There's a lot going on in a leaf 😉
There’s a lot going on in a leaf - thousands of chemical reactions occur in each one as part of photosynthesis – the process plants use to turn sunlight into energy. Each plant develops their own unique blend of ingredients from sunlight, water, and the nutrients they pull from the soil.
Plants also very cleverly have their own immune system. The unique makeup of each plant gives it distinct benefits by making it more resistant to pests - they literally make their own, amazing, natural pesticide. Bugs and fungus want to eat the plant’s sugar, yet plants are clever enough to makes their own protection via their own sugar - not daft, these plants. So, the plant creates a substance called resveratrol (resveratrol is a one of many plant compounds called polyphenols, which are powerful antioxidants), which kills the bug if it eats it - clever little plant! It just so happens that these properties can also be beneficial to horses. And us humans too - red grapes are especially high in resveratrol, and red wine is just one perk giving us plenty of this potent nutrient. 😊
These beneficial components are highly concentrated in the leaves of some plants, although some are also stored in barks, roots, seeds or flowers. Herbalists rely on the leaves of plants like mint, lemon balm and nettle for their medicinal properties, but we also rely on leaf shape as one of the ways to identify a plant. The terminology can seem a little confusing at first but once you learn that each leaf is made up of distinct zones, it soon starts to make sense.
First, there's the blade. Most leaves have a stem (or petiole) that attaches the leaf to the rest of the plant. The petiole sometimes extends into the leaf and divides the leaf into two equal halves, and when it does it’s called the midrib. The thin, leafy portion on either side of the midrib is called the blade.
The base of the leaf is the portion where the petiole - the stem - comes out to attach the leaf to the rest of the plant, and the apex is the other end – the tip of the leaf.
Many different terms describe the shape of a leaf, but here are some of the most common ones :
And a few different shapes of the base and apex:
Also, a leaf can be either simple or compound. A compound leaf has smaller leaflets that connect to the midrib with stems of their own, while a simple leaf is made up of a single blade.
The edges of the leaf, the margins, provide more important identification clues. If the margins are smooth, the leaf is described as entire. If there are teeth or notches along the edge, though, there are a few different ways to describe them:
The next clue to look at is how the leaves attach to the stem of the plant. The place where the petiole meets the stem is called the node. A node can have more than one leaf or only a single leaf:
I loved my early days of studying basic botany - I fondly remember my first year of studying Medical Herbalism, using my newly purchased and very tiny magnifier to open up my world of awesome leaf anatomy - meadowsweet was amazing - very hairy!
I still disappear into bliss mode when I get my magnifier out and get up close and personal with a leaf, identifying all the different the leaf shapes I come across. Who knew I'd ever become a leaf nerd?!