Using a black marker, I drew a line from leaf node to leaf node, showing the spiraling growth pattern of the leaf arrangement.
Pulling up some spent kale plants today, I was struck by the arrangement of leaves on the stems. I recalled from past study that the placement of leaves on a stem is governed by the Fibonacci Sequence. If you are not familiar with the Fibonacci sequence of numbers, Divine Template Creations explains it in the following way:
Plant growth is governed by the Fibonacci sequence, which can be understood as a law of accumulation. The sequence is created by adding one number to the one before it to find the next in the sequence, beginning with 0 and 1:
0 — 1 — 1 — 2 — 3 — 5 — 8 — 13 — 21 — 34 — 55 — 89 — 144 …
In effect, the sequence describes how things grow, building and multiplying according to what’s already there. This growth by accumulation is reflected in how trees branch, flowers form, and ferns unfurl.
The same site describes phyllotaxis in the following way:
Phyllotaxis (Leaf Arrangement)
The Fibonacci sequence governs the placement of leaves along a stem, ensuring that each leaf has maximum access to sunlight and rain. If you look straight down along a stem, the leaves (or branches) emerging from it will spiral such that when you count from one leaf to the one that lines up directly below it, the number of leaves between them and the number of times that group of leaves spirals around the stem will both be Fibonacci numbers.
An examination of my kale stem reveals a phyllotaxis ratio of 5/13 — five turns for each 13 leaves.
If we number one of the leaves marked in red as “0″ and count the leaves from red mark to red mark, the number we get is generally a term of the Fibonacci sequence, in this case 13.
Again, if we work along the stem from red mark to red mark, counting the number of times we revolve about it, this number, too, is generally a term of the sequence, in this case 5.
The arrangement of leaves can then be expressed as a ratio. The number of leaves between the two red marks is “13″, and the number of revolutions “5″. Our plant is said to have a phyllotaxis of 5/13. Each species is characterized by its own phyllotaxis. Almost always the ratios encountered are ratios of consecutive or alternate terms of the Fibonacci sequence.
After working this out, I composted my kale stems . . . and then went inside and made a pot of parsnip soup.