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This month . . .
Collecting Plants: A Pressing
Project
Making Herbaria, Field
Guides, Gifts
When
European explorers struck out in the 16th century to discover
parts unknown, they often returned with samples of plants they'd
met along the way. As this collection of treasures soon exploded,
botanic gardens were hard pressed to keep living samples of the
whole lot. So botanists devised a solution: create a collection
of pressed plants.
After
all, scientists wanted to compare their discoveries, identify
new plants, and document the diversity and distribution of plants
on Earth. The system they designed includes carefully pressing
plants, mounting each specimen on a sheet of heavy paper, and
creating an accompanying information card. These feature such
details as when and where the plant was found (and by whom), its
habitat, and the common and scientific names (if known). These
plant libraries, which scientists still use today, are called
herbaria.
Consider
engaging your students in gathering, identifying, and pressing
local plants (or parts, such as flowers). They might then create
scientific-style herbarium pages, bound into booklets, or design
a field
guide to the green denizens of the class butterfly garden, schoolyard,
or neighborhood. (Schoolmates and visitors can use the field guides
to tour the site and identify plants they encounter.) By
focusing on specific plant categories those with medicinal
uses, native trees, or plants pollinated by bees, for instance
you can enhance thematic studies. Flattened
flowers and interesting leaves can also inspire a host of art
and gift projects, including notecards, placemats, and decorative
candles.
As
your young scientists tune into what's growing around them and
compare flowers, leaves, and other plant parts from different
species, they will hone observation and classification skills.You
can encourage such plant collecting adventures through the season,
or integrate them into a shorter unit. The Curriculum
Connections page has suggestions for using the process and
products of your pressing experience to enrich learning.
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Materials
(You and your students can make your own plant presses or purchase
this one through
the Gardening
with Kids store.)
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For each plant press: squares of corrugated cardboard, sheets
of newspaper and/or blotting paper (check at craft stores), and
2 plywood or other boards, all cut to the same size; something to
bind the stack (belt, bungee cord, or a heavy rubberband) or weight
it (heavy books or bricks).
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For
mounting collections: sheets of white paper (card stock or other
heavy paper works well), thinned Elmer's white glue, tweezers (optional),
clear
contact paper (optional).
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Miscellaneous:
scissors, field guides, binders or folders for students' collections,
journals, or field notebooks. If you plan to make pressed wildflower
cards, you'll need card stock paper and clear contact paper.
Collecting
Plants: A Pressing Project
In the Field
-
Make
a plan. A scientific herbarium collection usually features plants
that grow naturally in a region. If your students want to create
a field guide to their butterfly or herb garden, or collect flowers
for an art project, they need not limit themselves to native plants.
Decide on your purpose for collecting and pressing plants, then
discuss as a class what types of plant parts to gather (wildflowers
or tree leaves, for example) and where to do so.

-
Get
out and gather. It's best to collect plants for pressing when
they are free of dew or rain. Students can use scissors to snip
flowers, leaves, or entire plants. If they are creating scientific
herbaria, they'll also want to collect some roots. (See sidebar,
Pick with Caution.) Flat flowers tend to press
better than bulky ones. Invite students to experiment with different
types of flowers and plant parts (by removing and pressing petals
of larger flowers, for instance). If plants are abundant, suggest
that students collect several flowers from a species so they can
display front, back, and side views. Collecting flowers at different
stages of bloom can also inspire a more interesting display.
To keep
collected plants fresh in the field, put them in sealed plastic
bags out of the sun. You'll want to get plants in the press as soon
as possible. If you need to keep them overnight, a wet paper towel
in the bag will keep them from wilting too much. Alternatively,
students can press and protect plants in a phonebook or catalog
until they get back to the classroom.
-
Make
field notes. If students are planning to create an herbaria
or field guide, they'll need to take notes on their subjects. Each
journal or field notebook entry should include such information
as date, location, environment (e.g., amount of sun), type of growth,
(herb, vine, and so on), description of seeds and/or fruits, and
collector's name. They might also want to include information that
may not be apparent once the plant is dried, such as original color
or aroma. (Your young scientists might also make sketches and take
photographs of plants in their habitats.)
