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7p
・しいタイプ
といる
訳じゃない
土
+27
In 1877, an unfamiliar type of weed appeared in Bon Homme County,
Bon Homme
22.3
24
291
3x145
South Dakota, and began spreading across the northern Great Plains. The
グレートプレーンズ
plant, called tumbleweed, has green stems intricate branches, a nearly round
(ア)
shape, and long leaves with sharp points on the end. Mice, mountain sheep,
とびった業
7212 47F2 Heal
and pronghorn antelope* feed on it. The branches are soft and green when
young but woody and gray when ( 1 ).
ださい
grous
tumbleweed does not spend its entire life rooted
KATERE
Unlike other plants the がう点に
Unlike other plants, the
the soil. In the fall, a layer
of cells in the stem weakens and the plant breaks off from its roots and rolls (
across the fields in the wind. The tumbleweed doesn't depend on wind, birds,
or mammals to disperse its seeds. As this woody sphere rolls along, it drops
its numerous seeds (up to 250,000 per plant). The seeds are unusual in that
tored food reserve. Instead, each seed is a coiled,
ブレット
じぶんと
