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Notes: Seedlings of white clover (cv. Grasslands Huia) were introduced as spaced plants into 3-year-old monoculture plots of eight grass species (Agrostis capillaris, Agrostis stolonifera, Dactylis glomerata, Festuca rubra, Holcus lanatus, Lolium perenne, Phleum pratense and Poa pratensis) during June 1984. In mid-April 1985 plots were split for application of propyzamide at the following concentrations: 0, 0·2, 0·4, 0·6 kg a.i. ha-1.During 1984 differences between clover seedling growth in the different grass species became apparent within 2 weeks; growth was greatest in F. rubra, P. pratensis and H. lanatus and smallest in D. glomerata, L. perenne and P. pratense. During 1985, when more N fertilizer was given, H. lanatus and D. glomerata, were equally competitive and clover contributed only 16–18% of the total herbage yield of 10·4 t ha-1 in them, compared with 33–50% of yields ranging from 9·6 to 119 t ha-1 in the other six species. Propyzamide decreased grass growth in mid-season by more than 50% but there was little overall persistent benefit to clover yield, except for A. stolonifera and P. pratense with 0·4 and 0·6 kg ha-1 treatments. Dactylis glomerata and perenne were least and H. lanatus, F. rubra and P. pratensis most suppressed by the herbicide.Possible reasons for the overall large clover contribution from a very sparse seedling population and the relatively small effects of propyzamide are discussed as well as future work required to improve the predictability of effects of grass suppression.

Notes: White clover (cv. Grasslands Huia) was slot-seeded in April 1982 into plots of permanent pasture of differing botanical composition and reserves of soil phosphate. In one investigation the short-term effects of placing different amounts of phosphate (P2O5) in different positions in relation to the slot were investigated. In another, emphasis was given to effects of a grass-suppressing herbicide, propyzamide, on herbage growth and clover contributon during the second year.Fewer seedlings established on plots with a high initial P status and abundant in Holcus lanatus and Alopecurus pratensis than on plots deficient in P2O5 and dominated by Agrostis capillaris and Festuca rubra. P2O5decreased numbers of establishing clover seedlings when applied in the slots but not when placed beneath them. Growth was increased most when placement was beneath the slot. Application of P2O5to plots previously supplied with it resulted in 7.2 g total above ground and 1.7 g stolon dry weight (m row)−1compared to 1.3 and 0.1 g respectively in plots with low reserves and DO applied P2O5.Propyzamide greatly increased the yield and the contribution of clover in the presence of high initial P status and applied P2O5. Without propyzamide, clover made only a small contribution until July, averaging 7% for the whole season with little benefit from residual P. Clover growth in late summer was increased from 41 to 292 kg DM ha−1 where P2O5 was applied to P-deficient plots sprayed with propyzamide in the previous autumn. The large increases in clover contribution following propyzamide application were accompanied by small decreases in total seasonal yield of grass. The proportions of H. lanatus and. F. rubra. were decreased and of A. capillaris, increased.Spread of clover from the slots was slow during the first year but was encouraged by both P2O5 and propyzamide during the second year. Factors requiring further investigation are discussed.

Notes: Seeds of six cultivars of white clover were sown in 1983 in slots in tares of permanent pasture in soil-filled tanks in spring and in small plots in the field during midsummer. The clover cultivars investigated were the large-leaved Olwin and Milk nova, the medium-leaved Grasslands Huia and Aberystwyth S100, and the small-leaved Kent Wild White and Aberystwyth S184. Seeds from an indigenous clover population were also sown in the tanks. All herbage was defoliated at three- to six-week intervals to simulate rotational grazing and assessments were made until autumn 1984.Leaf and stolon production and spread of stolons from the slots were more rapid in Milkanova, S184, Huia and Kent than in Olwen and S100 In the tanks, harvested yields of clover leaf and petiole were largest for Milkanova and Olwen and least for the indigenous population; both Olwen and S100 had a smaller percentage of their total weight outside the slot area than had the other varieties. In the field, Milkanova greatly out yielded all other varieties and S100 yielded the least, contributing 48 and 27%, resf actively, to total herbage yield. The yield of grass differed little between varieties in tanks but in the field it tended to be higher with the smaller than with the larger-leaved varieties. Total herbage yield was largest for Olwen and Milkanova in tanks and for Milkanova in the field. The greatest weight of stolons in tanks was produced by Olwen and in the field by Olwen and Kent, but the greatest length of stolons and number of nodes in both environments occurred in the smalt-leaved varieties, especially Kent. Least length of stolons and fewest nodes in the tanks were produced by Olwen and in the field by Milkanova.It was concluded that all the varieties investigated could be successfully slot-seeded into permanent pastures but that the choice of variety will depend on subsequent use and management of the resulting swards.

