Bulletin of the Torrey Botanical Club最新文献

{"title":"The Pocono till barrens: shrub savanna persisting on soils favoring forest1","authors":"R. Latham, J. Thompson, Sarah A. Riley, Anne W. Wibiralske","doi":"10.2307/2996782","DOIUrl":"https://doi.org/10.2307/2996782","url":null,"abstract":"LATHAM, R. E., J. E. THOMPSON, S. A. RILEY AND A. W. WIBIRALSKE (Department of Geology, University of Pennsylvania, Philadelphia, PA 19104-6316). The Pocono till barrens: shrub savanna persisting on soils favoring forest. Bull. Torrey Bot. Club 123: 330-349. 1996.-A previously undescribed shrub savanna community, which we refer to as the Pocono till barrens, occurs mainly on soils weathered from glacial till of Illinoian age on the southern Pocono Plateau of Pennsylvania. Unlike most \"barrens\" in east-central North America, its soils are not sandy or shallow to bedrock; the same deep, fine-loamy soil series underlie the barrens and nearby northern hardwoods forest. An unusual abundance of rare plant and animal species in and near the barrens has attracted the attention of scientists and biodiversity conservation professionals. In an effort to understand the ecological dynamics of the Pocono till barrens and why the barrens are different from their mostly forested surroundings, we undertook studies of vegetation history, landscape patterns, plant species distributions and water table depth. The Pocono till barrens (1) are old, pre-dating European settlement of the area; (2) have burned frequently and over large areas throughout their recorded history; (3) presently cover more than 22 km2 adjacent to a belt of xeric ridgetop barrens totaling approximately 18 kM2; (4) have in abundance plants usually found in moist or wet soil conditions living side-by-side with those normally associated with xeric habitats; and (5) include several vegetation types which are distributed on the landscape, in part, in association with a soil moisture gradient. The Pocono till barrens appear to flout the conventional wisdom that barrens vegetation reflects droughty, nutrient-poor soils. Although the Pocono till barrens substantially pre-date European settlement of the area, fire is clearly the key to maintenance of barrens vegetation in this system. We hypothesize that biotic factors are more important than abiotic factors in determining distributions of barrens and forest vegetation on the southern Pocono Plateau.","PeriodicalId":9453,"journal":{"name":"Bulletin of the Torrey Botanical Club","volume":"123 1","pages":"330"},"PeriodicalIF":0.0,"publicationDate":"1996-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2307/2996782","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68411538","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of fire-generated gaps on growth and reproduction of golden aster (Pityopsis graminifolia)\"","authors":"J. Brewer, W. Platt, J. S. Glitzenstein, D. Streng, W. Platt, J. S. Glitzenstein, D. Streng","doi":"10.2307/2996778","DOIUrl":"https://doi.org/10.2307/2996778","url":null,"abstract":"only slightly greater (- 10%), however, inside gaps than outside gaps in May-burned blocks four months after the May fires. We therefore conclude that golden aster potentially performs better within fire-generated gaps than within dense vegetation dominated by wiregrass, at least in years without lightning season (May) fires. We suggest, however, that such differences between gaps and dense vegetation likely have little effect on the long term performance of golden aster in pine savannas frequently burned in May.","PeriodicalId":9453,"journal":{"name":"Bulletin of the Torrey Botanical Club","volume":"123 1","pages":"295"},"PeriodicalIF":0.0,"publicationDate":"1996-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2307/2996778","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68410619","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of canopy opening on recruitment in Clethra alnifolia L. (Clethraceae) populations in central New Jersey wetland forests","authors":"R. Jordan, J. Hartman, J. Hartman","doi":"10.2307/2996777","DOIUrl":"https://doi.org/10.2307/2996777","url":null,"abstract":"JORDAN, R. A. AND J. M. HARTMAN (Graduate Program in Ecology and Evolution, P.O. Box 231, Cook College, Rutgers University, New Brunswick, NJ 08903). Effects of canopy opening on recruitment in Clethra alnifolia populations in central New Jersey wetland forests. Bull. Torrey Bot. Club 123: 286-294. 