green snake

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

• noun Any of several slender, yellow-green nonvenomous North American snakes of the genus Opheodrys, such as the grass snake.

from The Century Dictionary.

• noun One of two different kinds of grass-snakes of the United States, of a bright-green color, uniform over all the upper parts (changing to bluish in spirits), and of very slender form:

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

• noun any of numerous African colubrid snakes
• noun either of two North American chiefly insectivorous snakes that are green in color