Journal of the Torrey Botanical Society最新文献

{"title":"Cornus florida L. mortality and understory composition changes in western Great Smoky Mountains National Park.","authors":"M. A. Jenkins, P. White","doi":"10.2307/3088770","DOIUrl":"https://doi.org/10.2307/3088770","url":null,"abstract":"JENKINS, M. A. (Twin Creeks Natural Resources Center, Great Smoky Mountains National Park, Gatlinburg, TN 37738) AND P S. WHITE (Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599). Cornus florida mortality and understory composition changes in western Great Smoky Mountains National Park. J. Torrey Bot. Soc. 129: 194-206. 2002.-Remeasurement of woody vegetation on permanent plots in western Great Smoky Mountains National Park indicated that understory composition and dominance have changed over the past two decades (between 1977-1979 and 1995-2000). We observed heavy mortality of Cornus florida L., likely as a result of infection by Discula destructiva Redlin, a destructive fungus that causes dogwood anthracnose. Mortality was highest in smaller size classes and seedling density generally decreased. Cove and alluvial forests, where heavy shading favors dogwood anthracnose, had the highest mortality. While still high, mortality in oak-hickory and oak-pine forests was lower than that of cove and alluvial forests. Cornus florida density more than doubled on three plots located within an area that burned in 1976, likely as a result of sprouting and reduced shading in these fire-thinned stands. Over the same two decades, the importance of Tsuga canadensis (L.) Carr. greatly increased in cove, alluvial, oak-hickory, and oak-pine stands. Changes in understory composition in conjunction with the widespread loss of C. florida may greatly impact numerous ecological relationships in these forests, including calcium availability, nutrient cycling, and food source availability for wildlife.","PeriodicalId":49977,"journal":{"name":"Journal of the Torrey Botanical Society","volume":"129 1","pages":"194-206"},"PeriodicalIF":0.3,"publicationDate":"2002-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2307/3088770","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68730563","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The spread of woody exotics into the forests of a northeastern landscape, 1938-1999.","authors":"J. Hunter, Jennifer A. Mattice","doi":"10.2307/3088772","DOIUrl":"https://doi.org/10.2307/3088772","url":null,"abstract":"HUNTER, J. C. AND J. A. MATnCE (Department of Biological Sciences, State University of New York College at Brockport, Brockport, NY 14420). The spread of woody exotics into the forests of a northeastern landscape, 1938-1999. J. Torrey Bot. Soc. 129:220-227. 2002.-This study documents changes in the distribution of nonnative woody species from 1938 to 1999 within 30 forests of a 54 km2 landscape in Monroe County, New York. Within these forests, the mean number of exotic species increased nearly three-fold from 1938 to 1999, and two species not naturalized within the landscape in 1938, Lonicera morrowii and Rosa multiflora, had become widespread by 1999. In 1999, the most abundant exotic was Lonicera morrowii, which had greater cover within forests on wetter portions of the landscape where much of the surrounding agricultural land had been abandoned. Though exotics accounted for 25 % within patches > 100 nM2: Acer platanoides, Crataegus monogyna, Ligustrum vulgare, Lonicera morrowii, Robinia pseudoacacia and Rosa multiflora. These species in particular may represent on-going invasions that could alter this landscape's forested habitats.","PeriodicalId":49977,"journal":{"name":"Journal of the Torrey Botanical Society","volume":"129 1","pages":"220-227"},"PeriodicalIF":0.3,"publicationDate":"2002-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2307/3088772","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68730592","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Trillium pusillum Michaux complex (Trilliaceae): Analysis of pollen and leaf epidermal micromorphology1","authors":"Margaret Timmerman-Erskine, R. Dute, R. Boyd","doi":"10.2307/3088768","DOIUrl":"https://doi.org/10.2307/3088768","url":null,"abstract":"TIMMERMAN-ERSKINE, M., R. R. DUTE, AND R. S. BOYD (Department of Biological Sciences, Auburn University, AL 36849-5407). The Trillium pusillum Michaux complex (Trilliaceae): Analysis of pollen and leaf epidermal micromorphology. J. Torrey Bot. Soc. 129:175-186. 2002.-The T. pusillum complex consists of five or six southeastern morphogeographical taxa with a confused taxonomic history. Some authors have considered them as a single species, whereas others have split the complex into various combinations of species and varieties. Our study examined pollen and stomatal characteristics of these taxa for their utility as taxonomic characters. All T. pusillum varieties have pollen characterized by somewhat spherical and inaperturate grains with rounded granulate ornamentation. Stomatal complexes lacked subsidiary cells and were aperigenous and homostomatic. Although trends were identified in both pollen diameter and stomatal size and shape, these characters were not reliable variety-specific taxonomic characters. Only T. pusillum var. texanum exhibited both abaxial and adaxial stomata, a feature that consistently distinguished it from other putative varieties that we examined. We suggest that this complex be subdivided into two species, T. texanum Buckley and T. pusillum Michaux, based upon these stomatal distribution