Monocots and Dicots Worksheet MONOCOTS AND DICOTS Directions Determine

							                      MONOCOTS AND DICOTS
Directions:
Determine the characteristics of monocots and dicots by observing and/or
dissecting different plants.

Materials:


A. FLOWERS
▪ labeled flower diagram
▪ three flowers
    • one monocot (lily, palm, etc.)
    • one dicot (royal poinciana, hibiscus, porterweed, partridge pea, lignum
       vitae, wild cotton, tree hibiscus (Hibiscus tiliaceus) or other common
       dicots)
    • one additional monocot or dicot
▪ dissecting tools
▪ hand lens or dissecting scope

B. LEAVES
▪ three leaves, either dicots or monocots

C. STEMS
▪ prepared slides of monocot and dicot stem cross-sections
 OR
▪ hand sections of thin monocot or dicot twigs
▪ toluidine blue
▪ tree rings or a picture of a tree ring




                                       Stamen




          labeled flower
A. FLOWERS

Before dissecting your flowers, hold them and look at them closely. Answer the
following questions for each of your three flowers:

   1. Count how many sepals and petals your flower has. If you cannot
      distinguish petals from sepals, then your flower has what are called
      tepals. Count them.

          Flower 1 sepals _____ petals_____ tepals_____
          Flower 2 sepals _____ petals_____ tepals_____
          Flower 3 sepals _____ petals_____ tepals_____

   2. Find the male flower parts; count how many stamens you see. If your
      flower is tubular, you may have to cut it open to do this. If there are more
      than 10 stamens, simply write “many.”

          Flower 1 ____________________
          Flower 2 ____________________
          Flower 3 ____________________

   3. Find the ovary, stigma, and style (female flower parts); cut the ovary in
      half (cross section) and count how many ovules you see. A flower’s ovary
      will mature into the fruit while the ovule will mature into the seed.

          Flower 1 ____________________
          Flower 2 ____________________
          Flower 3 ____________________


Monocot flowers usually have their floral parts in multiples of 3 (3, 6, 9, etc.) while
dicot flowers usually have their floral parts in multiples of 4 or 5 (4/5, 8/10, 12/15,
etc.).

Using this information, what can you conclude about flowers 1, 2, and 3? Write M
if you think it is a monocot flower or D if you think it is a dicot flower.

          Flower 1 ____________________
          Flower 2 ____________________
          Flower 3 ____________________
B. LEAVES

   1. Look at the leaves and determine the type of venation (vein pattern) of
      each leaf. Write whether the venation is netted or parallel. Write M if you
      think the leaf is from a monocot and D if you think it is from a dicot.

          Leaf 1 ____________________
          Leaf 2 ____________________
          Leaf 3 ____________________
          Leaf 4 ____________________

C. STEMS

   1. Dicots and monocots have vascular bundles (each with xylem and
      phloem) in different arrangements.
         a. Make a thin cross section of a monocot stem
             (name:_______________). Place the stem section on a slide and
             stain with a few drops of toluidine blue. Rinse the toluidine blue
             from the slide with a few drops of water and observe the slide under
             the microscope.
         b. Repeat (a.) with a dicot stem (name:_______________).

          What differences do you see in the arrangement of the vascular
          bundles?
          ________________________________________________________

          ________________________________________________________

          ________________________________________________________

          ________________________________________________________

   2. Observe the two prepared tree cross-sections. One is a palm – a monocot
      stem – and one is a willow – a dicot stem. Can you determine which
      section is from a palm? Finding the vascular bundles on each tree section
      will help you determine the answer.
          ________________________________________________________

          ________________________________________________________



CLASSROOM EXTENSION ACTIVITY:

How do stem rings help to determine the age of a tree? What assumption is
made about a wood growth ring? This assumption is not true for many rainforest
trees? Why? Why is it difficult to age palms?