(Ho = 0.103 and HE = 0.121) were more than twice that found in D. foliosa (Ho = 0.037 and HE = 0.043). For both species, levels of heterozygosity were highest in Tennessee and lowest in Illinois, where levels half that found in Tennessee. Differentiation among populations within geographical regions (GSTc = 0.161 and 0.145 for A. tenneseensis and D. foliosa, respectively) was lower than when not clustered by regions (GsT = 0.217 and 0.441). In A. tennesseensis, the majority of species-level genetic diversity was contained within populations (Hs = 0.141 as compared to total diversity HT = 0.179), but in D. foliosa, the opposite was true (Hs = 0.060 as compared to HT =- 0.186). Given the high degree of differentiation among geographical regions, particularly in formerly glaciated Illinois, conservation strategies for these species should include consideration of their geographical affinities.
(Ho = 0.103, HE = 0.121)是叶黄花(Ho = 0.037, HE = 0.043)的2倍多。对于这两个物种来说，杂合性水平在田纳西州最高，在伊利诺伊州最低，后者的杂合性水平只有田纳西州的一半。地理区域内种群间的分化程度(GSTc分别为0.161和0.145)低于非地理区域聚类时的分化程度(GSTc分别为0.217和0.441)。种属间遗传多样性主要集中在群体内(Hs = 0.141，总多样性HT = 0.179)，而叶黄花的遗传多样性主要集中在群体内(Hs = 0.060，总多样性HT =- 0.186)。鉴于地理区域之间的高度差异，特别是在以前冰川覆盖的伊利诺伊州，这些物种的保护策略应包括考虑它们的地理亲缘关系。
{"title":"Genetic diversity in Astragalus tennesseensis and the federal endangered Dalea foliosa (Fabaceae)1","authors":"A. L. Edwards, B. Wiltshire, D. Nickrent","doi":"10.2307/4126934","DOIUrl":"https://doi.org/10.2307/4126934","url":null,"abstract":"(Ho = 0.103 and HE = 0.121) were more than twice that found in D. foliosa (Ho = 0.037 and HE = 0.043). For both species, levels of heterozygosity were highest in Tennessee and lowest in Illinois, where levels half that found in Tennessee. Differentiation among populations within geographical regions (GSTc = 0.161 and 0.145 for A. tenneseensis and D. foliosa, respectively) was lower than when not clustered by regions (GsT = 0.217 and 0.441). In A. tennesseensis, the majority of species-level genetic diversity was contained within populations (Hs = 0.141 as compared to total diversity HT = 0.179), but in D. foliosa, the opposite was true (Hs = 0.060 as compared to HT =- 0.186). Given the high degree of differentiation among geographical regions, particularly in formerly glaciated Illinois, conservation strategies for these species should include consideration of their geographical affinities.","PeriodicalId":49977,"journal":{"name":"Journal of the Torrey Botanical Society","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2004-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2307/4126934","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69302892","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}
Within the confines of New York City lies an overlooked oasis of green, the successional lichens, mosses and vascular plants that occupy the abandoned elevated High Line, a commercial railroad paralleling 10th Avenue between 13th and 34th Streets. The High Line consists of a 7.5 X 2330 m strip traversing 20 city blocks. It is exposed to full sun except in the area of 29th Street, which is partially shaded by tall buildings. Human visitors to the High Line have probably inadvertently transported seeds to the site, a source of new species. Additional environmental variables include shallow soil profile (0.01 to 0.7 m), thus inducing drought stress in dry weather, low fertility of soil, human trampling and cutting vegetation, and the smothering of plants by debris such as tires, bottles and additional trash. The aforementioned environmen
在纽约市的范围内，有一片被忽视的绿色绿洲，地衣、苔藓和维管植物相继出现，占据了废弃的高架线，这是一条与第十大道平行的商业铁路，位于第13街和第34街之间。高线由一条7.5 X 2330米的长条组成，穿过20个城市街区。除了第29街部分被高层建筑遮蔽外，它都暴露在充足的阳光下。高线公园的游客可能无意中把种子带到这里，这是新物种的来源。其他环境变量包括土壤剖面较浅(0.01至0.7米)，从而在干旱天气引起干旱压力，土壤肥力低，人类践踏和砍伐植被，以及轮胎、瓶子和其他垃圾等碎片使植物窒息。前面提到的环境