patterns.","PeriodicalId":49977,"journal":{"name":"Journal of the Torrey Botanical Society","volume":"129 1","pages":"175"},"PeriodicalIF":0.3,"publicationDate":"2002-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2307/3088768","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68730539","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental Test of the Role of Mammalian Herbivores on Old Field Succession: Community Structure and Seedling Survival","authors":"M. Cadenasso, S. Pickett, P. Morin","doi":"10.2307/3088773","DOIUrl":"https://doi.org/10.2307/3088773","url":null,"abstract":"CADENASSO, M.L., S.TA. PIcKETr (Institute of Ecosystem Studies, Box AB, Millbrook, NY 12545) AND PJ. MoRiN (Department of Ecology, Evolution, and Natural Resources, 14 College Farm Road, Cook College, Rutgers University, New Brunswick, NJ 08901). Experimental test of the role of mammalian herbivores on old field succession: community structure and seedling survival. J. Torrey Bot. Soc. 129:228-237. 2002.-When elucidating plant community dynamics, investigators have focused on plant-plant and plant-environment interactions and on the characteristics of individual plants. The role of animals has been relatively neglected. Herbivory may affect vegetation dynamics by altering community composition and structure and by influencing the performance of species. Therefore, herbivory can be an important factor in succession. We experimentally tested the role of mammalian herbivores in two fields at the Hutcheson Memorial Forest Center in central New Jersey. Both fields were released from active cultivation, one at the beginning of the experiment and the other 17 years earlier. Large exclosures (5 X 5 m) were used to exclude mammalian herbivores, and open units of the same size were used as controls. The effect of herbivore exclusion on the structure and composition of the plant community was analyzed. In addition, tree seedlings of three species-Acer rubrum, Cornus florida, and Juniperus virginiana-were planted in the experimental units in both fields. These species typically invade earlyto mid-successional old fields. The survival of these individuals was calculated and, using height as an indicator, their performance assessed. Herbivore exclusion primarily influenced the structure of the plant community rather than its composition. Percent cover of species and species richness of all plants were not affected by herbivory, but in one field the relative cover of exotics was greater in the exclosures. The height profile of the plant community in the exclosures was significantly taller than the community in the open plots. The survival and growth of planted A. rubrum and C. florida seedlings was significantly greater when protected from herbivores. In contrast, the survival and growth of J. virginiana seedlings was not affected by herbivores. Growth and survival of J. virginiana did differ by the field they were planted in, suggesting that physiological constraints may be more important than herbivory for this species. These results reenforce that herbivorous mammals play a key role in old field succession, particularly in the pivotal shift of dominance from herbaceous to woody cover.","PeriodicalId":49977,"journal":{"name":"Journal of the Torrey Botanical Society","volume":"129 1","pages":"228"},"PeriodicalIF":0.3,"publicationDate":"2002-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2307/3088773","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68730602","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Herbaceous layer contrast and alien plant occurrence in utility corridors and riparian forests of the Allegheny High Plateau","authors":"Darrin L. Rubino, C. Williams, William J. Moriarity","doi":"10.2307/3088726","DOIUrl":"https://doi.org/10.2307/3088726","url":null,"abstract":"communities by alien plant species that can adversely affect community structure and function. To determine how corridor establishment influences riparian vegetation of the Allegheny High Plateau of northwestern Pennsylvania, we compared the species composition and richness of the herbaceous layer (all vascular plants s 1 m tall) of utility corridors and adjacent headwater riparian forests, and tested the hypothesis that utility corridors serve as foci for the invasion of adjacent riparian forest by alien vascular plants. We contrasted plant species richness and vegetative cover, cover by growth form, species richness and cover of alien plants and cover of microhabitat components (open soil, rock, leaf litter, log, bryophyte) in utility corridors and adjacent riparian forest at 17 sites. Cluster analysis revealed that herbaceous layer species assemblages in corridors and riparian forest were compositionally distinct. Herbaceous layer cover and species richness were significantly (P s 0.05) greater in corridors than in riparian forest. Fern, graminoid, and forb species co-dominated herbaceous layer cover in corridors; fern cover dominated riparian forests. Cover of alien plants was significantly greater in corridors than in riparian forest. Alien plant species richness and cover were significantly and positively correlated with open soil, floodplain width, and active channel width in corridors but were significantly and negatively correlated with litter cover in riparian forest. Given that the majority of alien plant species we found in corridors were shade-intolerant and absent from riparian forests, we conclude that open utility corridors primarily serve as habitat refugia, rather than as invasion foci, for alien plant