116 The Mechanical Structnie of 'I^lants. 



The Mechanical Structure of Plants. 



BY J. COCHRANE, HAVANA, ILL. 



ED. Western Horticulturist: — 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 diversified combinations of the 

 elements; the immensity, harmony and diversity of the solar system, would almost 

 lead us to believe that variety alone, distinct from every other consideration, was the 

 motive and aim in the mind of the Creator, or with the agents of His will. The dis- 

 secting-room, the microscope and the laboratory but partially reveals to us the arcana 

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

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

 views of the Deity, though we cannot_familiarize with the minor details in this depart- 

 ment of His works. 



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 perfected. This intention shows itself, in the 

 first place, by the care which seems to be taken to protect and ripen by every advan- 

 tage that can be given them by situation in. the plant, those parts which most imme- 

 diately contribute to fructification, viz.: the anthers, the stamina, the stigma. These 

 parts are usually lodged in the center, the recesses or the labyrinths of the flower dur- 

 ing their tender and immature state ; are shut up in the stalk or in the sheltering bud ; 

 but as soon as they have acquired 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 form 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 fall down, 

 according as this purpose renders either change of position necessary. In the growth 

 of grain, whenever the plant begins to shoot, the two upper leaves join together and 

 embrace the head, and protect it till the pulp has acquired a certain degree of con- 

 sistency. In some water plants the flowering and fecundation are carried on with 

 the stem, which afterward opens and loosens the impregnated seed. The pea tribe 

 incloses the parts of fructification within a beautiful folding of the internal blossom, 

 itself protected under a pent-house formed by the external petals. This structure is 

 very artificial, and it adds to the value of it, though it may diminish the curiosity ; 

 it is very general. It has 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 on which its seeds depend. It is an aptitude which 

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

 as much so as the folding of the fans of the windmill, or the cap on the top of a 

 chimney. The poppy and many similar flowers, the head, while it is growing, hangs 

 down, a rigid curvature in the upper part of the stem giving it that position, and in 



