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SummaryLarvae of Nemognatha nitidula, N. lurida apicalis and N. nigripennis were reared in the laboratory on a diet composed of pollen collected by honeybees, honey, demineralized water, and mould inhibitor. TV. nitidula, which proved to be the most adaptable of the species, was fed on media containing the following pollens: Solidago + Polygonum, Robinia pseudoacacia + Prunus serotina, or Taraxacum officinale. The percentage of larvae surviving was greatest on the diet containing Taraxacum pollen.

The leaves of Prunus serotina and P. lusitanica contain a new triterpene, 2α,3α-dihydroxyurs-12-en-28-oic acid, isolated in form of its methyl ester. Other triterpenes present in these species are ursolic acid and ursol aldehyde. P. lusitanica also yields friedeline.

Black cherry occupies a key position in the dynamics of oak (Quercus spp.) forests in southern Wisconsin. Its relative importance in sapling and small—tree sizes averaged over 50%, and in some stands it was the only species in these strata. Age analysis of 854 cores showed that 58% of all black cherry stems were established between 1931 and 1941. The appearance of large amounts of black cherry in the 1930 decade was the result of drought and livestock—feed shortages. The latter were especially severe in 1934 and 1936 and resulted in large—scale disturbance of forests through grazing and possibly extensive cutting of forests for foliage. The presence of a strong shrub component exerted a major influence on the dynamics of the oak forest. An inverse relationship existed between overstory tree basal area and the importance of shrubs. Although density and cover of tree seedlings were independent of tree basal area and shrub cover, seedling numbers were insufficient for adequate restocking of most stands. In clear—cut forests the shrub layer was extensive, and regrowth of trees was largely confined to stump sprouts. Shrubs in disturbed forests averaged 38,635 stems/acre, 4,535 square inches basal area/acre, and 145.8% cover. In undisturbed forests, shrub competition (average 16,231 stems/acre, 1,036 square inches basal area/acre, and 51.4% cover) largely precluded seedling establishment by tree species, and maximum basal area levels in these forests were not maintained. Growth and survival of black cherry in the understory depended on the complex interaction of environmental factors. Tree overstory basal area and soil available water were the most significant factors controlling its vigor. Suppressed stems of cherry were as old as 60 years. Growth patterns in stem cores showed that stems responded to release after 39 years of suppression. The capacity of black cherry to develop basal sprouts and the occurrence of light intensities greater than 1,200 ft—c in the understory greatly aided its survival in this stratum. The important role of black cherry in the dynamics of the oak forests was based on opportunistic characteristics including widespread dispersal, delayed germination of seeds, and flexible seedbed requirements. Forest conditions, such as the isolation of forests as woodlots, pioneer environmental conditions, and widespread disturbance, predisposed invasion by opportunistic species. Dynamic processes were characterized by general rather than gradient compositional changes. Patterns of replacement were not orderly and predictable, but irregular as a result of chance dispersal and local catastrophe. Although not uncommon in oak forests in the northeastern United States, invasion by Acer saccharum is not occurring in southern Wisconsin. Succession to Acer—Tilia is confined to specific sites. The overall existing pattern is one of increasing diversity typical of many pioneer communities in an early phase of colonization.

Dynamic mechanical properties from 100 to 300°K have been determined for black cherry specimens carbonized up to 1200°K in a nitrogen atmosphere. It was found that the modulus of carbonized black cherry decreases and then begins to increase as a function of heat-treatment temperature. Modulus values appear to be at a minimum after carbonization to near 600°K. It is demonstrated that the internal friction (100 to 300°K) of the specimens after carbonization is complex.

Viable conidia of Septotinia podophyllina are found on sclerotia on dead last year's leaves of Populus in spring. Prunus serotina is described as a new host. Inoculation experiments on leaves in petri-dishes with Populus- and Prunus isolates demonstrated no host-specificity. A possible introduction of the organism from North-America, its native area, into Europe and Asia is considered.