{"title":"The flora on the High Line, New York City, New York","authors":"Richard Stalterl, R. Stalter, J. Bot","doi":"10.2307/4126942","DOIUrl":"https://doi.org/10.2307/4126942","url":null,"abstract":"Within the confines of New York City lies an overlooked oasis of green, the successional lichens, mosses and vascular plants that occupy the abandoned elevated High Line, a commercial railroad paralleling 10th Avenue between 13th and 34th Streets. The High Line consists of a 7.5 X 2330 m strip traversing 20 city blocks. It is exposed to full sun except in the area of 29th Street, which is partially shaded by tall buildings. Human visitors to the High Line have probably inadvertently transported seeds to the site, a source of new species. Additional environmental variables include shallow soil profile (0.01 to 0.7 m), thus inducing drought stress in dry weather, low fertility of soil, human trampling and cutting vegetation, and the smothering of plants by debris such as tires, bottles and additional trash. The aforementioned environmen","PeriodicalId":49977,"journal":{"name":"Journal of the Torrey Botanical Society","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2004-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2307/4126942","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69303087","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}
RICHARD W. HALSEY (Southern California Chaparral Field Institute, P.O. Box 545, Escondido, CA 92033). In search of allelopathy: an eco-historical view of the investigation of chemical inhibition in California coastal sage scrub and chamise chaparral. J. Torrey Bot. Soc. 131. 343–367. 2004.—Allelopathy between plants, whereby one species influences another by chemical means, has been speculated upon since the Greeks. During the second half of the twentieth century, southern California was the focal point of allelopathic research by several influential investigators. Frits Went suggested Encelia farinosa, a common desert shrub, inhibited annuals from growing under its canopy by chemical inhibition. Reed Gray and James Bonner conducted further investigations. Cornelius H. Muller questioned the allelopathic explanation for Encelia, but later felt chemical inhibition was the cause for vegetation patterns found in both southern Californian coastal sage scrub, primarily around Salvia leucophylla and Artemisia californica, and Adenostoma fasciculatum (chamise) chaparral. Various investigators challenged Muller’s conclusions, but Muller remained convinced allelopathy was an important ecological variable in southern California’s shrublands. Muller’s passionate belief in his scientific models led him to ignore contrary evidence, yet his dedication to science and the education of his students inspired many. Allelopathy remains a controversial topic today despite hundreds of investigations because of the difficulty in isolating all the possible variables affecting plant growth.
RICHARD W. HALSEY(南加州Chaparral Field Institute, Escondido, CA 92033邮政信箱545)。寻找化感作用:加利福尼亚海岸鼠尾草灌丛和chamise chaparral的化学抑制调查的生态历史观点。托里·博特。Soc》131。343 - 367。2004.植物之间的化感作用，即一种植物通过化学手段影响另一种植物，从希腊人开始就被推测出来。在二十世纪下半叶，南加州是几个有影响力的研究者化感疗法研究的焦点。Frits Went认为，一种常见的沙漠灌木，通过化学抑制作用，抑制了一年生植物在其树冠下的生长。Reed Gray和James Bonner进行了进一步的调查。Cornelius H. Muller质疑对Encelia的化感作用解释，但后来认为化学抑制是在南加州沿海鼠尾草灌丛(主要是在鼠尾草和加利福尼亚蒿周围)和束状树阴(chamise) chaparral中发现的植被模式的原因。许多研究者对穆勒的结论提出了质疑，但穆勒仍然相信化感作用是南加州灌丛地的一个重要生态变量。穆勒对他的科学模型充满激情的信仰使他忽视了相反的证据，然而他对科学的奉献和对学生的教育激励了许多人。化感作用在今天仍然是一个有争议的话题，尽管有数百项研究，因为很难分离出影响植物生长的所有可能的变量。
{"title":"In search of allelopathy: an eco-historical view of the investigation of chemical inhibition in California coastal sage scrub and chamise chaparral","authors":"R. Halsey, Richard W. H Alsey","doi":"10.2307/4126940","DOIUrl":"https://doi.org/10.2307/4126940","url":null,"abstract":"RICHARD W. HALSEY (Southern California Chaparral Field Institute, P.O. Box 545, Escondido, CA 92033). In search of allelopathy: an eco-historical view of the investigation of chemical inhibition in California coastal sage scrub and chamise chaparral. J. Torrey Bot. Soc. 131. 343–367. 2004.