]^80 TRANSACTIONS OF THE ILLINOIS 



call fruits. In grain, grasses, trees, shrubs, and flowers, the variety of 

 seed vessels is incomparable. We have the seeds, as in the pea tribe, 

 regularly disposed in parchment pods which though soft and membran- 

 ous are impervious to water; at other times as in the bean, lined with 

 a fine dovvn ; we have seeds packed in wool, as in the cotton plant, lodged 

 between hard and compact scales, as in pine cones, protected by spines as 

 in the thistle, placed under a penthouse as in the mushroom ; in ferns, in 

 slits on the back of the leaves, or, as in grains and grasses, covered by 

 strong close tunicles attached to a stem according to an order appropri- 

 ated to each plant. 



In the above enumeration we first notice a unity of purpose under 

 a variety of expedients. Nothing can be more single than the design, 

 more diversified than the means. Follicles, shells, pulps, pods, husks, 

 skins, scales armed with thorns are all mechanically employed for the 

 same end. Secondly, we may observe that in all these cases the purpose 

 is fulfilled within a just and limited degree. We can perceive that if 

 the seeds of plants were more strongly guardeti than they are, their 

 greater security would interfere with other uses ; many species of animals 

 would perish if they could not obtain access to them. Here as in many 

 cases a balance is to be maintained between opposite uses. The provi- 

 sion for the preservation of seeds appears to be directed chiefly against 

 the inconstancy of the elements, and inclement seasons, the depredations 

 of animals, and the injuries of accidental violence seem to be provided 

 against by the abundance of the increase. 



When nature has perfected her seeds, her next care is to disperse 

 them. The seed cannot fulfill its ends while it remains in the capsule. 

 After the seed ripens, the pericarpiuni opens to let them out, which is 

 according to rule in each species of plant. Some are opened by the ac- 

 tion of the frost, some by elastic explosion, throwing the seed to a dis- 

 tance. Those of most composite flowers are endowed with downy 

 appendages, by which they float in the air, and are carried to great dis- 

 tances. We are compelled to omit to notice the store of nutriment laid 

 up in the seed for the nutriment of the young plant. A striking analogy 

 exists between seeds and eggs of animals ; the same point is provided 

 for in the same manner. The white, and that only is used in the form- 

 ation of the chicken. The volk, very little altered or diminished, is 

 wrapped uji in the abdomen of the young bird, to serve for its nourish- 

 ment till it has learned to pick its own food. We give the most common 

 as illustrations because of their being the most forcible. 



Our second observation on the mechanical structure of i)lants is 

 upon the general property of climbers. In these |)lants, from each joint, 

 issue close to each other two shoots, one bearing the flower and fruit, 

 and the other drawn out to a tapering si^iral tendril that attaches to 

 anything within its reach, considering that two purposes are to be pro- 

 vided for, the fruitage of the ])lant and the sustentation of the stalk. 

 No means could be more mechanical than this arrangement presents to the 

 eye. " We do not sec," says a noted author, " so much as one tree, shrub, 