Pressing Concerns
Simply put, a plant
press sandwiches plant parts between layers of absorbant material
so they will dry quickly. (This better preserves specimens and color.)
Although you can press plants in old phone books or catalogs, a setup
that enables air movement speeds up the drying process. Here are some
tips on creating your own botanical presses.
-
Place
the plants. The guts of your plant press will consist of alternating
layers of plants arranged
on absorbent material (newspaper and/or blotter paper) and corrugated
cardboard. The cardboard enables air circulation so the plants dry
more quickly. Students should carefully lay each specimen in between
a folded sheet or two of newspaper (or blotter paper, sandwiched
in between newspaper). You can lay numerous flowers or plants of
the same thickness on the same piece of paper, as long as they don't
touch. Try to arrange flowers and other plant parts in a natural
way, so their parts will be visible when pressed.
- Make the sandwich.
In between each plant/paper layer, insert a piece of corrugated cardboard.
Finally, place wooden boards on either side of your layered pile.
Next, you'll need to bind or weight the stack to create pressure that
will help the plants dry. You can tighten straps or belts around it
or simply put something heavy on the stack. Some presses have screws
and nuts in each corner that can be tightened to create pressure.
Leave your press in a warm, ventilated location.

- Check your
specimens. Although many plants will dry adequately in ten days
to two weeks, some may take longer. If you find they are still moist
when you check them, and you have them between more than one newspaper
layer, you can change just the outer layer. (The delicate plants,
when moist, will likely stick to the piece they're touching.)
Displaying
Plant Collections
- Plan the layout.
Before students mount their pressed collections, consider your end
goal. If they're creating classic herbaria pages, students should
give each plant its own sheet of paper. If they're creating field
guides, they may organize pages by plant families and/or characteristics,
such as color.
- Identify your
finds. Unless your pressed plants are solely intended for an art
project, you'll want to have students identify what they've gathered
using online or printed field guides. They may have to extend their
initial observations to find specific characteristics listed in the
field guide keys. (For instance, Does the plant have opposite or
alternate leaves?)
- Mount them.
Have students use a thinned Elmer's white glue to attach plant parts
to heavy paper. If a flower, petal, or leaf seems breakable, put the
glue on the paper and let it sit until it dries a bit. Next, pick
up the flower with a damp fingertip and press it gently onto the glue.
Students may want to cover their herbarium or field guide pages with
clear contact paper or slip them into clear sleeves before putting
them into a binder. Consider diplaying individual pages or collections
in a school lobby or at a parents' night, or using them for self-
or student-guided tours of the schoolyard, garden, or neighborhood.
(See Curriculum
Connections for more ideas.)
Copyright©
2002 National Gardening Association
Growing Ideas Classroom Projects is a benefit for NGA's Education
Members
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Collecting Plants
Contents
Plants:
A Pressing Project
Background
Materials/Procedures
Curriculum
Connections
Creating
Field Guides
Cultivating
Mentors
Growing Classroom Exchanges
Pressed
Plant Projects
and Products
Resources
Web Sites
Books
and Field Guides
Botanical
Field Press
Related
Articles
Petal
Attraction:
Weaving Wildflower Lessons
Flower
Courtship
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Pick
with Caution!
Never collect or disturb any plant species that may be endangered
or protected. Learn your state laws by contacting a natural resources
agency. It's a good idea even with non-protected plants to use
the following rule of thumb: never pick a plant unless you can
see at least six in the area. Also, always get permission from
the owner of any property on which you intend to collect plants.
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Flowers
That
Press Well
Here
are just a few types of flowers that are good for pressing. Your
student scientists will surely want to experiment with others.
bleeding heart
buttercup
butterfly weed
columbine
daisy
dutchman's breeches
heather
larkspur
pansy
phlox
Queen Anne's lace
salvia
wood violet
(Also think
about using ferns, colorful leaves, and other plant parts to spice
up pressed flower displays.)
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