Toxicological Trivia from December 24, 2009: The scientific name for Dog’s Tooth Grass is Cynodon dactylon. Most types of this plant are not toxic but can cause occasional cases of type hydrogen cyanide toxicity (plant cyanogenetic). In the United States, is called  also Bermuda grass and can cause fotosensibización. Kidder, Beardsley and Erwin (1961) and Ndyanabo (1974) report that can have up to 10% of total dry matter:
a) Oxalic acid;
b) Citric acid;
c) Acetic acid.

Correct answer c: See FAQ in Spanish about Toxicity of Dog’s Tooth Grass. Read more in Wikipedia.