The Science of Botanical Art

Dissection

Dick Rauh

Originally appeared in The Botanical Artist - Volume 18, Issue 2

 

Dissection, especially if you have never done it before, can be a little daunting. You have been looking at flowers for a long time, and because you have been drawing and painting them you are that far ahead of those botanists who don’t have your eye.  I know the temptation to say, “I draw what I see,” makes this process a little more difficult. I want you to draw what you see, but I also want you to know what to see.  A scientist, or botanical juror, is generally looking for a typical representation of a particular plant. We are dealing with nature, which is filled with variables. You may be faced with a model that is anything but typical. Conversely, because two species are extremely alike, very subtle differences are extremely important for classification; things that you may need a hand lens or a dissecting scope to see. To know what to emphasize, to know when you are looking at a typical part of the flower, to know when you are looking at an artifact, or damage that was caused by bad handling is the goal of dissection.  Here is what I do. See if it works for you. 

  1. Check the written references about the species, and thus discover what is established as the typical characteristic of the plant.
  1. Look at the flower without a lens. Turn it around. Try to find the point of view that best shows the general shape, and the most information, about the parts. Measure the outer length and width of the flower, and perhaps the size of various parts.  Draw a rectangle lightly on your paper – tracing paper works well – and do a rough sketch of the entire flower/inflorescence.  This is known as the habit drawing, and includes the stalk/peduncle/pedicel and some leaves. Write down basic information, things that look interesting, note measurements and anything that jogs your memory for drawing a final image.
  2. Ask yourself these questions:

The inflorescence:

  • Is the flower solitary, or part of an inflorescence?
  • Is the flower regular/actinomorphic or is it irregular/zygomorphic?
  • How many series? Is the flower complete?
  • Is the flower perfect/bisexual?
  • Are flowers attached terminally or laterally?
  • How many sepals? Are they free or fused?
  • How many petals? Are they free or fused?
  • How many stamens? Where are they attached?

The pistil:

  • Is it visible or are any parts of it visible?
  • How many styles? Stigmas? Carpels?
  • What is the position of the ovary?

 At some point you will have recourse to use a hand lens or a dissecting scope. I keep one next to my drawing table, with no more than 10x magnification. You’ll want a pair of dissecting needles, a rigid wire sharpened to a point inserted into a handle, available at any scientific equipment company. Have a clean single-edge razor blade handy. These are sold at hardware or painting supply stores. Once you have drawn the entire blossom, the time for dissection has arrived. 

  • First, holding the flower in one hand, gently remove a petal(s), to see what’s inside. Try not to remove all. The filaments of the stamens may be adnate/attached to the petal. Removing all may take the stamens out. 
  • In some blossoms the petals are fused into a tube. In this case, take the needle; insert it inside the corolla, to break open the cylinder from bottom to top. Gently spread the corolla apart, to reveal its secrets. Gently is the key word in all these processes.
  • Petals are fairly easy to remove, as opposed to sepals that tend to be persistent and more difficult. If sepals get in the way, try bending them out of your field of vision with your needles. Get a clear view of what’s inside, and check it against your references to guarantee that what you are seeing is typical for that flower and family. Now you can begin to count and measure, and find the origins of the various series.
  • Next isolate a single stamen and view it from front and back.  How is the anther attached to the filament – at the base, like a lollypop/basifixed, or in the middle of the back/dorsifixed?   Look at its particular features. Make notes!
  • Now we can get rid of the androecium and view the pistil(s) in all their glory! Try a section, to discover how the ovary holds its immature seeds/ovules. A cross-section means a cut across the ovary perpendicular to its axis, a longitudinal section runs vertically. Checking the results of well-made sections under the ‘scope is a very satisfying experience, and perhaps a temptation to convert these into artwork, like the illustrations of Maud Purdy.

Longitudinal sectioning does not have to be confined to the ovary. Arthur Harry Church created incredibly beautiful floral images doing vertical sections through entire flowers, which he used for teaching purposes. For the most part, the purpose of dissection is to fortify your botanical knowledge of a plant so that your paintings are accurate as well as beautiful.

Keep this in mind as you throw caution to the wind and rip through your favorite blooms! When a dissection turns out to be inspirational, as well as useful, you may be creating a whole new aspect of botanical art, a world of highly enlarged and beautiful details of what makes flowers tick.

  • Papaver somniferumm, Opium Poppy, Sir Arthur Henry Church 1905. Church was known for his amazing dissection images. Church built up layers of paint in a precise manner, to raise the surface of the ovary in a natural sculpted shape