SEED. 
93 
103. General Remarhs upon Seeds. — The number of seeds in plants is variable ; 
some have but one ; some, like the umbelliferous plants, have two ; some havo 
four. The number varies from these to thousands, A stalk of Indian corn is said 
to have produced, in one season, twc thousand seeds ; a sunflower four thousand. 
A capsule of the poppy has been found to contain eight thousand seeds. It has 
been calculated tliat a single thistle- seed will produce, at the first crop, twenty- 
four thousand, and at the second crop, at this rate, five hundred and seventy-six 
milHons. In the same species of plants the number of seeds is often found to vary ; 
the apple and many other fruits might be given as examples. 
Seeds, according as thei/ vary in size, have been divided into four kinds : l:€'>'g€, 
from the size of a walnut to that of the cocoanut ; middle size, neither larger than a 
hazle-nut nor smaller than a millet-seed ; small, between the size of the seeds of a 
poppy and a bell-flower ; minute, like dust or powder, as in the ferns and mosses. 
When a pericarp separates itself from the parent plant, or when the valves open, 
the fruit has ceased to vegetate ; like tiie leaves at the end of autumn, it has lost its 
vital principle, and becomes subject to the laws which govern inorganized matter. 
The maturity of the seed marks the close of the life of annual plants, and the sus- 
pension of vegetation in woody and perennial ones. Nature, in fiivoring by various 
means the dispersion of these seeds, presents phenomena worthy of our admiration ; 
and these means are as varied as the species of seeds which are spread over the 
surface of the earth. 
a. The air, winds, rivers, seas, and animals, transport seeds, and disperse them in 
every direction. Those which are provided with feathery crowns, or egrets, as the 
dandelion and thistle, or with wings, as the maple and ash, are raised into the air, and 
even carried across the seas. Linnaeus asserted that the Ekigeron canadense was 
'introduced into Europe from America, by seeds wafted across the Atlantic Ocean. 
"The seeds," says he, " embark upon the rivers which descend from the highest 
mountains of Lapland, and arrive at the middle of the plains, and the coasts of the 
seas. The ocean throws, even upon the coasts of Norway, the nuts of the mahog- 
any and the fruit of the cocoanut-tree, which have been borne on its waves from the 
far-distant tropical regions ; and this wonderful voyage is performed without in- 
jury to the vital energy of the seeds." Some fruits, endowed with elasticity, 
throw their seeds to a considerable distance. In the oat, and in the greater num- 
ber of ferns, this elasticity is in the calyx. Tlie pericarp of the Impatiens'^ upon 
being touched, when the seeds are ripe, suddenly folds itself in a spiral form, and, 
by means of its elastic property, throws out its seeds. Animals perform their part 
in this economy of nature. Squirrels carry nuts into holes in the earth. The In- 
dians had a tradition, that these animals planted all the timber of the country. 
Animals contribute also to the distribution of seeds, by conveying them in their 
wool, fur, or feathers. Although distance, chains of mountains, rivers, and even 
seas, do not present obstacles sufiicient to prevent the dispersion of plants, climate 
forms an eternal barrier which they cannot pass. It is probable, that in future 
times the greater part of vegetable tribes which grow between the same parallels 
of latitude, may be common to the countries lying between them; this may be the 
result of the industry of man, aided by the efficient means which nature takes to 
promote the same object, in the dissemination of seeds ; but no human power can 
ever cause to grow within the polar circles the vegetables of the tropics, or those 
of the poles at the equator ; nature is here stronger than art. That much may be 
done to promote the growth of tropical plants in our climate is true, but how dif- 
ferent are they with us, from the same species in their own genial climate ! In 
New England the gardener may toil and watch for years to nurture an orange or 
lemon tree, which, after all, is stinted in its growth ; while in its own native home, 
the same plant would have grown spontaneously, in luxuriant beauty. 
b. The diffusion of seeds completes the circle of vegetation, and closes the scene of 
vegetable life. The shrubs and trees are despoiled of their foliage, the withered 
* The cultivated Impatiens is sometimes called Ladies^ -slipper, sometimes Balsamine. 
103. Number of the seeds variable — Size variable— Separation of the pericarp from the plant — What 
Is denoted by the maturity of the seed ? — a. Dispersion of seeds, hov*^ effected ? — Elasticity of soma 
iraits — Ajjency of animals — Etfect of climate upon the dispersion of plants — b. Circle of vegetation 
oompleted. 