bluffs less than 1 km. distant. A few species, all rare in this part of the Hudson Valley only a few years ago, have recently increased in abundance on sandy soils near the river from Columbia County southward; these include Strophostyles Jhelvola, Cenchrus longispinus, Mirabilis ?hirsuta, Salsola kali var. tenuifolia, and Triplasis purpurea. In summation, the newly established flora consists almost entirely of species whose immigration into denuded areas might have been expected in this part of New York and in this proximity to roadsides, abandoned fields, railroad embankments, and river marshes. The least-expected species was Epipactis helleborine, which in this part of New York is usually a plant of rich woodlands. As a general conclusion, it may be emphasized that succession on the sand-flats has been retarded except in the limited areas shaded by the clumps of cottonwoods which became established soon after 1930. Even in these clumps, the successional series are still in formative stages, dominated by a few woody vines and by Prunus serotina. No general pattern of succession is yet discernible among the herbaceous species, but it seems probable that in another decade, after formation of significant amounts of humus-containing soil, various additional native woodland species will replace many of the semi-weedy species now present. Succession in treeless areas, where by chance no cottonwood seedlings survived after the first formation of the sand-flats, has not established any recognizable pattern except that it may be presumed that the thickets of Robinia will eventually attain tree size and that these and the thickets of Rhus and Salix will presumably increase in extent and in density and ultimately shade out most of the herbaceous species now growing among them. Decrease in extent of unshaded areas is not apparent at this time (Fig. 6); little or no soil is being formed in them, and no significant increase in the cover has been noted since 1935, although the relative importance of certain species has changed.

Black cherry, Prunus serotinci Ehrh.,' is a very important species in the forests of the High Plateaus Region of northwestern Pennyslvania as described by Hough and Forbes (1943). In this area, it attains large size, excellent form, and is a major component of the hardwood forest. Its importance is indicated by a report of the Forest Survey (1948) for four counties lying in the heart of this region. In these four counties, black cherry leads all other species with 20.9 per cent of the total net board-foot volume, and 18.9 per cent of the total net cord wood volume of all species on all commercial forest land. The rapid growth and value of this species combined with its abundance make Prunus serotina an extremely desirable species to manage in northwestern Pennsylvania. The principal problem with which foresters have been confronted up to this time has been to find methods of regeneration which will produce stands of reproduction with a high percentage of vigorous, high-quality individuals. Accordingly, a study was undertaken to determine the relative success or failure of Prunus serotina regeneration under the environmental conditions which prevailed following various methods of cutting. The principal objective of the study was to determine the success of reproduction in relation to the density of the remaining stand (called residual stand density) and the form of cutting used. The density of the remaining stand was measured in terms of square feet of basal area per acre of all trees having a diameter of 0.6 inches or above at 4.5 feet above the ground (called the d.b.h. point). The residual stand here means that portion of a forest stand left standing following a cutting. This measure was used since it appeared to be the most applicable and reliable method of comparing the conditions in the series of stands studied. Light intensity, per se, was not thought to be a desirable measure in this study since it would have little meaning in some of the stands studied. An acre completely devoid of trees following a clear cutting and another acre with possibly three residual trees could show the same light intensity on almost their entire areas, al

New hosts of an introduced Oriental ambrosia beetle were tupelo (Nyssa aquatica), swamp cypress (Taxodium distichum), and black cherry (Prunus serotina). Known distribution was extended southward into North Carolina. A partial seasonal development with simple through complex gallery systems was observed.

An outbreak of congenital malformations in swine occurred in Warren County, Missouri, during the late spring and summer of 1968. Sows which farrowed malformed offspring were bred and spent their gestation cycle in one pasture. Sows in an adjacent pasture bred by the same boar during the same period, farrowed only normal offspring. Field observation and epidemiologic studies indicate that the cause of the malformations was environmental in nature rather than hereditary. A comparison of the critical time period of exposure and environmental factors suggest an association between the malformations and consumption of wild black cherries (Prunus serotina) by the pregnant sows. Other environmental factors which might have contributed to the cause of the outbreak are discussed.

