The history and the present state of the classification of the Gramineae are briefly reviewed and a number of the different characteristics on which phylogenetic systems have been based are considered. The subjects of chromosome morphology and the application of idiograms and karyotypes to taxonomic studies are discussed. Avdulov's recently reported findings on the phylogeny of the grasses are summarized and compared with the results of other workers and those obtained in the present investigation. Three species of bamboos were studied for the first time and evidence secured to indicate that the basic number of the tribe is probably not 12 as has been elsewhere reported. In the Festuceae the chromosome number of Phragmites communis Trin. was definitely ascertained, confirming Avdulov's supposition that the basic number for the genus is 12. The other three species investigated agreed with the arrangement as proposed by Avdulov. The tribe Chlorideae, with the exception of the genus Beckmannia, has been reported to be almost entirely Panicoid with respect to chromosome morphology. This was confirmed in the four species examined. Avdulov's rearrangement of the tribe Hordeae was somewhat altered and a confusion m the nomenclature of the genus Lepturus was corrected. An anomalous situation was cleared up in the tribe Agrostideae by the establishment of the chromosome number of Sporobolus tennuissinus Kuntz as 40. The specimen of Anthoxanthum odoratum L. (tribe Phalarideae) examined provided a very interesting example of secondary splitting in somatic chromosomes. One species was examined in the tribe Melinideae and six in the tribe Paniceae. In the latter tribe no difference could be detected between the several subdivisions of the genus Panicum. The same condition held for the large genus Andropogon in the tribe Andropogoneae. In the tribe Maydeae the chromosome number of Tripsacum dactyloides L. was found to be 9, and the suggestion was made that it may be a link, along with the genus Coix, between the Andropogoneae and the Maydeae. The other four species examined all had a basic number of 10.

The chromosome numbers of 56 varieties of greenhouse chrysanthemums were determined. Fifty-one varieties belonged to 10 'families' of sports and the chromosome numbers of the sports were compared with those of their vegetative parents. Sporting, mostly flower colour mutation, was accompanied by the gain or loss of a few chromosomes in about 30 per cent of the cases. Two plants with different chromosome numbers but with the true varietal flower colour were found.The most frequent chromosome number in the authors' material was 2n = 57. The range was 2n = 45–64. Mitotic irregularities and chromosome number variation within individuals were observed. Attempts to induce sporting by hot water treatment failed.Varieties with large inflorescences had higher chromosome numbers (2n = 58–64) than varieties with medium or small inflorescences (2n = 54–58), but in most of the material varieties with small inflorescences differed little in chromosome number from those with medium-sized inflorescences. Five additional varieties with very small inflorescences had lower chromosome numbers (2n = 45–55).

No abstract

No abstract

The parthenocarpic development of strawberry fruits was induced by spraying unpollinated blossoms with solutions of indolylbutyric acid, 1-naphthylacetic acid, and colchicine, and by dusting the blossoms with powdered acenaphthene. Fruits also developed from blossoms that had not been directly treated. This is explained on the basis of translocation of the chemical, or some other substance, from treated to untreated blossoms.It is suggested that colchicine, and possibly the phytohormones, induce parthenocarpy by acting as mobilizers of another substance or substances that move into the ovary and there initiate development.