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A comparison of climate, soils, vegetation, and biotic history of mediterranean ecosystems revealed closest ecological equivalence between the blue oak grassland in California and the vallonea oak grassland in Israel, both mediterranean oak savannas in which overall environmental resemblance seems closest. Ecological amplitude and syndynamics in most other comparable types are similar, but the chamise chaparral on non-calcic brown upland and lithosols differs from its maqui counterpart by its one-layered structure and by its adverse influence on the ecosystem. Annual grasslands in California foothills are comparable to seral batha dwarfshrub and grassland in Israel as human-induced degradation stages of chaparral and maqui. For such ecological comparisons a holistic ecosystem approach seems more suitable than any preconceived phytoclimatic and climax concepts

Phytoplankton seasonal and long-term succession can be described and functionally classified by associations similar as in terrestrial vegetation studies. Such a concept has to include 'climax' into pelagic succession which in turn leads to the question to what extent steady state assemblages occur and if during periods of dynamic equilibrium can be identified. Here we explore the situation with respect to the above question for deep, nutrient poor, alpine lakes in Austria. We first track the long-term development of phytoplankton biomass, their taxonomic structure and their relation to total phosphorus and chlorophyll-a as predictors of trophic state over the past 35 years. We then analyse this data set for coherent algal associations which can be ascribed to trait separated functional groups according to Reynolds et al. (2002). A three year period of stable environmental conditions has then be extracted from the progression of trophic state indices, having similar dominating species each year. These years were finally analysed for steady state conditions according to definitions given in Sommer et al. (1993). During thermal stratification, achievement of an equilibrium could be ruled out although coexistence of several dominating species lasted for several weeks. Habitat templates were constructed from environmental variables prior to biomass peaks for two species important in summer assemblages, the dinoflagellate Ceratium hirundinella and the diatom Fragilaria crotonensis. In summary, functional groups proved to be a valid and useful concept to describe species succession of phytoplankton in deep alpine lakes while pelagic climax is much less clear and steady state conditions were never met.

Of all the nutrients acquired from the soil for plant growth, nitrogen (N) is generally required in the greatest amount. The availability of N is dependent on the global N cycle, which relies on the formation of combined inorganic N from atmospheric N2, as very little N is made available to soils from weathering of substratum (Sprent 1987). Climate and soil organisms interact with soil building processes in such a way that the N cycle is very dynamic and has an important impact on habitat development and plant succession. Plants form a critical part of the dynamics of the N cycle in that they act as a large store for N, but also release much of their N back to the global cycle as tissues senesce and decay. However, as plant succession progresses to climax, more N is locked up in relatively larger and longer-lived species and N becomes a growth-limiting nutrient in most habitats. In such a situation, the N economy of a plant is likely to be under strong selection pressure. In the case of trees, they are faced with balancing acquisition of new or primary N, against retention and recycling of secondary N from old/storage tissue to new growth. Thus in senescing deciduous trees the maximum re-absorption of N for recycling is about 70%, with a slightly smaller value for evergreen species (Aerts 1996).

Forest trees respond to increased ozone levels and UV-B radiation by reduced photosynthesis, allocation and growth, but also by increased expression of plant defence systems. Ozone effects usually are cumulative and affect in particular deciduous trees such as beech and birch. Current concepts of forest succession, climax tree species and timber production are thereby made questionable.

The regrowth of vegetation after deforestation provides a paradox: of rapid growth but with species composition and diversity at odds with the original primary forest. Secondary species which regenerate from seed in the soil after clearance are totally different from the primary species which dominate ‘climax’ tropical rain forests. Regrowth of primary forest after disturbance depends on distance and access to seed sources of primary forest species. On-site biological effects of deforestation are also controlled by alteration of the physicochemical environment in which plants and animals live and grow, combined with the resilience to perturbation shown by plant and animal associations, both above and below the soil surface. Resilience is partly determined by reproductive abilities of plants, both vegetative and sexual, the volume, frequency, dispersal, dormancy and germination of their seeds. Resilience is also determined by the speed of vegetation regrowth, as this affects the rate of alteration of soil and microclimate conditions of the site. A range of research studies world-wide, in the neotropics, Africa and the Far East, have charted specific ecological changes taking place when tropical forests are removed. Some are site-specific, others provide more process-related information which helps in predicting how newly deforested sites might respond over time.