The eastern tent caterpillar, Malacosoma americanum (F.), completely defoliated several forest stands of black cherry, Prunus serotina Ehrh., in West Virginia in 1960. Because of possible growth losses and defects in the wood related to heavy defoliation, it was concluded that the eastern tent caterpillar should be considered a potentially important forest pest in high-value black cherry stands. Studies on the parasites of the eastern tent caterpillar showed that Theronia atalantae fulvescens (Cresson) reached peak populations 1 week later later than Itoplectis conquisitor (Say). With both species of parasites, males issued from prepupae more commonly than females. Eightynine to 94% of the parasites from pupae issued from the anterior end and 60 to 100% of the parasites from prepupae issued from the posterior end. T. atalantae fulvescens , in addition to being a common primary parasite, was also a hyperparasite attacking the primary pupal parasite, I. conquisitor . Gelis tenellus (Say) was an important hyperparasite attacking the larval parasites Hyposoter fugitivus fugitivus (Say) and Phobocampe clisiocampe (Weed). Itoplectis conquisitor was occasionally a hyperparasite of H. fugitivus fugitivus , but produced only undersized males in such cases. The apparent causes of pupal mortality of the tent caterpillar were recorded during 4 weekly collections. Although the various mortality agents varied in importance from week to week the total mortality rate remained stable between 95 and 99%. Thirty-two species of parasites, predators, and associated scavengers are discussed.

Seasonal variations in actual moisture content (MC), moisture content as percent of dry weight (% MC), and dry weight were determined for fruits of Acer rubrum L., Quercus rubra L., and Prunus serotina Ehrb. at weekly or 2-weekly intervals. On selected dates diurnal variations in MC, % MC, and dry weight of fruits or cones and leaves of Quercus rubra, Prunus serotina, P. virginiana L., and Pinus banksiana Lamb. were determined at 4-hour intervals during the day and night. Percentage moisture content of reproductive tissues and leaves was variously influenced by water uptake or loss, change in dry weight, or both of these. The water balance of different tissues of the same organ varied differently, both seasonally and diurnally, in the same species as well as between species. Percentage moisture content alone is not an accurate indicator of internal water balance of plants and should be interpreted in relation to both water weight and dry weight changes of tissues.

Seasonal and diurnal expansion and contraction of growing fruits of Acer rubrum L., Prunus serotina Ehrb., P. pensylvanica L., P. virginiana L., Quercus rubra L., and Corylus cornuta Marsh, var. cornuta were measured with modified Fritts dendrographs during the summers of 1966 and 1967. Throughout much of the summer the fruits exhibited recurrent shrinkage during the day and expansion at night. Fruit diameter fluctuations in 1967 were related to changes in vapor pressure deficit. Expansion of fruits generally occurred when vapor pressure deficit was decreasing or low and contraction resulted when vapor pressure deficit was increasing or high.

A blighted and lumbered oak—chestnut forest in the Allegheny Mountains of western Pennsylvania was studied 50 years after elimination of the American chestnut (Castanea dentata). This slope revealed a regeneration pattern not typical of previously studied chestnut sites. The removal of chestnut by lumbering has generated an area that resembles a mid—successional stand mixed with species associated with the former chestnut. Once dominated by chestnut, a mixture of oaks, and numerous co—dominant species, the study area is presently occupied by black cherry (Prunus serotina), red maple (Acer rubrum), sugar maple (Acer saccharum), black oak (Quercus velutina), black birch (Betula lenta), and sour gum (Nyssa sylvatica). Anticipated loss of blackcherry, a few remaining larger trees, and some red maple indicates that this forest will continue to change gradually throughout the next few decades. See full-text article at JSTOR

Sinds 1946 is bekend dat Amerikaanse vogelkers, een uiterst algemene struik of boom van lichte gronden in Nederland, fungeert als winterwaard van de perzikluis (Myzus persicae). In gebieden waar de perzik ontbreekt biedt Amerikaanse vogelkers, hoewel vele exemplaren minder geschikt zijn als waardplant, een goede mogelijkheid voor overwintering van de perzikluis. Vooral waar in de nabijheid pootaardappelen of bieten worden verbouwd, gewassen die ernstig lijden onder virusziekten door deze bladluis overgebracht, is de economische betekenis van Amerikaanse vogelkers buitengewoon groot. Ook andere bladluissoorten kunnen met succes op Amerikaanse vogelkers overwinteren en van deze soorten is de hopluis (Phorodon humuli) in het buitenland vaak bijzonder schadelijk op hop. Gevonden werd dat de appel-grasluis (Rhopalosiphum insertum) vaak ook op Amerikaanse vogelkers als ei overwintert, hoewel de literatuur uitsluitend winterwaardplanten uit de onderfamilie der appelachtigen (Pomoideae) vermeldt. Bovendien kolonissert de appel-takluis (Aphis pomi) soms met succes jonge scheuten van deze importboom. Veel bladluissoorten, die met succes op andere soorten van het geslachtPrunus als ei overwinteren, leggen vaak zeer grote aantallen eieren opPrunus serotina, zonder dat zich daaruit in het voorjaar volwassen bladluizen ontwikkelen. De schrijver beschouwt Ameriaanse vogelkers als een zeer gevaarlijk gewas voor land- en tuinbouw, speciaal als bron voor virusoverbrengende bladluissoorten.