Notes: We have studied three examples of benign thyroid tumours which conform to the lesion recently described as hyalinizing trabecular adenoma. The prominent feature of this trabecular epithelial lesion is the extracellular deposition of an eosinophilic material that does not show the features of amyloid; the epithelial cells may be elongated, sometimes radially arranged around the eosinophilic material. All three tumours showed positive immunocytochemical staining for thyroglobulin, keratin, chromogranin and neuron-specific enolase. One tumour showed isolated cells with immunoreactivity for somatostatin, argyrophil cytoplasmic granularity with the Grimelius technique, and ultrastructurally demonstrable cytoplasmic electron-dense endocrine granules. The hyaline extracellular material in all three tumours showed strong immunoreactivity for both type IV collagen and laminin. Previous radiation may be important in the causation of this tumour, and it shows a frequent association with severe thyroiditis. We conclude that the main histological feature of this lesion, the hyaline material, is due to the overproduction of a basement membrane-like material by the neoplastic follicular cells. The presence in one tumour of evidence of endocrine differentiation may reflect the potential for follicular cells to show biphasic differentiation, a feature which may be more frequent than has been previously recognized. Several of the other features of this tumour–-for example the frequent intranuclear cytoplasmic inclusions–-may lead to diagnostic problems, and the entity deserves wider recognition.

