Herbarium voucher specimens

Today the JCU Plant Ecology class prepared voucher specimens collected on 5 September 2013 at the Blanche Novak Sanctuary in Portage County, OH.  The specimens were pressed on 5 September and we mounted them on 24 October.  Typically voucher specimens provide presence/absence data which is collected to measure plant community richness, diversity and evenness.  These voucher specimens are intended to identify species and provide locality information for specimens.  Ideally plant voucher specimens are posed to show distinguishing features like leaves, flowers, fruits, stems and roots for ease of identification.  As wise person once said, “Mounting and pressing plant specimens is an art form.”

Proper plant mounting techniques.

The plant specimens were previously pressed to eliminate moisture and pose them for mounting.  To mount the specimens we glued them to acid free archival paper.  Gummed linen mounting strips were also used to secure larger plants with woody stems.  This acid-free paper will help to preserve the specimens as it will prevent the plants from becoming discolored.  Finally we labeled each specimen with the scientific name (Family, Genus species), collection information (like locality data – both geographic and plant community information) and the collectors.

Some common species found by the class were: Horsetail (Equisetum arvense), bird’s foot trefoil (Lotus corniculatus), various goldenrods (Solidago sp.), Queen Anne’s Lace (Daucus carota), narrowleaf plantain (Plantago lanceolata), and the New England Aster (which has had a recent change in classification from Aster novae-angliae to Symphyotrichum novae-angliae).  We also had 3 unknown grass and 9 unknown plants and 3 unknown goldenrod species.  These species may be able to be identified in the future and others may undergo changes in classification.

L: Horsetail (Equisetum arvense).  R: Queen Anne's Lace (Daucus carota).

Three unknown Solidago sp.

This is an important exercise because there are often changes in the taxonomic nomenclature of plants.  Voucher specimens can provide a sort of history of scientific names.  As such, having a record of past and present scientific names of a plant can be important in linking these changes to previous research.  Species can be compared, potentially split or reverted to a previous taxonomic classification.   

New England Aster (recent change in classification from Aster novae-angliae to Symphyotrichum novae-angliae).

If a location is sampled repeatedly over time, some questions can be answered about the richness, evenness and diversity of the plant community like:

1      Which plants make up the community?  (presence/absence data)

2      In what abundance?  (plant species richness)

3      Which plants are dominant in the area?  (plant species evenness and diversity)

New invasions of native or invasive plants or disappearances of rare species can also be observed.  This data can then be useful to land managers to create a management strategy tailored to the changing plant community to protect the rare species or defend against the invasive species.

For more information on plants native to Ohio and voucher specimens:

USDA plant database:

http://plants.usda.gov/java/

More information on plant voucher specimens:

http://www.ipaw.org/mapping/voucherhandout.pdf

http://www.flmnh.ufl.edu/herbarium/voucher.htm

Authored by:

Josh Traub

Angelica Bradac

Alex Cameron