry trees. Seeds are more constant in point of colour than the vessel which contains them. In the seeds, however, of the poppy, oats, pea, bean, and kidney-bean, variations are frequently observed. The root, too, although not remarkably subject to change, is found to vary in some species of carrot and radish. Leaves frequently become spotted, as in a species of orchis, hawk-weed, ranunculus, knot-grass, and lettuce; but seldom relinquish their green colour altogether. Those of some species of amaranthus, or flower-gentle, are beautifully coloured. The spots that appear on the surface of the leaves are of different colours, liable to vary, and not seldom disappear altogether. The leaves of officinal lungwort, and some species of sowbread, forrel, trefoil, and ranunculus, are covered with white spots. Those of dog’s-tooth violet, with purple and white. Those of several species of ranunculus, and orchis, with black and purple. Those of amaranthus tricolor, with green, red, and yellow. Those of ranunculus acris, and a species of bog-bean, with red or purple. The under surface of the leaves of some species of pimpernel and the sea-plantain is marked with a number of dots or points; a white line runs through the leaves of Indian reed, black-berried heath, and a species of Canary grass; and the margin or brim of the leaf, in some species of box, honeysuckle, ground-ivy, and the evergreen oak, is of a silver-white colour. The whole plant is often found to assume a colour that is unnatural or foreign to it. The varieties in some species of eryngo, mugwort, orach, amaranthus, purslane, and lettuce, furnish examples.

Such being the inconsistency of colours in all the parts of the plant, specific names derived from that quality are very properly, by Linnaeus, deemed erroneous; whether they respect the colour of the flower, fruit, seeds, roots, leaves, or express in general the beauty or deformity of the entire plant, with a particular view to that circumstance. Of this impropriety, committed by former botanists, Linnaeus himself is not always guiltless. Thus the two species of Farracena, or the fide-faddle flower, are distinguished by the colour of their petals into the yellow and purple Farracena; although the shapes and figure of the leaves afforded much more constant as well as striking characters. The same may be said of his Lupinus albus and luteus; re-fed a alba, glauca, and lutea; Angelica atro-purpurea; dictamnus albus; lamium album; Felago coccinea; fida alba; Passiflora rubra, lutea, incarnata, and coerulea; and of many others, in which the specific name is derived from a character or quality that is so liable to vary in the same species.

We shall conclude this article with observing, that of all sensible qualities, colour is the least useful in indicating the virtues and powers of vegetables. The following general positions on this subject are laid down by Linnaeus, and seem sufficiently confirmed by experiment. A yellow colour generally indicates a bitter taste; as in gentian, aloe, celandine, turmeric, and other yellow flowers. Red indicates an acid or sour taste; as in cranberries, barberries, currants, raspberries, mulberries, cherries, the fruit of the rose, tea-buckthorn, thorn, and service-tree. Herbs that turn red towards autumn, have likewise a sour taste; as forrel, wood-forrel, and bloody dock. Green indicates a crude alkaline taste, as in leaves and unripe fruits. A pale colour denotes an insipid taste, as in endive, asparagus, and lettuce. White promises a sweet luscious taste; as in white currants and plums, sweet apples, &c. Lastly, black indicates a harsh, nauseous, disagreeable taste; as in the berries of deadly nightshade, myrtle-leaved fumach, herb-christopher, and others; many of which are not only unpleasant to the taste, but pernicious and deadly in their effects.

To be ascertained of the acid or alkaline property of any plant, express some of the juice, and rub it upon a piece of blue paper; which, if the plant in question is of an acid nature, will turn red; if of an alkaline, green. For the methods of extracting colours from the different parts of plants, see the article COLOUR Making.

Difference of COLOUR in the Human Species. See COMPLEXION.

in Heraldry. The colours generally used in heraldry are, red, blue, black, green, and purple; which the heralds call gules, azure, sable, vert or sinople, and purpure; tenne or tawny, and sanguine, are not so common; as to yellow and white, called or and argent, they are metals, not colours.

The metals and colours are sometimes expressed in blazon by the names of precious stones, and sometimes by those of planets or stars. See BLAZONING.

Oenomaus is said first to have invented the distinctions of colours, to distinguish the gundillike of combatants at the Circennian games; the green for those who represented the earth, and blue for those who represented the sea.