International Association for Lichenology: the early years.
One of the main purposes of the International Association for Lichenology (IAL), inaugurated in 1967, was to establish a Newsletter in order to provide a forum for lichenologists worldwide to communicate with each other. In consequence, the early history of the IAL is in large degree the story of the International Lichenological Newsletter (ILN). Those responsible for organising the IAL at this time were essentially the editors of the Newsletter, hard-working people, collating hundreds of short notes on lichenologists and their current projects and opinions from all over the world, as well as reports of meetings and social events. Although the possibilities of communication have increased enormously in recent years, the function of IAL and its Newsletter remain the same, and the initial enthusiasm for exchanging ideas and results and reporting meetings continues undiminished.
Analysis of chemical and morphological variation in the Ramalina siliquosa species complex
In an attempt to clarify the taxonomy of the polymorphic maritime lichens of theRamalina siliquosa group in Europe, variation was analyzed in visible and chemical characteristics of 1042 specimens from four localities (one station each in Scotland, Wales, England, and Brittany). The plants belong to six major chemical types representing a replacement series of closely related medullary depsidones. There is a broad correlation of chemical and visible traits. The narrower-lobed often basally blackened individuals (corresponding approximately to the usual concept of “R. curnowii”) produce no medullary constituents nor norstictic or stictic acids. The broader-lobed unblackened ones (corresponding approximately to the usual concept of “R. siliquosa”) produce stictic, salazinic, protocetraric, or hypoprotocetraric acids. The proportion of each chemical type in the four populations studied varies markedly. The southern (English and French) populations together contain all six chemical variants in roughly similar proportions. However, to the north, in Wales and Scotland, the populations become simpler as some chemical races drop out and salazinic acid-producing plants predominate. These findings correlate well with the general geographic distribution of the chemical variants from a study of 117 herbarium specimens. The chemically distinct plants have different amplitudes of ecologic tolerance which appear to regulate niche selection in theRamalina zone, the conspicuous vegetational belt which these lichens form above the intertidal zone on the Atlantic and Baltic coasts of Europe. The complex is interpreted as a set of six species differing to an extent by visible traits but primarily by chemical, geographical, and ecological ones. Three of the species are new:Ramalina atlantica Culb.,R. stenoclada Culb., andR. druidarum Culb. A hypothetical scheme is suggested to explain the evolutionary origin of the species recognized.
Mississippian Barnett Shale: Lithofacies and depositional setting of a deep-water shale-gas succession in the Fort Worth Basin, Texas
The Mississippian Barnett Formation of the Fort Worth Basin is a classic shale-gas system in which the rock is the source, reservoir, and seal. Barnett strata were deposited in a deeper water foreland basin that had poor circulation with the open ocean. For most of the basin's history, bottom waters were euxinic, preserving organic matter and, thus, creating a rich source rock, along with abundant framboidal pyrite. The Barnett interval comprises a variety of facies but is dominated by fine-grained (clay- to silt-size) particles. Three general lithofacies are recognized on the basis of mineralogy, fabric, biota, and texture: (1) laminated siliceous mudstone; (2) laminated argillaceous lime mudstone (marl); and (3) skeletal, argillaceous lime packstone. Each facies contains abundant pyrite and phosphate (apatite), which are especially common at hardgrounds. Carbonate concretions, a product of early diagenesis, are also common. The entire Barnett biota is composed of debris transported to the basin from the shelf or upper oxygenated slope by hemipelagic mud plumes, dilute turbidites, and debris flows. Biogenic sediment was also sourced from the shallower, better oxygenated water column. Barnett deposition is estimated to have occurred over a 25-m.y. period, and despite the variations in sublithofacies, sedimentation style remained remarkably similar throughout this span of time.