species in riparian forests of the Allegheny High Plateau.","PeriodicalId":49977,"journal":{"name":"Journal of the Torrey Botanical Society","volume":"129 1","pages":"125"},"PeriodicalIF":0.3,"publicationDate":"2002-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2307/3088726","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68730006","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Frost pockets on a level sand plain: Does variation in microclimate help maintain persistent vegetation patterns?2","authors":"G. Motzkin, S. Ciccarello, D. Foster, S. Ciccarello, D. Foster","doi":"10.2307/3088728","DOIUrl":"https://doi.org/10.2307/3088728","url":null,"abstract":"tation patterns across broad geographic regions and areas of steep topography. However, few studies have evaluated the potential influences of local climatic variation on vegetation patterns or dynamics. We investigated the relationships between microclimatic variation, vegetation structure, and leaf phenology on a topographically level sand plain that is characterized by a forest mosaic with abrupt transitions to shrublands dominated by scrub oak (Quercus ilicifolia). The timing of bud break, leaf phenology, and height of scrub oak are strongly related to variation in temperature across the study site. Moderate maximum and minimum temperatures occur beneath forested canopies, whereas nearby shrublands experience frequent late-spring frosts and shorter frost-free growing seasons, resulting in chronic dieback of developing leaves, slow growth rates, and reduced stem height. Our results indicate that extreme radiational cooling in open areas on level, xeric sites may result in the development of 'frost pockets' similar to those that occur in topographical depressions and may contribute to slow establishment of a forest canopy after disturbance. Such frost-prone areas may have become more common as a result of historical cutting and burning and may contribute to the persistence of scrub oak stands that support several rare species and are high priorities for conservation.","PeriodicalId":49977,"journal":{"name":"Journal of the Torrey Botanical Society","volume":"129 1","pages":"154"},"PeriodicalIF":0.3,"publicationDate":"2002-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2307/3088728","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68730029","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Genetic variability and phenotypic plasticity in flowering phenology in populations of two grasses","authors":"J. A. Quinn, J. Wetherington, J. Wetherington","doi":"10.2307/3088723","DOIUrl":"https://doi.org/10.2307/3088723","url":null,"abstract":"QUINN, J. A. (Department of Ecology, Evolution, and Natural Resources, Rutgers University, New Brunswick, NJ 08901-1582) AND J. D. WETHERINGTON (Biometrics Division, DuPont Pharmaceuticals, Wilmington, DE 19880-0721). Genetic variability and phenotypic plasticity in flowering phenology in populations of two grasses. J. Torrey Bot. Soc. 129:96-106. 2002.-Genetic differentiation in flowering phenology has been frequently demonstrated among populations of wide-ranging species. However, fine-tuning of flowering phenology, i.e., responses to yearly fluctuations in the local environment, should best be accomplished via phenotypic plasticity. To test theoretical expectations as to the interaction of genetic differentiation and plasticity, and conditions under which each should be most important, populations of the inbreeding Sporobolus cryptandrus and the outbreeding Panicum virgatum were compared in genetic variation among clones and in amounts and patterns of plasticity in phenology. For each species, three years of data from replicated blocks of cloned genotypes in a common garden near Fort Collins, Colorado, were treated as characters measured in three environments as a way of quantifying \"environmental sensitivity\" and partitioning the variance in flowering time. The three years provided major differences in length of growing season, temperatures, precipitation, and evaporation rates. The outbreeding species possessed the greatest genetic variation among clones in a population, while the inbreeding species showed less genetic variation within and more between populations. Populations of both species varied significantly in amount and highly significantly in pattern of plasticity. The long-lived, clonal Panicum showed a significantly greater plasticity than the short-lived, non-clonal Sporobolus. The plasticity variance component was the largest component overall for Sporobolus, which is found over the widest range of environments heterogeneous in space and time, and there was a highly significant relation between a population's ecological history and the relative importance of plasticity in flowering phenology. The two species did not show a consistent relationship between amounts of clonal genetic variation and plasticity, emphasizing that experiments on a diversity of species are required to appropriately test theoretical expectations.","PeriodicalId":49977,"journal":{"name":"Journal of the Torrey Botanical Society","volume":"129 1","pages":"96"},"PeriodicalIF":0.3,"publicationDate":"2002-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2307/3088723","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68729940","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"First reports of Ceratophyllum echinatum A. Gray from Indiana with notes on the distribution, ecology and phytosociology of the species'","authors":"R. Scribailo, M. Alix, M. Alix, A. Gray","doi":"10.2307/3088729","DOIUrl":"https://doi.org/10.2307/3088729","url":null,"abstract":"SCRIBAILO, R. W. AND M. S. ALIX (Biological Sciences and Chemistry Section, Purdue University North Central, Westville, IN 46391-9528). First reports of Ceratophyllum echinatum A. Gray from Indiana with notes on the distribution, ecology and phytosociology of the species. J. Torrey Bot. Soc. 129:164-171. 