5S2 



FARMERS' REGISTER. 



[No. 10 



heads o( Root (ii); Stem (iii); Leaf-buds (iv); 

 Leaves (v); Flowers (vi) ; Sexes (vii); Fruit 

 (viii); and Seed (ix). 



II. Root. 



26. The root is flie prirt Hint ptnkes into the 

 earth when a seed beirins^ lo (jeniiinaie, ami vvhi. h 

 al'tervvanls cnnlinues to leiisMieii beneath tlie soil. 



27. It ig also the i)art whu-h is sometimes emit- 

 ted by tiie stem, lor the purpose o( ahsorbinif nu- 

 triment from the utmosph.ere; as in I vy, Air-[)lants, 

 Vines, &('. 



28. It is distinjui^iied Irom the stem by .he ab- 

 Fence of leaves in any slate, of reyuiar leaf-buds 

 (iv.); of evaporatinir pores (or siomataj (131); 

 and of pith in Exoirenoiis plants. 



29. Therelore, such underixround bodies as those 

 called Tuber (16) in the Potato Bulb ; (96.) in the 

 Onion; and solid Bulb orCormus (61.) in the Cro- 

 cus, are not roots. 



30. The office of the root is to absorb food in a 

 fluiil or gaseous state; and also to fix the plant in 

 the soil, or to some firm support. 



31. The latter offii'.e is essential to the certain 

 and regular perlbrmance of the Ibrmer. 



32. It is not by the whole of their surface that 

 roots absorb food; but only by their young and 

 newly firmed extremities, called Spongioles. 



33. Hence the preservation of the spongioles in 

 an uninjured state is essential to the removal of a 

 plant from one place to another. 



34. A Spongiole consists of very young vascu- 

 lar tissue (12.) surrounded by very young cellular 

 substance. (5.) 



35. It is therefore one of the most delicate parts 

 of plants, and the most easily injured, 



36. Hence whatever is known to produce any 

 specific deleterious action upon leaves or stems, 

 such as certain gases (298.) and mineral or vetje- 

 table poisons, will produce a much more fatal ef- 

 fect upon the spongioles. 



37. These organs have no power of selecting 

 their food, but will absorb whatever the earth or 

 air may contain, which is sufficiently fluid to pass 

 through the sides of their tissue. 



38. So that if the spongioles are developed in 

 a medium which is of an unsuitable nature, as 

 they will still continue to absorb, they cannot fail 

 to introduce matter which will prove either injuri- 

 ous or fiital 10 life, accordinsrto its intensity. 



33. This may often explain why trees suddenly 

 become unliealthy, without any external apparent 

 cause. 



40. Plants have the power of replacing spon- 

 gioles by the formation of new ones; so that an in- 

 dividual is not destroyed by their loss. 



41. But this power depends upon the co-opera- 

 tion of the atmosphere, and upon the special vital 

 powers of the species. 



42. If the atmosphere is so humid as to hinder 

 evaporation, spongioles will have time to form 

 anew; but if the atmosphere is dry, the loss by 

 evaporation will be so much greater than can be 

 supplied by the injured roots, that the whole sys- 

 tem will be emptied of fluid belbre the new spon- 

 gioles can form. 



43. This is the key to transplantation, (xv.) 



44. As roots are destitute of leaf-buds (vij, 

 and as leaf-buds are essential to the multiplication 

 of an individual (108.), it should follow that roots 



can never be employed tor the purpose of multi- 

 cation. • 



45. Nevertheless, roots, when woody, have, oc- 

 casionally, the power of generating adventitious 

 leaf-buds (iv.) ; and when this is the case, they 

 may be employed fir the purpose of multiplica- 

 tion; as those of Cydonia. Japonica, &c. 



46. The cause of this power existing in some 

 species, and not in others, is unknown. 



47. It is therefore a power than can never be 

 calculated upon; and whose existence is only to 

 betliscnvered by accident. 



48. Although roots are ireneraled underground, 

 and sometimes at considerable depths, yet access 

 to a certain quantity of atmospheric air appears 

 indispensable to the healthy execution of their 

 functions. This is constantly exemplified in plants 

 irrowing in the earth at the back of an ill-venti- 

 lated forcing house, where the roots have no means 

 of finding their way into the earth on the outside 

 of the house. 



49. It is supposed by some, that the introduction 

 of oxygen into their system is as indispensable to 

 them as lo animals. 



50. It seems more probable that the oxygen of 

 the atmosphere, seizing upon a certain quantity of 

 carbon, forms carbonic acid, which they absorb, 

 and feed upon. 



51. It is at least certain that the exclusion of air 

 from the roots will always induce an unhealthy 

 condition, or even death itself This may be one 

 of the reasons why stift' tenacious soils are so sel- 

 dom suited to the purposes of the cultivator, until 

 their adhesiveness has been destroyed by the ad- 

 dition of other matter. 



52. Spongioles secrete excrementitious matter 

 which is unsuitable to the san.e species alter- 

 wards as food; for poisonous substances are as 

 fatal to the species that secrete them, as to any 

 other species. 



53. But to other species the excrementitious 

 matter is either not unsuitable, or not deleterious. 



54. Hence, soil may be rendered impure (or as 

 we inaccurately say, worn out,) for one species, 

 which will not be impure lor others. 



55. This is the true key of the theory of rota- 

 tion of crops. 



56. This also may serve to explain in part why 

 light soil IS indispensible to so many plants, and 

 heavy or tenacious soil suitable !o so few, for in 

 the former case the spongioles will meet with lit- 

 tle resistence to their elongation, and will conse- 

 quently be continually quitting the place when 

 their excrementitious matter is deposited; while in 

 the latter case, the reverse will occur. 



III. Stem. 



57. The stem is that part of a plant, which i> 

 developed above-ground, and which took an up- 

 ward direction at the period of gemination. 



58. It consists of a woody axis, covered by bark 

 having stomata (131.) on its surface, bearing 

 leaves wiih leal-buds, in their axillae, and pradu- 

 cinir flovvers and fruit. 



59. The points where leaves are borne are call- 

 ed Nodi J the spaces between the leaves are Ih- 

 ternodta. 



60. The more erect a stem grows, the more vig- 

 orous it is; and the more it deviates from this di- 

 rection to a horizontal or pendulous position, the 

 less is it vigorous. 



