1838] 



FARMERS' REGISTER. 



595 



the trees alwaj's become slag-headed and un- 

 healthy. 



The leaves are necessary for the existence of the 

 individual tree ; the ftmuers for the continuance of 

 the species. Of all the parts of plants they are 

 the most refined, the most heautiful in their struc- 

 ture, and appear as the master-work of nature in 

 the vegetable kinjidom. The elenjance of their 

 tints, the variety of their tbrnis, the delicacy of 

 their oriranization. and the adaptation of their parts, 



ever, was the first person who attempted to gene- 

 ralize upon them, and much just reasoning on the 

 subject may be /inmd in his works. Linn;eus gave 

 a scientific and distinct form to tliat whicii Grew 

 had only generally observed, and has the glory of 

 establisiiing what lias been called the sexual sys- 

 tem, upon the basis of minute observations and 

 ac.'iirate experiments. 



The seed, the last production of vigorous vege- 

 tation, is wonderlLilly diversified in form. Bemg 



are all calculated to awaken our curiosity, and ex- ol the highest importance to the resources of na- 

 cite our admiration. 



In the flower there are to be observed, 1st, the 

 ^alyx, or <rreen membranous part forming the sup- 

 port for the colored floral leaves. This is vascular, 

 'and agrees with the common leafin its texture 

 <md orjianizalion ; it defends, supports, and nour- 

 ishes the more perfect parts. 2d, The corolla, 

 which consists cither of a single piece, when it is 

 called monopetalous ; or of many pieces, when it 

 is called polypetalous. It is usually very vivid in 

 in its colors, is filled with an almost infinite variety 

 of small tubes of the porous kind ; it incloses and 

 defends tlie essential parts in the interior, and sup- 

 plies the juices of the sap to them. These parts 

 are, 3d, the stamens and the pistils. 



The essential part of the stamens are the sum- 

 mits nr anthers, which are usually circular and of 

 a highly vascular texture, and covered with a fine 

 dust called the pollen. 



The pistil is cylindrical, and surmounted by the 

 style; the top of whicii is generally round and 

 protuberant.* 



In the pistil, when it is examined by the micro- 

 scope, congeries of spherical forms may usually 

 be perceived, which seem to be the bases of the 

 iuture seeds. 



It is upon the arrangement of the stamens and 

 the pistils that the Linnaean classification is found- 

 ed. The numbers of the stamens and pistils in 

 the same flower, their arrangements, or their divi- 

 sion in difl^erent flowers, are the circumstances 

 which guided the Swedish philosopher, and ena- 

 bled him to form a system admirably adapted to 

 assist the memory, and render botany of easy ac- 

 quisition ; and which, though it does not always 

 associate together the plants most analogous to 

 each other in their general characters, is yet so in- 

 geniously contrived as to denote all the analo- 

 gies of their most essential parts. 



The pistil is the organ which contains the rudi- 

 ments of the seed ; but the seed is never formed 

 as a reproductive germ, without the influence of 

 the pollen, or dust on the anthers. 



This mysterious impression is necessary to the 

 continued succession of the difli'erent vegetable 

 tribes. It is a feature which extends the resem- 

 blances of the different orders of beings, and esta- 

 blishes, on a great scale, the beautiful analogy of 

 nature. 



The ancients had observed that different date 

 tree« bore diffisrent flowers, and that those trees 

 producing flowers which contained pistils bore no 

 fruir, unless in the immediate vicinity of such trees 

 as produced flowers containing stamens. This 

 long-established fiict strongly impressed the mind 

 of Malpighi, who ascertained several analosous 

 facts with regard to other vegetables. Grew, how- 



• Fig. 12. represents the common lily^ a the corolla, 

 bbbbh the anthers, f the pistil. 



ture, it is defended above all other parts of the 

 plant ; by soft pulpy substances, as in the esculent 

 li-iiits; by thick membranes, as in the leguminous 

 vegetables; and by hard shells, or a thick epidermis, 

 as in the palms and grasses. 



In every seed there is to be distinguished, 1. the 

 orf^aa of nourishment ; 2. the nascent plant, or the 

 plume ; 3. the nascent roof, or the radicle. 



fn the common garden bean, the organ of nou- 

 rishment is divided into two lobes called cotyledons ; 

 the plume is the small white point between the 

 upper part of the lobes; and the radicle is the 

 small curved cone at their base.* 



In wheat, and in many of the grasses, the organ 

 of nourishment is a sintfle part, and these plants 

 are called monocotyledonous. In other cases it 

 consists of more than two parts, when the plants 

 are ca\\ei\ polycotykdonous. In the greater num- 

 ber of instances, it is, however, simply divided 

 into two, and is dicotyledonous. 



The matter of the seed, when examined in its 

 common state, appears dead and inert: it ex- 

 hibits neither the forms nor the functions of life. 

 But let it be acted upon by moisture, heat, and air, 

 and its ortjanized powers are soon distinctly deve- 

 loped. The cotyledons expand, the membranes 

 burst, the radicle acquires new matter, descends into 

 the soil, and the plume rises towards the free air. 

 By degrees the organs of nourishment of dicoty- 

 ledonous plants become vascular, and are convert- 

 ed into seed leaves, and the perfect plant appears 

 above the soil. Nature has provided the ele- 

 ments of germination on every part of the sur- 

 face, water and pure air and heat are universally 

 active, and the means for the preservation and 

 multiplication of life are at once simple and grand. 



To enter into more minute details on the vege- 

 table physiology would be incompatible with the 

 objects of these lectures. I have attempted only 

 to give such general ideas on the subject as may 

 enable the philosophical agriculturist to under- 

 stand the functions of plants ; those who wish to 

 study the anatomy of vegetables, as a distinct 

 science, will find abundant materials in the works 

 of the authors I have quoted, and likewise in 

 the writings of Linnaeus, Desfontaines, De Can- 

 dolle, De Saussure, Bonnet, and Smith. 



The history of the peculiarities of structure in 

 the different vegetable classes rather belonirs to 

 botanical than agricultural knowlodire. As I men- 

 tioned in the commencement of this lecture, their 

 organs are possessed of the most distinct analogies, 

 and are governed by the same laws. In the grasses 

 and palms, the cortical layers are larger in propor- 

 tion than the other parts; but their uses seem to 

 be the same as in forest trees. 

 In bulbous roots, the alburnous substance forms 



'Fio;. 13. represents the garden bean; an the co- 

 tyledons, b the plume, c the radicle. 