2002-During an extensive floristic survey to catalogue the aquatic macrophyte distribution of the Valparaiso Chain of Lakes Watershed, the first record of Ceratophyllum echinatum A. Gray in Indiana was made at Deep Lake in Porter County. The species has subsequently been found in fourteen additional lakes, predominantly throughout Northern Indiana. Although these are the first records of this species in Indiana, the historical scarcity of comprehensive aquatic plant surveys in the state and our knowledge of the geographical range of this species throughout the Midwest, leads us to believe that this species has been in Indiana for an extended period. The close similarity in vegetative morphology among Ceratophyllum echinatum, Ceratophyllum demersum L. and other aquatic plant species with finely dissected leaves, such as Myriophyllum species, has also likely been a contributing factor leading to an under representation of this species in floristic surveys. Voucher specimens of Ceratophyllum echinatum are deposited in the Aquatic Plant Herbarium of Purdue University North Central.","PeriodicalId":49977,"journal":{"name":"Journal of the Torrey Botanical Society","volume":"129 1","pages":"164"},"PeriodicalIF":0.3,"publicationDate":"2002-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2307/3088729","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68730067","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Floral Ontogeny of Salpiglossis (Solanaceae) and the Oblique Gynoecium","authors":"L. Ampornpan, J. Armstrong","doi":"10.2307/3088722","DOIUrl":"https://doi.org/10.2307/3088722","url":null,"abstract":"AMPORNPAN, L. AND J. E. ARMSTRONG. (Faculty of Science, Srinakharinwirot University, Bangkok, Thailand, and Campus Box 4120-Biological Sciences, Illinois State University, Normal, IL 61790-4120). Floral ontogeny of Salpiglossis (Solanaceae) and the oblique gynoecium. J. Torrey Bot. Soc. 129:85-95, 2002.-Inflorescence development in Salpiglossis consists of repeated modular units consisting of two floral bracts on an axis terminating in a flower. The calyx is initiated in a helix with the first primordium appearing on the abaxial side of the floral apex. Primordia of the corolla, androecium, and gynoecium arise in three successive whorls. Zygomorphy first becomes manifest with the slightly delayed initiation of a staminodial primordium. Growth of the corolla and androecium show a dorso-ventral asymmetry that also results in zygomorphy. During early development the median plane of many flowers is on the axillary plane. The median plane of other flowers is oriented 10-15? off the axillary plane, but this is less than half the expected 36?. The off-median orientation does not produce the oblique gynoecial orientation described in the literature as a defining feature of Solanaceae. The zygomorphic flowers of Salpiglossis have a gynoecium that is on the median plane and not oblique. Further the flowers are not obliquely oriented unless via pedicel rotation prior to anthesis. The floral orientation of Solanaceae, as exemplified by Salpiglossis, has the staminode and a calyx lobe in the abaxial position, which is a synapomorphy with respect to other Asteridae.","PeriodicalId":49977,"journal":{"name":"Journal of the Torrey Botanical Society","volume":"129 1","pages":"85"},"PeriodicalIF":0.3,"publicationDate":"2002-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2307/3088722","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68729892","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Role of intraspecific competition in mass seeding and senescence in Polymnia canadensis, a primarily monocarpic species","authors":"M. Bender, J. Baskin, C. Baskin","doi":"10.2307/3088724","DOIUrl":"https://doi.org/10.2307/3088724","url":null,"abstract":"MARTIN H. BENDER', JERRY M. BASKIN', AND CAROL C. BASKIN'2 ('School of Biological Sciences, University of Kentucky, Lexington KY 40506-0225, 2Department of Agronomy, University of Kentucky, Lexington, KY 40546-0091). Role of intraspecific competition in mass seeding and senescence in Polymnia canadensis, a primarily monocarpic species. J. Torrey Bot. Soc. 129:107-114. 2002.-Mass seeding and senescence in 2-year population cycles previously were documented in the primarily monocarpic species Polymnia canadensis. In the present study, small individuals of this species died in competition with large ones in field trials. These results suggested that intraspecific competition followed by synchronous semelparity in a dominant age-class could result in mass flowering and senescence and thus could play a role in population cycling in P. canadensis. It was also found in some trials that other environmental factors such as drought could eliminate small individuals, perhaps sometimes in interaction with competition.","PeriodicalId":49977,"journal":{"name":"Journal of the Torrey Botanical Society","volume":"12 1","pages":"107-114"},"PeriodicalIF":0.3,"publicationDate":"2002-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2307/3088724","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68729951","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}