PLANTING. 15 



from hot sunshine is highly beneficial to them, indeed, indispensable in 

 some states of the weather, for the thin covering 1 of soil which is neces- 

 sarily allowed them is soon affected by the action of the sun's rays, and 

 sudden drought quickly destroys the tender seedlings. The thickness in 

 which the seeds should be sown, according to the respective kinds, is on 

 an average from three to four on a square inch, so that the plants when 

 produced stand not nearer to each other than that scale of distances. 



The artificial fine state of culture of the soil in the seed beds, rendering 

 it less retentive of the due degree of moisture than is required, the beds 

 should be consolidated before and after the seeds are sown, either by the 

 use of a roller, or by the spade. 



In concluding this practical view of the structure of forest trees, and of 

 those natural agents, which obviously influence the growth of plants, it may 

 be useful to take a similar view of the process of vegetation. A perfect 

 and healthy seed consists of an outer covering, cotyledons, radicle, and 

 plumula. When sown in perfectly dry earth, it remains unchanged ; if in 

 an excess of moisture, it loses its vegetative powers and decays : in neither 

 case it vegetates. When the temperature of the soil is below a certain point, 

 all vegetation is suspended. Should the soil and the temperature be per- 

 fectly favourable to vegetation, yet if the seed be not planted shallow 

 enough to be within the influence of atmospherical air, no vegetation takes 

 place. Different species of seeds require different degrees of moisture, 

 temperature, and atmospheric influence, to render their vegetation the most 

 healthy and perfect. The natural constitution of different soils, as regards 

 their respective properties of retaining or easily parting with moisture ; the 

 proper season of sowing, as regards the temperature of the soil and the 

 atmosphere, by whatever local causes subject to be influenced; and the re- 

 spective depths to which the seeds should be deposited in the ground, as 

 above mentioned, apply directly to the skill of the cultivator to aid, modify, 

 and assist these primary essential agents of vegetation ; and on the right 

 adjustment of these depend the success and just reward of the planter in 

 this first stage of the process of his art. 



In whatever position the seed is placed, the radicle first bursts the cover- 

 ing, and takes a downward direction into the soil, where it becomes fixed, 

 and protrudes, at right angles from its sides, numerous rootlets, which in 

 their turn emit others ; then, and not till then, the cotyledons rise above the 

 surface and expand, shewing the plumula or bud of the stem, which now 

 advances in growth and unfolds the proper leaves. After the leaves are 

 fully expanded, the communication of the pith with the buds, formed or 

 forming, at the base of each leaf-stalk in the angle made by that and the 

 stem, may be traced. The loss of either of thesse organs of the seed at an 

 earlier period would have prevented farther growth ; for if the cotyledons 

 had been seriously injured or taken away, the radicle and plumula would 

 have died; if the radicle had been removed, the same effect would have 

 followed; or if the plumula had been taken away, the plant would have 

 made no farther progress. But as soon as the formation of the germ of 

 buds is effected, as now stated, the cotyledons may be removed ; the sum- 

 mit of the stem and the lower extremity of the radicle may be taken away, 

 and the plant will reproduce others, It is during the previous stage of 

 growth that the attacks of insects prove so fatal to seedling plants, and re- 

 quire the utmost care of the planter; and hence also the greater care and 

 attention that is demanded in the preparation of the soil for seeds than 

 for the reception of transplanted trees. This also points out the danger 

 of injury to the vegetating seeds, by disturbing the seed beds before the 



