-Leaf morphology was assessed in nine mixed oak stands (Quercus petraea and Q. robur) located in eight European countries. Exhaustive sampling was used in an area of each stand where the two species coexisted in approximately equal proportions (about 170 trees/species/stand). Fourteen leaf characters were assessed on each of 5 to10 leaves collected from the upper part of each tree. Three multivariate statistical techniques (CDA, canonical discriminant analysis; PCA, principal component analysis; MCA, multiple correspondence analysis) were used in two different ways: first on the total set of leaves over all stands (global analysis) and second, separately within each stand (local analysis). There was a general agreement of the results among the statistical methods used and between the analyses conducted (global and local). The first synthetic variable derived by each multivariate analysis exhibited a clear and sharp bimodal distribution, with overlapping in the central part. The two modes were interpreted as the two species, and the overlapping region was interpreted as an area where the within-species variations were superimposed. There was no discontinuity in the distribution or no visible evidence of a third mode which would have indicated the existence of a third population composed of trees with intermediate morphologies. Based on petiole length and number of intercalary veins, an "easy to use" discriminant function applicable to a major part of the natural distribution of the species was constructed. Validation on an independent set of trees provided a 98% rate of correct identification. The results were interpreted in the light of earlier reports about extensive hybridization occurring in mixed oak stands. Maternal effects on morphological characters, as well as a lower frequency or fitness of hybrids in comparison with parent species could explain the maintenance of two modes, which might be composed of either pure species or pure species and introgressed forms. morphology / leaf / Quercus robur / Quercus petraea / taxonomyRésumé -La différenciation morphologique des feuilles entre Quercus robur et Quercus petraea est stable à travers les peuplements mé-langés de chênes de l'ouest européen. La variabilité de la morphologie foliaire a été etudiée dans neuf peuplements mélangés de chênes (Quercus petraea et Q. robur) en Europe sur la base d'un échantillon exhaustif moyen de 170 arbres/espèce/peuplement. Trois méthodes d'analyses multivariables ont été utilisées (ACD : analyse canonique discriminante ; ACP : analyse en composantes principales ; AFC : analyse factorielle des correspondances). Les trois méthodes aboutissent à des résultats congruents. La première variable synthétique de chaque méthode se Ann. For. Sci. 59 (2002)

p-Glucans in barley endosperm cell walls exist as polymers of very high molecular weight (about 4 x 107 daltons) containing firmly linked peptide sequences. This peptidic material is an essential part of the structure of the p-glucan complex as it exists in the cell wall. Rupture of peptide bonds by hydrazinolysis or with the proteolytic enzyme thermolysin gives p-glucans similar in size to those from short-grown green malts (about 106 daltons). This suggests that proteolysis is the first step in p-glucan degradation.Large p-glucans are not all precipitated in 30% (w/v) ammonium sulphate; only 34% of the p-glucan in a hot aqueous extract of cell walls is precipitated. The amount is increased to 63% if the cell walls have been previously dehydrated.Prolonged incubation of cell wall p-glucan at 40°C, mechanical stress, chromatography lasting 8-10 h at or above 65°C, or chromatography in M sodium chloride causes some disassociation of high molecular weight p-glucan to a size of about 107 daltons. Heating a solution for 1 h at 100°C does not disassociate the p-glucan.Pentosans isolated from cell walls are not covalently linked to the p-glucans and can be separated from them by molecular sieve chromatography. They have a higher xylose/arabinose ratio than previously reported for barley pentosans. The pentosan molecules extracted by water are smaller (106 daltons) than those extracted by alkali (5 * 106 daltons).Little difference was observed in the chemical or physical properties of cell wall materials of barley cultivars of different malting qualities.

Heresy was the most feared crime in the medieval moral universe. It was seen as a social disease capable of poisoning the body politic and shattering the unity of the church. The study of heresy in late medieval England has, to date, focussed largely on the heretics. In consequence, we know very little about how this crime was defined by the churchmen who passed authoritative judgement on it. By examining the drafting, publicizing, and implementing of new laws against heresy using published and unpublished judicial records, this book presents a study of inquisition in medieval England. It argues that because heresy was a problem simultaneously national and local, detection relied upon collaboration between rulers and the ruled. While involvement in detection brought local society into contact with the apparatus of government, uneducated laymen still had to be kept at arm's length because judgements about heresy were deemed too subtle and important to be left to them. Detection required bishops and inquisitors to balance reported suspicions against canonical proof, and threats to public safety against the rights of the suspect and the deficiencies of human justice. The major figures in the prosecution of heresy were Thomas Arundel and Henry Chichele, archbishops of Canterbury. At present, the character and significance of lollardy, the heresy associated with John Wyclif, in late medieval England is the subject of much debate. The book considers that this debate has to be informed by a greater awareness of the legal and social contexts within which heresy took on its many real and imagined attributes.

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