Growth and survival rates of indigenous Malaysian tree species were monitored between December 1996 and December 1997 following their establishment in an experimental farm in Universiti Putra Malaysia. The species studied consisted of 21 tree species ranging from large emergent trees to shrubs and from pioneer to climax trees and also one liana species. The mean relative growth rate of height of all species studied was 0.0012 cm cm-1 day-1 and the mortality rate was 26.1%. Macaranga hypolenca showed the highest relative growth rate and Caesalpinia sappan exhibit the highest survival rate. Pioneer species favored a high light intensity and showed high growth and mortality rates. On the contrary, climax species had low growth and mortality rates. A partial shading condition was favored by some climax species. These results indicate that optimum light conditions varied between the species, suggesting that the selection of species to plant with respect to the light condition of a focal planting site needs to be considered for the successful end of a plantation program.

Management of the degraded forests in central and eastern Europe requires the development of an action agenda. At least one forest research project and management approach should be initiated and/or continued. The effort should be results-oriented and consistent with ecological balance. Conclusions should guide the application of remedial measures to convert forests to different species, or stabilize the health of existing forests. These measures will contribute to the overall goals of expansion of the European forest, both as a carbon sink and to invigorate the forest products industry in countries of the former United Soviet Socialist Republic (USSR). In particular, neutralization and fertilization of forest soils should be more fully investigated and probably more widely applied. Orderly conversion of softwood monocultures to climax stands should be encouraged. The development of pollution-resistant genotypes should be accelerated. This paper provides the rationale for these forest growth, expansion, and management recommendations.

It is now widely recognized that the forests of the Angara region, as they look today, developed essentially under the influence of fires (Popov 1957, 1982; Krauklis 1975, 1985; Buzykin and Popova 1978). Fires are a common disturbance event and an important ecological factor in taiga forests. Over the last few decades, spatial patterns of forest communities, at different stages of post-fire succession, are undergoing complicated changes due to increasing forest resource exploitation. Intensive forest harvesting leads to a great increase of areas occupied by young stands. In most parts of the Angara region, fires and cutting cause the replacement of climax dark conifers by light coniferous and hardwood species. Relatively frequent surface fires destroy dark conifer regrowth and the subordinate (lower) wood layer composed of spruce, fir, and Pinus sibirica, thereby hamper their regeneration. Wide local variations in age structure, species composition, and productivity of southern taiga forests of the Angara region are attributed to the heterogenity of ecological site conditions and different patterns of fire occurrence and harvesting, which in turn determine specific microclimatic situations. Since regeneration processes after human-caused disturbances in fact obey, the same laws as natural vegetation succession, it is reasonable to study post-fire and post-cutting vegetation successions in the context of general vegetation cover dynamics.

Rangeland is defined as land on which the indigenous vegetation (climax or natural potential) is predominantly grasses, grass-like plants, forbs, or shrubs and is managed as a natural ecosystem. If plants are introduced, they are managed as indigenous species. Rangelands include natural grasslands, savannas, shrublands, many deserts, tundras, alpine communities, marshes, and meadows (Forage and Grazing Terminology Committee 1991).

A study has been made of the floristic composition and the edaphic chracteristics of Q. rotundifolia forests and pine repopulations made on the holm-oak climax area. The number of taxa in the repopulations is 40% less than in the holm-oak forests. The pH values are also higher in the holm-oak forests samples.

Natural beechwoods established in the Fontainebleau biological reserves and protected from human intervention for several centuries, are unique in western Europe “La Tillaie”, a 34 hectares integral reserve, approaches a climax state and shows a patchy structure where beech (Fagus silvatica) is nearly the only component of the upper layer.

