j^78 TRANSACTIONS OF THE ILLINOIS 



THE MECHANICAL STRUCTURE OF PLANTS. 



BY J. COCHRANE, HAVANA, MASON COUNTY. 



The wonderful mechanism of the human eye, the arrangement and 

 construction of the ear, the number and diversified uses of the muscles, 

 the mechanical organisms of plants, the various combinations of the el- 

 ements, the immensity and harmony as well as the diversified arrangements 

 of the Solar System would almost lead us to believe that variety alone, 

 distinct from every other consideration was the motive in the mind of 

 the Creator or with the agents of His will. The dissecting-room, the 

 microscope, and the laboratory partially reveal to us the arcana of nature, 

 but the science of astronomy, beyond all others, displays to us the splen- 

 dor and magnificence of His operations. Through this the mind rises 

 to sublimer views of the Deitv, though we cannot familiarize ourselves 

 with the minor details in this department of His works as we may in the 

 one which I have chosen as my topic. 



There are a few observations on the vegetable kingdom that it will 

 be our aim to notice. One great object of nature in the structure of 

 plants is the perfecting of the seed, and its preservation until it be per- 

 fected. This intention shows itself, in the first place, by the care which 

 appears to be taken to protect and ripen, by every advantage which can 

 be given them by situation in the plant, those parts which most immedi- 

 ately contribute to fructification, viz : the anthers, the stamina, the stig- 

 mata. These parts are usually lodged in the center; the recesses, or the 

 labyrinths of the flower during their tender and immature state, are shut, 

 up in the stalk or are sheltered in the bud, but as soon as they have ac- 

 quired firmness of texture sufficient to bear exposure, and are ready to 

 perform the important office which is assigned them, they are disclosed 

 to the light and air by the bursting of the stem or the expansion of the 

 petals, after which they have, in many cases, — by the very tbrm of the 

 flower during its bloom, the light and warmth reflected on them from the 

 concave side of the cup. What is called also the sleep of plants is the 

 leaves or petals disposing themselves in such a manner as to shelter the 

 stem, buds, or fruit. They turn up or they fall down according as this 

 purpose renders either change of position necessary. In the growth of 

 corn, whenever the plant begins to shoot, the two upper leaves join to- 

 gether and embrace the ear and protect it till the pulp has acquired 

 a certain degree of consistency. In some water-plants the flowering and 

 fecundation are carried on with the stem, which afterwards opens to let 

 loose the impregnated seed. The pea tribe enclose the parts of fructi- 

 fication within a beautiful folding of the internal blossom, itself protected 

 under a penthouse, formed by the external petals. 



This structure is very artificial, and adds to the value of it, though 

 it may diminish the curiosity, as it is very general. It has also this 

 further advantage which is strictly mechanical, that all the blossoms turn 

 their backs to the wind whenever it blows strong enough to endanger 

 the delicate parts upon which the seed depends. It is an aptitude which 

 results from the figure of the flower, and as before remarked, strictly 



