Source: http://feeds.feedburner.com/~r/boingboing/iBag/~3/282242682/us-patent-for-common.html
In the 1990s, a Colorado man named Larry Proctor purchased some beans at a market in Mexico.He selectively bred them for a few years and claimed to have invented "a new field bean variety that produces distinctly colored yellow seed which remains relatively unchanged by season." He called it the "Enola bean," and was granted a "20-year patent that covered any beans and hybrids derived from crosses with even one of his seeds."
His claim of 60 cents per pound of beans sold in the US "caused a steep decline in exports of such beans from Mexico to the USA, according to Mexican government sources."
Today, the United States Patent and Trademark Office revoked Proctor's patent claims
Link
The bean was erroneously granted patent protection in 1999, as US Patent Number 5,894,079, in a move that raised profound concerns about biopiracy and the potential abuse of intellectual property (IP) claims on plant materials that originate in the developing world and remain as important dietary staples, particularly among the poor.
CIAT was able to dispute the inventor's claims to a unique color by providing published evidence of 260 yellow beans among the almost 28,000 samples of Phaseolus in its crop "genebank." At least six of the CIAT varieties were, to most observers, identical to the bean described in Proctor's patent documents on the basis of color and genetic markers. CIAT also put forward publications to show that the claims in the patent application took credit for research already widely available in scientific literature and thus claims made regarding the breeding of the bean in his patent also failed to meet the patent office's statutory requirements for "non-obviousness and novelty."