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This short paper presents some results of an attempt to derive a suitable function to explain unit costs in the water supply industry in England and Wales. The data we used were the latest available at the time of writing. The data, in effect, were for the year 1965-66. It was not possible, because of lack of data, to carry out a time-series analysis to supplement our cross-section findings. At the moment the industry is composed of some 331 undertakings; our sample, which is based on data provided by I.M.T.A.,' covers 162 of those under- takings. In effect, it covers: 67 local authorities; 75 water boards; and 20 water companies. In this paper then we are concerned with the derivation of an industry average cost curve, or function. Although the resulting curve could be similar to the envelope curve, or to part of the envelope curve, as we know it, it will differ from the usual conception of that curve because of the nature of production conditions in the water supply industry. Section II notes the type and characteristics of the four cost functions we have fitted to the data. Section III briefly presents and assesses the statistical results obtained from using those functions. Section IV then makes some comments on the major issue of amalgamation in the light of the statistical results.

The article focuses on the ecological and historical factors in the distributions of the British Helianthemum species. Among the specie of these plants is the Helianthemum chamaecistus which is widely distributed in short dry chalk and limestone grasslands in Wales and England. It is dominated by Festuca ovina, Seslerina caerulea, and Zerna erecta, and appears in substrata in dry Agrostis tenuis-Festuca ovina grasslands in Scotland. On the other hand, H. apenninum is confined to open xeric grasslands on slopes that faces south on Carboniferous and Devonian limestones in Southwest England.

The article looks into the rate of spread of Spartina townsendii in the sandy lower parts and relatively muddy upper areas of the Dovey estuary. It also examined the competition of two aspects of Spartina with other salt-marsh species. The invasion of established Spartina and the invasion of grazed saltings by Spartina were also investigated. Quadrats found in sandy and relatively muddy areas revealed that the muddy area was completely covered with Spartina in two or three years. The study also revealed that the invasion of established Spartina by other salt-marsh species is a conspicuous feature of the estuary. Existing vegetation in the estuary were not affected by the invasion of established Puccinellia, Armeria and Festuca sward by Spartina.

The article offers information on Impatiens parviflora, an erect annual herb, and its presence in Great Britain. The plant has stems branching from the axils of the cotyledons. Its flowers are 10 to 15 millimeters long including spur. Its seeds are oblong with fine longitudinal striations. The plant is frequently persistent in gardens and shady waste places in various parts of England, Wales and Scotland. It discusses the habitat, climatic and topographical limitations of the plant. It lists the most frequent species at more than 1 of 19 localities in England and Scotland.

The article offers observation on the ecology of Juncus conglomeratus and Juncus effusus in Great Britain. Differences in their capsule and stem are the only thing that separates the two species. It notes that the Biological Flora of the British Isles failed to take into account the very widespread distribution of the J. effusus variety, which is often mistaken for J. conglomeratus. Specimens of J. conglomeratus can be found in some Wales localities such as the Conway Valley and Cwm Gwara. The distribution of these species can be described as patchy and rare among an abundance of other rush species. However, J. effusus species and its variety have an extensive distribution on the mountain slopes, poor pastures retrogressive to moorland, and open parts of the woods in North Wales counties.