—Allelopathy between plants, whereby one species influences another by chemical means, has been speculated upon since the Greeks. During the second half of the twentieth century, southern California was the focal point of allelopathic research by several influential investigators. Frits Went suggested Encelia farinosa, a common desert shrub, inhibited annuals from growing under its canopy by chemical inhibition. Reed Gray and James Bonner conducted further investigations. Cornelius H. Muller questioned the allelopathic explanation for Encelia, but later felt chemical inhibition was the cause for vegetation patterns found in both southern Californian coastal sage scrub, primarily around Salvia leucophylla and Artemisia californica, and Adenostoma fasciculatum (chamise) chaparral. Various investigators challenged Muller’s conclusions, but Muller remained convinced allelopathy was an important ecological variable in southern California’s shrublands. Muller’s passionate belief in his scientific models led him to ignore contrary evidence, yet his dedication to science and the education of his students inspired many. Allelopathy remains a controversial topic today despite hundreds of investigations because of the difficulty in isolating all the possible variables affecting plant growth.","PeriodicalId":49977,"journal":{"name":"Journal of the Torrey Botanical Society","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2004-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2307/4126940","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69303016","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}
R. Schmid, N. P. Smith, S. Mori, A. Henderson, D. Stevenson, Scott V. Heald
Preface ix Contributors xi Acknowledgments xv Introduction xvii Editors' Note xxi Dicotyledons 1 Monocotyledons 403 Glossary 497 Literature Cited 525 Appendix I Cronquist Dicotyledon Classification 529 Appendix II Dahlgren et al. Monocotyledon Classification 531 Appendix III Families treated in Flowering Plants of the Neotropics 532 Appendix IV Families of Angiosperms treated by Judd et al. 533 Appendix V Aids to Identification 535 Index to Scientific Names 563
{"title":"Flowering plants of the neotropics.","authors":"R. Schmid, N. P. Smith, S. Mori, A. Henderson, D. Stevenson, Scott V. Heald","doi":"10.2307/4126945","DOIUrl":"https://doi.org/10.2307/4126945","url":null,"abstract":"Preface ix Contributors xi Acknowledgments xv Introduction xvii Editors' Note xxi Dicotyledons 1 Monocotyledons 403 Glossary 497 Literature Cited 525 Appendix I Cronquist Dicotyledon Classification 529 Appendix II Dahlgren et al. Monocotyledon Classification 531 Appendix III Families treated in Flowering Plants of the Neotropics 532 Appendix IV Families of Angiosperms treated by Judd et al. 533 Appendix V Aids to Identification 535 Index to Scientific Names 563","PeriodicalId":49977,"journal":{"name":"Journal of the Torrey Botanical Society","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2004-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2307/4126945","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69303095","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}
MULLIGAN, M. R., AND D. L. GORCHOV. (Department of Botany, Miami University, Oxford, OH 45056). Population loss of goldenseal, Hydrastis canadensis L. (Ranunculaceae), in Ohio. J. Torrey Bot. Soc. 131: 305310. 2004.-Goldenseal, Hydrastis canadensis L., is harvested from forests in the eastern U.S. for its rhizome, which is considered to have medicinal properties. While listed as rare or threatened in many states, its status in Ohio has not been assessed. To establish the status of historic goldenseal populations, we assessed 71 sites where voucher specimens had been collected from 1845 to 1998. Of these sites, 13% were deforested and no longer supported populations. Goldenseal was found on 65% of the remaining forested sites. Nearly half of documented goldenseal populations have become extinct, suggesting an overall decline of goldenseal in Ohio. The major cause of extinction appears to differ among Ecoregions, with deforestation important in the Eastern Corn Belt Plains, herbivory by white-tailed deer in Erie/Ontario Drift and Lake Plain, and overcollection in the Western Allegheny Plateau.
