Vascular Flora of Worcester, Massachusetts Robert I. Bertin Special Publication of the New England Botanical Club Availability of this Publication: Electronic or paper copies are available at cost. Direct inquiries to the Special Publications Committee, New England Botanical Club, Harvard University Herbaria, 22 Divinity Ave. Cambridge, MA 02138-2020 About the Author: Robert I. Bertin is a professor of biology in the Biology Department at the College of the Holy Cross. He teaches a variety of courses, including ecology, environmental biology and field botany. His academic interests include the flora and natural history of New England, the sexual systems of flowering plants, and the ecology of invasive species. Additions and Corrections: Communications concerning mistakes in this flora or potential additions to the species list are welcome. Any substantive modifications will be posted under the author’s name on the Biology Department web page at the Holy Cross web site. The author can be contacted through the Biology Department or at [email protected]. Cover Illustrations: Pictured are three species portraying different aspects of the Worcester flora. Acer platanoides, or Norway maple, is a non-native species and the most commonly planted street tree in Worcester. It is prominent in many City woodlands, where it competes with native species. The grass Elymus villosus is a state threatened species. The Worcester record is the only known occurrence of the species in Worcester County. The orchid Calopogon tuberosus, a native bog species, is known in the City only from historical records. Figures reprinted from Holmgren et al. (1998) Illustrated Companion to Gleason and Cronquist’s Manual, with the kind permission of the New York Botanical Garden. Vascular Flora of Worcester, Massachusetts Robert I. Bertin Biology Department College of the Holy Cross Worcester, Massachusetts 01610 Copyright © 2000 Robert I. Bertin All rights reserved Special Publication of the New England Botanical Club Table of Contents Acknowledgments ................................................................................................................. 1 Preface ................................................................................................................................... 1 Introduction ........................................................................................................................... 2 The Physical Setting .............................................................................................................. 2 Geology ................................................................................................................................. 5 Climate .................................................................................................................................. 6 Soils ....................................................................................................................................... 7 The Human Impact ................................................................................................................ 8 Vegetation ............................................................................................................................ 12 Methodology ........................................................................................................................ 15 Explanation of the Species List ........................................................................................... 15 Species Summary ................................................................................................................ 18 Species List: Ferns and Fern Allies ..................................................................................... 21 Species List: Gymnosperms ................................................................................................ 25 Species List: Dicotyledons .................................................................................................. 26 Species List: Monocotyledons ........................................................................................... 106 Appendix I – Sampling Sites ............................................................................................. 134 Appendix II – Fugitives and Waifs ................................................................................... 137 Appendix III – Species Excluded ...................................................................................... 139 Literature Cited .................................................................................................................. 140 Index .................................................................................................................................. 142 List of Tables and Figures Figure 1. Map of Worcester, Massachusetts showing locations of sampling sites and major roads ................................................................................................................ 3 Figure 2. Map of Worcester, Massachusetts showing topography and locations of streams and ponds ...................................................................................................... 4 Table 1. Percentage of Worcester occupied by forest, wetland and water at different times ........................................................................................................................ 10 Table 2. Taxonomic summary of the Worcester flora ........................................................ 18 Table 3. New Worcester County records ........................................................................... 19 1 Acknowledgments I thank the many individuals who have assisted me in this work. David Boufford, C. Barre Hellquist, Thomas Philbrick, Tom Rawinski, Karen Searcy, Paul Somers and Lisa Standley helped with difficult identifications. Tom Rawinski generously shared his knowledge of the flora of central Massachusetts and contributed several species records. Les Mehrhoff of the University of Connecticut herbarium, Ray Angelo, Maureen Kerwin, Tim Whitfield and Emily Wood of the Harvard University Herbaria, Stan Herwitz of the Hadwen Herbarium at Clark University, Karen Searcy of the University of Massachusetts Herbarium, Aaron Ellison of Mount Holyoke College, and Anthony Kirchgessner of the New York Botanical Garden provided information on specimens or assistance in the use of their respective facilities. Edmund Schofield helped track down historical information. Arthur Allen, Jennifer Bravo, George Hoffmann and Karen Searcy kindly reviewed a draft of the manuscript. Anne Barry, Susan Hunt, Lorrie Parent, Ken Scott and Joel Villa assisted with computer software. Hugo Cárdenas kindly made available the GIS facilities of Worcester’s Office of Planning and Community Development where Erin Whitaker expertly drafted the two maps. Special thanks to the NEBC special publication committee, Karen Searcy, Paul Somers and Lisa Standley, for their advice and careful editing of the manuscript. Holy Cross College and the Marshall Fund supported various aspects of this work. Finally, numerous landowners permitted access to their properties in the City, without which this work would not have been possible. Preface The southern New England states, including Massachusetts, probably contain a greater density of practicing botanists than any other state or province in the Western Hemisphere. Despite this fact, the botanical landscape is poorly known. New native vascular plant species continue to be added to state totals. The work for this flora in one city uncovered over 80 plant species that had not previously been recorded anywhere in the county. No complete flora of Massachusetts has ever been published (though parts were treated by Ahmadjian 1979), and no generally accepted classification of plant communities of this state has yet been developed. Thus, we have much to learn about our green environment. Floras for single towns or cities are uncommon. The only Massachusetts town floras from the past half century are Blake’s The Flora of Stoughton, Massachusetts (1964), Eaton’s A Flora of Concord (1974), and Sorrie and Dunwiddie’s The Vascular and Non-Vascular Flora of Nantucket, Tuckernut, and Muskeget Islands (1996). One might argue that the considerable effort required to produce a flora is of limited value when the geographic coverage is so restricted, and that one’s efforts are more profitably directed to a county, state, or region. Several regional floras cover the Worcester area, including Fernald (1950), Seymour (1972), Gleason and Cronquist (1991), Flora of North America Committee (1993-2000) and Magee and Ahles (1999). While floras at these larger scales are immensely valuable, they are necessarily limited in specificity. From a regional flora, for example, it can be difficult to determine the actual frequency with which a species occurs. By working at a more local level, it is possible to give much more detailed information on frequency, abundance, and distribution, and therefore on changes over time and the impact of human activities, as has been observed by Whitney (1994). 2 A floristic survey of an urban area is also somewhat unusual in that botanists tend to focus on more natural environments. A notable exception is the massive New York Metropolitan Flora project now underway under the auspices of the Brooklyn Botanic Garden. Such surveys of urban areas are helpful in allowing documentation of the loss of native species and the