i83Dj 



FARMERS' REGISTER. 



329 



organs is some multiple ofevery other, that the bo- 

 tanist in determining the Linn^ean class to vvhicli 

 any small flower belonjis, olien counts the petals, 

 and not the stamens. 3rcl, That the several organs 

 of Iruclification are severally convertible into leaves; 

 and vice versa, that leaves are convertible into the 

 several organs of fructification. Of the truth ol 

 this conclusion, proof has been already given. 

 The circumstance on which the convert^ion of 

 a ie'af-bud into a flower, and thus into iiuit, 

 seems mainly to depend, is the accumulation of a 

 larire quantity of nutritious matter in the part to 

 which the bud is attached. The elaboiaiion of 

 this nulritioup matter, as has been already men- 

 tioned, is performed by the leaves. Hence it is, 

 that a hyacinth, if deprived of its leaves one year, 

 will not blossom the next ; but if its leaves are so 

 fully exposed to the light and air that they go 

 throiiLrh their growth in uninterrupted health, and 

 if at the same time, the flowers of the first year are 

 removed, the bulb will hlo.ssom more finely than 

 ever the second year; fi)r, in this case, not only is 

 a sufficient quantity secreted by the leaves, but 

 the Slock prepared for the previous year remains 

 unexhausted, in consequence of the flowers, 

 which would have consumed it, having been des- 

 troyed. After a hoi and briirhl summer, when 

 the leaves have been in uninterrupted action, and 

 a great quantity of solid matter has been deposited 

 in the stem, an abundant quantit}^ of blossoms in- 

 variably results ; while the reverse takes place 

 after cold and gloopiy summers, when the shoots 

 produced are weak and watery. If a tree is 

 barren, its branches may be rendered fertile, by 

 depriving them of a ring of bark, near the point at 

 which the}' are inserted into the stem ; this inter- 

 rupts the backward flow of the elafioraled sap 

 causes nutritious matter to accumulate above the 

 place where the bark is removed, and thus brings 

 on the Ibrmation of flowers. An apple tree when 

 raised from seed, and left to itself, will not flower 

 in less than 7 or 8 years. But if a tree one year 

 old, be cut off and grafted upon an old bearina: tree 

 which is able to supply it with a lame quantify of 

 nutritious matter, it will bear thesecond year after 

 it is gralted ; so that in this way, in three years a 

 plant may be made to bear, which under ordinary 

 cir.'umstancesj would not flower in less than seven 

 or eight. 



While the previous accumulation of nutritive 

 matter in the part to .which a bud is attached, 

 seems favorable to its conversion into a flower, 

 and thus into fruit, the abundant supply of nour- 

 ishment through the roots, at the time when 

 the bud is opening, seems uniavorable. This 

 is illustrated by the fact, thai in wet and warm 

 sjirings, a great number of the blossom-buds 

 of pears and apples are converted into leaves 

 and branches. We account for this, by sup- 

 posing that the excessively rapid developement 

 which they undergo, breaks up the whorls of their 

 flowers, and by throwing an excessive quantity of 

 sap into the organs destined lor flowering, converts 

 them into leaves. 



Such is the commonly received theory respecting 

 the origin of the ilowc^r, and such the liicis by i 

 which it is supported. Whether we adopt this! 

 theory or not, this much seems certain; that a 

 leat'-bud, soon after its ibrmation, may be convert- 1 

 ed into a flower, then into fruit ; and also, that a 

 flower-bud, in the early stages of its growth, may I 

 Vol. VII— 42 



be converted into a branch and leaves. This is a 

 fact of great importance to these engaged in fruit- 

 culture, and European gardeners have long availed 

 themselves of the advantages which nature thus af- 

 fords. It is much to be desired, that we had a series 

 of accurate experiments, perlbrmed lor the purpose 

 of ascertaining all the circumstances which affect 

 these metamorphoses. That which is known, I 

 have attempted to give in the present chapter; but 

 it must be conliissed, that it is too uncertain to be 

 entirely satisfactory. 



Chap. XIII. 



SJfcED. THEIR STRUCTURE. MEANS OF DISPER- 

 SION. PROPAGATION OP CR YPTOGAMOUS 

 PLANTS, EFFECTED BY 3IEANS OF SPORES. 



The structure of the seed is very simple. In its 

 most perleci form, it consists of an external coat, 

 generally thick and hard, surrounding a cellular 

 mass in which the rudiments of a new plant lie 

 imbedded. The office of the external coat or skin 

 is evidently that of protecting the more important 

 and delicate parts within it. To this, its thick and 

 hard structure is admirably adapted. In some 

 seeds, this skin, or shell as it is more commonly 

 called, is perli?ctly smooth, as in the acorn ; in 

 others, it is irregularly furrowed, as in the peach 

 stone; in others, it is cross-banded, so as to 

 resemble net-work, as in the seed of the prickly 

 poppy. The marking of the surliace of seeds is 

 greatly diversified in different species, often ren- 

 dering the minuter kinds beautilul objects of 

 microscopic observation. When a seed germi- 

 nates, the younir [)lant has to burst through thi.s 

 shell, and in every instance, we find provision 

 made for this, in the formation of the seed. Where 

 the shell is very hard, it is always composed of 

 two distinct and separable valves, as in the stones 

 of the peach and cherry. The means by which 

 the shell is broken, is the absorption of water by 

 the cellular tissue of the kernel, through a small 

 opening left in the shell itself The force with 

 which cellular vegetable matter expands, during 

 its absorption of \\*ater, is almost irresistable. The 

 common method adopted in France, of splitting 

 out mill-stones from the quarry, may be men- 

 tioned as an example. The method is this : holes 

 are bored arounii the piece intended to be split out ; 

 into these wooden plucs are tightly driven, and 

 things being thus arranged, water is poured upon 

 these pliio-s. The cellular tissue of the wood 

 absorbs this water, and with snch irresistable force 

 does it expand, as invariably to split out the piece 

 of rock intended. On the shell of many seeds we 

 notice a scar, left by the separation of the seed 

 from its funicle, or the vessel which originally 

 connected it with the parent plant, and through 

 which it received its nourishment. This is termed 

 the hylum, or more comnionly the eye. It is very 

 conspicuous in peas and beans, in which it has a 

 different color from the remainder of the surface 

 of the seed. 



Next to this outer skin or shell, lies the albumen 

 consisting of a mass ol cellular tissue, filled with 

 nutritious matter. This is intended for the nour- 

 ishment of the younff plant, before its roots are 

 sufRrientl}- developed to enable it to gain nour^ 

 ishment immediately from the soil. The albumen 

 is fi-equently divided into two or more separate 



