31 July 2012

The Answer To The Pea Quiz

Drum roll ... the answer to the pea quiz is ... butterflies.

The question was what do clover, sweet pea and vetch plants have in common, apart from being generally leguminous?

They all have flower shapes that are papilionaceous. That is to say they have a butterfly-like form.

The flower head has a large upper petal with a distinct vertical groove, called the banner or standard petal. Two lateral petals are attached to this that look like the wings of a butterfly, hence the 'Papillion' association. Beneath the wings are two petals that have fused together to produce a keel shape. These protect the stamens.

(Between you and me, as grown-up women, a butterfly is not the first image that springs to mind when confronted with this diagram, but perhaps we have to make allowances for the sensibilities of our botanical forefathers of yore ;-)  )

But hold on, I hear you say, sweet pea and vetch flowers do look the same, but clovers are spherical, chunky little flowers, not butterfly-like at all.

Here we reintroduce the word inflorescence that was used when we were talking daisies. The clover flower, like the daisy, is composed of many little flowers, or florets. If you look closely each individual floret can be seen with its wings and keel.

There is however something that the clover flower as a whole does that sweet pea and vetch don't. When each floret has been pollinated it wilts - those are the lower brown petals - and the young virginal florets remain perky and inviting until they too have served their purpose.

Sound familiar?