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that is, downy appendages, by which they are enabled to float in the air, and are carried oftentimes by the wind to great distances from the plant which produces them. is the swelling also of this downy tuft within the seed-vessel, that seems to overcome the resistance of its coats, and to open a passage for the seed to escape.

But the constitution of seeds is still more admirable than either their preservation or their dispersion. In the body of the seed of every species of plant, or nearly of every one, provision is made for two grand purposes; first, for the safety of the germ; secondly, for the temporary support of the future plant. The sprout, as folded up in the seed, is delicate and brittle beyond any other substance. It cannot be touched without being broken. Yet, in beans, peas, grass-seeds, grain, fruits, it is so fenced on all sides, so shut up and protected, that, whilst the seed itself is rudely handled, tossed into sacks, shovelled into heaps, the sacred particle, the miniature plant, remains unhurt. It is wonderful also, how long many kinds of seeds, by the help of their integuments, and perhaps of their oils, stand out against decay. A grain of mustard seed has been known to lie in the earth for a hundred years; and, as soon as it hath acquired a favorable situation, to shoot as vigorously as if just gathered from the plant. Then, as to the second point, the temporary support of the future plant, the matter stands thus. In grain, and pulse, and kernels, and pippins, the germ composes a very small part of the seed. The rest consists of a nutritious substance, from which the sprout draws its aliment for some considerable time after it is put forth; viz. until the fibres, shot out from the other end of the seed, are able to imbibe juices from the earth, in a sufficient quantity for its demand. It is owing to this constitution, that we see seeds sprout, and the sprouts make a considerable progress without any earth at all. It is an economy also, in which we remark a close analogy between the seeds of plants, and the eggs of animals. The same point is provided for, in the same manner, in both. In the egg, the residence of the living principle, the cicatrix, forms a very minute part of the contents. The white, and the white only, is expended in the formation of the chicken. The yolk, very little altered, or diminished, is wrapped up in the abdomen of the young bird when it quits the shell, and serves for its nourishment, till it have learned to pick its own food. This perfectly resembles the first nutrition of a plant. In the plant, as well as in the animal, the structure has every character of contrivance

belonging to : in both, it breaks the transition from prepared to unprepared aliment; in both, it is prospective and compensatory. In animals which suck, this intermediate nourishment is supplied by a different source

In all subjects, the most common observations are the best, when it is their truth and strength which have made them common. There are, of this sort, two concerning plants, which it falls within our plan to notice. The first relates to what has already been touched upon, their germination. When a grain of corn is cast into the ground, this is the change which takes place. From one end of the grain issues a green sprout; from the other, a number of white fibrous threads. [Pl. XXXIV. fig. 5.] How can this be explained? Why not sprouts from both ends? Why not fibrous threads from both ends? To what is the difference to be referred, but to design; to the different uses which the parts are thereafter to serve; uses which discover themselves in the sequel of the process? The sprout, or plumule, struggles into the air; and becomes the plant, of which, from the first, it contained the rudiments: the fibres shoot into the earth; and thereby both fix the plant to the ground, and collect nourishment from the soil for its support. Now, what is not a little remarkable, the parts

*The seed, the last production of vigorous vegetation, is wonder fully diversified in form. Being of the highest importance to the resources of nature, it is defended above all other parts of the plant, by soft, pulpy substances, as in the esculent fruits, 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, first, the organ of nourishment; secondly, the nascent plant, or the plume; thirdly, the nascent root, or the radicle.

"In the common garden bean, the organ of nourishment 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 single part, and these plants are called monocotyledonous. In other cases it consists of more than two parts, when the plants are called polyeotyledonous. In the greater number 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 exhibits neither the forms nor the functions of life. But let it be acted upon by moisture, heat, and air, and its organized powers are soon distinly developed. 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 dicotyledonous plants become vascular, and are con verted into seed leaves, and the perfect plant appears above the soil

If

issuing from the seed take their respective directions, into whatever position the seed itself happens to be cast. the seed be thrown into the wrongest possible position, that is, if the ends point in the ground the reverse of what they ought to do, everything, nevertheless, goes on right. The sprout, after being pushed down a little way, makes a bend, and turns upwards: the fibres, on the contrary, after shooting at first upwards, turn down. Of this extraordinary vegetable fact, an account has lately been attempted to be given: "The plumule, (it is said,) is stimulated by the air into action, and elongates itself when it is thus most excited; the radicle is stimulated by moisture, and elongates itself when it is thus most excited. Whence one of these grows upward in quest of its adapted object, and the other downward."* Were this account better verified by experiment† than it is, it only shifts the con

Nature has provided the elements of germination on every part of the surface; 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.' Sir H. Davy's Elements of Agricultural Chemistry,

i. ed. p. 70.-Paxton.

*Darwin's Phytologia, p. 144.

+"Gravitation has a very important influence on the growth of plants; and it is rendered probable, by the experiments of Mr. Knight, that they owe the peculiar direction of their roots and branches almost enurely to its force.

