The family Leguminosae provides the classical examples of root nodule plants, and owing to the agricultural importance of that family of plants their root nodules have received continuous investigation for more than 50 years. Though no other large family is similarly characterised by the possession of root nodules, such structures are shown by a number of genera which occur in curiously scattered fashion through the Phanerogams, the only other particular feature in common being that the plants concerned are practically all of woody type. These non-legumes have been the subject of sporadic investigation, chiefly from the standpoint of the identity of the endophytes. Three nodulated genera represented in Europe are those mentioned in the title. These plants are abundant in the appropriate habitats, and the question of the functional significance of their nodules is of ecological and general interest.The species to which this paper refers are Alnus glulinosa (L.) Gaertn., Myrica gale L. and Hippopha~ rhamnoides L. In addition to the function of the nodules, the extent to which their development and activity are affected by environmental factors will also be considered. The comparative treatment of the three species will be based partly on new observations and partly on data already published by the authors in respect of individual species. Aspects which will not be specifically considered include the structure and cytology of the nodules, and the systematic position of the endophytes. In the last connection it may be noted that the endophytes *) Now of the West

Suminary. The growth has been tested in vitro of selected species of fungi, yeasts, bacteria, actinomycetes and green algae in the presence of the acetic and y-butyric acid forms of MCPA, 2,4-D and 2,4,5-T, The results show that at concentrations approximating to field rates of application, these chemicals were harmless. At much higher concentrations (above 500 ppm), however, the y-butyric acids were found to be highly toxic whereas the acetic acids has no effect on growth, Croissance in vitro de microorganismes en presence d'acides phenoxyacetiques et phenoxybutyriques substituesResume. Des especes choisies de champignons, de levures, de bact^ries, d'actinomycetes et d'algues vertes ont 6t^ cultiv^es in vitro en presence des formes d'acides ac^tique et y-butyrique du MCPA, du 2,4-D et du 2,4,5-T, I.es r^sultats montrent qu'a des concentrations voisines de celles obtenues dans les applications au champ, ces produits sont sans action nocive, Toutefois, a des concentrations beaucoup plus 61ev6es, (au-dessus de 500 ppm), les acides y-butyriques furent extremement toxiques alors que les acides ac^tiques n'avaient pas d'action sur la croissance. Die Beeinjlussung des \n-v'\\.to-Wachstums von Mikroorganismen durch substituierte Phenoxyessigsduren und PhenoxybuttersaurenZusammenfassung. Die Beeinflussung des m-Btira-Wachstums von bestimmten Pilzarten, Hefen, Bakterien, Actinomyceten und grunen Algen durch die Essigsaure-und y-Buttersaureformen von MCPA, 2,4-D und 2,4,5-T wurde untersueht, Konzentrationen, die ungefahr den praxisublichen Aufwandmengen entsprechen, schadigten die Mikroorganismen nicht, Bei viel hoheren Konzentrationen (uber 500 ppm) erwiesen sich jedoch die y-Buttersauren als sehr toxisch, wahrend die Essigsauren das Wachstum nicht beeinflussten,

Summary: Studies of the absorption and translocation of foliage‐applied ring‐labelled [14C]asulam [methyl (4‐aminobenzenesulphonyl) carbamate] were carried out using glasshouse and field‐grown bracken plants. Translocation of 14C from the treated frond was primarily according to a 'source to sink’pattern with intense accumulation of radioactivity in the metabolically active sinks viz. rhizome apices, frond buds, root tips and young frond tissue. In the case of field bracken, translocation and distribution of 14C was extensive in the rhizome system, accumulation occurring in the active as well as dormant buds situated on the non‐frond‐bearing and storage rhizome branches. Treatment of fully expanded fronds with 100μl of [14C]asulam (1 mg, 1.0–1.5 μCi) as 2 μl droplets resulted in a rapid initial uptake during the first week, followed by progressive entry and distribution with time. Basipetal translocation to the rhizome system was positively correlated with total uptake. High humidity (95%) and high temperature (30°C) stimulated uptake and subsequent basipetal translocation to a considerable degree. Uptake was greater through the stomatal‐bearing abaxial than through the adaxial cuticle. Incorporation of a surfactant (Tergitol‐7, 0.1%) increased penetration by up to 30%. Uptake declined markedly as the frond aged, while translocation was predominantly acropetal in young treated fronds, becoming exclusively basipetal when the fronds matured. Optimum uptake and maximum distribution of [14C]asulam in the rhizome and its associated buds was achieved when treatments were applied to almost fully expanded fronds. The translocated 14C (asulam and possibly some of its metabolites) showed a considerable degree of persistence in the rhizome system, 8% of the applied activity still remaining in the rhizome 40 weeks after treatment.

Foliage‐application of 4.4 kg/ha asulam [methyl (4‐aminobenzenesulphonyl) carbamate] to field bracken reduced frond density by 97.1, 87.6 and 77.8%, one, two and three years respectively, after treatment. Examination of the rhizome system from these plots revealed that a high proportion of the rhizome apices and frond buds were killed, the remainder being damaged or remaining dormant. Autoradiography of bracken plants grown from sporelings or fragments and treated with 14C‐ring‐labelled asulam revealed that uptake was rapid and progressive with time, whilst translocation was generally basipetal showing a typical source‐sink pattern, with intense accumulation in the apices and buds. Optimum penetration and basipetal translocation was achieved when treatments were applied to almost fully‐expanded fronds; application to immature fronds resulted in predominantly acropetal movement. Basipetal translocation was extensive in field bracken, accumulation occurring in the buds distant from the base of the treated fronds. There was evidence that asulam was relatively persistent in the rhizome system, 59 and 8% of the applied activity remaining in the rhizome, one and ten months respectively, after treatment. Hydrolysis of asulam produced small amounts of sulphanilamide (<10%) and traces of sulphanilic acid, 4‐aminophenol and benzene sulphonamide. Studies on the effect of asulam on the incorporation of 14C‐labelled precursors into RNA and protein indicate that inhibition of RNA and protein syntheses may be major sites of action of asulam.

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