Day #3: Botany II

Just when you think it’s safe to go into the garden or forest, botany – and its many exceptions to the rules – intrude.

Lessons Learned

We use the five parts of plant structure to help us identify plants:

  • Roots
  • Stems
  • Leaves (and leaflets)
  • Flowers
  • Seeds

If only it were that easy, however.

Where are the leaves on a cactus, for instance? They are those needle-sharp prickly things. And the green part is the plant stem.

hickory_bitternut_leaves

Many leaflets on one Bitternut Hickory leaf. (Iowa State Extension)

Want to really get wild? Take a look at the photo. Many leaves on a stem, right? Wrong. (Don’t fret; I got it wrong, too. It was meant to be.)

Hickory leaves like the one shown grow many leaflets along a stem-like (but it’s not a stem) rachis. The combination of rachis and leaflets constitutes one leaf.

And you’ve heard the old saw about poison ivy, “Leaves of three, let it be.” That is technically not correct. Those are three leaflets on a single rachis and together make up one leaf. So it should be, “Leaflets of three, let them be.”

How about those onions? When you chop up a big, fat old onion, you’re cutting up (and planning to eat) the leaves. The hard part at the bottom of the onion is the stem. Likewise, on a spring onion, the long green thingies that stick up out of the ground and turn to white toward the bottom, those are leaves, too.

Wow.

  • Bottom line: When looking at structure to identify a plant, consider the preponderance of evidence, not a single factor.
  • Photosynthesis formula: 6 CO2 + 6 H2O -> C6H12O6 + 6 O2

Quotation:

When you mulch, think T-shirts, not turtlenecks.

And never go for the “volcano look.” Self-explanatory.

Vocabulary

A very small sampling of the words we used in discussing botany:

  • Male parts of the flower
    • Stamen – Male organ of the flower, usually composed of anther and filament. [Memory trick: staMEN is male.]
    • Anther – Upper portion of a stamen containing the pollen grains
    • Filament – Long supportive structure of stamen that supports the anther.
  • Female parts of the flower
    • Pistil – Female part of the plant, generally shaped like a bowling pin and located in the center of the flower; consists of stigma, style and ovaries. [Memory trick: A pistil-packing mama would be female.]
    • Stigma – Upper portion of the pistil, connected by the style; the receiving surface for pollen grains.
    • Style – Part of the pistil that supports the stigma and connects it to the ovary.
    • Ovary – Part of the pistil that contains the eggs.
  • Other flower parts
    • Petals – The usually showy structures around a flower’s reproductive organs.
    • Rachis – A stem-like axis bearing flowers or leaves.
    • Sepal – Small, green, leaf-like structures on the base of the flower that protects the flower bud.

 Free Book

Our project speaker for the day pointed out that the U.S. Fish and Wildlife Service has a free, 85-page booklet on Native Plants for Wildlife Habitat and Landscape Conservation. You can download it from the National Park Service Web site here.

Homework

Read chapters on Soils and Nutrient Management.

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