The widespread view of tropical rain forest as a climatic climax is questioned. An understanding of the dynamics of rain forest ecosystems can best be gained by viewing the rain forest as a dynamic and unstable ecosystem. This approach will have important consequences on the interpretation of speciation in tropical areas. The existence of very diverse populations of many species in areas of inherent instability possibly strengthens the argument for punctuated equilibrium. In areas such as New Guinea where the ecosystems are very unstable, management practices for rain forest areas must be adapted to allow for the expected differences in regeneration strategies shown by the major commercial species.

A map of the existing vegetation represents the plant cover at the moment of investigation. This can be the very purpose of the map, but it can also be a disadvantage in view of the over-all observed phytodynamics. Among various solutions to deal with this problem (see Chapter 23) an often used technique is mapping the climax or the (potential) natural vegetation. Let us first briefly discuss the background and development of these concepts and then describe the principles of construction of the potential natural vegetation. Finally some examples of maps will be given.

The principal climax types of the Eurasian taiga are coniferous forests consisting of evergreen coniferous trees, such as the species of spruce (Picea abies, P, obovata, P. ajanensis and others), fir (Abies sibirica, A. nephrolepis and others), pine (Pinus sylvestris, P. sibirica, P. koraiensis) and summergreen coniferous trees, the larches (Larix sibirica, L. dahurica and others).

Ecologists seek to capture with concepts the meaning of vegetation change. The idea that this change could be described and understood was a major development in the history of ecology, that may be traced back to Kerner (1863), Hult (1885, 1887), Warming (1891, 1896), and others [see preceding articles and reviews of Ludi (1921, 1930), Furrer (1922), Cain (1939), Whittaker (1953), and Aleksandrova (1964)]. In counterbalance to the idea of vegetation change it was natural to recognize the condition of relative vegetational stability that came to be known as “climax”. Early sources of the concept of climax include Hult (1885, 1887), Warming’s (1896) Schlussverein, the chief associations of Moss (1907, 1910), the stable formations of Crampton (1911, 1912), and the American work of Cowles (1899, 1901, 1910, 1911), and Clements (1904, 1905, 1916).

In southeastern United States, a region where the zonal vegetation is deciduous forests, shallow soils over limestone and dolomitic bedrock support edaphic climax herbaceous plant communities known as cedar glades. The flora includes over 400 species of vascular plants; 79 of these are winter annuals and 47 are summer annuals. This chapter reviews the life cycle ecology of both groups of therophytes in the cedar glade habitat in relation to their tolerances, requirements and adaptations. Temperature, through its influence on seed dormancy, dormancy break and germination, is the single most important environmental factor regulating the timing of the life cycle of annual plants of cedar glades.

In succession community and environment are coupled together as parts of a functional system in which the interplay among species populations and the interactions between community and environment determine the course of development. Development continues until a stable community or climax, adapted to steady-state function and self-maintenance of its species in its biotope as affected by itself, results. It seems reasonable to consider the community changes during succession a community-gradient or coenocline (even though some replacements of species populations may be relatively abrupt). The progressive changes in environment during succession may be considered a seral complex-gradient (though successions differ widely in the degree of environmental modification they entail). A succession is thus an ecocline in time, comprising a parallel and functionally related coenocline and complex-gradient.

The forms and concepts of sentimental literature were evolving slowly in Russia. I. Dmitriev’s poems appeared at the climax of the sentimental movement. Their author was familiar with the conceptual framework of sentimentalism which already had an extended history going back to the 1750’s and 1760’s in Russia,—and another fifty to a hundred years, if we think of England.

Aromatic plants are part of a more general class of plants which emit a variety of secondary substances. The role of their volatile oils, composed of isoprene compounds, is not clear; they may contribute to regulating water loss, making plants more flammable or act as defense mechanisms. Aromatic plants, include a variety of primarily small shrubs (e.g. Thymus, Cistus) and some herbs (e.g. Lamium, Mentha) which are especially characteristic of dry mediterranean climates (i.e. garrigue, phrygana, or bathe, as opposed to maquis). Some larger shrubs (e.g. Myrtus, Rosmarinus) and even small trees (e.g. Juniperus) may also be included. Such vegetation is usually considered to be a fire climax or subclimax, since it burns regularly. The frequency and intensity of such fires depend mainly on the amount of phytomass accumulated since the last fire and on its flammability.

