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Consider this floral image of the family Solanaceae

The above image is a floral diagram of the family Solanaceae So I was hoping someone could explain how to read this floral diagram

The Centre suggestion axial placentation to me

The ameboid like structures suggest that it's bisexual

And the aestivation of the petals suggest Valvate aestivation

But how do I read the green part and the bumps at the edge of the diagram?

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1 Answer 1

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Edited to add: Floral diagrams have an interesting history, having been developed in 1875. Per Wikipedia, a floral diagram

is a graphic representation of the structure of a flower. It shows the number of floral organs, their arrangement and fusion. Different parts of the flower are represented by their respective symbols. Floral diagrams are useful for flower identification or can help in understanding angiosperm evolution. They were introduced in the late 19th century and are generally attributed to A. W. Eichler.

As you can see from my (very dry) answer, a simple diagram gives a lot of information, and can introduce a way to observe a flower more thoughtfully*. If wildflower identification is an interest, a simple drawn diagram in the field - no words required - helps to later identify those that were difficult to identify in the field. It also shows how it's related to hundreds of other flowers that might not be intuitive. It's just a fun little tool to most, but a serious one to botanists seeking classification, etc. In 2017, scientists found a fossil pushing back the appearance of the Solanaceae family (which includes potatoes, tomatoes, petunias and belladona) back to 52 million years ago. Potatoes may have been on the menu millions of years before we thought. (Cool! But maybe only to plant nerds like me.)


If this flower diagram is of the family Solanaceae, the green things are sepals. I assume the "bumps" for both the petals and the sepals represent the fact that they are fused (so the petals are gamopetalous, and the sepals are gamosepalous.) And yes, the placentation is axile, and the aestivation is valvate .

This is a link to the Solanaceae flower diagram. N.B. the floral formula. (In this case, it's for the potato, but that doesn't matter.):

enter image description here

Where ⊕ = Actinomorphic (radial symmetry), ⚥ = Bisexual, K(5) = Calyx: 5 sepals, gamosepalous, C(5) = Corolla – 5 petals, gamopetalous A5 = Androecium – 5 stamens, polyandrous (free), epipetalous (attached to petals),and G(2) = Gynoecium – bicarpellary, syncarpous (united), superior ovary.

Which is more than you asked for, sorry. Here's an image of Jimson Weed (Datura wrightii); you can easity see the fusion of the petals and the sepals. (From Southwest Colorado Wildflowers, non-copyrighted.)

enter image description here

*There is more information in that diagram than in my answer.

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  • $\begingroup$ thanks! How did you determine that the ovary is superior based on the diagram? $\endgroup$ Apr 22 at 0:57
  • $\begingroup$ @mathandphysicsforever - I can't tell from that diagram if the ovary is superior; that information is found in the flower formula, which is true of all Solanaceae. :) If triangles had been included near the ovary, it would show the position of the ovary. Cool question, btw! $\endgroup$ Apr 22 at 15:36

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