By means of thin-layer chromatography, 1424 local varieties of barley were investigated. Two collections of Hordeum spontaneum and one of H. agriocrithon were also analysed. In H . vulgare three distinctly different flavonoid patterns were found, designated A, B and C. The B pattern could be divided into two types: B1 and Bz. The flavonoid pattern of H. spontaneum deviates sharply from those of H. vulgare. Hordeum agriocrithon has the same flavonoid pattern as the A pattern in H. vulgare. The flavonoid patterns A and B occur throughout the cultivated area of H . vulgare. However, differences in frequency between the A and B patterns were revealed when different areas were compared. Flavonoid pattern C is, with a few exceptions, found only in varieties of barley from Ethiopia. Controlled crossing experiments between the different flavonoid types of H. vulgare were performed on a limited scale. The phylogeny of H . vulgare in relation to H. spontaneum and H. agriocrithon is discussed. The flavone glycosides that constitute these differences are briefly reviewed. Sune Frcst, Institute of Genetics, S-223 62 Lund, Sweden

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Twenty‐seven flavonoids have been identified variously in leaf extracts of the five known chemical races of barley. Five are flavone O‐glycosides, the remainder being C‐glycosylflavones based on apigenin, luteolin or chrysoeriol. Most of the variation is due to the attachment of various sugars, including galactose, to the C‐glucosyl moieties in the 6‐positions, but there are also a range of 7‐O‐glycosides, including two with acyl attachments. Analyses of the results indicate that race A is closest to race C, races B1 and B2 are very similar and race S is about equidistant from A, B1 and C. Genetic evidence shows that the S pattern is the original one and that the others have evolved from it; the chemical results are completely consistent with such an interpretation.

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Phenolic compounds from leaves of 19 apomictic Potentilla biotypes, belonging to seven different species, were studied by means of thin‐layer chromatography, together with material of Fragaria vesca. Leaves were collected for analysis from both young and mature plants within each biotype. More than 100 different spots were observed in the chromatograms of the total material. Obvious differences were found between species, and, to a smaller extent, between apomictic biotypes within the same species. However, pronounced differences were also observed between chromatograms from young and mature plants. The experimental results point to the necessity of careful choice of plant material for chemotaxonomic comparisons. The usefulness of chemotaxonomic methods in the study of apomictic form groups is discussed.