During the first half of this century, the frame of reference for understanding vegetation was a stable or constant plant community — the climax — which developed in the absence of disturbance and which was dependent upon only climate. Ecologists recognized that such stable communities were seldom achieved. Most communities were in various successional stages, which nevertheless were thought to be trending towards the climax. So at least an ecologist knew where the vegetation was going even if it was not there. An underlying assumption of this model was constancy of climate. The more recent realization that climate is always changing greatly diminishes the value of this conceptual model for understanding vegetation (Davis, 1986). Vegetation as it grows today is the instantaneous state of a system responding to processes operating on various time and space scales. Populations are expanding, contracting, and migrating, often slowly, but at times rapidly. These changes in populations are key for understanding vegetation and are strongly influenced by historical events. A historical perspective is critical for interpreting such important dynamical properties of communities as (1) whether communities are in equilibrium or disequilibrium, (2) whether they are constant, stable, and persistent, and (3) whether their composition and diversity are determined by local, regional, or global processes (Grimm, 1984; Chesson and Case, 1986; Ricklefs, 1987).

Just before the First World War it was discovered that the addition of the rare metal molybdenum could form an alloy steel with superior properties for toolmaking. For many years the world’s supply came largely from this deposit. It is one of the most important deposits in the famous ‘Colorado Mineral Belt’, and in many respects resembles a ‘porphyry copper’ deposit, many of which also contain molybdenite. Climax was the home mine of a company of the same name, which was one of the partners of the merger that formed the international mining and metallurgical corporation, AMAX.

Net production and respiration of alpine dwarf shrub communities (Loiseleuria heath, Vaccinium heath) were determined. The results indicate that there is no gain in the biomass by these alpine dwarf shrub heaths at Mt. Patscherkofel (Central Alps near Innsbruck) over long periods. The production coefficient PB/R with little over 1 shows that these communities present a protective ecosystem (according to ODUM, 1972) with a closed nutrient cycle. The total gross primary production remains in this mature “climax” ecosystem.

Conventional ecological theory holds that grazing by livestock reduces productivity and alters botanical composition of rangeland plant communities. Changes in composition from that of the “climax” community are considered to be detrimental, but it is usually assumed that these changes will be reversed when grazing animals are removed. Reducing stocking rate and alternating periods of rest and grazing are attempts to mitigate undesirable effects of grazing. Recent research indicates that range ecosystems may retain their productivity and composition when grazed by livestock at seasons and stocking rates which resemble the grazing patterns under which the ecosystems evolved. Weather and fire may have more effect than grazing on productivity and composition, or may interact with grazing. In ecosystems with long-lived woody perennials, changes in composition may be reversible only after centuries or not at all. Finally, communities at early seral stages or communities including introduced plant species may be more productive than climax communities. All these findings indicate that protection of soil and maintenance of stable plant communities at whatever stage of succession may be more reasonable goals of grazing management than efforts to produce and maintain climax communities.

The phenomenon of succession cannot readily be separated from the whole of vegetation dynamics, which is the object of this section of the handbook. The complexity of vegetation change has been revealed to us in ever-greater detail since the turn of the century when Cowles (1899) and later Clements (1936) formally defined the phenomenon of community replacement and suggested that the combined forces of the environment were conducive to a sort of convergence which they called the climax.

Methods of tillage employed in Toledo range from primitive subsistence hoe farming to use of the most modern tractors, but oxen and plow predominate in this maize-oriented economy. Inasmuch as Toledo is in a climax stage of pioneering (with a large range of agricultural methods) the question must be raised as to whether the economy will become stagnant or will develop into a model of agricultural colonization complete with vertical integration. If Toledo is to achieve a high level of agricultural technology, outside help for the individual will be needed. This chapter examines present levels of agriculture and steps necessary for raising substantially the standard of living of individual colonists who have not as yet achieved operational levels beyond the pioneering stage.

Up to now, little attention has been paid to the relations of climate and cultivated plants by biogeographers, because they were more interested in natural vegetation. However, on account of the growing population pressure in developing countries, it becomes more and more necessary not only to know the climax vegetation but also the climax cultivation. This depends not only on climate of course, but climate is the first frame for any kind of land use pattern further differentiated by soils, marketing facilities and so one.