"That gentleman fixed some seeds of the garden bean on the circumference of a wheel, which in one instance was placed vertically, and in the other horizontally, and made to revolve, by means of another wheel worked by water, in uch a manner, that the number of the revolutions could be regulated; the beans were supplied with moisture, and were placed under circumstances favorable to germination. The great velocity of motion given to the wheel was such, that it performed 250 revolutions in a minute. It was found that in all cases the beans grew, and that the direction of the roots and stems was influenced by the motion of the wheel. When the centrifugal force was made superior to the force of gravitation, which was supposed to be done when the vertical wheel performed 150 revolutions in a minute, all the radicles, in whatever way they were protruded from the position of the seeds, turned their points outwards from the circumference of the wheel, and in their subsequent growth receded nearly at right angles from its axis; the germens (plumules) on the contrary, k the opposite direction, and in a few days their points all met in the ce e of the wheel.

"When the centrifugat force was made merely to modify the force of gravitation in the horizontal wheel, where the greatest velocity of revolution was given, the radicles pointed downwards about ten degrees below, and the germens (plumules) as many degrees above the horizontal line of the wheel's motion; and the deviation from the perpendicular was less in proportion, as the motion was less rapid.

"These facts afford a rational solution of this curious problem, respect

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trivance. It does not disprove the contrivance; it only removes it a little farther back. Who, to use our author': own language, "adapted the objects?" Who gave such. a quality to these connate parts, as to be susceptible of dif ferent stimulation;" as to be " excited" each only by its own element, and precisely by that which the success of the vegetation requires? I say, "which the success of the vegetation requires:" for the toil of the husbandman would have been in vain; his laborious and expensive preparation of the ground in vain; if the event must, after all, depend upon the position in which the scattered seed was sown Not one seed out of a hundred would fall in a right di rection.

Our second observation is upon a general property of climbing plants, which is strictly mechanical. In these plants, from each knot or joint, or as botanists call it, axilla, of the plant, issue, close to each other, two shoots; one bearing the flower and fruit; the other, drawn out into a wire, a long, tapering, spiral tendril, that twists itself round anything which lies within its reach. Considering, that in this class two purposes are to be provided for, (and together,) fructification and support, the fruitage of the plant, and the sustentation of the stalk, what means could be used more effectual, or, as I have said, more mechanical, than what this structure presents to our eyes? Why, or how, without a view to this double purpose, do two shoots, of such different and appropriate forms, spring from the same joint, from contiguous points of the same stalk? It never happens thus in robust plants, or in trees. "We see not, (says Ray,) so much as one tree, or shrub, or herb, that hath a firm and strong stem, and that is able to mount up and stand alone without assistance, furnished with these tendrils." Make only so simple a comparison

ing which, different philosophers have given such different opinions; some referring it to the nature of the sap, as De la Hire, others as Darwin, to the living powers of the plant, and the stimulus of air upon the leaves, and of moisture upon the roots. The effect is now shown to be connected with mechanical causes; and there seems no other power in nature to which it can with propriety be referred but gravity, which acts universally, and which must tend to dispose.the parts to take a uniform direction. "The direction of the radicles and germens (plumules) is such, that both are supplied with food, and acted upon by those external agents wnich are necessary for their developement and growth. The roots come in contact with the fluids in the ground; the leaves are exposed to light and air; and the same grand law which preserves the planets in their or bits is thus essential to the functions of vegetable life.”—Davy's El. Agr. Chem. ii. Ed. p. 32.—Paxton.

as that between a pea and a bean. Why does the pea pu. forth tendrils, the bean not; but because the stalk of the pea cannot support itself, the stalk of the bean can? We may add also, as a circumstance not to be overlooked, that in the pea tribe these clasps do not make their appearance till they are wanted; till the plant has grown to a height to stand in need of support.

This word "support" suggests to us a reflection upon the property of grasses, of corn, and canes. The hollow stems of these classes of plants are set, at certain intervals, with joints. These joints are not found in the trunks of trees, or in the solid stalks of plants. There may be other uses of these joints; but the fact is, and it appears to be at least one purpose designed by them, that they corroborate the stem; which, by its length and hollowness, would otherwise be too liable to break or bend.

Grasses are Nature's care. With these she clothes the earth; with these she sustains its inhabitants. Cattle feed upon their leaves; birds upon their smaller seeds; men upon the larger: for few readers need be told, that the plants which produce our bread-corn belong to this class. In those tribes, which are more generally considered as grasses, their extraordinary means and powers of preserva tion and increase, their hardness, their almost unconquerable disposition to spread, their faculties of reviviscence, coincide with the intention of nature concerning them. They thrive under a treatment by which other plants are de stroyed. The more their leaves are consumed, the more their roots increase. The more they are trampled upon, the thicker they grow. Many of the seemingly dry and dead leaves of grasses revive, and renew their verdure, in the spring. In lofty mountains, where the summer heats are not sufficient to ripen the seeds, grasses abound, which are viviparous, and consequently able to propagate themselves without seed. It is an observation, likewise, which has often been made, that herbivorous animals attach themselves to the leaves of grasses; and, if at liberty in their pastures to range and choose, leave untouched the straws which support the flowers.*

The GENERAL properties of yegetable nature, or properties common to large portions of that kingdom, are almost all which the compass of our argument allows to bring forward. It is impossible to follow plants into their several species. We may be allowed, however, to single out three

With. Bot. Arr. vol. i. n. 28. ed. 2d.

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