Potentilla obscura et leucotricha
نویسندگان
چکیده
منابع مشابه
Leonardo and the Camera Obscura
If Leonardo's studies of the camera obscura stand in a well established tradition, they remain important for at least three reasons. One is their sheer quantity: there are no less than 270 diagrams of camera obscuras in Leonardo's notebooks. Second, he uses it to demonstrate a wide range of optical principles: inversion of images, non-interference, images all in all, intensity of light and shad...
متن کاملX-Ray Effects on Drosophila Pseudo-Obscura.
In order to procure new material for the study of problems connected with the non-disjunction of the sex chromosomes in Drosophila pseudoobscura, a series of X-ray experiments was carried out. Among the species of Drosophila,pseudo-obscura is distinguished by the length of itsxchromosome, whose genetic map is the longest recorded in any species (LANCEFIELD 1922). The work of LANCEFIELD has made...
متن کاملNatural selection in Potentilla glandulosa revisited
Clausen, Keck and Hiesey’s studies of clonal transplants during the 1930s and 1940s are famous for demonstrating ecotypic variation. Less appreciated are their studies on natural selection, even though at the time there was little hard evidence of its operation in nature. Here we present new analyses of their study of natural selection in Potentilla (Clausen et al., 1940; Clausen and Hiesey, 19...
متن کاملAnomalous Chromosome Pairing in the Male Drosophila Pseudo-Obscura.
The chromosome complement The Diptera have not proved to be the most favorable material for the study of chromosome behavior, but the extensive work of STEVENS, METZ, KEUNEKE, and others has shown two exceptional properties in most sections of the order, namely, the pronounced somatic pairing of homologous chromosomes at mitosis, and the apparent lack in the male of the characteristic stages of...
متن کاملMorphometrical evolution in a Drosophila clade: the Drosophila obscura group
Five morphometrical traits (wing and thorax length, ovariole number, and thoracic and female abdomen pigmentation) were investigated in laboratory stocks of 20 species belonging to the Drosophila obscura group (subgenus Sophophora). These species originated from four biogeographical regions and represent all five of the presently recognized, taxonomic subgroups. Size-related traits (wing and th...
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ژورنال
عنوان ژورنال: Oesterreichische Botanische Zeitschrift
سال: 1886
ISSN: 0378-2697,1615-6110
DOI: 10.1007/bf01680807