1996.-We measured stem growth and recruitment in three populations of Clethra alnifolia established in wetland forests, in canopy gaps, and in a recently cleared powerline right-of-way (ROW) to assess the ways in which C. alnifolia responded to canopy disturbance. Seasonal growth and density of stems and flowering rates were greater in canopy gaps, although greater overall recruitment occurred in the closed canopy forest. Total stem density, extension growth, and flowering significantly increased in the ROW and were directly related to distance from the ROW edge. Seedling density and new stem recruitment also increased significantly in the disturbed area. Clethra alnifolia demonstrated a \"light flexible\" response to canopy disturbance, regenerating established populations in the forest primarily through vegetative reproduction and producing greater stem density and aerial cover under disturbed canopies, but requiring significant or long-term canopy disruption to initiate increased sexual reproduction.","PeriodicalId":9453,"journal":{"name":"Bulletin of the Torrey Botanical Club","volume":"123 1","pages":"286"},"PeriodicalIF":0.0,"publicationDate":"1996-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2307/2996777","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68411075","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ten years of tree seedling establishment and mortality in an Ohio deciduous forest complex","authors":"R. Boerner, J. Brinkman, J. Brinkman","doi":"10.2307/2996780","DOIUrl":"https://doi.org/10.2307/2996780","url":null,"abstract":"BOERNER, R. E. J. AND J. A. BRINKMAN. (Department of Plant Biology, Ohio State University, 1735 Neil Avenue, Columbus, OH 43210 U.S.A.) Ten years of tree seedling establishment and mortality in an Ohio deciduous forest complex. Bull. Torrey Bot. Club 123: 309-317. 1996.-This study quantified tree seedling establishment and mortality over a ten year period (1984-1993) in an Ohio deciduous forest complex which included upland beech-maple (Acer-Fagus) forest, lowland ash-elm (Fraxinus-Ulmus) forest, and young pin oak (Quercus palustris) forest. Annual establishment averaged 316 seedlings/100 m2, of which approximately 70% were ashes and 17% were maples. There were distinct peaks of ash and maple establishment in 1988 and 1990, and of elm establishment in 1986, 1988, and 1991. There were no significant correlations between ash or maple establishment and seasonal precipitation patterns whereas peaks of elm establishment correlated with drier-thanaverage springs. Ash seedlings were more abundant in lowland than upland plots, whereas the pattern for maple seedlings was the reverse. Maple seedlings were most abundant in canopy gaps, whereas ash seedlings were most abundant in wet depressions. Median longevity for most seedlings was 5-7 months, and >95% died within one year. Of the 2553 seedlings monitored, only two grew out of the seedling size class during this decade. In this site, deer browsing was more important than environmental gradients or climate factors in determining seedling longevity and mortality.","PeriodicalId":9453,"journal":{"name":"Bulletin of the Torrey Botanical Club","volume":"9 1","pages":"309"},"PeriodicalIF":0.0,"publicationDate":"1996-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2307/2996780","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68410667","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Stem and Leaf Anatomy of Saruma henryi Oliv., Including Observations on Raylessness in the Aristolochiaceae","authors":"W. Dickison","doi":"10.2307/2996773","DOIUrl":"https://doi.org/10.2307/2996773","url":null,"abstract":"","PeriodicalId":9453,"journal":{"name":"Bulletin of the Torrey Botanical Club","volume":"123 1","pages":"261"},"PeriodicalIF":0.0,"publicationDate":"1996-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2307/2996773","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68410799","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Composition, structure, and disturbance history of Crabtree Woods: an old-growth forest of western Maryland'","authors":"B. Mccarthy, D. Bailey, D. Bailey","doi":"10.2307/2996783","DOIUrl":"https://doi.org/10.2307/2996783","url":null,"abstract":"MCCARTHY, B. C. AND D. R. BAILEY. (Department of Environmental & Plant Biology, Ohio University, Athens, OH 45701-2979). Composition, structure, and disturbance history of Crabtree Woods: an old-growth forest of western Maryland. Bull. Torrey Bot. Club 123: 350-365. 