Robert W. Freckmann Herbarium
University of Wisconsin - Stevens Point

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Wisconsin's Potentially New Invasive Plants

The Wisconsin Department of Natural Resources and the Wisconsin State Herbarium have announced a new initiative.
Wisconsin Invasive Plants Reporting and Prevention Project
Prevent the spread of plants known to be newly invasive in Wisconsin or in nearby states.
Identify these population and control or destroy them before they can spread.
We hope the information presented here will assist in this effort.

Voucher Making Instructions

Invasive Plants of the Future

image of common teasel    

Invasives Home
Invasive Plants Targeted
Upland
Aquatic / Wetland
You Can Help
Collecting & Reporting Guidelines
Invasive Plant Report Form (pdf -Adobe® Reader®)

To voucher a plant for this project you may make a pressed plant collection or use a fresh plant, partial specimens and/or photograph.  Be sure to collect and present adequate evidence no matter which method is used.  In order to confirm the identity of the specimen, you should present (as example) distinctive leaves,  flowers, and/or fruit either fresh or dried  Photographs with sufficient details will also suffice.  The best voucher is a complete, well-preserved dried specimen but for this project we mainly want to identify and destroy these new invasives before they become widespread in Wisconsin. 

The following information has been supplied by the Wisconsin Dept. of Natural Resources to aid in this project.

A voucher specimen . . . is a dried plant sample consisting of pressed leaves, stems, flowers, roots and/or fruits that is used by experts to verify species identification.  Vouchers are valuable because they provide the physical evidence to confirm the presence of plant species in specific locations.  They have a variety of uses, such as documenting the occurrence of rare plants or revealing the geographic spread of invasives over time.  Once received by a herbarium (a plant specimen "library"), vouchers may be mounted, labeled and kept for future reference and research.

Equipment needed

1. Plant Press (or any device in which to flatten and dry specimens.  Instructions below.)

2. Invasive Plant Report Form (pdf -Adobe® Reader®) (or equivalent listing of specimen-related data). 

Basic steps for preparing vouchers

1. Collect plant in the field.
2. Record specimen data on Plant Report Form (pdf -Adobe® Reader®).
3. Press immediately, or transport temporarily in a plastic bag and press ASAP.
4. Dry quickly and completely.
5. Send specimen and Plant Report Form to the State Herbarium at UW-Madison. 

WHAT TO COLLECT 

Select one or more healthy plants that are typical of the population.  Take samples of the whole plant, if possible, or enough leaves and stems to show leaf shape and size, opposite or alternate branching, and buds.  If possible, include flowers and/or fruits, which may be needed to confirm a plant's precise identity.  For grasses and grass-like plants, try to include roots. For large specimens, fold stems into a V or N shape.  Thick stems may be cut in half lengthwise.  For small plants, collect several and press together.  Show upper and lower surfaces of leaves and flowers. Press flowers with the blossom open, and if possible slice one in half lengthwise to show internal structures.  Be sure to press the plant before it wilts.   

PRESSING PLANTS 

Use a standard-sized (12 x 18 inch) plant press, if you have one, or make your own.  Herbarium specimens are mounted (glued) on standard 11.5 x 16.5 inch sheets of heavy paper.  Specimens must not exceed this size (though large plants often are divided up and glued to multiple sheets).   

For this invasive species project, plant press dimensions can be as small as 9 x 12 inches.  This makes it easy to carry the press in a backpack, as well as to send specimens by mail (in large, business-size envelopes).   

MAKING A PORTABLE PLANT PRESS   

End Boards.  Prepare two 9 X 12 inch rectangles of a rigid material.  Use plywood, masonite, pegboard, the backs of two clipboards, the covers from a 3-ring binder, or even cardboard (several sheets glued together for rigidity).  Between the end boards – and cut to the same dimensions -- place alternating layers of corrugated cardboard, moisture absorbers, and newspaper specimen "folders."  See diagram below.   

Corrugated Cardboard.  Cut from corrugated boxes, having the lines of corrugation run across the shortest distance.  This will enhance air flow through the press.

Moisture Absorber.   To wick moisture away from the drying specimens, use sheets of newspaper or paper-toweling.  Sheets of thick blotter paper work well, if available.

Newspaper Specimen "Folder."  Specimens are arranged carefully within a folded piece of newspaper (like placing a document in a file folder).   

Assembling the press.  When putting plants in the press, each newspaper specimen folder is sandwiched between moisture-absorbing layers and cardboard.  For bulky specimens, extra layers of moisture absorber and cardboard may be needed.  Tie the press together tightly with rope, bungee cords, large rubber bands, or buckle straps.  You may need to adjust tightness as plants dry and flatten out.  To quicken drying for high-moisture plants, change the folder and moisture absorbing layers at least once.  Include 5 to 10 (or more) specimen folders – and surrounding layers – in your press, or as many as you can comfortably carry.  

 

End Board

 

Corrugated Cardboard

 

Moisture Absorber

 

Newspaper Specimen Folder

 

Moisture Absorber

 

Corrugated Cardboard

 

Moisture Absorber

 

Newspaper Specimen Folder

 

Moisture Absorber

 

Corrugated Cardboard

 

End Board

 

 

SPECIMEN INFORMATION 

For each specimen or field observation, basic information about the occurrence is needed.  For all specimens collected, make sure that all documentation stays with, or can be linked to, the sample.  Some collectors write data on the newspaper specimen folder or on a sheet enclosed with the sample.  Others use a notebook with code numbers that correspond to a specific sample.   

Use the Invasive Plant Report Form (pdf -Adobe® Reader®) to submit information, or create your own that covers these categories: For each specimen, note the state, county, date collected, and plant name (common or Latin).  Estimate the size and density of the infestation.  Note location landmarks, such as city name, roads, intersections, power lines, lake edges and other natural and cultural features.  Provide a habitat description, such as forest interior, forest edge, old field, prairie, wetland, lakeshore, crop field, pasture, disturbed ground, urban setting type.  Tell if found on public or private land.  Be sure to provide the collector's name, address, phone and email so they can be reached for more details.  Enclose a completed form with each specimen.  If the landowner or land manager is known, provide their name and contact information.   

Accurate information about location is essential.  Try to provide exact geographic coordinates using a GPS unit, topographic map, or the Wisconsin Gazetteer AND Town Range Section Quarters.  If you have access to the internet, you can use http://www.TopoZone.com to find the precise location on a digital topographic map.  When you click the cursor on the exact collection site, its coordinates (choose UTM or Latitude/Longitude) are automatically printed in the text above the map.  Include a printed or photocopied map with a colored dot showing the spot.

Mail specimen with its report form to: 

     Invasive Plants Reporting & Prevention Project,
    
UW Herbarium – Botany Dept.
     430 Lincoln Dr.
     Madison, WI 53706 

Questions?  Contact David Eagan, Project Coordinator
                        InvasivePlants@mailplus.wisc.edu
                        (608) 267-7612

Vascular Plants

Plants of Wisconsin

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