Leaves - Shape Part 1



When autumn's high color is past, leaves rain down upon my garden, signaling weeks of raking and vacuuming to remove them from drive, paths and evergreen perennials. Shoveling leaves into a leaf vac by hand offers ample opportunity for close examination. It's also not exactly mental rocket science; the mind tends to wander. Mine started wandering down the path of wondering just why leaves take different shapes.


The majority of leaves are from oak trees; specifically two species that were identified for me a couple of years ago by the Suite's own Treeman, Wesley Ford. At the time I was searching for identification, I thought I had several species because of the rather significant differences in leaf shape that you can see in these scans.

Upon close examination, the key similarities are evident, but why does one tree produce such marked variations in leaf shape? Pursuit of an answer to this question opened the door to the absorbing world of leaves.

Vocabulary of Leaf Shapes

Before we can talk about what shape a leaf is, we need to know what to call the shape. All of us refer to the myriad leaf shapes we encounter by some name...round, long, narrow, pointed...but the world of botany has taken this vocabulary to a much finer level, assigning specific names for the overall shape of leaves, their edges, their form and the way they are attached to the stem.

We encounter these terms describing the morphology (shape) of leaves when we research plants as they are used as frequently as botanical binomials because of their accuracy.







Some of these descriptive terms are easy to remember and associate with the appropriate shape; some are not, at least for me, as they refuse to stick in my brain. But, like botanical names, continued encounter with them eventually embeds them to the point of recognition.

Some of them are fairly obvious:

lanceolate = lance-shaped (longer than wide, broader at base, narrower at tip)
ovate = egg-shaped (more or less rounded at both ends, widest at the bottom)
elliptical = ellipse-shaped (narrow at each end, widest in the middle)
spatulate = spoon-shaped

Some are not as familiar:

cordate = heart-shaped (petiole [leaf stem] attached to the center of the rounded end)
auriculate = having ear-shaped lobes at the base of the leaf

The copyright of the article Leaves - Shape Part 1 in Shade Gardening is owned by Marge Talt. Permission to republish Leaves - Shape Part 1 in print or online must be granted by the author in writing.

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