1996.-Crabtree Woods is an old stand of mixed Appalachian hardwoods which has been identified as one of the finest examples of this vegetation type in Maryland. Because few botanical studies have been conducted on the Allegheny Plateau of Maryland and because the old-growth nature of this stand is unique in its present landscape, we undertook this study to describe the composition, structure, and disturbance history of the stand. A one hectare permanent plot was established in which all trees, saplings, snags, and logs were quantified. Woody seedlings and herbs were subsampled from 25 quadrats to describe the understory. Increment cores were obtained from all Quercus rubra trees within the plot and used for dendroecological analysis. The stand shows many structural and compositional features characteristic of old-growth forest. The overstory was dominated by Acer saccharum, Q. rubra, and Tilia americana. The stand exhibited a reverse-J diameter distribution typical of old forests and a number of trees were observed to have a diameter >100 cm DBH. Acer saccharum and Hamamelis virginiana were the prominent understory constituents. Quercus rubra was essentially absent from seedling and sapling size classes and does not appear to be regenerating. Logs and snags were abundant and occurred in a variety of decay states and diameter classes. Thirty-nine species of herbs were discovered, with Dicentra canadensis, Urtica dioica, and Impatiens pallida being the most abundant. Stem increment analysis shows multiple periods of recruitment likely associated with gap dynamics. However, certain synchronous releases suggest possible light anthropogenic disturbance (e.g., selective cutting or chestnut salvage).","PeriodicalId":9453,"journal":{"name":"Bulletin of the Torrey Botanical Club","volume":"123 1","pages":"350"},"PeriodicalIF":0.0,"publicationDate":"1996-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2307/2996783","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68411553","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of Fire Frequency on Plant Species in Oak Savanna in East-Central Minnesota","authors":"J. Tester","doi":"10.2307/2996779","DOIUrl":"https://doi.org/10.2307/2996779","url":null,"abstract":"TESTER, J. R. (Department of Ecology, Evolution and Behavior, University of Minnesota, St. Paul, MN 55108). Effects of fire frequency on plant species in oak savanna in east-central Minnesota. Bull. Torrey Bot. Club 123: 304-308. 1996.-From 1964 through 1984, nine forest sites, ranging in size from 2.6 to 27.5 ha, were each burned from two to 19 times. Percent cover of 13 of 14 true-prairie grasses was positively correlated with burn frequency. Of these, eight have C4 and six have C3 photosynthetic pathways. Cover of 34 of 39 true-prairie forbs, and of Amorpha canescens, increased with frequency of burning. All except Aster oolentangiensis are C3 species. Cover of six of seven native, not prairie, species, all C3, decreased with increasing burn frequency. These data suggest that the adaptation of true-prairie species to repeated burning outweighs the effects of their photosynthetic pathways.","PeriodicalId":9453,"journal":{"name":"Bulletin of the Torrey Botanical Club","volume":"123 1","pages":"304"},"PeriodicalIF":0.0,"publicationDate":"1996-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2307/2996779","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68410632","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Pollination biology and breeding system of Alliaria petiolata (Brassicaceae)","authors":"R. Cruden, A. M. McClain, G. P. Shrivastava","doi":"10.2307/2996775","DOIUrl":"https://doi.org/10.2307/2996775","url":null,"abstract":"CRUDEN, R. W., A. M. MCCLAIN (Department of Biological Sciences, University of Iowa, Iowa City, IA 52242) AND G. P. SHRIVASTAVA (School of Environmental Biology, APS. University, Rewa (M.P.), India 486 001). Pollination biology and breeding system of Alliaria petiolata (Brassicaceae). Bull. Torrey Bot. Club 123: 273-280. 1996.