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Leaf extracts from twelve chlorophyll-deficient mutants of sweetclover (Melilotus alba Desr.) were compared spectrophotometrically and chromatographically with extracts from normal plants to determine contents of chlorophylls a and b Total chlorophyll contents in cotyledons and leaves of all mutants were significantly lower than those in corresponding tissues of normal plants. Chlorophyll contents were generally higher in later emerging leaves of both normal and mutant plants. Chlorophyll alb ratios in first trifoliolate leaves were similar to normal in mutants ch7 and ch8, higher in mutants ch8, ch9, ch10, and ch11, and extremely high in mutant ch4. A lower than normal alb ratio was observed in mutant ch12. The four allelic ch5 mutants were unique in that chlorophyll b was not detected in any of the tissue extracts. The ch5 mutants appear to be only the third reported instance in higher plants of a viable mutant lacking chlorophyll b, the previously reported cases being in barley (Hordeum vulgare) and Arabidopsis thaliana.