Susan Posch, age 10, of Cleveland, Ohio, for her question:

What are tumbleweeds?

Whoever heard of a plant going for a stroll? The tumbleweed does. Come late summer, this round ball of dry twigs goes rolling and bowling before the wind, over the dry deserts and the prairies. Actually, this tumbling tumbleweed is on a very important mission. It is a parent plant, scattering its seeds as it rolls over the ground.

To avoid over crowding, seeds should be scattered some distance from the parent plant.  There are countless tricks in the plant world for scattering seeds far and wide, for every parent plant tries to give its seeds a good start in life   or so it seems.

Pea pods become pea shooters. They dry up and split open with a sudden jerk which sends the ripe seeds flying through the air in all directions. The elm tree and the dandelion rely on the wind to scatter their seeds, The elm seeds float away from home on gliding wings. The dandelion launches its seeds on feathery parachutes. The burdock and the cocklebur depend on passing animals. Their seeds have hooks for clinging to furry coats, But the tumbleweed goes to even more trouble to scatter its seeds,

As the seeds ripen on the tumbleweed bush, the leaves wither and blow away. The twigs become dry and brittle. Now the plant waits for a strong gust of wind. Suddenly the stem snaps off close to the ground and the tumbleweed is ready to travel. The breezes blow through the light dry twigs, lifting and rolling the round, bushy plant over the ground. The tumbling tumbleweed i s bounced and shaken   which suits it just fine. For this is what shakes out the seeds and scatters them Dr and wide.

Several plants scatter their seeds in this way and all of them go under the name of tumbleweed. The largest of the tumbleweeds is also known as the Russian thistle. This native of Europe is a very prickly little bush and one parent plant can scatter a million seeds. Another native of Europe is the witch grass, alias the couch grass or panic grass. This tumbleweed also spreads by underground rhizomes, Both these plants rate as weeds,

The bugseed and the tumbling pigweed are native American tumblers. The bugseed gets its name from its oval, bug shaped seeds. The tumbling pigweed is also known as the green amaranth. Poets once imagined a flower that never fades and they named this impossible flower the amaranth. This word was borrowed to name a lovely garden flower and the green flowered tumbling pip weed dust happens to belong to the same family.