a closer look

What do you see when you look at a patch of flowers?

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Coneflowers — they all look the same, right?

Maybe not — let’s take a closer look.

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The central (cone) portion of these Coneflowers (Rudbeckia species) are distinctly different in shape, with yellow tips emerging from different places in the cone.

Sunflowers, coneflowers and other members of the Compositae (or Asteraceae) plant family actually have two types of flowers on their floral structure.  The colorful petals are sterile ray flowers (produce no sexual structures) designed to attract insect pollinators, while the tiny yellow projections from the central cone are the disk flowers that project first male (pollen), and then female (ovary) sexual structures.  When fertilized, each ovary houses developing seeds, which cause the central cone to swell in size and in height.

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A newly emerged flower has an almost flat profile, with a central disk that shows no projecting disk florets at all.

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Later, a single row of disk florets emerges, and then fades after a couple of days, giving way to the next inner row of developing disk florets.

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A cone is starting to form on this older flower, as the last rows of central disk florets emerges.

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The seed head is almost fully formed here, and eventually the aging flower will drop its rays (petals), so that just the cone of developing seeds remains.

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And so ends the lifespan of the flower…

Leaving a tightly packed seed head, ready to be harvested by hungry seed-eaters.

10 thoughts on “a closer look

  1. that was very interesting. I have these plants and have been cutting off the flowers when the petals start to drop, didn’t know that the rest was a seed head. I will now leave the rest of them and see who comes to harvest the seeds.

  2. I’ve grown Rudbedkia for the first time this year and I have been watching the strange way the seed head grows but some of mine seem to have much larger disk florets as they age, giving a double flower effect. Only some do this, is it common? Amelia

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