摘要:

The vegetation of the region south of the St. Lawrence estuary, more specifically L'Islet and Kamouraska counties, is described in relation to soils and physiographic features.In the first part, a climatic, geologic, geomorphic, and phytogeographic approach is made, summarizing known data for the region. The second part is devoted to the natural vegetation, particularly in its primeval state.On the estuarian lowlands, in the southwest part, the dominant feature is a sugar maple forest which maintains itself in good condition along the coast as far as Saint-Roch-des-Aulnaies. Farther to the northeast, maples are restricted to the Champlain terraces, along the appalachian foothills. The perpetuation of the maple woods is relatively precarious on account of the cold climate. In many cases, maple woods seem to be a relic vegetation. White spruce often reclaims hills where maples have been cut down, especially when the parent-material of the soil has a low calcium content. In the northeast, spruce is the dominant feature of the landscape, on account of the siliceous rocks and a slightly colder climate.On the seashore, the sandy beach facies is characterized by a lyme-grass fringe, and the alluvial mud-flat facies is characterized by salt-water cord-grass. The latter constitutes the original phase of the silty clay soils of the lower plain. In the fresh-water section of the estuary, the alluvial muds, under tidal influence, are characterized by American bulrush and wild rice.Because of its fertile soils, the upper clay plain of the lowlands is entirely under an agricultural régime. Some reliquary fragments of forest allow us to reconstruct the primeval vegetation. In the southwest, a stand, of red maple, associated with American elm, possibly covered these flat and poorly drained soils. In the northeast, there might have been a spruce–sphagnum type of vegetation.The upper Appalachian Plateau has a rolling topography. A maple forest grows on the glacial till of the hills, where limestone delays podsolization. More often a mixed wood occurs, with white spruce, red maple, balsam fir, aspen, and white birch. The depressions are characterized by a black spruce forest, often associated with American larch and eastern white cedar. It seems that red pine and white pine have been characteristic elements of fluvioglacial soils. A coniferous forest is dominant on all sites in the northeastern part of the Plateau.

ISSN:0008-4026    

DOI:10.1139/b55-017

出版商:NRC Research Press    

年代:1955

数据来源: NRC

摘要:

In the lowbush blueberry, floret primordia appear during June. Floral parts appear in acropetal succession during July. Ontogenetically the carpels are at first appendicular and later receptacular. The epigynous floret, in miniature, is formed by the first of August. During this month, some reproductive tissue is differentiated in both ovary and stamens. The characteristic resting stage is assumed during the autumn. Mitosis was observed in material collected during January and by late winter a number of ovules had two adjacent archesporial cells, the outer one later becoming functional. Definite differentiation starts during March. Active growth, including the initiation of meiosis, becomes general during April. Meiosis is completed in the anthers during the first week of May and about a week later in the ovules. Subsequent development in the ovule is of thePolygonumtype. The flower is mature by the last week in May.

ISSN:0008-4026    

DOI:10.1139/b55-018

出版商:NRC Research Press    

年代:1955

数据来源: NRC

摘要:

Cordana pauciseptatais illustrated and redescribed from North American collections on wood and bark and from isolations from wood. The history of the genus is reviewed.Brachysporium apicole(syn.Monotospora triseptata, syn.Acrothecium anixiae) andBrachysporium obovatumare discussed, and North American collections as represented in Herb. DAOM are listed.Brachysporium polyseptatum(syn.B.bloxami) is illustrated andB.pendulisporumis described as new.Phragmocephala cookeiandP.glandulaeformis(syn.P.minima) are recorded for North America.

ISSN:0008-4026    

DOI:10.1139/b55-019

出版商:NRC Research Press    

年代:1955

数据来源: NRC

摘要:

A virus disease occurring on Himalaya blackberry (Rubus procerusP. J. Muell.) was transmitted to Washington red raspberry (R.strigosusMichx.), tropical black raspberry (R.albescensRoxb.), and North American black raspberry (R.occidentalisL.). A net-like chlorosis of the tissue bordering the smaller leaf veins is the characteristic symptom, consequently the name "Rubus yellow-net" is proposed for the virus and disease. The virus is transmitted by the raspberry aphidAmphorophora rubiKalt. It may be acquired by the aphid after a one-hour feeding and usually persists in the vector less than four hours.

ISSN:0008-4026    

DOI:10.1139/b55-020

出版商:NRC Research Press    

年代:1955

数据来源: NRC

摘要:

Thirteen-day-old wheat plants were placed on solutions of C14labelled glucose and the amounts of glucose taken in were determined. Plants were then placed in darkness for three hours and their CO2production was measured. It was found that the amount of glucose absorbed by plants was directly proportional to the amount of water taken in while the presence of inorganic phosphate depressed absorption. Glucose was absorbed in larger amounts than glucose-1-phosphate and the absence of oxygen had no effect on the amounts taken in. An increased production of CO2, following glucose absorption, came both from the glucose taken in as well as from the endogenous substrate.

ISSN:0008-4026    

DOI:10.1139/b55-021

出版商:NRC Research Press    

年代:1955

数据来源: NRC

摘要:

In tests with seven different liquid media in which the common nitrogen source was potassium nitrate and the carbohydrate substrate was glucose, at a concentration of only 0.1%, most of the 1914 soil fungi isolated fell into one of three nutritional groups requiring, respectively, for maximum growth amino acids, amino acids plus growth factors, or yeast extract. Relatively few isolates required growth factors alone or a combination of yeast and soil extracts. Most of the isolates grew poorly in the basal medium containing only mineral salts, and glucose, with or without soil extract. Although fungi requiring yeast extract were much less frequently isolated from soil on, rather than remote from, tubers grown in a soybean green-manured plot, isolates requiring amino acids, or yeast plus soil extracts, were correspondingly increased on immature and mature tubers, respectively. In a second plot, however, not specially treated, no differences were observed in the nutritional spectra of fungi isolated from the two kinds of soil environment.

ISSN:0008-4026    

DOI:10.1139/b55-022

出版商:NRC Research Press    

年代:1955

数据来源: NRC