bottle tree

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun Any of various Australian trees of the genus Brachychiton, especially B. rupestris, having a swollen, sometimes bottle-shaped trunk and cultivated in warm regions as an ornamental.

from The Century Dictionary.

• noun An Australian tree, Sterculia rupestris, so called from the shape of its trunk, which resembles a soda - water bottle.
• noun Any tree with a swollen trunk.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun an Australian tree of the genus Brachychiton
• noun an Australian tree of the genus Brachychiton