Flower Dissection!

When you get a biologist flowers, they may not stay intact. For beautiful things we see every day, there is actually an amazing amount to discover by not only stopping to smell the roses, but look inside them too. In our case, we're going to dissect lilies! Time to put the petal to the metal.

• What: Flower Dissection!
• Oh, but why: We have to learn somehow
• Concepts: biology, botany, anatomy, plant reproduction
• Time: ~30 minutes with a class
• Cost: ~ $0.30 per lily depending on local prices
• Materials:
  • One lily
• Tools:
  • Cutting device (scissors, razor blade, or X-acto)
  • Magnifying glass (optional)
  • Tape (optional)

For other guides on dissecting a flower, I love this one for high school classes, so check it out. Otherwise, it's flower time!

Look at your flower to see how it's all formed. How many petals are there? How are the leaves shaped? What do you see inside, what do you think it all does. Pull off the leaves from the stem, and explore. You know, poke to learn!

We are using white lilies, but there is a range you'll find out there. Make sure to purchase flowers that still have their anthers (the pollen parts) intact. Many florists or flower markets will clip these off if they think it will get pollen all over their purdy flowers.

The outer ring of your flower consists of sepals, and the inner ring is of petals. In many flowers, these look different, but in these lilies they look nearly identical. Peel them off and count how many are in each ring. You may notice that there's pollen already on them (the orangey stuff), and on many they will have nectar guides which are patterns to help attract bees and other pollinators. Neatly, only some of these patterns are visible to the human eye.

Your petals and sepals will be the most fragrant part of the flower, so give one a small tear and smell it up! If you use your cutting tool, to cut across its stalk, you can also see evidence of its xylem and phloem running nutrients, water, and sugars around the plant.

Once you peel away the petals and sepals, your flower looks quite a bit more naked. We're going to start with the stamen, which contains all the male parts of the flower. These mostly consist of anthers (the elliptical heads) and filaments (the supporting stalks). Anthers contain pollen, which will either be exposed or still enclosed in your anther. You can split them open and draw with the pollen, which is great with kids.

If you have a strong magnifying glass or microscope, you can even see the shape of the pollen grains. These are designed so pollinators can taken them incidentally while traveling from flower to flower for nectar. Count how many you have, draw the shapes, and again, poke to learn.

Neatly, flowers with both male and female parts (like lilies) are called perfect flowers, whereas ones without are referred to as "imperfect flowers."

Well now your flower looks really naked. The long stalk remaining is the pistil (the female parts), the end of which is the stigma. If the flowers are fresh, the stigma will be sticky for catching pollen. If you open it up, you can see the chamber inside, and the path down the style (the stalky part), and down to ovule. Cut the style to see the semi-hollow tube inside for the pollen travel down.

So the ovary is also part of the female parts, but it deserves its own step. Right at the base of the style is the ovary, and is often a strong structure that contains all the wee little ovules that can become viable seeds if fertilized with pollen. If you cut the ovary in half, you can see the little ovules (in picture 3) all in a row. BABY PLANTS! If you have a microscope, throw them under to see their shapes, which are widely varied from species to species.

At the connection point of the ovary in lilies is the location of the main nectary. You can cut it open to see evidence xylmen and phloem, and depending on the state of the flower, you may find nectar excreted. In other flowers, the nectaries can be located elsewhere so be on the lookout!

There are so many flowers and so little time! Check out others, and see the amazing variety of ways that flowers attract their pollinators, and reproduce.

If you want to do this with a class, I recommend this worksheet for older students and this one for younger. If you want to go deeper in to flower anatomy, this website will take you very deep.

Otherwise, happy botanizing!