there is a species of bamboo which forms forests in the marshes of many
leagues in extent, and yet Mutis, who botanized for nearly twenty
years in the parts where it grows, was never able to detect the
fructifications."--_Humboldt_.

The produce of vegetable seeds in a hundred-fold degree is common, and
many trees and shrubs bring forth their fruit by thousands. A single plant
of the poppy will produce above 30,000 seeds; and, of tobacco, above
40,000; and Buffon remarks, that from the seeds of a single elm-tree, one
hundred thousand young elms may be raised from the product of one year.
Some ferns, it is said, produce their seeds by millions.

_Why should seeds be uniformly kept dry before sown?_

Because the least damp will cause an attempt at vegetation, when the seeds
necessarily die, as the process cannot, as they are situated, go on.

_Why, in summer, is continued watering required to newly sown seeds?_

Because, if the soil is only moistened at the time of sowing, it induces
the projection of the radicle, or first root, which, in very parching
weather, and in clayey cutting soil, withers away, and the crop is
consequently lost, for want of a continued supply of moisture.

_Why is selection important for procuring abundance of genuine seeds?_

Because we may then choose the most vigorous plants, which naturally prove
of greater fecundity. Thus, in 1823, Mr. Shirreff marked one vigorous
wheat plant, near the centre of a field, which produced him 2,473 grains.
These were dibbled in the autumn of the same year, the produce sown