-Alliaria petiolata (Bieb.) Cavara and Grande is widely naturalized in the northeastern 1/4 of the United States and adjacent Canada, where it is an aggressive invader of moist woods. The plants are facultatively xenogamous, and the white flowers attract a variety of short-tongued bees and flies. High fruit and seed set by open-pollinated, emasculated flowers demonstrated that flower visitors move pollen between flowers. Cross-pollination resulted from the bees visiting only one or two flowers per plant. High fruit and seed set by bagged flowers demonstrated that flowers self-pollinate in the absence of pollinators. The nectar contained 51% fructose, 44% glucose, and little sucrose, which is typical of the nectars of flowers pollinated by short-tongued bees. The nectar contained no free amino acids, but did contain numbers of peptides, which, when hydrolyzed, yielded most of the amino acids present in floral nectars.","PeriodicalId":9453,"journal":{"name":"Bulletin of the Torrey Botanical Club","volume":"35 1","pages":"273-280"},"PeriodicalIF":0.0,"publicationDate":"1996-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2307/2996775","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68411019","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of canopy gaps and flower patch size on pollinator visitation of Impatiens capensis","authors":"B. B. Walters, E. Stiles","doi":"10.2307/2996793","DOIUrl":"https://doi.org/10.2307/2996793","url":null,"abstract":"WALTERS, B. B. AND E. W. STILES (Graduate Program in Ecology and Evolution, Rutgers University, Piscataway, NJ 08855). Effect of canopy gaps and flower patch size on pollinator visitation of Impatiens capensis. Bull. Torrey Bot. Club 123:184-188. 1996.-We measured pollinator visits of Impatiens capensis flowers found in different-sized patches beneath canopy gaps and beneath closed canopy in a mature, old-growth deciduous forest in New Jersey. Honeybees, bumblebees and halictid bees made up the majority of visitors. Visitation rates per flower increased slightly, but not significantly, in relation to flower patch size (number of open flowers) and floral density. By contrast, pollinator visitation rates, floral density and seed production per pod were all significantly higher in patches located beneath forest canopy gaps compared to patches located beneath closed canopy.","PeriodicalId":9453,"journal":{"name":"Bulletin of the Torrey Botanical Club","volume":"123 1","pages":"184"},"PeriodicalIF":0.0,"publicationDate":"1996-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2307/2996793","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68411159","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A comparison of growth efficiency of plants on the east and west sides of a forest canopy gap","authors":"L. S. Barden","doi":"10.2307/2996799","DOIUrl":"https://doi.org/10.2307/2996799","url":null,"abstract":"BARDEN, L. S. (Department of Biology, University of North Carolina at Charlotte, Charlotte, NC 28223). A comparison of growth efficiency of plants on the east and west sides of a forest canopy gap. Bull. Torrey Bot. Club 123:240-242. 1996.-The theoretical distribution of light in a circular forest canopy gap is symmetrically equal on the east and west sides of the gap. However, small plants on the west side of the gap receive maximum light in the morning when air temperature and vapor pressure deficit are relatively low, while plants on the east side receive maximum light in the afternoon when temperature and VPD are high. To test the hypothesis that plants on the west side of a gap are able to use light more efficiently, Microstegium vimineum, a shade-adapted annual grass, was grown in pots in a forest canopy gap, both in the actual open gap and in the extended gap. In the actual gap there was no difference in growth efficiency. However, in the extended gap growth efficiency was 39% greater on the west side than on the east side under equal light (integrated photon flux density). Thus, asymmetry of microclimate on the east and west sides of a canopy gap causes an east-west asymmetry in plant growth efficiency and may induce asymmetry in species composition of understory vegetation.","PeriodicalId":9453,"journal":{"name":"Bulletin of the Torrey Botanical Club","volume":"123 1","pages":"240"},"PeriodicalIF":0.0,"publicationDate":"1996-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2307/2996799","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68411375","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}