The insistence of plant geographers in giving undue importance to the influence of climate has been paralleled among ecologists ever since Clements proposed the concept of the climax, and among pedologists since the Russians developed the zonal classification of soils. There is a discussion in Beard (1945) of the difficulties surrounding the monoclimax theory in the tropics, while Beadle (1951) has spoken against it in an Australian context. The catenary sequences of soils and vegetation on the West Australian plateau immediately pose questions of status and development, as the example given for the Boorabbin area by beard (1969) well shows. Which of the five vegetation-types concerned would be considered as the climatic climax, and what is the status of the others?

When mineral material is exposed at the surface, it is gradually colonised by vegetation — herbaceous plants first of all, then shrubs, and finally, in a humid temperate climate, trees. At the same time, the soil forms and develops: first of all a humus-rich horizon is formed on the surface (AC type profile) then a (B) or B horizon gradually appears and thickens little by little: thus a succession of profiles of increasing development occurs in parallel with the succession of plant communities. This twofold development leads to a stable equilibrium that characterises both vegetation and soil, and which ecologists refer to as the climax; such a development towards the climax can be referred to as progressive.

The primary productivity of successional stages is of interest for various reasons. The climax communities in the different biomes of the world operate with different levels of biomass and humus per unit area. The contribution of the successional stages before the climax equilibrium is reached must be of primary importance for the early establishment of the climax community.

Judging by species composition we can quote some times of plant succession to a more or less equilibrium state. Ives (1941) believed the fire scar in Colorado which showed a plant succession from Salix to Populus tremuloides to Picea engelmanii—Abies lasiocarpa would vanish in some 300 years. Viereck’s (1970) Picea glauca forest along the Chena River of interior Alaska was 220 years old, and presumably the Picea mariana climax muskeg which developed from the more productive white spruce forest was only a few hundreds of years older. The succession in the subalpine belt of the Swiss National park described by Braun-Blanquet, Pallmann & Bach (1954: 43, 153—164) and Braun-Blanquet (1964: 669—673) probably developed a climax Rhododendreto-Vaccinietum cembretosumin somewhat less than 2000 years. Cooper’s classical studies (1923, 1931, 1939) of plant succession at Glacier Bay, Alaska have been followed up by Lawrence (1958), Decker (1966) and Ugolini (1966).

Some generalizations on plant community biomasses and their accumulation during succession are offered by Woodwell & Whittaker (1968). Their overall curve agrees more or less with Fig. 1. (of article 2). They postulate oscillations following a maximum although they define the climax as a steady state. In their discussion of a seral pine forest (Whittaker & Woodwell 1968, 1969), they calculate its respiratory losses are 83% (correcting their net ecosystem production figures) of annual gross productivity when 100% would be a steady state. This criterion cannot be used alone, however, since the increasing rate of litter losses (tree mortality, branch and root shedding, etc. cf. Rodin and Bazilevich 1965, 1967) is also important. A 17% growth rate on the curve of Fig. 1 would be a very high growth rate indeed.

Alpha diversity, or species richness, of East Asian mainland evergreen broadleaved forests, expressed by indices of Fisher’s alpha (α) and S(100), a new index showing species number in a 100-individual sample, is significantly correlated with the climatic favorableness, expressed by Kira’s warmth index. On the contrary, diversity values of insular forests studied on Kyushu satellites of Japan, the Bonins, the Eastern Carolines of Micronesia, and the Galapagos in the eastern Pacific, are below those expected from the climate of respective oceanic islands. Species-individual curves, comparing mainland-and insular communities, also support clearly the above conclusion of species poverty in the insular communities studied.

Five plant communities contrasting in successional status and human impact from the southern part of the ‘Wienerwald’ (Austria) are analyzed using vegetation releves, spectra of area types and a newly proposed disjunction quotient. A climax community (Asperulo-Fagetum), a subclimax community (Querco-Carpine-tum s.l), an anthropogenous substitute community (Mesobromion) and two natural, non-climax permanent communities (Euphorbio saxatilis-Pinetum nigrae and Fumano-Stipetum eriocaulis) are recognized.

