Aristotle

“ We therefore assert that sensation is common to all animal life, because sensation marks the distinction between life and death; but the heavens, which pursue a nobler and more sublime path than we do, are far removed from life and death. But it is fitting that animals should have [19] some common characteristic perfect in itself but less sublime, and this is the acquisition and deprivation of life. And one ought not to shrink from the use of these terms on the ground that there is no mean between the animate and the inanimate, between life and the deprivation of life ”

“ The reason is that, while in any animal its height is much the same as its width, in a plant it is far from being so, because water and fire, the elements which compose it, rise quickly, and therefore the plant grows. Variety in the branches of a plant is due to excessive rarity, and, when the moisture is intercepted there, the process of nature will cause it to grow hot and will hasten the concoction, and thus boughs will form and leaves will appear, as we have already said. ”

“ But if the place is covered up by snow, plants will grow in it, but without leaves, because it is cut off from the equable temperature of the earth which is congenial to it. This is the reason why there are numerous flowers and leaves on small plants in places where the air and water are temperate, and few flowers and leaves on a plant which occurs in the snow. So too in very salty and dry places plants do not usually appear, because these places are far from being temperate; and the ground is impoverished, because heat and moisture, which are the characteristics of fresh water, are absent. ”

“ When it bears leaves and fruit its life will continue and its youth return to it. No excrement [39] will be produced from plants. A plant does not require sleep for many reasons, for it is placed and planted in the earth and attached to it and has no movement of itself, nor has it any definite bounds to its parts, nor does it possess sensation or voluntary motion, or a perfect soul; nay, it has only part of a soul. [40] Plants are only created for the sake of animals, and animals are not created for the sake of plants. ”

“ The wise men of old used to assert that all leaves were really fruits, but so much moisture was present, because the fruit did not mature or solidify owing to the presence of heat above and the sudden attraction exerted by the sun, and consequently the moisture on which the process of assimilation had had no effect changed into leaves; the leaves, they said, are simply intended to attract the moisture and serve as a protection to the fruit from the violence of the sun. ”

“ Some one will urge that a plant requires food which is easily obtained and poor, yet it needs it very regularly and continuously, and without interruption. If it were agreed that a plant has an advantage over an animal, it would follow that things which are inanimate [41] were better and nobler than those which are animate; yet we see that the function of the animal is nobler and better than that of the plant, and we find in the animal all the virtues which are present in the plant and many others. ”

“ BOOK II A plant has three powers, the first derived from the element of earth, the second from that of water, the third from that of fire. From the earth the plant derives its solidity, from water the unity, and from fire the concretion of its solidity. We see much the same thing in vessels of pottery, which contain three elements—clay, which is, as it were, the material of pottery ”

“ Some trees are more productive when they are young than when they are old; others, on the contrary, are more fertile when they are old, almond-trees, for example, and pear-trees and holm-oaks. Wild and garden plants can be distinguished by identification with the male and female, each being recognizable by its peculiar characteristics; for the male is thicker and harder and has more branches and less moisture and a smaller fruit, and as does not reach such maturity ”

“ Of this we can only be certain because nutrition and growth are parts of the soul, and when we find a plant to be possessed of such a nature, ve perceive of necessity that some part of a soul is present in it; but we ought not to contend that a plant which lacks sensation is a thing possessed of sense, because while sensation is the cause of the glorification of life, nutrition is merely the cause of growth in the living thing. ”

“ Some plants are indoor plants, others garden plants, and others wild, in the same way as animals. I think, too, that all species of plants which are not cultivated become wild. Some plants produce fruit, others do not; some bear flowers, others do not; some have leaves and not others; some plants shed their leaves, others do not. Plants differ greatly in their large or small size, in beauty and ugliness, and in the excellence, or the contrary, of their fruits. Trees in a wild state bear more fruit than garden trees, but the fruit of the garden tree is better than that of the wild. ”

“ Now the parts of plants are usually rare, because the heat draws the moisture into the extremities of the plant, and the material is distributed through all its parts, and that which is superfluous will flow away; just as in a bath the heat attracts the moisture and turns it into vapour which rises, and, when it is present in superfluity, it will turn into drops of water. ”

“ The suckers are the parts which sprout from the root of a tree, while the branches are above the suckers. They are not found in all plants; and in some plants which have branches these are not permanent, but only last from year to year. There are plants which do not have branches or leaves, fungi, for example, and mushrooms. Branches are only found on trees. Bark and wood and the pith of a tree are produced from moisture; some call this pith the womb of the tree, others the vitals, others the heart. ”