{"title":"Population loss of goldenseal, Hydrastis canadensis L. (Ranunculaceae), in Ohio'","authors":"Margaret R. Mulligan","doi":"10.2307/4126936","DOIUrl":"https://doi.org/10.2307/4126936","url":null,"abstract":"MULLIGAN, M. R., AND D. L. GORCHOV. (Department of Botany, Miami University, Oxford, OH 45056). Population loss of goldenseal, Hydrastis canadensis L. (Ranunculaceae), in Ohio. J. Torrey Bot. Soc. 131: 305310. 2004.-Goldenseal, Hydrastis canadensis L., is harvested from forests in the eastern U.S. for its rhizome, which is considered to have medicinal properties. While listed as rare or threatened in many states, its status in Ohio has not been assessed. To establish the status of historic goldenseal populations, we assessed 71 sites where voucher specimens had been collected from 1845 to 1998. Of these sites, 13% were deforested and no longer supported populations. Goldenseal was found on 65% of the remaining forested sites. Nearly half of documented goldenseal populations have become extinct, suggesting an overall decline of goldenseal in Ohio. The major cause of extinction appears to differ among Ecoregions, with deforestation important in the Eastern Corn Belt Plains, herbivory by white-tailed deer in Erie/Ontario Drift and Lake Plain, and overcollection in the Western Allegheny Plateau.","PeriodicalId":49977,"journal":{"name":"Journal of the Torrey Botanical Society","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2004-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2307/4126936","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69302904","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}
different overstory tree species, with loblolly pine (Pinus taeda L.), shortleaf pine (Pinus echinata Mill.), and white oak (Quercus alba L.) comprising the majority of stand basal area. Hardwoods are most numerous, dominated by shade-tolerant species such as red maple (Acer rubrum L.), flowering dogwood (Cornus florida L.), blackgum (Nyssa sylvatica L.), and winged elm (Ulmus alata Michx.), especially in the subcanopy and understory. Large pines, oaks, and sweetgum are scattered throughout the stand, with some individuals exceeding 100 cm DBH and 45 m tall. Overstory trees rarely proved sound enough to age, but some stumps, logs, and increment cores suggest that the dominant canopy pines are 100 to 150 years old, with the largest individuals exceeding 200 years. Pines contributed the greatest amount of coarse woody debris. The average volume of dead wood was noticeably less than other examples of old-growth upland forest in the eastern United States, attributable largely to salvage. Increased windthrow and the salvage of dead and dying pines have become the primary perturbations of the LWDE Without large-scale disturbance like catastrophic fire or logging, shadeintolerant pines, oaks, and sweetgum (Liquidambar styraciflua L.) will decline in prominence, to be replaced by more shade-tolerant species.