Newly-emerged worker honey bees confined in small cages were fed 33 isonitrogenous diets containing 25 species of pollen. The growth-stimulation of the hypopharyngeal glands was determined by morphological examination after 7 days of feeding. Twenty-two species of pollen were evaluated and compared when they were fed as 10% concentrations of protein, three as 7.5%, six as 5%, two as 2.5%, and one each as 1.25 and 0.625% concentrations. A 0.625% concentration of protein from pollen ofTaraxacum officinale was just as effective in the diet as a 2.5% concentration of protein from pollen ofBaccharis viminea or a 5.0% concentration of protein from pollen ofSorghum. A concentration of 1.25% protein from pollen ofT. officinale in the diet stimulated as much gland growth as either a 7.5% concentration from pollen ofSorghum andB. viminea or a 5.0% concentration of pollen fromZea mays var.saccharata. At a 5.0% concentration of protein, pollen fromRobinia pseudoacacia andPolygonum promoted significantly better development thanRanunculus arvensis andT. officinale fed at the same level. At a 10.0% concentration, pollens fromTrifolium pratense, T. officinale, Prunus serotina, Malus pumila, andPopulus fremonti were significantly better than pollen fromAgoseris, Populus nigra var. italica, orMedicago sativa. Longevity data were obtained for nine species of pollen, six at a concentration of 10% protein, three at 7.5%, four at 5%, and two at 2.5%.

A phytochemical investigation of the tannin content of wild cherry bark USP showed the presence of nonhydrolyzable flavanoidal-type tannins, consisting of monomeric and polymeric leucocyanidin units. Identification was accomplished by paper chromatography, visible and IR spectrophotometry, with commercial samples, and fragmentation by potassium fusion.

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Eingefuhrt 1629? Bon der atlantischen Kuste bis Rebraska und Leras, sehr verbreitet, 60–80 Fus hoch mit einem Stammdurchmesser bis 4 Fus, gedeiht auf verschiedenem Boden und entwickelt sich demgemas naturlich sehr verschiedenartig. Langsam sich entwickelnd auf armem Boden an der Seekuste in sehr erponirter Lage, dem salzigen Wasser ausgesest, hier eine sehr nusliche Schuspflanze und sehr wider-standsfahig, wachst er mit groser Eschnelligkeit an der rechen Flusufern des Dhio und seiner Rebenflusse, wo er die grosten Dimensionen erreicht. In den nordlichen und mittleren Staaten ist er ein haufig vorkommender Waldbaum.

Following extensive disturbance of oak forests in southern Wisconsin in the 1930 decade, black cherry, Prunus serotina Erhr., successfully established across a wide range of habitats. The purpose of this study was to assess its ability to reach maturity on all parts of the moisture gradient. Radial growth in 122 black cherry saplings and trees was correlated with edaphic and micrometeorological parameters during 3 growth seasons. Although total basal area change and the duration of rapid growth increased consistently from suppressed through the dominant crown class, the metabolic potential was distinctly lower in the suppressed crown class. The intermediate crown class was very similar in metabolic potential to codominant and dominant classes. Correlation of growth rate to environmental parameters was complicated by marked within-season changes. Correlation between soil moisture and growth rate in 1965 showed a consistent monthly increase from May through August (r = .19*, -.27**, .34**, .38**, respectively*,** = statistical significance at .05 and .01 probability levels) but decreased in September (r = .14). Rapid soil moisture depletion in June coincided closely with the period of maximum growth acceleration. The growing seasons of 1964, 1965, and 1966 contrasted sharply in temperature and soil moisture levels. The Palmer severity index indicated that drought in 1964 was greater than in 1934. May-September air temperature and precipitation in 1965 departed only slightly, from normal while in 1966 air temperature was low. Analysis of growth response by principal components analysis and multiple regression clearly reflected these differences. Despite low metabolic potential and notable dependence on soil moisture levels, prediction of survival in suppressed strata was complicated by the marked capacity of black cherry to regenerate by means of basal sprouts and the eventuality of disturbance in the oak canopy. INTRODUCTION The purpose of this study is to determine significant factors controlling radial growth of black cherry (Prunus serotina Erhr.) in southern Wisconsin oak forests. In this area, oak forests originated with the cessation of fires which maintained prairie and oak savanna in the era predating Europ;ean settlement 125 years ago (Curtis, 1959). Black cherry is presently the most abundant species in sapling and small tree sizes but is relatively uncommon as a canopy tree (Curtis, 1959; Cottam, 1963). Its widespread establishment is the result of ubiquitous disturbances in the oak forest and its marked capacity for opportunistic behavior (Auclair and Cottam, 1971). Climax species such as Acer saccharum and Tilia americana with 1 Present address: Biology Department, McGill University, Montreal 101, Quebec, Canada.