Notes: Summary. The growth of seedlings of Agropyron repens (L.) Beauv. and Agrostis gigantea Roth, in pots was studied in two experiments in 1968 and 1969. In Experiment 1 their growth was compared with that of wheat and in Experiment 2 they were grown in sandy loam (Woburn) and silt loam (Rothamsted) soil at four levels of nitrogen.Both species grew faster than wheat, mainly because they had a larger leaf area ratio. Tillering began earlier in wheat, but continued longer in the grasses, which eventually had many more shoots. Ears emerged in the order: wheat before Agropyron before Agrostis. Although Agrostis had much lighter seeds than Agropyron, it grew faster, but Agropyron initiated rhizomes sooner, usually when it had 1–2 tillers and 4 leaves. Agrostis did not initiate rhizomes until it had at least 10 tillers and 6 leaves. In Experiment 2 the seedlings at first grew more in Woburn than in Rothamsted soil but later more in Rothamsted than in Woburn soil. There was no evidence of a species/soil interaction but nitrogen had more effect on both species in Woburn than in Rothamsted soil. Neither soil type nor nitrogen affected the time at which rhizomes were initiated.Etude de la croissance de plantules d'Agropyron repens (L.) Beauv. et d'Agrostis gigantea Roth.Résumé. La croissance de plantules A'Agropyron repens (L.) Beauv. et d'Agrostis gigantea Roth, cultivdes en pots a étéétudiée au cours de deux expériences en 1968 et 1969. Dans la premiére experience, leur croissance fut compareée à celle du blé et dans une seconde experiénce, ces deux espéces furent cultivées sur un sol sablo-limoneux (Woburn) et sur un sol argilo-limoneux (Rothamsted) á quatre niveaux d'azote.Les deux mauvaises herbes poussérent plus vite que le blé, principalement en raison de leur rapport plus éalevé de surface foliaire. Le tallage commenga plus tot chez le bié, mais se poursuivit plus longtemps chez les deux mauvaises herbes qui, en fin de compte, eurent plus de tiges. L'épiaison se produisit dans l'ordre suivant: bléa, Agropyron, Agrostis. Bien que I'Agrostis ait des semences plus petites que I'Agropyron, il poussa plus vite, mais I'Agropyron émit des rhizomes plus tôt, habituellement au stade 1 à 2 talles et 4 feuilles. L'Agrostis n'émit pas de rhizome avant d'atteindre au moins le stade 10 talles et 6 feuilles. Dans la deuxième experience, les plantules poussérent d'abord plus dans le sol de Woburn que dans celui de Rothamsted mais, plus tard, plus dans le sol de Rothamsted que dans Celui de Woburn. II ne fut pas décelé d'interaction entre le sol et les espéces, mais I'azote fit un effet plus marqué sur les deux espéces dans le sol de Woburn que dans celui de Rothamsted. Ni le type de sol, ni le niveau d'azote n'eurent d'influence sur l'époque à laquelle les rhizomes commencérent de croître.Untersuchungen zum Wachstum von Keirnpjlanzen von Agropyron repens (L.) Beauv. Und Agrostis gigantea Roih.Zusammenfassung. Das Wachstum von Keimpfianzen von Agropyron repens (L.) Beauv. und Agrostis gigantea Roth, in Töpfen wurde 1968 und 1969 in zwei Versuchen untersucht. In Versuch II wurde das Wachstum mit dem von Weizen verglichen. In Versuch II wurden sie in sandigen Lehmboden (Woburn) und Silt-Lehm-(Rothamsted) Boden bei vier Stickstoffstufen angezogen.Beide Arten wuchsen in erster Linie wegen ihres grösseren Blattflächenanteils schneller als Weizen. Die Bestockung begann fruher bei Weizen, zog sich jedoch bei den Gräsern, die schliesslich wesentlich mehr Halme hatten, langer hin. Ahrenschieben erfolgte am frühesten bei Weizen, dann bei Agropyron und schliesslich bei Agrostis. Obgleich Agrostis viel leichtere Samen hatte als Agropyron, wuchs es schneller, doch entwickelte Agropyron fruher Rhizome, nornialerweise bei 1–2 Bestockungstriebe und 4 Blättern. Agrostis entwickelte Rhizome nicht ehe es mindestens 10 Bestockungstriebe und 6 Blätter hatte. In Versuch II wuchsen die Keimpflanzen zunächst besser in Woburn- als in Rothamsted-Boden, später wieder besser in Rothamsted als in Woburn-Boden. Es gab keine Anhalts-punkte für eine Interaktion zwisehen den Arten und dem Boden, doch wirkte Stickstoff bei beiden Arten besser in Woburn- als in Rothamsted-Boden. Weder Bodentyp noch Stickstoffmenge beeinflussten den Beginn der Rhizombfldung.

Notes: Summary. To assess the role of seed production and seedling behaviour in the biology of the perennial grass weed Agrostis gigantea Roth, seed germination and seedling emergence of the species were investigated in the glasshouse and in the laboratory. These studies showed that the species may produce a large number of seeds: panicles collected from a cereal field in 1971 and 1972 contained about a thousand viable seeds in both years. Mature seeds of the species are mostly non-dormant and germinate readily on moist soil surfaces. Freshly-harvested seeds require light and alternating tempratures for germination, but older seeds can germinate in constant temparature in the dark. Covering seeds with 0·6 cm soil halved the percentage emergence and few seedlings emerged from seeds sown deeper than 3±8 cm, but many seeds survived under enforced dormancy. A. gigantea seeds may also persist long in frequently cultivated shallow soil. The species flowers late but its seeds become viable quickly—in 1969 a third of the number that were finally viable became so within a week of flowering. Germination des semenes d' Agrostis gigantean Roth.

