Leaf volatiles from Thymus vulgaris, T. serpyllum, T. praecox, T. pulegioides and T. x citriodorus (Labiatae)

Wound–emitted leaf volatiles in soe species of Thymus were analysed. Fresh shoots without flowers were used. The volatiles were isolated by adsorption on a porous polymer (Tenax GC). The emitted components were separated by a capillary gas chromatograph modified to give reproducible retention time values. The identifications are based on mass spectra and retention time values of reference compounds. The results indicate the mildness of the method used. This is one part of the methodological work of an investigation concerning the biochemical background of pest and disease resistance in plants. Attention is drawn to the urgent need in resistance breeding for a taxonomic survey of the intraspecific allelochemic multitude.     

On the Genus Athyrium Ser. Epiraches Ching et Y. T. Hsieh ex Y. T. Hsieh

This paper,third in the series of an account of the genus Athyrium in China, presents a revision of the series Epiraches Ching et Y．T．Hsieh ex Y．T．Hsieh．A total of 11 species are recognized from China,and more than 20 names are reduced to synonyms in the present paper．Ser．Epiraches is anatural group in Athyrium,it is distinguished from all the other groups of the genus by its Asplenioid sori and indusia,The series is entirely Asian tropical,subtropical and primarily montane．Its northern limits in central and eastern China are not beyond the Yangtze River．Southwestern part and Taiwan of China and Japan Islands are centers of diversity for the series,each with more than five species．Some speciesare disjunctly distributed in southwest China-Taiwan-Japan;one species(Athyrium roseum) occurs discontinuously between Yunnan and Taiwan;one endemic to Hainan(A. hainanense)is the only representative of Athyrium on the island．All members of this series grow in evergreen broad-leaf forests,generally from 500 to 1800 m above sea level．A key to the species,and illustrations of the middle pinnae from different specimens are provided．