摘要:

AbstractThe genusBuchholziaconsists of 2 species:B. coriaceaEngler andB. thollonianaHua. Several proposed species are reduced to synonymy. The species are described and pictured; a key is given.

ISSN:0044-5983    

DOI:10.1111/j.1438-8677.1964.tb00149.x

出版商:Blackwell Publishing Ltd    

年代:1964

数据来源: WILEY

摘要:

AbstractElectron microscopic investigation of germinatingPetuniapollen has yielded new data concerning fine structure of the pollen tube wall and of the protoplasm. The cell wall reveals two layers, an inner one containing cellulose microfibrils, embedded in a matrix, and an outer one consisting of acid resistant material. The multi‐net growth theory is applicable to the growth of the pollen tube.Round the generative nucleus, there is a generative cytoplasm containing organelles. This cytoplasm is separated from the vegetative cytoplasm by a cell wall‐like structure. So we ought to speak of a generative cell.The vegetative nucleus is lobed and is surrounded by a nuclear envelope containing pores.The Golgi apparatus produces vesicles which accumulate in the tip of the pollen tube and probably have a function in building up the cell w

ISSN:0044-5983    

DOI:10.1111/j.1438-8677.1964.tb00150.x

出版商:Blackwell Publishing Ltd    

年代:1964

数据来源: WILEY

摘要:

AbstractThis paper gives a review of the Leptopeltaceae, a family of the Ascomycetes belonging to the Dothiorales. The genusPycnothyriumDiedicke is fully discussed as member of the family. It is characterized by superficial or subcuticular, shieldlike ascomata and by hyaline ascospores, mostly fourcelled when ripe. The genus namesDothithyriellav. Höhn.,Leptopeltellav. Höhn.,LeptopeltinaPetr.,LeptopeltinellaPetr.,MoesziellaPetr. andStigmastomaBat.&Maia are considered as synonyms ofPycnothyrium. All the four species placed in the genus are saprophytic fungi growing on dead stems of ferns and dicotyledons.Microthyrium lunariaeFuck, has twocelled ascospores and is placed in the genusLeptopeltopsisPetr. The genusSeynesiosporaBat. must be placed in the synonymy ofCyclothecaTheiss.&Syd. The type species is identical withCyclotheca iochromatis(Rehm) v. Ar

ISSN:0044-5983    

DOI:10.1111/j.1438-8677.1964.tb00151.x

出版商:Blackwell Publishing Ltd    

年代:1964

数据来源: WILEY

摘要:

AbstractData are presented concerning the internal structure of the woody stem ofCorylus avellanaL. ‘Contorta’, the twisted Hazel. In the primary state the pericycle is noteworthy because of its poor development, which is in striking contrast to the situation in the normal Hazel.Because the primary shoot is twisted from the very beginning, the cambial cylinder is also twisted. In the loops, unequal amounts of secondary xylem are formed, with a larger quantity at the inner bends than at the outer bends.The changes in the cambial areas—decrease at the inner and increase at the outer bends—are almost completely parallel to the changes observed in the dimensions of wood vessel elements—decrease in length from the pith towards the inner bends of twisted parts of branches and increase in length towards the outer bends.In the majority of cases tension wood proved to be present at the outer bends. A method for localizing tension wood using fluorochromes is

ISSN:0044-5983    

DOI:10.1111/j.1438-8677.1964.tb00152.x

出版商:Blackwell Publishing Ltd    

年代:1964

数据来源: WILEY

摘要:

AbstractThis paper reports a palynological investigation of Lower Triassic rock salt samples from the eastern part of the Netherlands. Bisaccate pollen grains average 99% in the spore‐pollen complexes. Most important constituent is the group of non‐striate pollen grains (about 91%), whereas striate pollen grains occur only in a small number (about 8%). 19 pollen species are recognized and described, of which 5 are new. Two new genera are described:EridospollenitesandAngustisulcites. The pollen assemblages are compared with Upper Permian and Lower Triassic assemblages from other localit

ISSN:0044-5983    

DOI:10.1111/j.1438-8677.1964.tb00153.x

出版商:Blackwell Publishing Ltd    

年代:1964

数据来源: WILEY

摘要:

AbstractIn this investigation special attention was paid to phytosociological aspects. The period in which the layers were formed could be dated as extending from the beginning of the Atlanticum to the present day. Radio‐carbon dating is necessary, however, in order to obtain more precise results. It is not excluded that transgressions have influenced the succession. More investigations are necessary to complete our image of the holocene development of this are

ISSN:0044-5983    

DOI:10.1111/j.1438-8677.1964.tb00154.x

出版商:Blackwell Publishing Ltd    

年代:1964

数据来源: WILEY

ISSN:0044-5983    

DOI:10.1111/j.1438-8677.1964.tb00155.x

出版商:Blackwell Publishing Ltd    

年代:1964

数据来源: WILEY

摘要:

AbstractThis paper deals with the results of a microscopical analysis of the lignites of the miocene browncoal from the quarry “Anna” in the south of Limburg (Netherlands). They appeared to consist of 14 wood species, distributed overConifers(6).Monocotyledons(1) andDicotyledons(7). Four dicotyledonous woods were found for the first time and described here. Some conclusions about vegetation and climate are added.ZUSAMMENFASSUNGDie Braunkohle der Grube “Anna” zu Haanrade in Niederländisch Limburg hat sich in einer denMyricaceae‐Cyrillaceae‐Buschmooren Teichmüllers sehr ähnlichen Buschmoorvegetation gebildet, die indessen eine trockenere Variante davon darstellt.Die in dieser Grube gefundenen und beschriebenen Hölzer gehören zu 14 Arten, verteilt auf 12 Gattungen. Von diesen sind 6 Holzarten vonKoniferen, eine von einerPalmeund 8 vonDikotyledonen. Die führenden Hölzer dieser Ablagerung sindSymplocoxylon latiporosumunaLaurinoxylon nectandrioides.Fagaroxylon Limburgense, Piceoxylon pseudotsugaeundPalmoxylon bacillarebilden ein von trockenerem Boden stammendes Element.Das Klima muss gemässigt‐subtropisch mit längeren feuchten und trockenen Perioden gewesen sein, in denen die Höhe des Wasserstandes extreme Werte erreichte, wobei ein ständiges Ansteigen des Meeresspiegels die Entwicklung mächtiger

ISSN:0044-5983    

DOI:10.1111/j.1438-8677.1964.tb00156.x

出版商:Blackwell Publishing Ltd    

年代:1964

数据来源: WILEY

摘要:

Abstract1The changes in growth substance composition of buds and scales of Wedgwood iris bulbs during flower formation were determined.2The scales contain several thermostable flower forming substances which, in the course of a low temperature treatment, are transported to the bud.3The flower forming substances have physiological and chemical properties of gibberellins.4Compounds with RF 0.3, 0.45‐0.50 and 0.75 in 80% isopropanol successively accumulate in the bud and attain maximum concentrations at successive stages of differentiation of the floral primordium.5The significance and possible mode of action of the gibberellins in flower formation is discusse

ISSN:0044-5983    

DOI:10.1111/j.1438-8677.1964.tb00157.x

出版商:Blackwell Publishing Ltd    

年代:1964

数据来源: WILEY

ISSN:0044-5983    

DOI:10.1111/j.1438-8677.1964.tb00158.x

出版商:Blackwell Publishing Ltd    

年代:1964

数据来源: WILEY