Distribution of Kranz Syndrome Among Asteraceae

A broad survey of the Asteraceae, involving visual characters, was undertaken to ascertain the occurrence of possible Kranz‐type (C 4 ) plants. One hundred and seven taxa representing 51 genera were examined by mass spectrometry for their 13 C/ 12 C ratios in dried leaf tissue. Species possessing the high 13 C/ 12 C ratio typical of the Kranz syndrome were found in genera belonging to the following tribes: Heliantheae (subtribe Coreopsideae)— Chrysanthellum (4 spp.), Eryngiophyllum (1 sp.), Glossocardia (1 sp.), Glossogyne (1 sp.), Isostigma (5 spp.); Tageteae— Pectis (21 spp.); and Helenieae— Flaveria (4 spp.). The only genus to possess both C 3 and C 4 species was Flaveria in which all but four species appear to possess a C 3 ‐type metabolism. When appropriate, the phyletic input of these data is discussed.