s transport the undigested seeds to remote localities. The pods
often remain on the trees all winter, and when dry, will float on
the water of overflowed streams without any injury resulting to the
hard seeds. By themselves the seeds sink at once.

CHAPTER V.
SEEDS TRANSPORTED BY WIND.

17. How pigweeds get about.--In winter we often see dead tops of
lamb's-quarters and amaranths--the smooth and the prickly
pigweeds--still standing where they grew in the summer. These are
favorite feeding grounds for several kinds of small birds, especially
when snow covers the ground.

Many of the seeds, while still enclosed in the thin, dry calyx, and
these clustered on short branches, drop to the snow and are carried
off by the wind. Notwithstanding the provision made for spreading
the seeds by the aid of birds and the wind, the calyx around each
shiny seed enables it to float also; when freed from the calyx, it
drops at once to the bottom. Many kinds of dry fruits and seeds in
one way or another find their way during winter to the surface of
the ice-covered rivers. When the rivers break up, the seeds are
carried down stream, and perhaps left to grow on dry land after the
water has retired. Most of the commonest plants, the seeds of which
are usually transported by water, are insignificant in appearance
and without common names, or with names that are not well understood.
This is one reason for omitting the description of others which are
ingeniously fitted in a great variety of different ways for traveling
by water.

18. Tumbleweeds.--Incidentally, the foregoing pages contain some
account of seeds and fruits that are carried by the aid of wind, in
connection with their distribution by other methods; but there are
good reasons for giving other examples of seeds carried by the wind.
There is a very common weed found on waste ground and also in fields
and gardens, which on good soil, with plenty of room and light, grows
much in the shape of a globe with a diameter of two to three feet.
It is called _Amaranthus albus_ in the books, and is one of the most
prominent of our tumbleweeds. It does not start in the spring from
seed till the weather becomes pretty warm. The leaves are small and
slender, the flowers very small, with no display, and surrounded by
little rigid, sharp-pointed bracts. When ripe in autumn, the dry,
incurved branches are quite stiff; the main stem near the ground
easily snaps off and leaves the light bal