{"title":"Composition, structure, and dynamics of a pine-hardwood old-growth remnant in southern Arkansas","authors":"D. Bragg","doi":"10.2307/4126938","DOIUrl":"https://doi.org/10.2307/4126938","url":null,"abstract":"different overstory tree species, with loblolly pine (Pinus taeda L.), shortleaf pine (Pinus echinata Mill.), and white oak (Quercus alba L.) comprising the majority of stand basal area. Hardwoods are most numerous, dominated by shade-tolerant species such as red maple (Acer rubrum L.), flowering dogwood (Cornus florida L.), blackgum (Nyssa sylvatica L.), and winged elm (Ulmus alata Michx.), especially in the subcanopy and understory. Large pines, oaks, and sweetgum are scattered throughout the stand, with some individuals exceeding 100 cm DBH and 45 m tall. Overstory trees rarely proved sound enough to age, but some stumps, logs, and increment cores suggest that the dominant canopy pines are 100 to 150 years old, with the largest individuals exceeding 200 years. Pines contributed the greatest amount of coarse woody debris. The average volume of dead wood was noticeably less than other examples of old-growth upland forest in the eastern United States, attributable largely to salvage. Increased windthrow and the salvage of dead and dying pines have become the primary perturbations of the LWDE Without large-scale disturbance like catastrophic fire or logging, shadeintolerant pines, oaks, and sweetgum (Liquidambar styraciflua L.) will decline in prominence, to be replaced by more shade-tolerant species.","PeriodicalId":49977,"journal":{"name":"Journal of the Torrey Botanical Society","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2004-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2307/4126938","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69302955","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}
through time when vegetative growth must also be supported from a limited pool of photosynthate. We compared reproductive performance characteristics among natural stands in Upper Michigan, USA across seven years. In addition, we inquired whether small or deeply shaded shrubs tended to be less consistent fruit producers. Fruit set fluctuated considerably over the period, but several conspicuously good and poor years did not correspond to temperature patterns. Flower production was largely stable at the stand level over the seven year period, with increases in years 2000 and 2001. Fruit production was a function of shrub size and did not differ between years or between stands. At an individual level, small and deeply shaded individuals tended to have one or two conspicuously good fruiting years against a background of low fruit production; sunlit and larger individuals were more consistent fruit producers. Fruit production was not related to the previous year's fruit crop. Shrub size and, secondarily, light availability were the important determinants of fruit production, implying that stand age and history govern the population recruitment of leatherwood.
{"title":"Annual, local, and individual variation in the inflorescence and fruit production of eastern leatherwood (Dirca palustris L. Thymelaeaceae)'","authors":"K. Schulz, J. Zasada, E. Nauertz, E. Nauertz","doi":"10.2307/4126935","DOIUrl":"https://doi.org/10.2307/4126935","url":null,"abstract":"through time when vegetative growth must also be supported from a limited pool of photosynthate. We compared reproductive performance characteristics among natural stands in Upper Michigan, USA across seven years. In addition, we inquired whether small or deeply shaded shrubs tended to be less consistent fruit producers. Fruit set fluctuated considerably over the period, but several conspicuously good and poor years did not correspond to temperature patterns. Flower production was largely stable at the stand level over the seven year period, with increases in years 2000 and 2001. Fruit production was a function of shrub size and did not differ between years or between stands. At an individual level, small and deeply shaded individuals tended to have one or two conspicuously good fruiting years against a background of low fruit production; sunlit and larger individuals were more consistent fruit producers. Fruit production was not related to the previous year's fruit crop. Shrub size and, secondarily, light availability were the important determinants of fruit production, implying that stand age and history govern the population recruitment of leatherwood.","PeriodicalId":49977,"journal":{"name":"Journal of the Torrey Botanical Society","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2004-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2307/4126935","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69302898","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}
of detached terminal segments that become established for 25 cactus species. We hypothesized that cactus species with more segments per stem should require more force to remove terminal segments. Regression analyses of mean maximum stress at failure of terminal joints versus mean number of segments for the species tested gave a line equation of y = 380x + 1350 with a regression coefficient of 0.85. We hypothesized that cactus species with few segments per stem for adult plants should have good establishment of detached terminal stem segments while species with many segments on adult plants should have low levels of establishment of detached terminal segments. Regression analyses of mean establishment of terminal segments as a function of mean number of segments gave a line equation of y = - 1.73x + 80.6 with a regression coefficient of 0.77. In contrast, plant height was not related to either maximum normal stress at failure or segment establishment. We conclude that number of stem segments on longest stems of plants was a good predictor of force necessary to remove terminal segments. Number of stem segments was also a good predictor of rooting and establishment of terminal segments. Overall, the data of this study show that Cylindropuntia and Opuntia species with large numbers of stem segments along each stem rely mostly on sexual reproduction for procreation while species with fewer stem segments rely mostly on asexual reproduction via rooting of detached stem segments.
