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The article presents various titles of research papers related to geography by the Association of American Geographers. Some of papers included are "The General Magnetic Survey of the Earth," by L.A. Bauer, "Land Sculpturing in Arid Lands with Observations from Northeastern Africa," by W.H. Hobbs, "The Platforms of Barrier Coral Reefs," by T. Wayland Vaughan, "Botanical Phenomena and the Problem of Coastal Subsidence," by D.W. Johnson, "Characteristics of the Mississippi Delta in the Light of Comparative Studies of Some Old-World Deltas," by E.W. Shaw.

The article provides an overview of various publications on foreign vegetation. The Finnish Forest Survey deals with the results of estimations of the forest vegetation, tree production and soil character, along 39 survey lines. The paper "The Plant Formations on the Coral Reefs Along the Northern Coast of Cuba," by J. C. Th. Uphof in the "American Journal of Botany," found that the reefs form masses of stone near the shore or at some distance out. The principal vegetation types occurring west of the hundredth meridian are enumerated in "Types of Vegetation in the Semiarid Portion of the United States and Their Economic Significance," by A. E. Aldous and H. L. Shantz in the "Journal of Agricultural Research."

Features a book offering perspectives on arid land regions. Range of topics and subject matter explored by the book; Author credits; Publisher information.

The article offers information on Haloxylon articulatum in, an unpalatable subshrub that characterizes the Haloxyleto-Hordeetum of the Syrian arid zone. It is said that the seeds germinate quickly in a wide range of temperatures, but the temperatures are similar to those that exist in nature during the seed dispersal season. It is mentioned that the fruit lacks inhibitors since the seeds germinate without fruit-wing removal or leaching. Germination is indifferent to lightand soil levels and is able to occur at up to four percent sodium chloride.

The article focuses on the study of three populations of wild rabbit confined with large enclosures to determine various aspects of rabbit biology. The influence which rabbits exert on pastures has received limited attention from Australian workers, despite of its well-documented evidence published by British workers which showed damage pastures brought by rabbits. The study started in July 1957 in the three tow acre enclosures with tree densities of rabbit populations. Moreover, several studies reveal the harmful effects of rabbits on every class of habitat which they inhabit from alpine to semi-arid regions. In addition, rabbits seems to be more competent than sheep in selecting pastures for food.

Focuses on the nature and origin of the Canadian Dry Belt, dry regions in the Great Plains of North America. Measurement of annual precipitation; Variability of precipitation; Classification of climate.

Heavy exploitation of groundwater resources, with the help of government credit and infrastructural investment, has created the most important agricultural/district of Baia California Sur in the Santo Domingo Valley. Colonization of the Valley in the 1950s illustrates the interrelated problems of opening desert land for agriculture. These problems involve adjustment to the natural environment and to the sociopolitical milieu that produced the need for colonization. Attempts to ‘extend the life’ of the Valley include new water-conserving irrigation techniques and diversification of the economy, but these attempts appear threatened by demands for redistribution of land to the evergrowing number of landless poor. [ABSTRACT FROM AUTHOR]

The article examines the germination characteristics of three annual species from an arid region of Western Australia. The three species include the summer-germinating grass, Aristida contorta, and the winter-germinating composites, Helipterum and Helichrysum cassinianum. According to the author, Aristida contorta and Helipterum occur over large areas of the central and eastern arid areas of the state. The author also discusses germination of seed in samples of soil, temperature effects on germination, seed storage, seed viability and seed treatments.

The article deals with the occurrence of striped vegetation patterns on sheet wash surfaces of the arid and sub-arid zones. Based on the article the stripes are commonly seen on gently sloping surfaces. Unlike the intervening lanes between vegetation, it is claimed that the stripes are denser, taller and physiognomically more complex. The linear groves of Acacia aneura on sheet wash slopes in Western Australia occur on siliceous hard-pan soils, while the brousse tigrée studied in Niger were formed by woodland strips of Combretum species.

The article focuses on the seasonal heat resistance limits of the plants in Western Australia and their connection with water deficits, cell sap properties as well as the regeneration ability of heat damaged plants. Based on earlier literature on leaf heat resistance limits for arid and semi-arid regions in Western Australia, semi-succulent and woolly, mesophytic species have higher resistance values compared to Acacia. In 1969, researcher W. Schwarz observed that the heat resistance limit of Pinus cembra and Rhododendron ferrugineum is affected by the prevailing temperature, the daylength and the endogenous rhythm.

The article examines the characteristics of the deserts of Western Australia. It aims to determine where the boundaries of these deserts lie and in what way they are distinguished from one another and from other parts of Western Australia not popularly considered to be desert. It also presents a historical review of the exploration of this area, given down to the botanical exploration of the past 7 years. The article concludes with some discussion of the potential for economic use of this area and of the growth forms of Australian desert plants.

The article presents an ecophysiological studies on Rhagodia baccata (Labill.) Moq. in arid and semi-arid regions in western Australia. The study reveals that the plants exert control over water loss and have a higher net assimilation rate as compared to other native plants of Western Australia. Moreover, the plants also have a high resistance to heat and has drought-resistant properties. These also exhibited capacity to grow on a wide range of soil types, ease of propagation, and pallability for sheep.

