The Kranz Syndrome in the Gramineae as Indicated by Carbon Isotopic Ratios

The Kranz syndrome, as indicated by relatively high 13C/12C ratios is characteristic of 16 ½ tribes and about ½ of the species of the Gramineae. Data are given for 198 species from 129 genera and 47 tribes, and from at least 6 subfamilies of grasses. This information is correlated with data from the literature on anatomical and physiological characters of both Kranz and non-Kranz grasses. All subfamilies, tribes, and genera seem to be uniformly all Kranz or non-Kranz except the subfamily Panicoideae and the genus Panicum which have both Kranz and non-Kranz species represented.