{"title":"Relationships between number of stem segments on longest stems, retention of terminal stem segments and establishment of detached terminal stem segments for 25 species of Cylindropuntia and Opuntia (Cactaceae)1","authors":"L. Evans, Grace J. Imson, J. Kim, Z. Kahn-Jetter","doi":"10.2307/4126950","DOIUrl":"https://doi.org/10.2307/4126950","url":null,"abstract":"of detached terminal segments that become established for 25 cactus species. We hypothesized that cactus species with more segments per stem should require more force to remove terminal segments. Regression analyses of mean maximum stress at failure of terminal joints versus mean number of segments for the species tested gave a line equation of y = 380x + 1350 with a regression coefficient of 0.85. We hypothesized that cactus species with few segments per stem for adult plants should have good establishment of detached terminal stem segments while species with many segments on adult plants should have low levels of establishment of detached terminal segments. Regression analyses of mean establishment of terminal segments as a function of mean number of segments gave a line equation of y = - 1.73x + 80.6 with a regression coefficient of 0.77. In contrast, plant height was not related to either maximum normal stress at failure or segment establishment. We conclude that number of stem segments on longest stems of plants was a good predictor of force necessary to remove terminal segments. Number of stem segments was also a good predictor of rooting and establishment of terminal segments. Overall, the data of this study show that Cylindropuntia and Opuntia species with large numbers of stem segments along each stem rely mostly on sexual reproduction for procreation while species with fewer stem segments rely mostly on asexual reproduction via rooting of detached stem segments.","PeriodicalId":49977,"journal":{"name":"Journal of the Torrey Botanical Society","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2004-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2307/4126950","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69302645","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}
across the landscape favorable for specific species groups. We also tested two multivariate methods for quantifying associations among species groups, and found that Mantel tests using traditional distance measures were inappropriate because of the double-zero problem of species absences, whereas canonical correlation modeled species group associations consistent with species distributions among sites. This study is among the first to develop ecological species groups in the southern United States, and the species group approach was useful for explaining vegetation-environment relationships, identifying groups of ground-flora and tree species that varied together across the landscape, and for determining the environmental gradients most strongly associated with species distributions.
{"title":"Ecological species groups of South Carolina's Jocassee Gorges, southern Appalachian Mountains","authors":"Scott R. Abella, V. Shelburne","doi":"10.2307/4126952","DOIUrl":"https://doi.org/10.2307/4126952","url":null,"abstract":"across the landscape favorable for specific species groups. We also tested two multivariate methods for quantifying associations among species groups, and found that Mantel tests using traditional distance measures were inappropriate because of the double-zero problem of species absences, whereas canonical correlation modeled species group associations consistent with species distributions among sites. This study is among the first to develop ecological species groups in the southern United States, and the species group approach was useful for explaining vegetation-environment relationships, identifying groups of ground-flora and tree species that varied together across the landscape, and for determining the environmental gradients most strongly associated with species distributions.","PeriodicalId":49977,"journal":{"name":"Journal of the Torrey Botanical Society","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2004-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2307/4126952","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69302678","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}
R. Decandido, Adrianna A. Muir, Margaret B. Gargiullo
DECANDIDO, R. (Department of Biology, The City College of the City University of New York, New York, NY 10031), A. A. MUIR (Graduate Group in Ecology, 2148 Wickson Hall, University of California, Davis, CA 95616), and M. B. GARGIULLO (City of New York Department of Parks and Recreation, Natural Resources Group, 1234 Fifth Avenue, New York, NY 10029). A first approximation of the historical and extant vascular flora of New York City: Implications for native plant species conservation. J. Torrey Bot. Soc. 131: 243-251. 2004.-This historical and extant vascular flora of greater New York City is a literature review supplemented with field work and examination of herbarium specimens held in New York State. For the historical and modern periods combined, 2177 species in 779 genera and 161 families were found in New York City. The City retains 57.4% of its native plant species diversity with 779 extant native species compared to 1357 ever recorded. Extirpations have disproportionately affected native vs. non-native species. Staten Island (Richmond County) has the greatest diversity of the five boroughs with 154 families and 1633 species known from both the historical and modern time periods combined, as well as the greatest number of extant species (921), and the greatest number of native extant species (621). However it has lost approximately 35% of its native flora in the last 70 years. Brooklyn (Kings County) has the lowest diversity of any borough with 695 native and alien species known from both the historical and modern periods combined. Manhattan (New York County) and Brooklyn have lost more than 75% of their native species. Queens County has lost the greatest number of native species (585). In New York City since the mid-19th century, 46.4% of all native herbaceous species have been extirpated, while 22.9% of native woody plants have been lost. In the last 70 years, extirpations have continued even in natural areas protected in parks. Strategies are recommended for preserving New York City's significant native plant species diversity.
