Genus

About: Genus is a research topic. Over the lifetime, 68921 publications have been published within this topic receiving 590966 citations. The topic is also known as: monospecies genus & genus (zoology).

Pollination in the Genus Arum - a review

Abstract: The 28 species of the genus Arum (Araceae) attract and temporarily trap insects (mainly flies, and beetles in a few cases) during a complex pollination process. At anthesis, the appendix of the inflorescence produces heat and emits a specific odour which attracts insects. The lured insects are trapped within the floral chamber when stigmas are receptive. They will be released about 24h later after pollen emission, ensuring pollen dissemination. Studies on the reproductive biology of the genus have shown some degree of variability in the pollination strategies: morphological variations, flowering and heating periods, odour types and the type of pollinating insects. Most of Arum species have never been studied in depth but data available from the literature indicate quite a high diversity of pollination strategy within this genus. Consequently, a general pollination model is not valid at the level of the whole genus. The origin of this diversity certainly results from the biogeographic history of the genus. The plants (i.e. species) have developed adaptations in response to different climatic, ecological and biotic (i.e. entomofauna) constraints (i.e. selective pressures) according to the various habitats occupied in the different regions of Europe and the Middle East. However, in the absence of phylogenetic data, it is actually impossible to determine how these different reproductive strategies have developed and evolved during the history of this genus.

A karyosystematic investigation in the gramineae

Abstract: 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 repo...

Evolution in the genus cucurbita

Abstract: For the study of evolution the genus Cucurbita offers several unique advantages: (a) Cucurbita is a comparatively small closed system composed of about two dozen species concentrated in a relatively small land mass. Because of their conspicuous vines and fruits, it is unlikely that more than one-half dozen species are yet to be discovered, although a few new species might be expected from Baja California, the west coast of Mexico opposite the peninsula of Baja California, and in southern Mexico and Central America. These are areas that have not yet been thoroughly explored by botanists. (b) All species have 20 pairs of chromosomes. For this reason species differentiation must be largely genic or cytoplasmic, rather than dependent upon gross chromosomal rearrangements. (c) There are both wild and cultivated species in the genus. This situation presents an opportunity to compare the evolution of closely related species under cultivation contrasted with the evolution of species in nature. (d) From archaeological remains it is possible to trace man's association with these plants backward in time for a maximum of 10,000 years.