The article presents a study which examines the patchiness of vegetation in the semi-arid land of the northern Sudan. Examples of types of patchiness in the distribution of vegetation and their causes are discussed. The study found that the patchiness is chiefly due to the variability of soil moisture conditions which result from the interaction of topography, water, wind, soil characteristics and vegetation itself. It is said that the interaction between wind, water, topography, soil and the vegetation itself plays an important role in the occurrence and distribution of vegetation in the semi-arid regions.

The article discusses the cacti species' cold resistance and its geographical distribution. According to the study conducted by the Department of Botany at the University of Arizona in Tucson, Arizona, the geographical distribution of cacti, which are entirely adapted to a dry climate, is mainly dependent on the cold resistance of the species. It also says that not only cold resistance manifest itself for the new species occurring in the northern latitudes of the U.S. and Canada, but it determines the distribution of cacti at the higher altitudes proximity to the southern deserts where they are abundant. Furthermore, various species of cacti are also presented.

This article discusses the definition of xerophily. In 1822, the term xerophyte was introduced as referring to plants that inhabit dry places. But since then, various definitions were introduced by writers. In 1889, xerophyte was defined as a plant of dry locality that shows the effects of warm sun and dry air. Then in 1913, a writer defined the term as a plant of dry locality exhibiting diminution in transpiration. Based on examinations of available evidences, xerophily cannot be defined in terms of habitat, of anatomy, or of physiology alone. This term is a natural conception that involves the total reaction of plant to environment.

A general survey of the pollen-rain from the vegetation of north-west India is described. The Survey is based on the study of 114 modern pollen spectra from sixty-four different sites. It is revealed that with certain qualifications the major aspects of the extant vegetation belts of north-west India are reflected in the pollen-rain falling within them. In the territory as a whole, the pollen of herbs dominates that of trees and shrubs except in close proximity to one of the latter. Amongst the woody plant pollen that of shrubs is commonest in the arid belts but tree pollen asserts itself as rainfall increases. The long-distance transport of pollen from one region to another does not affect the overall picture of the pollen-rain to any significant degree except in the areas bordering the Himalayas where pine pollen is over-represented. Cerealia type pollen usually occurs in areas where there is cereal cultivation but remains unrepresented in the very arid belt which is free of cereal agriculture. The pollen frequencies of Acacia, Prosopis, Zizyphus, Salvadora, Maytenus and the species belonging to Leguminosae, Labiatae and Geraniaceae are Under-represented. On the other hand 5% pine pollen occurs even as far as 600 km from the source. [ABSTRACT FROM AUTHOR]

In the present study the whole sample of 772 desret gerbils was collected from the semi-arid areas in and around Jaipur (Rajasthan, India). The male exhibits active spermatogenesis and well maintained accessory reproductive organs at any time of the year. Reproductive organs of the male gerbil are bridfly described. The vaginal and urinary openings are independent in the gerbil. There are four pairs of mammae. Follicular development takes place cyclically. Maximum artresia of follicles is noticed during metoestrus. A well developed Graafian follicle measures 590 μ across its widest diameter. The average diameter of the ovum is 65 μ. At the time of ovulation formation of stigma occurs which gives way to the ovum. The corpus luteum is formed from the remaining granulosa cells of the ovulated follicle. Fully formed corpus luteum of the cycle (during dioestrus) measures 740 μ. Maximum development of the corpus luteum is seen during late pregnancy (22-25 days) when it measures 1250 μ. During pregnancy large Graafian follicles are absent. After parturition the ovary shows corpora lutea of lactation. Histological changes in the uterus and vagina during the oestrous cycle of the gerbil are described. There is less proestrus distension of the uterus as compared with the rat. During oestrus the uterine endometrium hypertrophies and there are some degenerative changes in the epithelial lining. The changes in the vaginal epithelium are clear cut and are correlated with the ovarian activity. During proestrus proliferation of the epithelium occurs and at 'heat period' or oestrus the epithelium shows formation of the stratum corneum and the shedding of cornified cells. In the dioestrus the vaginal epithelium is heavily infiltrated by leucocytes. There are three peaks in the incidence of pregnancy rate, i.e., February to April, July, and September to November. Pregnancy rate is lowest during monthly litter size shows almost similar changes. The average length of gestation period is 30 days. There is post-partum heat in this animal. Formation of a vaginal plug is noticed following copulation. [ABSTRACT FROM AUTHOR]

The poor quality coal of Leigh Creek. South Australia, located in an arid region and isolated from the populated areas of the state, has lain unused for most of the time since its discovery. But in the post-war years economic pressures and technical advancements have brought about the utilization of these deposits. In the development of the coalfield many problems have arisen, not the least of which was the need to establish a town with all the necessary amenities in a harsh environment and to devise efficient techniques for the mining, transport, and utilization of the coal. However, changing economic conditions and technology, making available alternative sources of energy at competitive prices, will ultimately lead to the abandonment of the Leigh Creek coalfield, probably long before the coal deposits are physically exhausted. [ABSTRACT FROM AUTHOR]