DECANDIDO, R.(纽约城市大学城市学院生物系，纽约，NY 10031)， A. A. MUIR(生态学研究生组，加州大学戴维斯分校威克森厅2148号，CA 95616)和M. B. GARGIULLO(纽约市公园和娱乐部，自然资源组，纽约，NY 10029)。纽约市历史和现存维管植物区系的初步近似:对本地植物物种保护的启示。托里·博特。社会科学学报。131:243-251。2004.这篇历史上和现存的大纽约市维管植物群是一篇文献综述，补充了对纽约州植物标本馆标本的实地工作和检查。在历史和现代时期，纽约市共发现161科779属2177种。该市保留了57.4%的本地植物物种多样性，现存的本地物种为779种，而有记录的本地物种为1357种。物种灭绝对本地物种和非本地物种的影响不成比例。斯塔顿岛(里士满县)在五个行政区中拥有最大的多样性，有154科和1633种已知的历史和现代时期，以及最大数量的现存物种(921)和最大数量的本地现存物种(621)。然而，在过去的70年里，它已经失去了大约35%的本土植物。布鲁克林(国王县)是所有行政区中多样性最低的，从历史和现代时期已知的本地和外来物种加起来有695种。曼哈顿(纽约县)和布鲁克林已经失去了超过75%的本地物种。皇后县失去了最多的本地物种(585种)。在纽约市，自19世纪中叶以来，46.4%的本地草本物种已经灭绝，而22.9%的本地木本植物已经消失。在过去的70年里，即使在公园保护的自然区域，灭绝也在继续。建议保护纽约市重要的本地植物物种多样性的策略。
{"title":"A First Approximation of the Historical and Extant Vascular Flora of New York City: Implications for Native Plant Species Conservation","authors":"R. Decandido, Adrianna A. Muir, Margaret B. Gargiullo","doi":"10.2307/4126954","DOIUrl":"https://doi.org/10.2307/4126954","url":null,"abstract":"DECANDIDO, R. (Department of Biology, The City College of the City University of New York, New York, NY 10031), A. A. MUIR (Graduate Group in Ecology, 2148 Wickson Hall, University of California, Davis, CA 95616), and M. B. GARGIULLO (City of New York Department of Parks and Recreation, Natural Resources Group, 1234 Fifth Avenue, New York, NY 10029). A first approximation of the historical and extant vascular flora of New York City: Implications for native plant species conservation. J. Torrey Bot. Soc. 131: 243-251. 2004.-This historical and extant vascular flora of greater New York City is a literature review supplemented with field work and examination of herbarium specimens held in New York State. For the historical and modern periods combined, 2177 species in 779 genera and 161 families were found in New York City. The City retains 57.4% of its native plant species diversity with 779 extant native species compared to 1357 ever recorded. Extirpations have disproportionately affected native vs. non-native species. Staten Island (Richmond County) has the greatest diversity of the five boroughs with 154 families and 1633 species known from both the historical and modern time periods combined, as well as the greatest number of extant species (921), and the greatest number of native extant species (621). However it has lost approximately 35% of its native flora in the last 70 years. Brooklyn (Kings County) has the lowest diversity of any borough with 695 native and alien species known from both the historical and modern periods combined. Manhattan (New York County) and Brooklyn have lost more than 75% of their native species. Queens County has lost the greatest number of native species (585). In New York City since the mid-19th century, 46.4% of all native herbaceous species have been extirpated, while 22.9% of native woody plants have been lost. In the last 70 years, extirpations have continued even in natural areas protected in parks. Strategies are recommended for preserving New York City's significant native plant species diversity.","PeriodicalId":49977,"journal":{"name":"Journal of the Torrey Botanical Society","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2004-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2307/4126954","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69302695","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}
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