Question

Floral patterns for angiosperm families sometimes are described with a certain "code" - does anyone know how to interpret this "code"? For example, boraginaceae's floral pattern is: CA (5) CO (5) A 5 G (2)...what exactly do all these letters and numbers represent?

Answer 1

Ah - found it. Never should have doubted Wikipedia's capabilities...

http://en.wikipedia.org/wiki/Flower#Morphology

for anyone interested.

Answer 2

Thank you for the link - something I didn't know but do now.

Answer 3

Ah yes, floral formulae. They featured prominently in my botany course last semester because Germans love them: note that a good portion of the floral diagrams on the English Wikipedia are originally from German books.

If you happen to come across a German flower formula, it may be written SLIGHTLY differently. Boraginaceae's is written like this:

*K(5) [C(5) A5] G(2) with a line under the 2

K = Ca = Calyx (i.e. sepals)
C = Co = Corona (i.e. petals)
and A and G are the same

The * indicates radial symmetry, the brackets indicate that elements are fused (that includes the square brackets -- in this case, the corona and stamens have fused), and the line underneath the 2 in G(2) means that the ovary is superior, i.e. above the insertion point of other elements. There's an explanation of the position of the ovary here: http://en.wikipedia.org/wiki/Ovary_%28plants%29#Classification_based_on_position

Answer 4

Thanks so much, @Calliope ! That was very helpful. A few questions, if you don't mind - How would you indicate bilateral symmetry then? And do the parenthesis around a number (5) indicate anything?

Answer 5

If you want to indicate that there's just one axis of symmetry (e.g. in many plants in Lamiaceae or Fabaceae), use a downward-pointing arrow.

For a flower with two axes of symmetry (e.g. Brassicaceae), use a + with a stretched out horizontal line.

This article may help (it's in German, but you can run it through Google translate: the English Wikipedia article isn't particularly good): http://de.wikipedia.org/wiki/Bl%C3%BCtenformel

The parenthesis around the (5) also indicates that the structures are fused together. To use the example of petals, if you see C5 (that's the same as Co 5, I just prefer to use the German version) with no brackets, that means the petals aren't fused together and you can easily pull them out one by one. If you see C(5), that means they're fused together, so you can't just pull one petal out on its own: it's attached to the petals beside it. This is common in e.g. bellflowers (Campanulaceae), but in a lot of other families too.