Notes: Summary. The growth of Agropyron repens seedlings, or of clones derived from them, raised from seeds collected from different areas was compared; the growth of seedlings raised from seeds from single spikes and from seeds of a cross of two clones was also compared.The number and length of shoots and the amount of rhizome produced differed between seedlings from different areas. Seedlings with a large weight of rhizomes often had a small weight of shoots. Many of the differences found between seedlings from different areas were confirmed by comparing clones established from some of them. Comparisons of both seedlings and clones showed that the percentage of shoots that developed spikes differed between genotypes; clones with the least weight of rhizome tended to have most weight of spikes. Large variations also occurred between clones established from seedlings from a given area, particularly in the way their dry weight was partitioned between primary and secondary shoots and in the time the spikes emerged.The amount of rhizome per seedling varied greatly between seedlings from seeds from single spikes and from seeds from a cross of two clones. There was some evidence of a negative correlation between per cent shoot and per cent rhizome dry weight with seedlings from single spikes and between number of shoots and number of rhizomes per seedling with seedlings from a cross of two clones. Variation en croissance de plantules issues de semences et de clones d' Agropyron repens (L) Beauv.

Notes: Seeds of Agropyron repens (L.) Beauv, have little innate dormancy and germinate mainly during autumn, but germination may be delayed by cold, inadequate moisture or deep burial. Seedlings emerged from all viable seeds sown 5 cm deep but from only 4% of those 10 cm deep. Many seeds are viable when green and immature. At Rothamsted, spike emergence and flowering were earlier in 1970 than in 1968 and 1969 but more seeds became viable more rapidly in 1969. Higher temperatures in May and early June in 1970, and after flowering in 1969, probably account for most of these differences. Germination is facilitated by a diurnal alternation of temperature, but more old than young seeds can germinate at a constant temperature.

Notes: Summary. Seeding of Agropyron repens (L.) Beauv. und Agrostis gigantea Roth were grown in two photoperiods and with amounts of nitrogen. On two occasions plants transferred between photoperiods.The early growth of the seedlings was increased most by increasing the light intensity, but later nitrogen had the greatest effect. In short photoperiods, plants of both species were decumbent and had many more shoots than in long photoperiods. At the end of the experiment, plants of both species responded more to nitrogen in bright than in dim light, and the dry weight of Agropyron was increased more than that of Agrostis by increased photoperiod and nitrogen. Agropyron initiated rhizomes sooner than Agrostis; it had fewer rhizomes but they were longer and thicker and weighed more. Brighter light, longer photoperiod and nitrogen all increased rhizome weight. Photoperiod did this mainly by producing more rhizomes, light by increasing thickness or density, and nitrogen by both. The effects of photoperiod and nitrogen on the rhizome dry weight of Agropyron, but not of Agrostis, were additive.Transferring plants from short to long photoperiods or from long to short, respectively increased or decreased total growth, but had an opposite effect on the rhizomes.

Notes: Summary. Seedlings and plants derived from single-node rhizome fragments of Agropyron repens and Agrostis gigantea were grown in au unheated glasshouse, separately or together with wheat (cv. Kolibri), in sandy loam soil in well-spaced pots, adequately watered and moderately fertilized. Samples of crop and weeds were taken for growth analysis in mid- May, late June and early August (when the wheat was ripe).On average, wheat decreased the weight of weed shoots by 84% and of rhizomes by 77%, but the weeds decreased the weight of wheat shoots by only 7% and of grain by 13%. Without wheat, seedlings of both weed species had, by late June, grown as much as plants from rhizomes, but with wheat, the weed seedlings were throughout most of the experiment more susceptible to competition than were plants from rhizomes. There was no simple relationship between the final dry weights of the weeds and the amount they decreased wheat yield: although Agropyron seedlings in competition with wheat were much lighter than Agrostis from rhizomes, they decreased grain yield of wheat as much, suggesting that they competed more intensely for a limiting factor, possibly nitrogen.It is concluded that the faster initial growth rate of wheat seedlings relative to the weeds from rhizomes and a larger initial seed reserve relative to the weed seedlings enabled the wheat to dominate the weeds. Comparaison de la croissance et comportement compétitif de plantules et de plantes issues de rhizomes d'Agropyron repens (L.) Beauv. et d' Agrostis gigantea Roth