An endotrophic mycorrhiza was found during a study of the morphological forms of ectotrophic mycorrhizae of northern red oak (Quercus rubra L.) and southern red oak (Q. falcata Michx.). The endotrophic type was frequently found on short roots of 7 northern red oaks and 4 southern red oaks from each of 3 locations in the Mountain, Piedmont, and Sand Hills regions of North Carolina. The mycorrhizae are beadlike (FIG. 1), with 1-9 beads in succession, dull white, and range from 2 to 8 mm in length and 0.4 to 0.8 mm in diam. Root hairs were not observed. Occasionally branched forms were found and in all instances, the branches were also beaded. To avoid mistaking roots for those of surrounding plants, all root samples were carefully traced back to the tree in question. Microscopically the type is a typical vesicular-arbuscular endotrophic mycorrhiza with intracellular hyphae (FIG. 2), well developed arbuscular haustoria (FIG. 3), and intracellular vesicles (FIG. 4). There was no evidence of a fungal mantle or Hartig net. Attempts to grow the fungal symbiont in pure culture failed. This endotrophic mycorrhiza is similar to those formed by species of Endogone (Gerdemann, personal communication). Most mycorrhizae formed by species of Quercus are ectotrophic (Trappe, 1962); however, Henry (1933), reported an ectendotrophic mycorrhiza on Q. rubra. To find an endotrophic mycorrhiza commonly occurring on red oak is unusual and to my knowledge, the form described has not been previously reported. Descriptions of beaded endotrophic mycorrhizae have been reported on roots of Acer platanoides L. (Henry, 1933), A. rubrum L. (McDougall, 1914; Henry, 1934; Vozzo and Hacskaylo, 1964), A. saccharum Marsh. (Kessler, 1966), Amelanchier canadensis (L.) Medic. (Henry, 1934), Cornus florida L. (Henry, 1933), Ilex opaca Ait. (Vozzo and Hacskaylo, 1964), Liquidambar styraciflua L. (Vozzo and Hacskaylo, 1964; Filer and Toole, 1966), and Nyssa sylvatica Marsh.; Populus alba L.; Prunus serotina Ehrh.; and Sorbus americana Marsh. (Henry, 1934). The beaded endotrophic mycorrhiza described in this report is simi408

On Sugar Loaf Hill, on the southern coast of eastern Long Island, Suffolk County, New York, is a small colony of Polypodium vulgare growing on sand, a most unusual habitat for this species in eastern North America. I was taken to this colony by Mr. George Peter, an amateur naturalist and former Long Island resident, and by M\rs. Grosvenor Atterbury, owner of Sugar Loaf Hill, which is one of the Shinnecock Hills west of Southampton. The Polypodium (Fosberg 50490, US) is found on the eastern slope of the hill, at about 65 m elevation, in a patch of hardwood forest growing on a sandy morainal soil with no rock outcrops or even boulders in the immediate vicinity, although there are glacial boulders not far away. It is in a rather dense but not very tall hardwood forest of Prunus serotina, Robinia pseudo-acacia, and several oaks, with a thick undergrowth of Smilax, Viburnum, and other shrubs.