With temperatures cooling off and the leaves starting to turn, now is the perfect time to get out there and take a close look at some leaves!
This piece will be about all the myriad shapes that leaves can take, and all the exotic words that botanists use to describe those shapes. This topic might not interest everyone—most people don’t care whether a leaf is undulate or crenate when the word “wavy” seems to work just fine. But I’m a word nerd, and so I care. Like Mark Twain said, “The difference between the right word and the almost-right word is the difference between lightning and a lightning bug.”
The correct (fancy) term for “leaf shape” is “leaf morphology”. This figure is the best illustration I have found so far of leaf morphology. It breaks down all the different leaf types and the proper words to describe them. Some of the most commonly-used terms you might see on Wayside or other garden websites are: lanceolate (lance-shaped) leaves, alternately arranged leaves, oppositely arranged leaves, elliptically shaped leaves, dentate (toothed) margins, serrate (saw-toothed) margins, and crenate (rounded-tooth) margins. My personal favorite terms are the goofier “reniform” (kidney-shaped) and “spatulate” (spoon-shaped).
This image was created by McSush (updated version from Cwbm) and is used with attribution under the terms of the Creative Commons Attribution-Share Alike 3.0 Unported license.
As an exercise, I’ll attempt to use my new vocabulary to describe the leaves I found in my backyard:
- Rhomboid with serrate margins and cross-venulate venation,
- Lanceolate with entire margins and longitudinal venation,
- Orbicular with serrate margins,
- Deeply lobed with pinnate venation,
- Elliptic with serrate margins and pinnate venation, and
- Ovate/Aristate with serrulate margins and palmate venation.
The leaves that were lying around my back yard.
I’m not a botanist, so I could be wrong. If any of you are more educated in these matters and have a better phrase in mind to describe any of these leaves, feel free to speak up!
Side note: I don’t know what plants all these leaves come from. I know 4 is an oak leaf and that 1 comes off of a catnip plant. I grew my own catnip plant once, so the leaves and bloom were familiar to me, but it really got confirmed when I came inside and my cats immediately mobbed me trying to get at that leaf. If you are ever wondering about a catnip plant, just poll a cat—they’ll tell you faster than Google!
While we’re talking botanical terms, here are some other common ones to be aware of:
- The colorful, decorative parts of plants aren’t always “petals”, often they are technically “bracts”, the outer leaves that surround the smaller flowers. The colorful outer bracts form a pseudanthium, or false flower around the true flowers. Examples: Dogwood, Poinsettia, Bougainvillea, and Handkerchief tree (Davidia involucrata).
- Sometimes even on true flowers, what you want to call a petal isn’t always a petal, but might actually be a “sepal”. Petals refer to the outermost ring of leaves in a flower, while sepals refer to the modified leaves that encase the developing plants. While petals are usually the showy, colorful ones, in some plants (e.g. Daylilies and Tulips) the sepals are just as big and colorful, in which case the petals and sepals are both collectively referred to as “tepals”. The way that I remember this is that “Tepals are petals and sepals Together.”
- A “picotee” refers to a thin line of color running just along the margin of a petal. Picoteed flowers look like they were ever-so-lightly dipped in paint. It’s a fun word, and a very stylish look. Just check out these examples.
- “Variegation” refers to distinctive markings on plants leaves, typically white or yellow. This can happen to a plant because of the masking of green pigment in the cells, or can be due to areas of the leaf surface being made reflective by silvery hairs or by a “blister” of air on the leaf’s surface. Most variegated species were not created but by evolution, but rather are mutations that people have cultivated for their decorative qualities.
What’s your favorite bit of botanical vocab? Tell me in the comments!