Data are presented which suggest the mangal ‘climax’ is not necessarily at the rear of the mangrove swamp. Biomass and soil nutrients are greatest in the Bruguiera and/or Ceriops zone and leaf area ratio and environmental fluctuations (temperature) are least in the Bruguiera zone. Supporting observations are also discussed. It is suggested that if the mangrove climax is separated from the land by a series of sub-climax zones, mangrove and terrestrial succession are independent and it is not justified to view the mangal solely in terms of a pioneer assemblage leading to a terrestrial climax; but, rather, the mangal should be considered as an entire community with its own climax.

Range managers have generally accepted that assessment of range condition should be related to the successional status of vegetation on a given range site. The traditional concept of succession employed has been based on Clementsian ecology. Succession has been seen as an orderly process of ecosystem development leading, in the absence of abnormal disturbance, to a stable and predictable endpoint (climax) which is used as a standard for measuring condition. Regression from climax was viewed as a reversible, linear process related to the nature, degree and duration of disturbance (including livestock grazing). This approach has worked well in some grasslands but has not been adequate in situations where invasion of shrubs and exotic species is not spontaneously reversible, and it is not adequate for multiple use management or to report the real state of range management on public ranges. The climax approach is untenable in view of modern ecological theory which stresses the importance of disturbance and chance occurrence of rare events as they interact with life histories of plants and animals. Vegetation change may take multiple pathways and enter multiple steady states. New approaches to range condition assessment, more in line with modern ecology, are being developed to meet the needs of managers.

1. Development of mangrove forests from a geological perspective.- 2. Evidence for an Upper Carboniferous mangrove community.- 3. Ecological notes on the mangroves of Fujian, China.- 4. A general account of the mangroves of Princess Charlotte Bay with particular reference to zonation of the open shoreline.- 5. Aspects of the development of mangals in the Townsville Region, North Queensland, Australia.- 6. Distribution of mangrove species in Australia.- 7. The New Zealand Mangrove Association.- 8. Mangroves in New Zealand.- 9. An introduction to the nomenclature and taxonomy of the mangrove flora in Papua New Guinea and adjacent areas.- 10. Mangrove fishes of New Guinea.- 11. The faunal communities of Australian mangroves.- 12. Distribution of Phycomycetes in mangrove swamps with brackish waters and waters of high salinity.- 13. Inheritance of Albinism in the Red Mangrove, Rhizophora mangle L..- 14. Significance of cryptovivipary in Aegiceras corniculatum (L.) Blanco.- 15. Succession in zoned mangrove communities: where is the climax?.- 16. Degradation of mangrove leaf and stem tissues in situ in Mgeni Estuary, South Africa.- 17. Mangroves and sewage: a re-evaluation.- 18. Ecology of a mangrove swamp near Juhu Beach. Bombay with reference to sewage pollution.- 19. Impact of oil spills on mangrove forests.- 20. The effects of oil pollution on mangroves and fisheries in Ecuador and Colombia.

Girdling the Earth north and south of the equator are the world’s grasslands. Their distribution is determined by climate, soil and topography, but their existence is due also to biotic factors, principally grazing animals, and fire. Man, also, has extended the world’s grasslands by clearance of forests for cropping and for grazing his domestic animals (Fig. 1.1). Indeed, cultivated grasslands, established in regions whose natural climax is forest, are the most intensively used and, agriculturally, the most productive. The evolution and ecology of the grasslands are complex and controversial (Moore, 1964) and man’s activities have so modified the world’s grasslands that, today it is often difficult to distinguish the natural from the man-made. The casual observer viewing the brown top clad foothills of New Zealand’s South Island may be surprised to learn that the species (Agrostis tenuis) only arrived in New Zealand with the European settler! There is disagreement as to whether the natural grasslands represent a climax community and about the extent to which the distribution of grasslands is determined by climate as against soil and biotic factors (Moore, 1964). Limited rainfall, or at least the occurrence of a dry season, especially when reinforced by other factors, particularly fire and grazing, appears to be a common factor preventing the formation of a forest canopy.

