All the odoriferous[1963] substances, and consequently the plants, differ from one another in their colour, smell, and juices. It is but rarely[1964] that the taste of an odoriferous substance is not bitter; while sweet substances, on the other hand, are but rarely odoriferous. Thus it is, too, that wine is more odoriferous than must, and all the wild plants more so than the cultivated ones.[1965] Some flowers have a sweet smell at a distance, the edge of which is taken off when they come nearer; such is the case with the violet, for instance. The rose, when fresh gathered, has a more powerful smell at a distance, and dried,[1966] when brought nearer. All plants have a more penetrating odour, also, in spring[1967] and in the morning; as the hour of midday approaches, the scent becomes gradually weakened.[1968] The flowers, too, of young plants are less odoriferous than those of old ones; but it is at mid-age[1969] that the odour is most penetrating in them all. The rose and the crocus[1970] have a more powerful smell when gathered in fine weather, and all plants are more powerfully scented in hot climates than in cold ones. In Egypt, however, the flowers are far from odoriferous, owing to the dews and exhalations with which the air is charged, in consequence of the extended surface of the river. Some plants have an agreeable, though at the same time extremely powerful smell; some, again, while green, have no[1971] smell at all, owing to the excess of moisture, the buceros for example, which is the same as fenugreek.[1972] Not all flowers which have a penetrating odour are destitute of juices, the violet, the rose, and the crocus, for example; those, on the other hand, which have a penetrating odour, but are destitute of juices, have all of them a very powerful smell, as we find the case with the two varieties[1973] of the lily. The abrotonum[1974] and the amaracus[1975] have a pungent smell. In some plants, it is the flower only that is sweet, the other parts being inodorous, the violet and the rose, for example.