“ But a good plant is not likely to be produced from a bad seed, nor a bad tree from a good seed. Instances, however, of good producing bad and vice versa often occur among animals.
A tree which has hard bark and has become barren, if its root be split and a stone inserted in the cleft will become fruitful again. In palms too, if the leaves or pollen or bark of the male palm be applied to the leaves of the female palm so as to cohere, its fruits will come to maturity quickly, and it will prevent their falling off. ”

“ For the heavenly bodies feel no outside influence, and sensation is an effect produced on a sentient being. Now a plant has no movement of itself, for it is fixed in the earth, which is itself immovable. ”

“ Anaxagoras declared that plants are animals and feel joy and sadness, deducing this from the bending [6] of their foliage; while Empedocles held the opinion that sex has a place in their composition. Plato indeed declares [7] that they feel desire only on account of their compelling need of nutriment. If this be granted, it will follow that they also feel joy and sadness and have sensation. I should also like to reach some conclusion as to whether they are refreshed by sleep and wake up again, and also whether they breathe, and whether they have sex through the mingling of the sexes or not. ”

“ Places which are secluded from the sun's rays will not produce much plant life (just as they will not produce much animal life) , because the sun makes the day long or short according to the duration of its presence or absence, [152] and it is the sun which draws out the moisture; and so plants which grow in sunless places will not have the strength to produce leaves and fruit. ”

“ This, then, is the cause of earthquakes in solid bodies; there will, therefore, be nothing to correspond to an earthquake in the parts of plants and animals, though it will occur in other things—often, for example, in pottery and glass, and in some cases in minerals. Any body which has considerable rarity tends to rise upwards, for the air supports it. This we often see when we throw a gold coin or some other heavy substance into the water and it immediately sinks; whereas if we throw in a piece of wood, which has rarity in it, it does not sink. ”

“ Even salt water rises in that part of it which heat dries out into the element of air, and, because air is always higher than water, that which rises from salt water is fresh. We shall often find the same thing taking place in baths. When heat takes hold of salt water, its parts will be rarefied, and vapour will rise in a contrary direction to the depth of the bath, and the particles of salt and the natural moisture become separated, for the latter is of the nature of air and follows the vapour ”

“ And because the dryness of the earth gains the upper hand in the water, it changes it into an earthy nature, or something like it, and makes both the earth and water crisp; and this process of drying goes on as long as the earth remains in its place and there is water still left, and it splits up the soil into small particles; and for this reason the earth near the sea is always sandy. The same thing happens on plains which have nothing to protect them from the sun, and which are far from fresh water ”

“ Some trees come into existence by being planted, some from seeds, others spontaneously. Those which are planted are separated either from the root, the stem, the branches, or the seed, or else the whole is transplanted; some are slightly bruised before being planted. Some are planted in the earth, others are planted, that is, grafted, on other trees. Grafting of one on another is better in the case of trees which are similar and have the same proportions ”

“ A kind of plant also grows which appears above the surface of the water and is smaller in quantity than that just mentioned, because it is like the nature of earth, and it neither grows upwards nor expands. Often, too, one plant grows out of another plant of a different form from itself, without any root, and spreads all over the plant. ”

“ The root acts as an intermediary between the plants and its food, and for that reason the Greeks call it the root and cause of life in plants, for it supplies the plant with its means of life. The stem is the only part which grows out of the ground and forms, as it were, its erect stature. ”

“ The two sexes cannot be found combined in any plant; if this were so, a plant would be more perfect than an animal, because it would not require anything outside itself in order to generate; whereas the plant does require the right season of the year and sunshine and its natural temperature more than anything, requiring them at the time when the tree sprouts. ”

“ In animals there is a third process of assimilation; this is due simply to the diversity of their limbs and to the distinctness of their parts from one another. Plants, on the other hand, are more homogeneous and repeat the same members over and over again, and the nutritive material generally has a downward tendency. ”

“ The shapes of plants will depend on the character [161] of the seed, while the flower and fruit is dependent on the water and nutritive material. In all animals the first process of maturation and concoction of the nutritive liquids [162] takes place within the animal; there is no exception to this rule. But in plants the first concoction and maturation takes place in [163] the nutritive material. Every tree continues to grow up, until its growth is completed and it dies. ”

“ Natural soil, therefore, will be the basis of sand, and will only become 824a sand accidentally and under certain circumstances, namely, when the sun's rays dwell on it for a long time and it is far removed from fresh water. The saltness of the sea is to be accounted for in a similar way; for the basis of all water is fresh water, and saltness is accidental, occurring only under the circumstances which we have mentioned. The fact that the earth is below the sea and the sea naturally and necessarily above the earth is a self-evident proof of this. ”