TENDENCY OF PLANTS TO REPRODUCE THEMSELVES. 
40*7 
We have been led to make these remarks from observing (the first 
time in our life) in the Chelsea Botanical Garden, ten days ago (Nov. 
2nd), the flowers of the Jerusalem artichoke (Helianthus tuber'osas') 
nearly expanded. This is a circumstance which but rarely occurs in 
this country, owing, no doubt, to these plants being cultivated in rich 
soil, which induces the production of tubers rather than flowers. 
But this last summer has been remarkable for its great heat and long 
continued drought, and consequently, the soil being exhausted of that 
degree of moisture necessary to the production of tubers, an extraordi¬ 
nary effort has been made by the plants to reproduce themselves by 
seeds; and which is quite conformable to the general law of vegetable 
development, as instanced in other similar cases. 
The ingenious T. A. Knight, Esq., P. H. Society, has founded a 
rule in practice on this very circumstance, as applicable to the potato. 
The greater number of the varieties of this useful plant reproduce 
themselves by both seeds and tubers at the same time. But it forcibly 
struck the inquiring mind of that gentleman that no plant can produce 
both in such quantity or perfection as one of them only. And he also 
knew that, by defructifying the top, additional energy would be given 
to the underground offspring. This was sound philosophy; and the 
results of manifold trials have been to confirm his doctrine. 
On the same principle other practical expedients are based. Both 
Dutch and other florists not only prevent their breeding bulbs from 
flowering, but mutilate by cutting off the upper half of their most 
valuable bulbs, to cause an extra ejection of offsets. And our own 
exotic plant growers find it difficult to propagate some of the choice 
African bulbs without having recourse to the same manoeuvre. 
There are several other plants which show this property of reproduc¬ 
tion by other than the ordinary modes. Wheat, which is either an 
annual or biennial, according to the time of the year at which it is sown, 
will, if repeatedly eaten or cut down, continue to produce side shoots, 
and ripen seed in the third year. The strawberry, if divested of its 
first flowers, will produce others, and yield fruit in the autumn. A 
filbert tree, surrounded by a great number of suckers, seldom bears 
many nuts. Horse-radish, whose growth is chiefly towards enlarging 
the root, seldom flowers or bears seed ; and many other similar instances 
may be adduced. 
The knowledge of this power or faculty of plants is necessary to the 
practitioner, whether in gardening or farming. The first, by directing 
the vigour to the useful members of the plant, may have them in greater 
perfection ; and the second, by mowing his thin crops of grass early in 
the season, will much sooner obtain a thicker sward. 
