Start with Leafsnap, an electronic field guide.
Check your results using this book: New York City Trees
Then, if you are still in doubt, check any of these online resources:
Start with Leafsnap, an electronic field guide.
Check your results using this book: New York City Trees
Then, if you are still in doubt, check any of these online resources:
Posted at 06:18 AM | Permalink | Comments (0)
There are several alternative techniques for preserving leaves to use in the classroom.
An article about the history of herbaria, from the American Biology Teacher. Download Herbaria
Plant specimens preserved in herbaria can become important research subjects many years after they were collected. Here are 3 examples: Julius Bisky in Flushing, Xyris-a new species, Global Warming evidence found in herbarium specimens
Some links to images in virtual herbaria:
http://www.tropicos.org/Image/1350
http://sweetgum.nybg.org/vh/specimen.php?irn=568357
http://linnean-online.org/view/collection/linnean=5Fherbarium/Acer.html
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Some articles about plant blindness:
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In the mid-1800s, nearly all high school students studied botany and learned to identify plants.
This is a link to the full text version of a popular text of the day. Written by pre-eminent botanist, Asa Gray, most of the text is still accurate and useful today.
Here's my article about the history of botany education.
And here's the Regents Exam in Botany:
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Here are links to K-12 resources provided by the two major professional societies for botanists,
The Botanical Society of America and the American Society of Plant Biologists
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Here is my handout summarizing terms used in describing plant stems and leaves.
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This is the dichotomous key that goes with the leaf identification kit that we used in class. Download Leaf Identification key
The kit is available from Young Naturalist Company.
Other dichotomous keys for trees are available online. Try the Arbor Day Foundation Tree Key.
The only polyclave that I could find online is here. But it doesn't work very well.
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Two papers documenting the value of trees in the urban environment:
Download NYC Parks 12 page report
Download USDA summary statistics 3 pg
Links to urban forestry resources from US Forest Service, Alliance for Community Trees, New York State Urban & Community Forestry Council, Trees New York.
Posted at 06:55 AM | Permalink | Comments (0)
This is the link to the interacitve map: http://stewardship.nycparks.org/add_trees.php
(Zoom the map in all the way to see the location of trees in any NYC neighborhood.)
BONUS MATERIAL:
Take a walk to see the biggest (champion) trees in NYC. Download this 75 page guide. Download GreatTreeWalkGuide1990
Posted at 06:59 AM | Permalink | Comments (0)
Treesgrow in girth throughout their lives, through the action of two "lateral meristems," the vascular cambium (which forms xylem and phloem) and the cork cambium (which forms the bark). Helpful references: this Wikipedia article and images from my slides.
Some FAQs:
Posted at 01:16 PM | Permalink | Comments (0)
Trees grow in height only through the growth from the tips of their branches. (If you carve your initials in a tree trunk and come back in 10 years, the carving will be at the same exact height above the ground.)
(from Pinterest) My attempt to spread reason: Trees do not grow taller from the ground up. If you carved your initials in a tree when you were 10 years old and come back when you're 75, those initials will still be at the same height you originally carved them. The tree would have grown in girth, but those initials would not have risen any higher than the day they were carved. And then there's the bike itself. This bike (or at least all the parts that are visible) are NOT 100 years old. I swear. So although this is a completely FABULOUS photograph and it is fantastic that this bike and tree inspired a wonderful story, that does not mean that the bike was chained there by a boy in 1914. Sorry to be a party pooper. :-)
Posted at 01:30 PM | Permalink | Comments (0)
Objective: To learn to make accurate observations and then communicate these observations by drawing. We will do this by constructing a figure of how the leaves of two different types of plant are arranged on the stem from two different perspectives.
Prerequisite Process Skills: Observation, Measurement, and Communication
Materials: Chrysanthemum plant (alternate) 1 Vinca plant (opposite) 1 Styrofoam cup marking pen, tape, rulers
Procedure
1. Tape the cup upside down on the table. Punch a small hole in the center of the cup with a pencil. Make marks in a "clock-like" manner at 12, 3, 6, and 9 around the cup with the pen. Remove about a 4 inch piece of one of the plants and place it in the hole.
2. Side View. Look carefully at the stem in the cup. Draw a horizontal line to represent the top of the cup. Measure the length of the stem from the cup to the top. Draw a line coming from the "cup" that long to represent the stem. Measure the distance from the cup to the first leaf. Draw a line at a right angle to the "stem" at this distance to represent the leaf. Just draw the lines at right angles to the stem and do not worry about whether they go forward or back. Measure to the next set of leaves and then draw them. Repeat this until you can't measure any more.
3. Questions. How does it look? Does this accurately represent the stem? How are the leaves arranged? Are they always the same? Look at some other people's drawings. Are the leaves always the same distance apart? Can you see any pattern? Can you attempt to explain this pattern?
4. Top View. Don't remove the stem from the cup. Look down on the stem from above. Using another cup draw a circle to represent the bottom of the cup. Place marks around the circle in the clock positions the same as on the cup. In the center of the circle place a dot to represent the stem. Looking from position coming off the stem with a "lollipop" to represent the leaf. Number the leaves starting with the 1 to help keep track. Move up the stem and draw the position of as many leaves as possible before it gets too confusing. Can you see a pattern?
5. Repeat parts 2 and 4 using the other plant.
6. Compare the two patterns. What is different? Which type of leaf arrangement do you think might work better? Think about shade.
(This activity is from a seminar presented in
Central Illinois Saturday Science Education Seminars for Elementary Teachers,
1993, by Donald Schmidt, Horticulturist, Illinois State Univ. Normal, IL. http://www.bio.ilstu.edu/armstrong/biolab/eled/leaves.htm )
Posted at 01:34 PM | Permalink | Comments (0)
In plants, growth in length is accomplished primarly through the activity of apical meristems.
New leaves start out as just a few cells: the leaf primordia.
Mitosis (cell division) occurs continuously in the apical meristems and cell enlargement then results in the increase in size of the leaf primoridia.
Posted at 02:11 PM | Permalink | Comments (0)
Twigs and Buds, Kirigami leaves, etc.
Download Adopt a bud (a year-round activity to do with your students.)
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Auxin is important in apical dominance:
Apical buds produce auxin, which is trasported to the lateral buds where it prevents them from growing out (makes them dormant).
When an apical bud is removed or dies (or grows far enough away from the lateral buds), the source of auxin is lost, and the lateral buds are released from dormancy and begin to grow.
Posted at 02:46 PM | Permalink | Comments (0)
Ethylene is a gas emitted by ripening fruits and stressed plants. There are also artificial sources: at the turn of the century street lights were lit with coal gas that released ethylene and inhibited growth of street trees.
Ethylene can have the following effects:
Posted at 02:53 PM | Permalink | Comments (0)
Plants that receive insuffient light may be "etiolated." Etiolated plants lack chlorophyll and have relatively long internodes and undeveloped leaves like the pea seedling on the left.
In many tree species, leaves in the top part of the canopy are adapted to higher intesity light than are leaves of the lower branches.
Compared to sun leaves, shade leaves have a greater ratio of area to perimeter (are not so deeply lobed). They are often larger and have a thinner cuticle than sun leaves.
Posted at 02:59 PM | Permalink | Comments (0)
We ran out of time and I didn't get to present this piece.
Download Flowering Plant Phylogeny
The main points are:
Posted at 03:34 PM | Permalink | Comments (0)
Perhaps all the mulberries we are seeing are actually the invasive species.
Read more about mulberries here: Download Which mulberry
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