摘要:

The flowers and caryopses of Festuceae, Festucinae (sensu Pilger, 1954) have been morphologically studied. All the genera, which show non-festucoid features in respect to non-morphological characters, are also different from true Festuceae, Festucinae in such details of their morphology as lodicules, pistils, and caryopses. On the other hand, the festucoid genera are very closely related to one another as regards these organs. The systematic positions of the genera showing non-festucoid traits in non-morphological characters are being considered in connection with their characteristics of flowers and caryopses. The results clearly indicate that the conventional treatment of morphological characteristics, in which stress is laid on some macroscopic characters, such as inflorescences or the appearance of lemmas, is quite inadequate, and that great attention should be paid to the features of flowers and caryopses, as well as spikelets and other morphological characters. A new tribe Brylkinieae is proposed.

ISSN:0008-4026    

DOI:10.1139/b60-085

出版商:NRC Research Press    

年代:1960

数据来源: NRC

摘要:

Culture studies of a marine green alga, described from the Pacific Coast of North America asCollinsiella tuberculataSetchell and Gardner, have shown it to be a stage in the life history of a form ofEnteromorpha intestinalis(L.) Link. TheCollinsiella-stage is thought to be the sexual phase, or a basal remnant of theEnteromorpha-stage, and produces biflagellate gametes. The typical tubular thallus ofEnteromorphahas been grown in culture from zygotes of theCollinsiella-stage and zoospores of theEnteromorpha-stage. Parthenogenetic development of gametes is also indicated. Some of the tubular plants produce biflagellate gametes which cannot be distinguished from those of theCollinsiella-stage. Others produce quadriflagellate zoospores, which may be meiospores or mitospores. An accessory method of reproduction by quadriflagellate mitospores (neutral spores) occurs and this asexual cycle has been carried through three successive generations in culture without an intervening sexual phase. Tubular thalli ofEnteromorpha inteslinalis(L.) Link producing biflagellate gametes during the spring and early summer and quadriflagellate zoospores during the late summer are found in nature in the same area from which theCollinsiella-stage was obtained. These are believed to represent in nature the normal sexual life cycle of this plant, which has been reported to have an alternation of isomorphic generations. The possible relationships between the stages obtained in culture and those observed in nature are discussed. A number of hypothetical conclusions have been drawn with respect to the systematic position of the genusEnteromorphaand related genera. These studies are being continued to clarify several unknown aspects brought out by this preliminary study. A cytological study is being undertaken to substantiate the conclusions drawn from the morphological data.

ISSN:0008-4026    

DOI:10.1139/b60-086

出版商:NRC Research Press    

年代:1960

数据来源: NRC

摘要:

The range in cultural variability ofFusarium oxysporumf.cubenseon potato dextrose agar was studied. Several hundred isolates obtained from diseased varieties ofMusawere categorized into four morphological groupings or cultivars. These were termed 'Sporodochial', 'Ropy', 'Cottony Alba', and 'Slimy Pionnotal'. The morphological cultivar 'Sporodochial' was further divided physiologically into 'Odoratum' and 'Inodoratum' cultivars. Clones producing sporodochia were the parental forms from which all other cultural types could arise by mutation. Mutants did not revert to their parental types. A system is proposed for cataloguing clones of plant pathogenicFusariumspecies. Based on morphological characters, the catalog is intended to serve as a collection of data which provides also for the categorizing of cultivars.

ISSN:0008-4026    

DOI:10.1139/b60-087

出版商:NRC Research Press    

年代:1960

数据来源: NRC