- With the exception of flowers, leaves are the most morphologically diverse plant structures. We’d need a lot more than 10 facts to do them justice.
- There are more than 60 botanical terms used to describe the structures and forms of leaves.
- Leaves are plant organs, usually having two basic parts: the blade (lamina) and the petiole, which is the short “stem” that attaches a leaf to the rest of the plant.
- Most photosynthesis takes place in the leaves, although some does occur in green stems.
- The principle site of photosynthesis in leaves is inside the mesophyll, a layer of spongy tissue located just below the epidermis on the upper leaf surface.
- Mosses and liverworts look like they have leaves, but they don’t. A true leaf is composed of more than one layer of cells, including a cuticle (waxy outer covering), stomata (for gas exchange), xylem (water-conducting tissue), phloem (sap-conducting tissue) and internal air spaces.
- The first leaves that appear on a plant after germination are called cotyledons. They all look about the same and do not look like the true leaves of a plant that develop later.
- Monocots, which are plants with narrow, sword-like leaves such as grasses, grains, onions, tulips and bananas, produce one cotyledon. Dicots, which are broad-leafed plants like tomatoes, beans, lettuce and oak trees, produce two cotyledons upon germination.
- Do conifers have leaves? Yes, needles are leaves that are specialized to resist desiccation.
- What about cacti? Yes, they have leaves too, but they are either microscopic or soon fall off after a short growth spurt in the spring.
10 Facts on Leaves
Takeaway: There are more than 60 botanical terms used to describe the structures and forms of leaves.