Nevertheless, the tree has proved exceptionally hardy.

By that time it had been tried out of doors without winter protection and proved hardy in the south of England.

Specimens introduced to the Netherlands by Heybroek in the 1960s did not prove hardy.

Not a bad one, though-all of them were proven hardy and industrious, and able to fight when necessary.

The voice, as on previous occasions, proved hardy and attractive if not particularly glamorous.

However Alloxylon flammeum has proven adaptable and hardy, while the others are more exacting in their requirements.

For example, hard-shell clams, originally used to test if material to be dredged was poisonous, proved too hardy.

In Gaul and Britannia it will not have proved hardy.

But the Media Lab culture has proved surprisingly hardy.

That they should prove so hardy in so deeply a conservative Congress, at least so far, may be surprising.