Bare Ground and open water are the classical starting points for describing ecological succession in vegetation, with its stages (often broken, delayed or diverted) towards climax that are adopted here as the main basis for formation-types in defining animal habitats. They were indeed the actual starting points for all those parts of the country’s surface covered by the last ice-sheet, or destroyed by frost and flood on the periphery (cf. Plate II). It is now quite established192 that a good many of the plants and at least some of the animals that had widely colonized the bare and open ground of Full-glacial and Late-glacial times — that is, over 10,000 years ago — have since survived on maritime cliffs and shingle and dune, or on mountains, where conditions are still sufficiently unstable or climatically extreme to maintain the right conditions. Godwin gives a list of eighty-one such species (for example the moss campion, Silene acaulis, and the dwarf willow, Salix herbacea) of open mountain or subarctic habitats that then occurred widely in the lowlands, and are now chiefly found on cliff-ledges, screes and subalpine meadows. He also has a list of forty-six ‘weeds’ of arable land, saying that ‘The very long list of species which we now regard as ruderals or weeds indicates the prevalence of open conditions, bare soil surfaces and freedom from competition in the Full-glacial and Late-glacial periods alike.’ Some of these species are really more meadow forms than weeds of arable land, e.g. the bladder campion, Silene cucubalus, and the greater knapweed, Centaurea scabiosa.

In the spring of the year 1898 the long rivalry of Britain and France in West Africa reached a dangerous climax. At stake was dominance within the great western bulge of Africa via control of the Niger River along its middle course. The contest for possession of this thousand-mile stretch of the Niger was waged for the most part quietly throughout the final decade of the nineteenth century. Aside from an occasional flurry of diplomatic activity or a foray by an English or French officer into some little known realm of the Western Sudan, the protracted struggle for control of the river artery received comparatively little notice. Even the crisis of the spring of 1898 has been somewhat neglected by students of the African partition, perhaps because the Fashoda confrontation of October has tended to overshadow the events of May and June in the boucle du Niger — the great bend of the Niger in its middle course — so that the earlier climax appears merely a curtain raiser.1 Perhaps also the complexities of the geographical factors along with the extended duration of the dispute has served to diminish the significance of the West African crisis and of the Anglo-French Convention of 14 June, 1898 which resolved it. But since the accord established the northern and western frontiers of Nigeria, yoking together a vast and dissimilar population of tribes whose pre-partition associations had been minimal, it had an enormous impact upon millions of Africans.

In the nights preceding the expected return of their Messiah instructions were given on how contact with the dead and the return of the Koreri could be brought about. This was to be achieved by reaching an organized climax by the performance of appropriate songs and dances and by the use of imitative magic. Mass-psychosis, artificially achieved visions, possession and glossolaly are attendant phenomena.

The reform measures undertaken by Pius IX at the beginning of his reign in 1846 were coincidental with the outbreak of revolution in Europe. His innovations in Italy were the climax of a movement which, sporadic in Italy since 1815, revealed a much greater strength than before and also a wider range of activity. Through the earliest of his policies, which were at once economic and political, the reforming pope brought his government into conflict with that of Austria. The collision of these interests enlarged the already evident contrast between the status quo and reform, between the principle of autocratic suppression and that of constitutional amelioration.

Malenkov’s resignation from the Premiership at the February 1955 Supreme Soviet session marked the close of the second period of the post-Stalin era.1 It would be an oversimplification to consider this merely the climax of personal rivalries, although that element was present. His downgrading actually symbolized the destruction of the coalition which had ruled Russia for the 18 months following Beria’s unsuccessful bid for power and the formation of a new one oriented around Khrushchev, but not completely dominated by him.

The last hundred days were to climax with unanimous press support for American participation in the war. Paradoxically, the period opened with widespread and deep sentiment for peace. The campaign of 1916 had indicated that there was great popular feeling for remaining neutral in the war. Wilson’s re-election underscored this sentiment. To many observers in the press, the decisive “out of war” slogan had implicated the President in an effort to seek an end to the war. After Hughes officially conceded on November 23, New York journalistic circles were rife with reports of peace “feelers” and proposals.