This species spreads to 1 or 2 metres in width.

"For starters we want to see how far these species have spread nationally," says Evans.

Once it is established, a new species may spread to some places and not others.

The species probably arose in the tropical reaches of southern Asia, and later spread across its current range.

It is suspected that the species later spread into the rest of the continent.

The species spread to other worlds, several with intelligent indigenes.

But the species has spread spectacularly over the last half century.

This species has spread throughout the world as an ornamental plant.

These resistant species spread and take the place of those harmed or killed by the stress.

The species might have spread slowly because a lot of muskmelons taste bad.