160 THE MAGAZINE OF HORTICULTURE. 



the apple, the southern fruits have a rind Hke that of the 

 lemon and the orange, or are enclosed in a case, like the 

 banana. The fruit is thereby enaliled to resist the extremes 

 of the climate, and will not suffer decay so rapidly as the 

 northern fruits, which are destined, by the regular course of 

 the seasons, to be destroyed by frost, before many weeks. 

 Another provision for the protection of tropical fruits and 

 foliage, is the essence contained in their outer case, rind or 

 covering. This aroma, being far more volatile than water, 

 evaporates rapidly from the surface, and keeps the fruit and 

 the substance of the leaf constantly cool, even when exposed 

 to the direct rays of the sun, in a hot and dry atmosphere, 

 without exhausting their juices. The pulp is thus preserved 

 in a moist state, until the seed is fully ripened ; and the foliage 

 is kept moist until it has performed its destined functions, by 

 the free evaporation of this volatile essence. Probably by 

 the operation of some chemical principle, the water, which is 

 used up in the elaboration of this essence, is small compared 

 with what would be consumed, were the cooling process car- 

 ried on by the direct evaporation of water from the surface 

 of the leaves and fruit. 



In northern climes, the plants are organized with reference 

 likewise to two opposite seasons, not of moisture and drought, 

 but of heat and cold. Summer and winter they have, instead 

 of a wet and a dry season. Hence, for the most part, the 

 trees are furnished with a deciduous foliage, and the herba- 

 ceous plants with leaves and stalks, that die down to the sur- 

 face of the soil, and continue their existence by means of 

 their roots. Some of these roots suffer their period of rest 

 chiefly in the latter summer and autumn, and vegetate in 

 winter below the action of frost, and produce their flowers in 

 early spring. Such are the hyacinth, the crocus, and the 

 snow-drop, and many other bulbous-rooted plants, whose 

 bulbs remain so deeply buried in the soil as to allow their 

 fibrous roots to push downwards below the frozen earth, and 

 to be in readiness to sustain the wants of the plant at the 

 very earliest thawing of the earth. The future plant being 

 preserved in an embryo state in the bulb, is able to endure 



